KYMENLAAKSON AMMATTIKORKEAKOULU University of Applied Sciences Energy Engineering Double Degree / Specialization

KYMENLAAKSON AMMATTIKORKEAKOULU University of Applied Sciences Energy Engineering Double Degree / Specialization
University of Applied Sciences
Energy Engineering Double Degree / Specialization
Iuliia Gerlitc
Rinat Biktuganov
Bachelor’s Thesis 2013
University of Applied Sciences
Energy Engineering
Gerlitc Iuliia
Biktuganov Rinat
A Review to Wind Energy Utilization in North-West
Bachelor’s Thesis
79 pages + 1 page of appendices
Mäkelä Merja, Principal Lecturer
Commissioned by
Empower Oy
November 2013
Wind turbines, electrical grid, and grid connection
The problem of using renewable energy sources is studied in this thesis work. The attention is concentrated on the feasibilities of using the wind energy in the North-West
Russia and on some problems which can appear. Some of them are the place of a possible wind farm, laws of new sources connection, and the protection of the electrical
The aim of the work was to realize the possibility of inserting new energy resources
into the Russian electrical grid and the importance of using renewables. An answer
was sought to the question why the country network had no changes for a long time
and what factors are preventing the changes.
The study was carried out with the help of technical encyclopedias and energy companies official websites. Some information was retrieved through the conversation
with specialists from the largest Russian energy companies.
The idea of inserting new energy resources in the Russian economy looks very promising. Naturally, some investments and time are needed. In the next few years the
problem of renewables will become very actual and then this work will be very useful.
2.1 Fossil fuels
2.1.1 The elementary composition of the solid and liquid fuels
2.1.2 Nonrenewable energy sources
2.1.3 Approximate prices for the fossil fuels
2.2 Renewable energy sources
2.2.1 Solar energy
2.2.2 Geothermal and hydro energy
2.2.3 Wind energy
2.2.4 Solid waste and biomass
2.2.5 Fuel cells
2.3 Types of power plants
2.3.1 Steam turbines
2.3.2 Thermal power plants
2.3.3 Nuclear power plants
2.3.4 Water power plants
2.4 Day and night time load
2.5 Rational use of energy
3.1 Total energy production in Leningrad region
3.2 Lack of energy
3.3 Electricity transfer networks and Vyborg DC link
3.4 Technical concepts of connecting wind power to electrical network
3.5 Internal electrical network of a wind power park
4.1 Owners of the grid
4.2 Grid of North-West Russia
4.3 The transfer prices and the electricity prices
4.3.1 Electricity market
4.3.2 Electricity prices in North-West Russia
4.4 Comparison of EU and Russian regulations
4.5 Economic benefits of wind farms
4.5.1 Economic benefits of existing wind farms
4.5.2 Methods of rising economy of wind farms
5.1 Power from wind
5.2 Wind power potential
5.3 Vertical wind generators
5.3.1 Orthogonal wind turbines
5.3.2 Wind turbines with Savonius rotor
5.3.3 Wind turbines with a Darrieus rotor
5.3.4 Wind turbines with a Helicoid rotor
5.3.5 Multibladed wind turbines
5.4 Horizontal-axis wind generators
5.5 Present wind farms in Russia
6.1 Operation of wind turbines
6.1.1 Faults
6.1.2 Determining the state of system components
6.2 Devices used for grid connections
6.2.1 Transformers
6.2.2 Switches and axual devices
6.3 Grid protection
6.3.1 Short-circuit current
6.3.2 Islanding and auto recloser
6.4 Voltage control
6.5 Grid effects
6.5.1 Wind turbines power quality
6.5.2 Output behavior of wind power plants
6.5.3 Voltage and frequency response
6.5.4 Harmonics and methods to reduce them
6.6 Grid connection rules
Energy is a decisive sector for the development of the Russian economy, because
without its progress the development in the country is not possible. Heat energy takes
the principal place in the energy balance of Russia, which accounts for about 40 % of
the fuel produced in the country. The part of energy of the fossil fuels in the fuel and
energy balance (FEB) of the country is 25 %. Of particular interest to the individual
regions is the use of renewable energy sources, such as the use of wind. The share of
wind power in the Russian fuel and energy balance cannot be more than 1 - 2 %, even
with the present intensity of its development. This energy source, as an autonomous
one, is certainly promising. To increase the gross output with maximum use of all
kinds of energy saving, it is necessary to increase the production of electricity.
For many years, Russian energy was based on the use of organic fuels to convert heat
into electrical energy by using steam turbines. At the moment this technology and the
level of improvement of these facilities behind the world, and this gap is to overcome. Increasing of the energy capacity of Russia should be mainly implemented due
to the production of electricity through the use of organic fuels. One of the most significant problems in the long term period is the technical re-build of existing power
plants, extending the life of power plant facilities. In recent years, because of the financial crisis, there is a constant increase in the volume of equipment that has reached
its economic life, which leads to a lack of efficiency of the electricity generation and
reduction the reliability of electricity supply. It is necessary to modernize the energy
Prospective development of the main power grid of Russia has to ensure its stable and
reliable operation under the conditions of market power and electricity. In order to
eliminate technical constraints to the development of competition in the market, special attention has to be paid to the development of backbone electric grids, increasing
their branching and bandwidth and reconstruction. The development of electric power
industry in the future will depend on the rate of growth of the economy, the implementation of structural reforms in the sector, aimed at creating a competitive market
economy that will improve the efficiency and investment attractiveness of energy.
This thesis aims at giving an overview of the status of power supply in North-West
A definition of energy in a dictionary ( says that: “Energy is a scalar
physical quantity that is a common measure of the various forms of motion and transition measure of the movement of matter from one form to another.” The energy resources are material objects, in which the energy is concentrated. Energy resources are
divided into renewable and non-renewable. The former are those that continuously regenerates by nature (water, wind), and the later are the previously accumulated in nature, but in the current geological conditions are not forming (coal, oil, gas). The energy extracted directly from the nature (fuel, water, wind, geothermal, nuclear), is called
the primary. The energy obtained after the conversion of primary energy in special
plants, is called secondary. (Physicalsystems, 2013)
2.1 Fossil fuels
Any substance capable of combustion to pick out significant amount of heat may be
called a fuel. According to the definition given by Mendeleev (quoted in Bystritskyi,
2005, 34) "fuel is a combustible matter, deliberately burned to produce heat." The
practical feasibility of fuel is determined by the quantitative inventory, production facilities, the rate of combustion, calorific value, the possibility of long-term storage and
harmless combustion products for people and equipment. Chemical energy release is
the process of an oxidation reaction of fuel and oxidant. (Bystritskyi, 2005, 34)
2.1.1 The elementary composition of the solid and liquid fuels
The fuel in the form in which it comes to be burned in the furnaces or combustion engines is called the working. In general, the content of solid or liquid fuel includes carbon C, hydrogen H, oxygen O, nitrogen N, sulfur S and non-combustible mineral impurities – ash A and moisture W.
For the working fuel mass the equation is obvious:
Characteristics of the fuel composition, according to the working masses, are very unstable, as it can vary greatly depending on the method of its production, transportation
and storage. The moisture contained in the fuel, together with ash, called a ballast of
fuel. The ballast significantly reduces the value of the fuel, reducing its calorific value.
Moisture is harmful in the fuel because, firstly, heat is consumed for its evaporation
when combustion, and secondly, it reduces the relative amount of combustible material in the fuel. The presence of ash not only reduces the heat of combustion, but makes
process of combustion in the furnace and its operation more difficult. (Bystritskyi,
2005, 86)
The approximate composition and thermal performance of a combustible fuel mass
are presented in table 1:
Table 1. Composition and thermal performance of different fuels (Bystritskyi, 2005,
Composition of combustible fuel mass, %
V, %
64 - 78
0,3 - 6
3,8 – 6,3
0,6 – 1,6
40 - 60
75 - 90
0,5 - 6
2 - 13
1- 2,7
9 - 50
According to table 1, it is possible to sum up that oil and natural gas are the best fuels
for combustion because of the high heating value and low amount of emissions.
2.1.2 Nonrenewable energy sources
It is difficult to calculate how many years oil reserves will be enough. If current trends
continue, the annual consumption of oil in the world by 2018 will reach 3 billion tons.
Even assuming that the using reserves will increase substantially, geologists have
come to the conclusion that by 2030, 80 % of the world's oil reserves will be exhausted.
Coal reserves are easier to estimate. Three quarters of the world's reserves (approximately 10 000 000 000 000 t.) are situated in the countries of the former Soviet Union,
the U.S. and China. Although there is much more coal in the world than oil and natural gas, its reserves are not unlimited. In the 1990s the global consumption of coal was
more than 2.3 billion tons per year. Differently from the oil, coal consumption has
increased significantly, not only in developing countries but also in industrialized
ones. According to current forecasts, coal reserves should last for another 420 years.
However, if the consumption will grow at their current pace, there will not be enough
coal reserves even for the next 200 years.
In 1995, more or less authentic global uranium reserves were estimated at 1.5 million
tons. Additional resources were estimated at 0.9 million tons. The largest known
sources of uranium are found in North America, Australia, Brazil and South Africa. It
is believed that the countries of the former Soviet Union have large amounts of uranium. In 1995, the number of operating nuclear reactors around the world reached 400
(in 1970 - only 66), and their total capacity was about 300 000 MW. In the U.S. only
55 new nuclear power plants planned and under construction, and 113 other projects
were canceled. (Encyclopedia of Kol’er, 2000)
2.1.3 Approximate prices for the fossil fuels
The prices for some fossil fuels are presented in table 2. Two countries are shown for
Table 2 Fossil fuels prices (Volgograd consumer, 2013)
Natural gas,
fuel oil (crude
The prices explain why traditional energy production, by burning fossil fuels, is still
so popular in Russia. In addition, we know that the amount of fuel still storing in Earth
crust is not forever. The problem of finding new alternative sources of energy is already present.
2.2 Renewable energy sources
Renewable or regenerative energy ("green energy") is the energy from sources that are
on a human scale could be called inexhaustible. The basic principle of the use of renewable energy is its removing from occurring in the environment processes and
providing it for technical uses.
