DANFOSS-TLX6Pro-TLX8Pro-TLX10Pro-TLX12.5Pro-TLX15ProkW-soluciones-2

DANFOSS-TLX6Pro-TLX8Pro-TLX10Pro-TLX12.5Pro-TLX15ProkW-soluciones-2
MAKING MODERN LIVING POSSIBLE
Medium to large scale solutions
based on TLX Pro
Danfoss Solar Inverters A/S | concept Paper | MAY 2011
Table of content
1 Introduction .........................................................................................................................5
2 Photovoltaic panels ...........................................................................................................6
2.1 Monocrystalline panels or Polycrystalline panels. ..........................................6
2.1.1 Standard polycrystalline panels . ....................................................................6
2.1.2 Standard monocrystalline panels ..................................................................6
2.2 Thin film panels . ..........................................................................................................6
2.3 Layout factor .................................................................................................................6
2.4 Maximum DC voltage and operating voltage ..................................................7
2.5 Maximum Power Point Tracker (MPPT) ...............................................................8
2.6 Cable loss .