2.2.1 Solar energy
Solar energy has two main advantages. Firstly, there is a lot of it and it relates to renewable energy resources: the duration the sun existence is estimated at about
5 000 000 000 years. Secondly, its use does not result in harmful environmental effects. However, the use of solar energy is bothered by a number of difficulties. Although the total amount of this energy is huge, it is scattered without control. To obtain
large amounts of energy collecting large areas are required. In addition, there is the
problem of instability of energy supply: the sun does not always shine. Even in the desert, where cloudless weather is the predominant, night follows day. Consequently,
collectors of solar energy are required. Finally, many using methods of solar energy
do not yet have been tested, and their economic viability is not proven. You can specify three main areas of solar energy:
for heating (including hot water) and air conditioning
for the direct conversion into electricity by means of solar photovoltaic cells
for large-scale electricity production from thermal cycling.( Encyclopedia of
Kol’er, 2000)
2.2.2 Geothermal and hydro energy
Geothermal energy, i.e. the heat of the Earth's interior, is already used in a number of
countries, such as Iceland, Russia, Italy and New Zealand. The crust thickness of 3235 km is much thinner than the layer lying beneath it - the mantle, extending about
2 900 km to the hot liquid core. The mantle is a source gases-rich fiery liquid rock
(magma), which are erupted by the active volcanoes. Heat mainly appears due to the
radioactive decay of substances in the earth's core. Temperature and the amount of
heat are so great that it causes the melting of mantle rocks. Hot rocks can create thermal "bags" which are heated under the surface. After a contact with them, water is
heated and even converted to steam. Because such "bags" are usually sealed, hot water
and steam are often under high pressure and temperature of them exceeds the boiling
point of water at the surface. The largest geothermal resources are concentrated in the
volcanic areas and the borders of the cortical plates. The main disadvantage of geothermal energy is that its resources are localized and limited, although surveys do not
show the presence of significant deposits of hot rocks or the possibility of drilling
wells to the mantle. A significant contribution of this resource in the energy sector can
be expected only in the local geographic areas.
Hydropower provides nearly a third of the electricity used in the world. Norway,
where the electric power per person is more than anywhere else, lives almost totally
with hydroelectric power. In water power plants and pumped storage power plants the
potential energy of the water is used, accumulated by dams. At the base of the dam located turbine rotated by the water (which is supplied to them under normal pressure)
and the rotating rotor generators of electric current. There are really large power
plants. Two large hydropower plants in Russia are widely known: Krasnoyarsk (6000
MW) and Bratsk (4100 MW). The largest water power plant in the United States is
Grand Coulee, the full capacity 6480 MW. In 1995, hydroelectricity accounted for
about 7 % of the electricity generated in the world. Hydropower - one of the cheapest
and cleanest energy resources. It is renewable in the sense that the reservoirs are fulfilled with river and rain water. The question remains to be open about the feasibility
of building hydroelectric power stations on the plains.
There are tidal power plants, which use differences of water levels, which are formed
during high tide and low tide. To do this, the low coastal basin is separated by a dam,
which delays the tidal water at low tide. The water is then released, and it turns the
turbine. Tidal power plants can be a valuable local energy help, but there are not many
suitable places in the world for their construction, so they cannot change the overall
energy situation. (Encyclopedia of Kol’er, 2000)
2.2.3 Wind energy
Wind energy is the energy sector, specializing in the conversion of kinetic energy of
air masses in the atmosphere to electrical, mechanical, thermal, or in any other form of
energy that is convenient for use in the economy. Such a transformation can be carried
out by such units as the wind generator (for power), windmill (for conversion into mechanical energy), sail (for use in transport), and others. Wind energy is a renewable
form of energy, as it is a consequence of solar activity. Wind power is a booming industry, so at the end of 2010 the total installed capacity of all the wind turbines in the
world was 196.6 GW. In the same year, the amount of electrical energy produced by
wind turbines in the world was 430 terawatt-hours (2.5 % of the electrical energy produced by mankind). Some countries are particularly rapidly developing wind energy.
In 2011 in Denmark wind power produced was accounted in 28 % of all electricity, in
Portugal – 19 %, Ireland – 14 %, Spain – 16 %, in Germany – 8 %. In May 2009, 80
countries used wind power on a commercial basis. (Encyclopedia of Kol’er, 2000)
2.2.4 Solid waste and biomass
Approximately half of the solid waste is water. That is easy to collect only 15 % of
waste. The best result that can provide solid waste is approximately 3 % of energy
corresponding to oil and 6 % to natural gas. Consequently, without radical improvements in the organization of solid waste collection, people are unlikely to provide a
major contribution of the production of electricity. Biomass - wood and organic waste
accounts for about 14 % of the total energy consumption in the world. Biomass - a
common household fuel in many developing countries. There have been proposals to
grow plants (including timber) as a source of energy. Fast-growing aquatic plants are
capable of producing up to 190 tons of dry matter per hectare per year. Such products
can be burned as fuel or started the distillation to produce liquid and gaseous hydrocarbons. In Brazil, sugar cane was used for the production of alcohol fuels to replace
gasoline. The cost is slightly higher than the cost of conventional fossil fuels. With
proper management of such energy, source can be recharged. More research is need-
ed, especially in growing crops and their cost-effectiveness, taking into account the
costs of collecting, transporting and grinding. (Encyclopedia of Kol’er, 2000)
2.2.5 Fuel cells
A fuel cell is an electrochemical device like an electrochemical cell, but differs in the
material. For the electrochemical reaction are fed into it from the outside - in contrast
to the limited amount of energy stored in a galvanic cell or battery. Fuel cells carry out
the conversion of chemical energy into electricity, avoiding inefficient combustion
processes following with heavy losses. This is an electrochemical device that generates electricity as a result of high-performance "cold" combustion of fuel directly.
(Encyclopedia of Kol’er, 2000)
2.3 Types of power plants
Kinds of power plants that can be chosen, when natural energy is converted into electrical. For these purposes special facilities were developed - power plants. There are
many types of power plants such as:
thermal power plants
water power plants
nuclear power plants
solar power plants
geothermal power plants
diesel power plants
tidal power plants
wind farms.
2.3.1 Steam turbines
A steam turbine - is continuously operating thermal unit, which is the working body of
water and steam. A steam turbine process converts the potential energy of compressed
and high temperature steam into kinetic energy of rotation of the turbine rotor. It includes a steam turbine and auxiliary equipment. Steam turbine plants are used to drive
turbine generators in thermal and nuclear power plants.
In the power plant the mechanical energy converts into electrical energy by using an
electrical generator. A schematic diagram of the steam turbine which drives an electric
generator is shown in Figure1. There is steam from the boiler unit (1), where it receives heat from the combustion of the fuel supplied to the turbine (2), and expanding
there, it does mechanical work, turning the electric generator rotor (3). After exiting
the turbine, the steam enters the condenser (4) where it is condensation. Condensates
of exhausted steam worked in the turbine pass through a preheater (6) to the deaerator
(7) with a condensate pump (5). A feed pump (8) takes the water from the deaerator
through the heater (9) in the boiler unit. Heaters (6) and (9) and a deaerator (7) make a
system of regenerative feed water heating, which uses steam from unregulated extractions of the steam turbine. (Scheglyaev, 1976)
Figure 1. Schematic diagram of the steam turbine
2.3.2 Thermal power plants
A thermal power plant is a reliable and productive power plant that produces electricity exclusively. The basic principle is in the action of steam turbines. Fuels for condensing power plants can be such as natural gas, oil or coal, pulverized recycled to the
state. Burning gas, oil or coal in the boiler furnace produces large amounts of heat,
this heats the purified and desalinated water in the pipes inside the boiler and turns it
into steam. In the superheater the steam continues to heat and at a temperature above
500 ° C and pressure 13 - 24 MPa enters the condensing turbine. Under the influence
of steam turbine rotor is set in motion, a generator transforms the rotational energy of
the rotor into electrical energy. This steam expands and cools, its pressure drops to
very low numbers. Cooled vapor is returned to a liquid state. Condensates are pumped
back to the boiler. For this purposes, the condenser and feed water pumps are used.
Thus, the steam-water circuit is almost closed. Water for cooling condensers may be
pumped from natural waters reservoirs and at the end of the cycle. It could be output
back or constantly circulated through the system, cooling by air or water in the reservoirs or cooling towers. The benefits of thermal power plant are: simple flow chart reliability, a small amount of backup equipment and the possibility of rational expansion
or renovation, thanks to modular construction.
Thermal power plants are built close to the places of fuel extraction and convenient
water supply. They are made of a series of modular units with a capacity of 20 to
1 200 MW of energy producing supply in the network 110 - 750 kV. Thermal power
plants units are not sufficiently maneuverable: the preparation of starting, starting up,
synchronization and load take set 3 - 6 hours. Therefore it is preferable for them for
operation with a uniform load. The efficiency of thermal power does not exceed 32 40 %. They have a strong influence on the environment - polluting the atmosphere,
changing the thermal regime of water sources.
Combined power plants are built near heat consumers, while they generally use imported fuel. Operating these power plants is most economical. The efficiency of heat
is as high as 60 – 70 %. Units have a capacity of 30 - 250 MW. Energy goes into the 6
- 10 kV grid. (Bystritskyi 2005, 153)
2.3.3 Nuclear power plants
Nuclear power plants may be constructed in any geographic area, including inaccessible, areas it there is a water supply source. The amount of fuel consumed is low, therefore there is no need of transport links. Under the terms of the regulation and operation the mode with a uniform load is preferred. The efficiency is about 35 - 38 %.
NPPs pollute the atmosphere very little. Emissions of radioactive gases and aerosols
are small, that allows constructing nuclear power plants near cities and loading centers. One difficult problem is the disposal or recovery of spent fuel elements. (Bystritskyi 2005, 159)
2.3.4 Water power plants
A water power plant (WPP) is a power plant using water flow as a source of energy.
Water power plants are usually built on the rivers by building dams and reservoirs.
Two main factors require efficient production of electric power: a guaranteed supply
of water all year round and possibly high slopes of the river and also water engineering favor canyon terrains.
The principle of the water power plant is quite simple. The circuit of hydraulic structures provides the necessary water pressure entering the turbine blades which drives a
generator producing electricity. Required water pressure generated by the construction
of the dam, and as a consequence of the concentration of the river in a certain place, or
diversion - the natural flow of water. In some cases, to obtain the required water pressure and the dam and the diversion are used together. All needed hydroelectric power
machines are situated in the building. Depending on the purpose, it has a definite division. Hydroelectric machines which is located in the engine room, directly converts
the energy of the water flow into electrical energy. In addition, there are more kinds of
auxiliary devices and control systems, transformer stations, distribution systems, and
etc. A schematic diagram of a water power plant is shown in the fig. 2.2. (Martens,
Figure 2. Schematic diagram of a water power plant
2.4 Day and night time load
We can notice that the graph (Figure 3) of the power system load is not uniform. Also,
summer and winter schedules are different. A very distinct peak appears in the period
from 14:30 to 16:30. Secondly there are two further peaks: one in the morning and one
in the evening. This is easily explained by the fact that electricity consumption occurs
mostly during the day in homes and factories, but that does not diminish the difficulty
of generating electricity. During the peak load additional power is needed while at
night some power less is needed. To solve that problem a population needs more
rational ways of energy usage. The energy consumption during the day is shown in the
figures below. (Sustainable energy authority of Victoria, 2004)
Fig.3. Energy consumption during summer day
Figure 4.Energy consumption during winter day
2.5 Rational use of energy
While the world has no shortage of energy in the coming two to three decades in most
countries, the potential for serious problems exists if there will be no alternative
sources of energy, or no limitations of its consumption. Obvious, there is need for a
more rational use of energy. There are a number of proposals to improve the efficiency of storage and transportation of energy, as well as more efficient use of it in various
branches of industry, transport and households.
The load power varies during the day. There are also its seasonal changes. The efficiency of the power plant can be improved if in times of graph’s failure to expend excess energy load power for pumping water in large tanks. Then, during peak periods
the water can be produced, causing generating of additional electricity for pumped
storage. More widespread use could be found by using the basic mode of power plants
in pumping compressed air into underground cavities. Turbines operating on compressed air would allow saving the primary energy during periods of high load.
Large energy losses associated with the transmission of electricity. To reduce losses,
the use of transmission lines and distribution networks with high-voltage increases.
An alternative direction is the using of superconducting power lines. The electrical resistance of some metals drops to zero when cooled to temperatures close to absolute
zero. Superconducting cables could transmit power up to 10 000 MW, so to provide
electricity for the whole New York only by using one cable with a 60 cm diameter. It
was found that some ceramic materials become superconducting at very low temperatures which can be reached by conventional refrigeration art. This surprising discovery
could lead to important innovations not only in the field of power transmission but also in the field of land transport, computing and engineering of nuclear reactors.
Hydrogen is a light gas, but it liquefies at -253 ° C. The heating value of liquid hydrogen is 2.75 times greater than natural gas. Hydrogen has environmental advantages
over natural gas: the combustion air makes it basically only water vapor. Hydrogen
can be transported without difficulty by pipeline for natural gas. It is also possible to
keep it in liquefied form in the cryogenic tanks. Hydrogen diffuses readily into some
metals such as titanium. It can be accumulated in such metals, and then sampled by
heating the metal. (Encyclopedia of Kol’er, 2000)
Electric power is one of the leading production areas in the Leningrad region. Its percentage of the total gross income is accounted for 7 %. Electricity is generated by one
nuclear power plant, one thermal power plant, 14 combined power plants, 6 water
power plants. More detailed list of power plants is shown in Table 1. (Newsruss,
3.1 Total energy production in Leningrad region
Table 2. List of power plants in Leningrad region (Appendix 1)
Name and type of power plant
Energy production, MW
Leningrad NPP
Kirishskaya TPP
Avtovskaya CPP
Vasileostrovskaya CPP
Vyborgskaya CPP
Dubrovskaya CPP
Pervomaiskaya CPP
Pravobereznaya CPP
Severnaya CPP
CPP – 2
CPP - 3
Iuznaya CPP
CPP of glass factory
Luzskaya CPP
Verhne-svirskaya WPP
Volhovskaya WPP
Lesogorskaya WPP
Narvskaya WPP
Svetogorskaya WPP
Severo-zapadnaya CPP
Except for big power plants, the Leningrad region has plenty of small ones which are
connected with some special factory. Overall energy production in the region is accounted for 11.1 GW. In spite of such a huge amount of energy produced, Leningrad
region is lacking the energy needed for manufacturing and the general population.
3.2 Lack of energy
Against the backdrop of economic crisis, the Russian generating companies have to
reduce capacity because of falling demand which, according to the System Operator
UES, in January 2009 compared to the same period last year decreased by 7.7 %.
However, the Leningrad region is the least likely for this process. Because of the high
degree of deterioration of generating equipment and insufficient capacity of the power
grid, consumption of electricity is limited in a number of industrial enterprises in the
region. In particular, the deterioration of transfer lines of Lenenergo reaches 60 %, and
the deterioration of substations – 80 %. Many substations use German devices and
machines 80 year old.
There are problems with the commissioning of new capacity. For example, the case
when the start of the second block of the Severo-Zapadnayay Power Station in St. Petersburg was postponed due to lack of gas.The most problematic area of the Leningrad
Region is currently Vsevolozhskiy. The total energy deficit in the area is 1.5 GW. In
addition the Vyborg District is included. In every deficient area from Zelenogorsk to
Primorsk, problems with the supply of electricity exist.
The situation in the St. Petersburg is equally difficult where the shortage of energy today in different parts is 120 - 150 MW. Since many years the city has had no new
power suppliers. According to the Committee for Economic Development, Industrial
Policy and Trade of the City Government, by 2014 in St. Petersburg, 704 MW of generating equipment will run out. That is 24 % of the installed capacity of thermal power
Wear and tear on the facilities of electric substations of different voltage classes (330220-110 kV) at the moment is not less than 50 %. Other unsatisfying moments are at
electric grid facilities 35 kV, located in the center of the city: its deterioration is esti-
mated at 100 %. Heating systems each year wait for relaying the pipeline of 300 km
but actually an average of 170 km is made. (Aenenrgy, 2013)
3.3 Electricity transfer networks and Vyborg DC link
In the Leningrad region a number of different voltage levels are represented: 110 kV,
220 kV, and 330 kV. Also one line from the Leningrad nuclear power plant reaches a
voltage of 750kV. Detailed location and voltage class lines are shown on the map in
Appendix 1.
On the map (Appendix 1), it is possible also to see the extent of energy supply network in the Leningrad region goes. The situation is shown in February 2006. It is easy
to see that about 1.2 GW come to the region from the Kaliningrad nuclear power
plant. 200 MW goes to the Pskov region, 200 MW to Estonia, about 200 MW to Karelia, and approximately 700 MW to Finland. Energy exchange with Finland has become possible by inserting a DC link.
The DC link Vyborg is Russia's only link of direct current. It was built for the export
of electricity from the Soviet Union to Finland. This operation began in 1981.
The DC power transmission was chosen for economic reasons. The commonly used
line with the alternating current of electrical systems of the USSR and Finland should
have been synchronized. The costs of synchronization would have exceeded the economic profits of exports. The power line connects Vyborg substation (400 kV) and
substations Yllikkälä and Kymi (400 kW). From substation Kamennogorsk (city Kamennogorsk) is installed overhead 330 kV (W1D and W2D) to Vyborg substation (v.
Perov) while the 330 kV AC is converted to DC 400 kV and is exported to Finland. In
the 2010 - 2011, a two-sided transmission was implemented. Now, Finland can sell up
to 350 MW of electricity from its grid (which will certainly be a good idea at the
forced repair / crash) to Russia.
The station consists of four independent units of thyristor converters operating at a
constant voltage 85 kV DC. The capacity of each unit is 355 MW. At the moment, the
transmitted power is 1 400 MW which makes this link the most powerful in the world.
(Balyberdin p. 63-67)
3.4 Technical concepts of connecting wind power to electrical network
There are some common patterns connecting consumers to wind power systems. At
the same time, each case must be considered as an individual project following wind
power concepts are this guidance for developers.
Figure 5. Wind generator with a battery pack
Consumer devices are powered exclusively by a wind turbine. (Alternativenergy,
Figure 6. Wind generator with a battery pack and a backup diesel generator
ATS - automatic transfer switch
If there is no wind or the speed is insufficient, the wind turbine will not start. When
the battery is discharged a backup generator automatically starts. (Alternativenergy,
Figure 7.The hybrid autonomous system using sun and wind.
This option provides the connection of solar cells to the system of the wind turbine.
Connection can take place through a hybrid controller or a separate controller, which
is used for photovoltaic systems. (Alternativenergy, 2010)
Figure 8.Wind generator with a battery pack and switching network
If there is no wind or the speed is insufficient, the wind turbine will not start. When
battery is discharged, the ATS allows the user to switch to the main grid. This circuit
can be used in a bidirectional mode, i.e. on the contrary in this case the wind generator
is used as a backup power source. In this case, the ATS will switch you to the battery
of wind turbine in case of loss of power supply from grid. (Alternativenergy, 2010)
In the wind industry there are problems with an alternative network and local network
connection. How the household with 1 kW energy consumption but short-term of 3
kW consumption should be supplied. Then there are save the batteries, but they do not
last forever, and the other for 1 kW wind turbine inverter needed of 3 kW. It is significantly more expensive than 1 kW. Civilized countries have found another way: if
somebody have clean energy, more than needed, give it to the neighbors across a public network (recovery, such as counter spinning in the opposite direction). If somebody needs more electricity, then get out of the local network and even earn money or
cover consumption. (V.Moseichuk, 2009)
3.5 Internal electrical network of a wind power park
According to the textbooks (Rozkova, 1986, pp. 3, 365-377, 415-420) for 110 kV circuit to take two workers (A1, A2) and bypass (A0) bus systems (Figure 5). According
to the textbooks (Rozkova, 1986, pp.402-411) for 6 kV circuit one partitioned bus system is acceptable. Switching circuit is shown in Figure 9.
Figure 9.Scheme of internal connection of the wind turbines
Russia is actively involved in globalization, including the electricity sector. The development of the correct political doctrine is one the questions of global energy field.
The role of legal regulations in this process is crucial. The cause of energy reforms are
the issues connecting with the lack of full competition in these sectors, which, in its
turn, leads to a lack of investments to main funds, shortages of energy resources, loss
of reliability of energy supply, etc. Today the main goal of energy reforms is to open
energy market to competition and to attract new investments.
4.1 Owners of the grid
Unified Energy System of Russia (UES of Russia) consists of 69 regional energy systems, which form 7 integrated energy systems: East, Siberia, the Urals, Middle Volga,
South, Central and North-West. All systems are connected with power lines of 220 500 kV and above and work in a synchronous mode. The total installed capacity of
power plants of UES is about 223 070 MW (223 GW).
As a result of major events related to the reform of the electricity industry in 2008,
the structure of system has become quite complicated. This industry section consists
of several groups of companies and organizations, each of which performs a particular
function. They are divided into wholesale generation companies (OGK), electrical
network companies, supply companies, companies that manage the power grid modes,
the companies which responsible for the development and operation of a commercial
market infrastructure, organizations implementing the control and regulation of the
industry, electricity consumers and small producers of electricity.
Generating companies (OGK) own different types of power plants. There are twenty
companies which own in total all the thermal power plants, there is one company
which controls all electricity production in hydropower plant (RusHydro) and one
company which manages all nuclear power plants - ROSENERGOATOM. Among
twenty thermal companies, six of them manage large thermal power plants GRES
(State District Power Plant), the total installed capacity of each is over 8 GW. Power
plants are situated in different regions of Russia. Also there are 14 territorial generating companies (TGK) who own the medium-sized thermal power stations. All power
stations belonging to one TGK are located in one part of the country. In addition, there
are several large generating companies that are not controlled by RAO UES. They are
four so-called independent companies: Tatenergo, Bashkirenergo, Novosibirskenergo
and IrkutskEnergo. In several parts of Russia there are still power plants, controlled by
the state, because of the serious imbalance of power generation capacity and low demand for electricity. Such areas are called non-market areas and include the regions
which are far away from the central part of the country: Far East, Kamchatka, Chukotka, Sakhalin, a large part of Yakutia, the Kaliningrad Region, the Komi Republic
and Arkhangelsk region.
Electrical Network Company is represented by one big company called FSK (Federal
Grid Company) and by interregional distribution grid companies (MRSK) which are
combined into a single holding company - Holding MRSK. This holding was renamed
JSC RosSeti in 2013, and FSK also become a part of this company. FSK owns transmission networks including the high voltage power lines of 220 kV, 330 kV and 500
kV. These power lines connect different energy systems (power plants) in a whole
country, providing the possibility of significant amounts of electricity and power flow
over long distances between remote large power systems. FSK is mostly controlled by
the government, which owns nearly 80 % stock in the company. JSC RosSeti consists
of several local companies:
JSC MRSK of Center and Volga Region
JSC MRSK of South
JSC MRSK of North - West
JSC MRSK of Northern Caucasus
JSC MRSK of Volga
JSC MRSK of Urals
JSC MRSK of Siberia
JSC TyumenEnergo
JSC Moscow Electric Grid Company
JSC Lenenergo
JSC Yantarenergo.
The last four companies are small territorial grid organizations (TSO), they can belong
as to the municipal authorities so to the private investors. There are also local grids
which do not have any legal owners.
Supply companies are represented by so called guaranteeing supplier companies and
independent suppliers. We as consumers buy electricity from these suppliers. The
structure of the electricity market will be described in the next paragraphs.
Companies that regulate the power grid modes of Russia are the System Operator of
the Unified Energy System of Russia (SO UES) and its subdivisions. The operation
way of SO UES is obligatorily for generating and Electrical Network companies. Unfortunately, not all electrical energy systems of Russia are connected to one whole
system. Due to this there are also some local companies which regulate the power grid
modes in isolated power districts, for example, in the northern territories of Yakutia.
The company which is responsible for the development and operation of a commercial
market infrastructure is Non-Commercial Partnership Market Council and its subsidiary companies: JSC ATS and CJSC CFR. Non-Commercial Partnership Market
Council involves all participants of the wholesale market of electrical energy. The
main function of this company is to develop and finalize an agreement of joining to
the trading system of the wholesale market. This agreement defines all the rules and
orders of functioning of wholesale market. Also Non-Commercial Partnership Market
Council develops rules for the functioning of retail markets. JSC ATS is the commercial operator of the wholesale market. He organizes the work of the market and the interaction of market participants. CJSC CFR holds financial calculations on the market.
The control and regulation of the electricity industry is provided by various bodies of
executive power in Russian Federation and its subdivisions. Direct influence on the
processes in the industry has the Ministry of Energy. Significant roles are played by
the Federal Tariff Service (FTS), Ministry of Economic Development, Government of
the Russian Federation itself, Rostehnadzor company, State Corporation Rosatom and
etc. The retail market is regulated by the bodies of executive power in the field of regulation of tariffs (regional energy commissions, committee’s rates, etc.). (NonCommercial Partnership Sovet Rinka, 2013)
4.2 Grid of North-West Russia
The main grid company in Northwest-Russia is JSC Lenenergo. It is an electrical network company whose main function is the transmission of electric energy through the
networks 110; 35; 6; 0.4 kV, and the connection of consumers to electric networks in
St. Petersburg and the Leningrad region. JSC RosSeti owns 53.41 % of the stocks of
JSC Lenenergo, 26.57 % stocks belong to the government of Saint-Petersburg and
other stocks belong to the private investors. The total amount of power is about 21 952
MVA which includes 377 substations of 35 - 110 kV and 15 025 substations of 6 - 35
The area where we plan to install wind turbines belongs to the Leningrad region. The
Leningrad region includes the Vyborg district where the small town Primorsk is
situated. This Primorsk district is the place where we exactly consider to install wind
turbines. The owner of Primorsk electrical grid is a branch of JSC Lenenergo Vyborg electrical networks. It is responsible for uninterrupted power supply of
Vyborg, Priozersky and some parts of Vsevolozhsk districts of the Leningrad region.
Figure 10.Part of the Leningrad region (Map. Google, 2013)
Vyborg’s electrical networks include five districts (Figure 10): Vyborg district electric
networks (RECs), Roshchinskiy RES, Priozersky RES, RES Sosnowski, High voltage
district. RES is russian abbreviation for a distric electrical grid. The biggest electricity
consumers in this region are:
JSC Poultry Roskar
poultry company Primorje
JSC Svetogorsky Pulp and Paper Mill
JSC The Soviet PPM
compressor station of JSC Gazprom Port and port Ltd. Vysotsky.
Large communities are:
workers' settlements Roshino
Overhead power lines with voltage range of 100 V – 0.4 kV are extending 6 316 kilometers away and cable lines for 279.91 kilometers. There are about 41 substations of
35 - 110 kV. The total power of Vyborg district is about 1271 MWA. (Lenenergo,
4.3 The transfer prices and the electricity prices
The final unit price of electricity can vary widely not only in different regions, but also for a variety of customers of the same supplier. The price depends on the type of
the tariff, used by the consumer to calculate the cost of consumed electricity.
4.3.1 Electricity market
Russian Federation has a two-tier market for electricity: wholesale and retail. In the
wholesale market, electricity suppliers (generating companies, importers of electricity)
sell to customers (to guaranteeing supplier companies, large consumers, exporters of
electricity) two products - electricity and heat. The wholesale market operates on the
most territory of the country, and it is divided into two connected price zones: the European part of Russia including the Urals, and Siberia. The regions of the Far East,
Kaliningrad, Arkhangelsk region and Komi Republic belong to the so-called non-price
areas. In these regions, due to technological reasons (isolation from the unified power
grid), the organization of a competitive market is currently not possible.
Wholesale market prices can vary considerably in some regions, due to the different
efficiency of power plants serving different regions of the country and the insufficient
capacity of the transmission lines. In the retail market, guaranteeing suppliers and
supply companies sell purchased in the wholesale market electricity to final consumers. The guaranteeing supplier Energy Company is obliged to sign a contract with
each customer that appears in its area of operation. Conditions of contract are same for
all consumers. The service area of a guaranteeing supplier usually coincides with the
boundaries of the subject of the Russian Federation. Other retail companies which are
not supplying the population can sign contracts with customers on any terms. In the
retail market there are several possible tariffs: so called two tariffs which include
payment for electricity and power (double-rate fare); and the single tariff for electricity which takes into account the price of power (single rate). The cost of electricity to
final consumers is primarily determined by the amount of electricity, for which the
guaranteeing supplier will pay fixed (controlled) price in the current year.
For electricity and heat over the volume recorded in the regulated contracts, the consumers pay the price according to the price in the wholesale electricity market plus all
the necessary payments (transfer services, marketing allowance, etc.).The amount of
electricity which can be sold for free prices by guaranteeing suppliers during each
month is calculated by the commercial operator JSC ATS (its subsidiary company of
Non-Commercial Partnership "Market Council"). These data are published on website
The whole price package is calculated for retail buyers: single rate tariff (for electricity by taking into account price for the power), double-rate tariff (separate payment of
electricity and heat), zone tariff (price, differentiable on the time of day - night, semipeak, peak), prices for consumers with hourly cost of electricity (with the establishment of prices for each hour of the day). Rates are calculated separately for payment
deviations from the planned consumption .The limit (finite) levels of unregulated prices in retail markets are calculated on the relevant settlement period and reported to the
customer organization delivering electrical energy.
In addition to the cost of electricity and heat on the regulated and unregulated prices,
the end user pays for: 1) Services infrastructure organizations of the wholesale electricity market for the operation of its IT infrastructure (system operator) and commercial infrastructure (commercial operator), 2) for the services of a supplier, 3) the purchase of electricity from the generating companies of retail market (if necessary).
(Non-Commercial Partnership Sovet Rinka, 2013)
4.3.2 Electricity prices in North-West Russia
First of all we need to determine which consumers do we have and which tariffs
should be used. For example, electricity prices for population are set in accordance
with the type of settlements (urban or rural). The price for urban population depends
on whether it has a gas stove or an electric one (electric heaters). Moreover, electricity
prices are calculated in accordance with the time of the day. Most groups of population pay so-called single prices, when the cost of one kilowatt per hour does not dependent on the time of the day. However, a number of people choosing a two-part
(day-night) or even three-part tariff is increasing. In this case, the electricity is cheaper
for the consumer at night and more expensive in the afternoon.
Table 3. Electricity tariffs for the population living in urban areas of the Leningrad
Region in houses, equipped with gas stoves. (Energovopros, 2013)
Prices, euro/kWh
One-part tariff for electricity
Electricity tariff, consisting of the two zones of the day
day area (from 7 am to 11 pm)
night area (from 11 pm to 7 am)
Electricity tariff, consisting of the three zones of the day
peak area (7 am to 9 am and 5 pm to 8 pm)
semi peak area (from 9 am to 5 pm and from
8 pm to 11 pm)
night area (from 11 pm to 7 am)
Table 4. Electricity tariffs for the population living in urban areas of the Leningrad
Region in houses equipped with electric stoves, and (or) electric heating appliances.
(Energovopros, 2013)
Prices, euro/kWh
One-part tariff for electricity
Electricity tariff, consisting of the two zones of the day
day area (from 7 am to 11 pm)
night area (from 11 pm to 7 am)
Electricity tariff, consisting of the three zones of the day
peak area (7 am to 9 am and 5 pm to 8 pm)
semi peak area (from 9 am to 5 pm and from 8 pm
to 11 pm)
night area (from 11 pm to 7 am)
Electricity tariffs for the population of the Leningrad region, living in rural areas are
the same as in Table 5.
4.4 Comparison of EU and Russian regulations
The creation of competitive market needs new mechanisms and the decrease of government regulation. The competitive market relies on self-regulation mechanisms that
liquidate the possibility of extremely high income. Competition forces companies to
reduce costs, stimulates innovation and development.
The creation of competitive market with legal regulation goes unequally in different
countries. In the European strategy for sustainable, competitive and secure energy
(2006), Europe has not yet created a fully competitive internal energy market. In 2003,
new instructions were adopted by the EU in the energy supply sector (2003/54/EC),
which creates a common format for the liberalization of the relevant markets of 25
countries - members of the EU. In 2007 a new package of amendments and changes to
the EU directives on electricity was published.
The current EU electricity directive, adopted in 2003, requires a separate transportation and production between the different organizations, but they can be part of an integrated company. In the case of the adoption of new directives major European energy companies such as, for example, the German E.ON and France's EDF will be broken up and for Gazprom it will be closed the path to expansion in Europe.
The legal regulation of energy market in Russia is affected by the international integration processes in the energy sector, for example the membership of World Trade
Organization (WTO). The main feature of the legal system of WTO is that the obligations accepted by its members, do not require special fixation on the national legal
systems. However the necessity to meet the obligations makes to create appropriate
institutions and procedures in the national legal systems. (Skurko EV WTO, 2003, рp.
84 - 85).In the case of Russia's joining to this international organization, the legal system has to follow the norms of the WTO laws, including the energy sector.
In the electricity sector in the countries of EU since July 1, 2004 all regulations are
carried out in accordance with the EC Directive on electricity 2003/54/EC. According
to this Directive, the electricity market is based on the following principles of public
service: safety and security of supply; standards of quality, moderate price, environmental protection, etc.
Another EC Directive 2005/89/ES focuses on the actions of security of electricity
supply and infrastructure investment. Particularly, this directive obliges the countries
to take some measures to improve the level of security and reliability of electricity
One basic principle in EU is the protection of consumer rights as the main condition
for the effective functioning of market economy. It is reasonable because the ongoing
reforms without social and legal mechanisms will lead to lower quality of life. In accordance with these directives, since July 1, 2007 all EU consumers got an opportunity to purchase electricity from any supplier. This indicates quite high level of competition in the European energy markets.
Nowadays reforms in the electricity sector are carried out by more than a hundred
countries around the world. Russia began reforms in the energy sector later than many
industrialized countries. Some of them did not introduce full competition in all sectors
of the market and the establishment of limited competition in the wholesale markets.
Large manufacturers have started to sell electricity energy directly and freely to largest (energy-consuming) buyers. However, most countries have established full competition regardless of the size of producers and consumers. After several years of reform
two thirds of countries - members of the IEA have received as a result of steady
growth markets.
Russia began to carry out reforms in the power sector in 2003, with the adoption of
legislation aimed at market reforms in this sector of the economy. It is assumed that
these reforms will bring the industry out of the crisis, and the economy will eliminate
the infrastructure constraints to growth. The reforms are a fundamental change of the
subject composition of the industry. First of all, it is about the emergence of new market players: Commercial Operator, System Operator, the Federal Grid Company, the
wholesale generating companies and territorial generating companies, distribution
companies, etc. The law set in April 1, 2006 bans on combining natural monopoly activities (transmission and operational control) to potentially competitive production
and marketing.
The area of supply cannot be controlled only in the plane of private law, as it objectively laid the public (common) interests that require special legal regulation mechanisms (defense). It is obvious that Russia has not yet had the understanding of social
and public role of energy sector as infrastructure and life-supporting industry for the
economy of the country. It was not a principal in the previous model of regulation, as
it was based on the direct management of the sector by the government, as owner of
the major energy assets. Therefore, the public interest is taken into account through
the mechanism of state property management and direct price regulation. In the course
of market reforms, usually accompanied by the privatization of production and marketing, as well as in terms of free prices, these problems tend to be purely theoretical.
It should be understood that a significant increase in the price of electricity can make
it unaffordable product for the population, and the freedom of contract in its pure form
can lead to discrimination on the part of consumers of electric power industry, with
market power.
During the development of a new model of regulation in the infrastructure sectors of
the Russian economy it should be taken into account the experience of regulation of
energy markets in Europe. In EU directives, the protection of consumers in energy
markets requires significant regulatory effort on the part of the state. The total regulatory policy in Europe means that the state does not rely only on market forces but creates a clear format of regulation.
Trends in International Energy Regulation show the unavoidable complications of the
regulatory system as we move toward the creation of competitive markets. There are
new trading technologies, new trading facilities, new services and new markets. The
role of legal regulation in the transition to a market increases significantly which
should be taken into account when making the decision to hold the state of a given reform. So, now in the power sector reform, the organization of the wholesale and retail
markets require quantitative and qualitative complexity of rules and regulatory institutions. (Ad Hoc Group, 2005, p.243)
4.5 Economic benefits of wind farms
Until recently the development of the energy sector had a clear consistent pattern: the
development was in such energy production areas which provide a fast direct economic effect. Social and environmental impacts were considered only as an attendant and
their role was negligible.
With this approach, we considered renewable energy just as an energy source of future, when the traditional sources of energy will be exhausted or their production will
be extremely expensive and time-consuming. Since this future seemed to be really far
away, the use of renewable energy was an interesting and exotic modern discussion
rather than a practical problem.
The situation dramatically changed when humanity understood that there are ecological limits to growth. Rapid exponential growth of negative human impacts on the environment leads to significant deterioration of the human environment. Maintaining
this in normal conditions and the possibility of self-preservation is becoming one of
the priority objectives of the society. Today it is not enough to evaluate and consider
just economical sides of some energy production. We also have to take into account
social and environment aspects.
4.5.1 Economic benefits of existing wind farms
The impulses for intensive development of renewable energy for the first time became
not promising economic calculations but it was public pressure, based on environmental requirements. The belief that the use of renewable energy sources will significantly
improve the environmental situation in the world - that's the basis of this pressure.
Renewable or regenerative energy means energy from sources that are on a human
scale are inexhaustible. The basic principle of the use of renewable energy is that it is
permanently removed from occurring in the environment of processes and the provision of technical applications. Unfortunately nowadays there is not a lot of wind energy production in Russia, at the moment wind farms are just experiments.
4.5.2 Methods of rising economy of wind farms
The main advantage of wind sources of energy is that it is inexhaustible and environmentally clean. It can help resolve the problems of energy security and reduction of
environmental load. Using wind sources do not alter the energy balance of the planet.
This caused the rapid development of renewable energy abroad and very optimistic
projections of their development in the next decade.
Wind energy has also significant social advantages over conventional energy sources.
For example, in Russia the increased use of renewable energy technologies could help
to reduce unemployment, improve the conditions of life, to stop the outflow of population from rural areas and the northern and eastern areas. Replacement of traditional
energy sources in the green renewable energy technology could also lead to a decrease
in the level of degradation of the environment and improve health and well-being of
the population.
Most of the territory of Russia is not economically developed and populated. About 80
% of its 145 million of the population lives in the European part of the country. The
population density varies from 26.6 h/km2 in European and 2.4 h/km2 on the Asian
side. About three quarters of the population lives in cities, the most populated Central,
Urals, North Caucasus and the Volga economic region. Currently, more than half of
the territory of Russia, especially Far North, the Far East and Eastern Siberia does not
have a centralized electricity and heat. In addition, there a significant proportion of
farms, horticultural areas, logging companies and a number of local industries remain
without electrification in the European part of Russia. The problem of electricity supply is relevant not only for the facilities of the national economy but also for the posts
of law enforcement agencies, solving important national problem.
Solving the electrification of low-power distributed objects by conventional methods
(as was done in Alaska and northern Canada), according to expert estimates on the
sparsely populated territory of Russia will require more than $ 350 000 000 000 and
nearly half a century for its implementation.
About 10 million people in Russia who do not have access to the electrical grid are
currently served by autonomous systems which traditionally run on diesel or gasoline.
According to available information, about half of diesel and gasoline units do not
work, due to disruptions in the supply of fuel and high prices for imported fuel. In remote areas of the Far North and the Far East, fuel is delivered by rail or by road, and
sometimes by helicopters. These supplies are unreliable and expensive. Installations of
wind turbines will be good economical solutions in such cases even with sufficiently
large capital investments but with low operating costs, the absence of a fuel component and environment impact. (Energovopros, 2013)
A wind generator (a wind power installation or a wind turbine) is a device for converting wind flow kinetic energy into mechanical energy of rotation of the rotor with its
subsequent transformation into electrical energy. Wind turbines can be divided into
two categories: industrial and domestic (for private use). Industrial ones are built by
the state or large energy corporations. As a rule, they are combined in the network, resulting in a wind power plant. Its main difference from the conventional power plants
(thermal, nuclear) is an absence of both raw materials and waste. The only important
requirement for a wind farm is a high average annual wind. The power of modern
wind turbines reaches to 7.5 MW. (Valeryi Chumakov, 2008)
5.1 Power from wind
Modern wind turbines are operated when wind speeds extend from 3 - 4 m/s to 25
m/s. The dependence of power output from the wind conditions is illustrated in the
figure 10. The power wind turbine depends on the area, which the blades of the generator are sweep off. For example, a 3 MW turbines (V90) provided by the Danish company Vestas have a total height of 115 meters, the tower height of 70 meters and a
blade diameter of 90 meters. In August 2002, a prototype of the Enercon E- 112 wind
turbine capacity of 4.5 MW was built. Prior to December 2004 remained the largest
turbine in the world. In December 2004, the German company REpower Systems has
built its wind turbine power capacity of 5.0 MW. The diameter of the rotor of the turbine 126 meters, the nacelle weight - 200 tons, the height of the tower was 120 meters
to the end of 2005, Enercon has increased its capacity to 6.0 MW wind turbine. The
diameter of the rotor was 114 meters, the tower is 124 meters. The company develops
Clipper Windpower 7.5 MW wind turbine for offshore use. The historical development of wind turbines is shown in the figure 11. (Altalgroup, 2010)
Figure 10.The turbine power curve (Evea, 2013)
Figure 11.The capacity of wind turbines (Tuulivoimayhdistys, 2013)
Pros and cons of wind turbines:
Advantages of wind turbines conclude:
The wind is an inexhaustible resource.
Wind turbines do not consume fossil fuels.
A 1 MW wind turbine reduces annual emissions of 1 800 tons of CO2,
9 tons of SO2, 4 tons of nitrogen oxides.
Unlike conventional thermal power plants, wind farms do not use water
which can significantly reduce the pressure on water resources.
The disadvantages of wind turbines:
Wind power is an unregulated source of energy.
Large wind turbines are experiencing significant problems with a repair. The replacement of large parts (blades, rotor, etc.) at a height of
100 m is difficult and costly.
Wind turbines produce a lot of noise.
When operating wind farms in the winter when humidity is high, the
formation of ice build-up on the blades. The expansion of ice is possible in a big distance. As a rule, the territory in which the cases are possible icing of blades are installed warning signs at a distance of 150 m
from the wind turbine.
Metal parts of wind turbines, especially the elements in the blades can
cause significant interference to the radio signals. (Altalgroup, 2010)
5.2 Wind power potential
The potential of wind energy is distributed unevenly through the territory of Russia.
Wind Atlas Russia indicates that there are many areas where the average wind speed
exceeds 6.0 m/s. Figure 12 shows wind energy resources at a height of 50 meters
above ground level for five different topographic conditions of the area. Colors mean
highest wind speeds are found along the coast of the Barents, Kara, Bering and
Okhotsk seas. Other areas with relatively high wind speeds (5 - 6 m/s) include the
coast of the East Siberian and Chukchi seas and the Laptev Sea in the north and the
east of the Sea of Japan. Slightly lower wind speeds (3.5 - 5 m/s) are found on the
shores of the Black, Azov and Caspian seas in the south and the White Sea in the
north- west. Significant resources are also in the Middle and Lower Volga region, the
Urals, in the steppe regions of Western Siberia, Lake Baikal. The lowest values of the
mean wind speed observed over the Eastern Siberia near the Lena -Kolyma core Asian
Hills and
Open ground
Sea cost
Open sea
>11 >1800
<3.5 <50 <4.5
Figure 12.Distribution of the wind speeds in Russia (Altalgroup, 2013)
Over most of the territory of the Russian wind speeds during the day is higher than at
night, and these differences are much less pronounced in winter. The annual course of
the mean wind speed (i.e. the difference between maximum and minimum average
daily rates) in most parts of Russia is insignificant and varies from 1 to 4 m/s, with an
average of 2 - 3 m/s. Higher amplitudes are observed in the central part of European
Russia, Eastern Siberia, Western Siberia (except for the northern regions) and especially in the Far East, where they reach 4 m/s. Annual amplitude which is less than 2
m/s are observed over the South-East and South-West of the European part of Russia
and over central Siberia. In winter and autumn times winds speeds are bigger over
most part of Russia, except of the southern part of central Siberia where the wind
speed reaches its maximum in the warmer months. The highest wind speed over Yakutia and Transbaikal observed in April and May. (Altalgroup, 2013)
5.3 Vertical wind generators
Among the vertical wind turbines are the following set of rotors: orthogonal, Savonius, Darrieus, Gelikoydny, multi blade generator with guide vanes. The main advantage of the vertical wind turbine is no need to direct them to the wind. One disadvantage of limiting the range of their use and the unit capacity is their lower efficiency, as compared with horizontal-axis wind turbines, with the same swept area and
higher material consumption, for the same capacity. (Alternativenergy, 2013)
5.3.1 Orthogonal wind turbines
Orthogonal vertical wind turbines have a vertical rotation axis and in parallel to it
there are several blades remote from it by a certain distance. The advantages of orthogonal wind turbines are: no need to use in their construction the guidance mechanisms, as the work of these plants does not depend on the wind direction. Due to a
vertical main shaft, the driven equipment can be located on the ground level, which
greatly simplifies its operation. The disadvantages of these systems are lower terms of
service support units, due to higher dynamic loads on them by the wind turbine rotor,
because when the rotor rotates, the lift of each blade changes its direction by 360 °,
which creates additional dynamic load. Blade systems of orthogonal generators are
more massive than equivalent capacity for axial horizontal installations. The efficiency of the system of orthogonal paddle installations is lower compared to horizontal axis as during one rotation of the rotor, the attack angle of wind flow on the blade vary
within wide ranges, while in horizontal wind generators wind angle can be put close to
the optimal. (Alternativenergy, 2010)
Figure 13. Orthogonal axis wind turbines (Alternativenergy, 2010)
5.3.2 Wind turbines with Savonius rotor
As Savonius rotor blades two or more parts of cylinders are used. Savonius turbines
have a high starting torque. They work at relatively low speeds and relatively high
manufacturability of its production. Disadvantages of Savonius rotors are lower efficiency of a blade system, compared with horizontal-axis wind turbines and relatively
high material consumption. Currently Savonius wind turbines are available in the
power range up to 5 kW. Savonius rotor is often combined with the Darrieus rotors, to
ensure a high starting torque for Darrieus rotors. (Alternativenergy, 2010)
Figure 14. Wind turbines with a Savonius rotor
5.3.3 Wind turbines with a Darrieus rotor
Darrieus turbines have a rotor with a vertical axis of rotation, and two or three blades.
It has a flat strip having no typical airfoils. The advantages of Darrieus rotors are the
lack of orientation to the wind, technological ease of the blades fabrication, the ability
to accommodate the driven, equipment at ground level, which greatly simplifies
maintenance. Darrieus rotors disadvantages are the relatively low efficiency of the
blade system, compared with a horizontal -axis wind turbines, a lower lifetime of support assemblies, due to higher dynamic loads on the rotor side. The lift of each blade
changes direction by 360 ° which creates additional dynamic load. Two-bladed wind
turbines with a Darrieus rotor, with a uniform free stream cannot run by their own.
(Alternativenergy, 2010)
Figure 15. Wind turbines with a Darrieus rotor
5.3.4 Wind turbines with a Helicoid rotor
A helicoid rotor or Gorlov’s rotor (his second name) is a modification of the orthogonal rotor. Due to the twist of the blades, the rotation of the rotor is more uniform that
significantly reduces the dynamic load on the bearings and, thereby, increases their
life, compared with the bearings of the orthogonal rotor. However, the technology of
production is considerably complicated because of the twisted blades, which affects
increasing their cost. (Alternativenergy, 2013)
Figure 16. Wind turbines with helicoid rotors
5.3.5 Multibladed wind turbines
Multibladed wind turbines with guide vanes are a modification of the orthogonal rotor. They have two rows of blades, the first row is fixed. It is a guiding device, the
purpose of which is to capture the wind flow, to compress it to increase the speed and
pitch the wind flow at an optimal angle on the second row of blades which are rotating
the rotor. The advantage of this type of rotor is its higher efficiency compared to other
vertical wind turbines; operation at low wind speeds. The disadvantage of this rotor is
it’s a higher cost due to the use of a large number of profiled blades. (Alternativenergy, 2013)
Figure 17. Wind turbines with multi bladed with guide vanes
5.4 Horizontal-axis wind generators
The horizontal-axis wind turbines (HAWT) got their widespread use due to their high
efficiency. Even not the best horizontal wind turbine easily reaches the utilization of
wind energy flux in 30 %. The most thoroughly well-functioning vertical one gets its
best at 20 %. (Chumakov, 2008)
Figure 18. Wind turbines with horizontal axis of rotation (Energybalance, 2013)
Figure 19. Structure of a wind generator (Altalgroup, 2013)
1. Turbine blades
2. The rotor
3. The direction of rotation of the blades
4. Damper
5. Leading axis
6. The mechanism of rotation of the blades
7. Electric generator
8. Controller rotation
9. Anemoscope and wind sensor
10. Shank anemoscope
11. Nacelle
12. The axis of generator
13. The mechanism of rotation of the turbine
14. Engine rotation
15. Tower
5.5 Present wind farms in Russia
Figure 20. Anadyrskaya windfarm
There are a few wind power plants in Russia. Installed power of the Anadyrskaya
windfarm on 1 January 2011 was 2.5 MW, which is less than 1% of the total installed
capacity of the Chukotka Autonomous District. Electric power generation in 2011 will
not exceed 0,2 million kW ⋅ h. At the same time diesel power plants are installed.
Figure 21. Wind farm Tyupkildy
Wind farm Tyupkildy is located near the village of Tyupkildy Tuimazinsky district of
Bashkortostan Russia. It is one of the most powerful Russian wind farms - 2.2 MW
(the third largest installed capacity). It consists of four wind turbines made in Germany.
In 2010, the WPP has produced 0.30 million kWh of electricity in 2009 - 100 000
kWh in 2008 - 0.40 million kWh. The capacity factor in 2008 - 2010 did not exceed
2.2 %. (annual report "Bashkirenergo", 2010)
Figure 22. Zelenogradskaya wind farm
Zelenogradskaya wind farm’s establishing electrical capacity is 5.1 MW.
There are several turbines in Zelenograd Wind farm:
1 type of wind turbine Wind World 4200/600 0,6 MW
20 wind turbines type Vestas V27/225 capacity of 0,225 MW each.
Equipment Zelenograd WPP purchased a used (1992 - 1993 model year wind turbine),
and it ran between 1998 and 2002. By the end of 2012 five wind turbines had to be repaired. The generated power was:
4 690 000 kWh in 2008
3 538 000 kWh in 2009
3 596 000 kWh in 2010
3 878 000 kWh in 2011
3 057 000 kWh in 2012. (Kaliningrad Generating Company 2010)
Wind turbines cannot be directly connected to the grid due to variable power outputs.
Wind turbines are like winds – always changing their output parameters and unpredictably. Different devices such as transformers, inverters, switches and etc. should be
used between the grid and wind turbine. Nowadays, the grid connection of a wind turbine is one biggest and main challenging issue in this field of electricity production.
6.1 Operation of wind turbines
Mr.J.F.Manwell and Mr. J.G.MeGowan point out nine main operating states.
Following stationary and transitional operation states are used:
period of checking of the system
readiness for operation
connection to the grid
electricity production,
disconnection from the grid
general and
emergency shut- down of the system (see Figure 6.1).
Some of these states can be absent or can consist of different several combinations.
When the turbine operates in some states for long time then these states are called stationary states. Other type of operating states is transition state. It appears during
switching from one state to another.
Figure 28. Typical turbine operating states (Manwell and McGowan, 2009, p. 217)
As can be seen in the figure, the first states is checking of the system (Transitional).
The system check is performed when the control system starts working. This is transitional state. It checks the system readiness for use.
Readiness for Operation (Stationary)
Ready for operation state is characterized by a stationary rotor and the parking brake.
When the operating conditions are identified and the system checks find no fault, this
state is started. There have to be enough wind to start the turbine. This is a stationary
state in which the turbine may remain for a long period of time.
Starting point (Transitional)
The start begins when all conditions are reached and brake is released. Many turbines
start to accelerate to nominal speed without intervention, but pitch mechanism
shouldbe regulated to accelerate the rotor. For variable speed turbine this state can require the dynamic controllers operation.
Connection to the grid (Transitional)
Some turbines may be needed run up to the operating speed by connecting the generator to the network for disengagement of the brake. After connection and achieving the
correct speed electricity generation begins.
Electricity Production (Stationary)
During the production of electricity there are can be faults caused by electric current.
The supervisory controller monitors the faults in the system, the yaw orientation of the
turbine, output power and the speed of rotation of the rotor.
Disconnection from the grid (Transitional)
The main idea of this state is to disconnect the generator from the grid, which includes
disengaging different control systems and providing new set-points. This state is transitional.
Freewheeling (Stationary)
It is the state when generator is disconnected from the grid and rotor works freely until
good conditions will not be reached for connecting to the grid or otherwise turbine
will be shut down. Mainly this state happens when rotor waiting for needed range of
wind flow.
Shutdown (Transitional)
This state happens when wind or power is above some nominal level or vice versa
wind is too low to produce power, and also it can happen when monitoring system indicates some faults and then give command to shut-down.
Emergency Shutdown (Transitional)
The difference between emergency shutdown and general shut-down is that emergency shut-down is faster. And sometimes general shut down system can be broken and
not possible to do his functions.
6.1.1 Faults
Different kinds of faults can happen in the wind turbine. These faults have different
degrees of seriousness. Some are very serious and the wind turbine has to be rapidly
shut-down while others are less severe.
A number of sensor faults are possible. For example, in the pitch position sensors can
have electrical or mechanical faults and due to this measured values can be incorrect.
Sensor faults can lead to unpredictably chains of controller operations even to shutdown of the wind turbine.
The converter and pitch systems can fail. The reason of these faults can be fails in hydraulic pitch systems. These hydraulic faults can result in changed dynamics due to
dropped pressure or high air content in the oil.
System faults like changed dynamics of the drive train due to increased friction is not
serious in the beginning, but during a period of time it leads to total wear and breakdown of drive train and then this will be a really serious fault.
System all the time have to be monitored to detect faults including component failures, sensor failures, grid failure and other unwanted operating conditions. Failures
can be detected directly or indirectly. For example, if we see that the generator and rotor speeds do not correspond to each other than it means that there is the failure of a
coupling between the generator and the gearbox. Such a failure could also be detected
when the rotor speed is accelerating, or it is too high. The system is monitored mostly
by using different sensors and transmitters. Due to these most robust and accurate sensors have to be chosen for a wind turbine, nevertheless sensor failures can also occur.
To make more reliable systems, we should use two different sensors for the same
measurements. Sensors have to be selected to withstand different weather conditions.
6.1.2 Determining the state of system components
To determine the system components wind turbines need in good control systems. For
example, a control system can measure wind speed, check the health of system components, implement blade pitch settings, and etc. Without good control system, a wind
turbine cannot successfully produce power. There are two levels of control system:
supervisory and dynamic control. Supervisory control manages and monitors turbine
operations and sequences control actions like brake release and contactor closing. Dynamic control manages machine operation aspects like changing blade pitch in response to turbulent winds.
6.2 Devices used for grid connections
The wind turbines can be connected to the grid at different voltage levels: low,
medium, high and extra high voltages.
Figure 23. Connection of wind-turbine to the grid (Intechopen, 2013)
The turbine rotor, generator and gear box are the main components for electricity production. The rotor converts the wind energy into mechanical energy. The generator
converts the mechanical power of the rotor into electrical energy, which is then fed into the grid. The gear box is used to adjust the rotor speed to the generator speed. DC
link is used to get required frequency of the output power.
The main grid connection components of the wind turbines are the transformer,
safety equipment (circuit breaker) and the electricity meter. To reduce losses in
low voltage lines, each of the turbines in the wind power plant are featured with
its own transformer which converts the voltage level of the turbine to the voltage line
of the grid. The transformers are located directly near the turbine in order to use less
cabling. In case of small wind turbines it can be used only one transformer to connect
to the grid. Large wind farms with high powers are needed of a separate substation for
transformation from the medium voltage level to the high voltage level. Between a
wind turbine and the grid, at the point of common coupling (PCC), a circuit breaker
has to be installed to provide disconnection in case of fault. The circuit breaker is usually installed at the medium voltage system, in the feeder, together with the electricity
meter. The meter has its own voltage and current transformers.
6.2.1 Transformers
Power transformers are important components in power system. They are used for
converting the generated power to the voltage level of the local electrical grid. In addition, different measuring transformer can be used for monitoring, control system and
Power transformers are usually in the 5–50 kVA range. Transformers which are situated in substations has power range between 1000 kVA and 60 000 kVA. Transformers consist of two or more copper coils and metal core. Copper coils are called the
primary and secondary windings. (Manwell and MeGowan, 2013, p. 21)
6.2.2 Switches and axual devices
Figure 24. Typical circuit of wind turbine connection to the grid (Kawady, Naema
Mansour and Abdel-Maksoud I. Taalab, 2007, p.269)
Power from generator have to be transferred through the tower to electrical cubicle at
the base. This is done by using power cables. Three-phase generators have four copper
conductors, which include ground or neutral. In order not to damage cables due to yaw
system there is a slack is left in them. With sufficient slack the cables never wrap up
tight in most sites.
Figure 25. Wind Turbine high-voltage equipment (Manwell and MeGowan, 2009, p.
There are circuit breakers and fuses between the generator and the electrical grid. Circuit breakers are used for connection/disconnection and protection purposes. The fuses are used only for protection aims. Circuit breakers can be reset after fixing the
fault. Fuses have to be replaced.
6.3 Grid protection
Protection system is one of the most important parts related to the interconnection of
wind generators (WG). Radial systems are general form of distribution network configuration. They are usually protected by using overcurrent protection schemes. Connection of WG to grid influences the existing protection schemes. If not carefully everything is set, then this can lead to failure of protection equipment.
6.3.1 Short-circuit current
Short circuit level is one main parameter in the selection of circuit breakers, fuses,
current transformers (CTs) and reclosers, and the coordination of overcurrent relays.
Short circuit current is level of fault current. It is characterized by the equivalent system resistance at the failure point. When wind turbine is connected to the grid then
equivalent network resistance can decrease and this cause in fault level growth. There
can be high fault currents which can exceed the interrupting capacity of existing circuit breakers. High fault currents can lead to СT saturation. Moreover, the changed
fault levels can influence the coordination between overcurrent relays which may lead
to their unsatisfactory operation.
The fault current level significantly exceeds load current level by this relays understand when to operate. When the contribution of fault current from a WG is limited, it
becomes difficult for protection relays to effectively detect faults. Induction generators make a limited contribution of fault current to asymmetrical faults. Small synchronous generators are even not able to supply fault currents because they are greater
than the rated current. Power semiconductor equipment cannot withstand significant
overcurrent for long time and therefore power electronic converters are designed to internally limit the output current.
6.3.2 Islanding and auto recloser
Islanding is the situation when a part of the network is disconnected from the main
grid and operates like independent system with one or more generators. Islanding results in variations of frequency and voltage in the island. If an auto recloser will open
during a fault, it may lead to the formation of two independent systems with different
frequencies. Reclosing of the auto recloser while the two systems are out of phase
could bring to disastrous results. Islanding is recognized as an unsafe situation, because of which immediate disconnection of the WG from the grid is needed.
6.4 Voltage control
Interconnection of wind turbines with grid makes changes in power flows and the
voltage profile in the feeder, and also results in overvoltage. Power quality depends on
voltage and also voltage can influence in operation of under/over voltage relays.
Selection of tap settings for transformers becomes difficult with the increased amount
of connected wind turbines. When the wind turbines are not equally distributed in the
feeders it is become more difficult to set appropriate tap for transformer. Such a case
is shown in Figure 25. There are two feeders supplied by same transformer, but wind
turbines are connected on only one of them. When the wind turbine is connected, the
current through the transformer is decreased because the wind turbine supplies with
the power the nearby loads. So because of that, the transformer tap should be changed
to the light load setting. The resulting voltage can cause a voltage disturbance at the
end of the feeder without wind turbine as in Figure 6.6. If to leave the transformer tap
at heavy load it can cause overvoltage in the feeder with wind turbines.
To control the feeder voltage it can be used switched capacitors and static compensators but these solutions are often too expensive.
Figure 26. Possible WG interconnection configurations (Rajapakse, Muthumuni and
Perera, 2006, p. 112)
Another effect of connection of wind turbines at distribution level is unbalanced voltage profile. As illustrated in Figure 30, the loads and wind turbine can be three- phase
or single-phase. Single phase connection increases the system unbalance. Unbalanced
distribution systems can make problems for the three-phase connected wind turbines:
the unbalance currents in the wind turbine can cause overheating and frequent shutdowns.
Figure 27. Possible WG interconnection configurations (Rajapakse, Muthumuni and
Perera, 2006, p. 113)
6.5 Grid effects
Interconnection of wind turbine with grid causes different undesirable effects such as
harmonics, voltage and frequency fluctuation, active and reactive power flow. To
avoid disturbances and damages in the system it should be investigated and controlled
grid effects.
6.5.1 Wind turbines power quality
Power quality can be expressed in terms of the physical characteristics and
properties of the electricity and described in terms of voltage, frequency and
their fluctuation. A perfect power quality is sinusoidal voltage waveform with
constant amplitude and frequency. Figure 6.9 shows the classification of different
phenomena affecting power quality.
Figure 28. Classification of different power quality phenomena
The international standards say that the quality of the voltage should be fulfilled to
allow a power source to connect to the grid. The voltage disturbances are
divided into several categories: flickers, voltage variations, harmonic and transients
distortions. Wind turbines affect power quality and are affected by disturbances
which come from the grid. Large power system has usually stable frequency and the
wind turbine normally does not cause interruptions in high voltage grid. When it
is autonomous grids with diesel engines or wind turbines, the frequency variation
should be taken into account.
6.5.2 Output behavior of wind power plants
Wind turbines influence in fluctuating real and reactive power values and may result
in voltage and current transients or voltage and current harmonics. Constant-speed
turbines usually use induction generators. Induction generators produce real power (P)
for the system and consume reactive power ( Q ) from the system. Real and reactive
power are constantly changing during wind turbine operation. Low-frequency real
power fluctuations occur when the average wind speed changes. Higher frequency
fluctuations of real and reactive power occur because of wind turbulence, dynamic effects from drive train, and blade vibrations.
Wind turbines with synchronous generators operate in a different manner than with
induction generators. When connected to a large electrical network with a constant
voltage, the field excitation of the synchronous generators can be used to change the
line power factor and to control reactive power.
Variable speed turbines usually have a power electronic converter between the generator and the grid. It can control the power factor and voltage of the power. Power electronic converters should supply reactive power to support the magnetic field in the
generator. The converter components can provide current to the grid at any power factor. This can be used to improve grid operation. When generators are connected or
disconnected from a power source, voltage fluctuations and transient currents can occur.
When an induction generator is connecting then significant over current is occurred.
These high currents can be limited using of a ‘soft-start ’ circuit. When induction generators are disconnected from the grid, voltage spikes can occur. Synchronous generators have not high starting current requirements. Nevertheless, voltage transients can
still occur.
6.5.3 Voltage and frequency response
Wind plants have to be able to operate continuously even when the voltage and frequency variation in normal operation range of the system but differ from nominal values. This ability depends on the voltage level at the point of common coupling (PCC)
of the wind generator and the grid. Transmission level voltages are110 kV and above.
Lower voltages such as 35 kV and 10kV are usually sub-transmission voltages. Voltages less than 35 kV are used for distribution. Voltages above 220 kV are extra high
voltages and special devices should be used.
The lowest voltage level in most countries has not to be lower than 90 % from nominal value. In some countries voltage can drop even until 70 % from nominal value but
only for 10 seconds.
The frequency is one of the most important parameters. It varies by country. Most
electric power is generated at 50 or 60 Hz. All the generating equipment operates at
strict frequency. Usually frequency variation rang is 49.5 and 50.5 Hz. Even deviations from the nominal frequency during short time may lead to the loss of generation
capacity. Further frequency deviation may lead to blackout.
Figure 29. Typical voltage and frequency dimensioning for wind generators (Eltra &
Ekraft System, 2004)
In this diagram:
VL is the lower voltage limit
VLF is the lower voltage limit for full-load range
VN is nominal voltage
VH is the upper voltage limit
VHF is the upper voltage limit for full-load range.
In the full-load range wind farm can supply its nominal power without any disturbances (continuous operation area).
6.5.4 Harmonics and methods to reduce them
The harmonics are voltage components with frequencies being multiples of the nominal frequency, i.e., 100Hz, 150Hz, 200Hz, etc. The interharmonics are components
having frequencies located between the harmonics of the nominal frequency. Voltage
and current harmonics and interharmonics are always present on the utility
grid. They are produced mainly by the rectifiers and inverters in motor drives,
non-linear loads, power electronic loads, etc.. There are many negative effects of
harmonics presence:
Problems of instantaneous occurrence include:
distortion of the supply voltage
voltages drop in the distribution network
the effect of harmonics that are multiples of three (in three-phase systems)
resonance effects on the frequencies of the higher harmonics
interferences in the telecommunications and control networks
increased acoustic noise in the electromagnetic equipment
vibration in the electric machine systems.
Problems of a long-term occurrence include:
heating and additional losses in transformers and electrical machines;
heating capacitors;
heating cable distribution network.
Heating capacitors Filters are LC systems, parallelly connected to the power supply.
The role of the filter LC is to retard higher harmonics. Figure 6.11 shows a typical circuit for filtering harmonics. There are three filter branches Related to 5, 7,11th harmonics. Number of branches arranged filter depends on the required the reactive power required for compensation as well as the measurement and accurate specific analysis of the content of harmonics in the network.
Figure 30. Typical circuit for power factor correction
6.6 Grid connection rules
The first “Grid Code” in the world, regulating the procedure for connecting wind farm
to the network, was performed in Germany in 2003. The main points of this document
Operation of wind farm in the network during a fault (short-circuit current).
The creation of an intelligent system for the possibility of separation different
groups of wind turbines in wind farm to separate loads (" Island formation ").
The reverse connection of wind turbine to the wind farm with a minimum
voltage or frequency deviation.
Minimize power losses of wind power plant.
At the moment, in every European power system, there are some technical requirements for connecting wind farm to the grid. Uniform requirements for assessing the
possibility of parallel operation of wind farm and power system is not developed, but
in each document there are certain general requirements. These documents are generally classified by voltage of networks which connect the wind farm. The first group
includes documents regulating wind farm connection to the network voltage below of
100 kV, the second group - a voltage above of 100 kV. There are basic requirements:
maintaining required frequency
maintaining required voltage
indicators of quality of electric energy
protection and automation of wind farm.
The basic requirement for the development of wind farm capacity is the organization
of a more or less uniform power. In general, the output power of wind farm is the uniform and have only seasonal fluctuations when the wind changes. Seasonal fluctuations of output power of wind farm are almost unavoidable. If the output power of
wind farm reaches 15-20 % of the installed capacity of the whole unified power system, then the wind farm power fluctuations can affect the dynamic stability of the
power system. In some European countries, the share of wind farm exceeds 30 % of
the capacity of unified energy system (Denmark), so to maintain required frequency,
near nominal value is really important. Basic requirements for wind farm in frequency
is to maintain the frequency range f = 50 ± 0.5 Hz for 97 % of the time.
Power system with high share of wind farm needs reserved power production source
in the conventional power plants with the total capacity which equal to wind farms total output power. Traditional power plants must be able quickly generate power in
case of wind farm disconnection, for these purposes it is better to use HPS (Hydroelectric power plants). Thus, the guaranteed capacity of wind farm is considered to be
Voltage in unified energy system is characterized by fluctuations caused by uneven
production and consumption of reactive power. The voltage at the nodes of the network depends on the balance of reactive power. It should be noted that the asynchronous generator (ACG) and a synchronous generator (SG) which are used in wind turbines produce reactive power; thereby they influence the voltage at the connection
point to the network. Asynchronous generators consume reactive power; therefore,
they require the installation of static capacitor banks at the output of wind turbines.
Technical papers about parallel operation of wind farm with the network say that the
voltage at the output of wind turbines has to be in the range ± 10 % of nominal value.
Voltage level can be regulated by transformers equipped with OLTC (On-load tapchanger).
Power quality of electric energy includes the definition of the limits of flicker, harmonics, and the availability of voltage variation. According to the technical documents of European power systems, presence of flicker, the harmonics and voltage variation is regulated by the European standard EN 50160. Limit of voltage drop is also
determined on the basis of standard EN50160. On the basis study of Russian and European technical documents it can be concluded that there are no uniform requirements for connecting the wind farm to the grid. This is explained by the uneven development of wind power in the countries: the share of wind farm in UES, types of
wind turbines, etc. However, in all technical documents have the same requirements:
Provision of wind turbines under specified conditions;
regulation of the power and speed of the rotor;
control of active and reactive power in certain ranges.
Nowadays production electricity from wind power is one the interesting and developing fields in the world. Because people understand that conventional energy sources
are limited and also health of environment is limited.
In Russia there are a lot of places with good conditions where wind turbines can be installed. Several wind farms exist in different parts of Russia, but they are unfortunately only experimental. The main reasons of poor development of wind farms in Russia
low economic benefits
politics, no low regulations
grid connection challenges
a lot of capacity of conventional energy source
In this thesis we tried to consider these problems and solve some solution for their reduction. Mostly thesis contains a review to wind energy utilization in North-West
Russia. According to our thesis we can say that wind energy can be utilized in NorthWest, but it will be a long process. With our review we tried to move this process
somewhat forward.
Also it can be concluded that it is needed to develop technical document for regulations the connection and parallel operation of WPP with grid. Considering that about
70% of the Russian area refers to areas of decentralized power supply with high cost
of electricity, we can talk about the possibility of building a joint wind- diesel plants
in these areas. Important part of the construction will be the organization of parallel
operation of wind power plants and diesel generators.
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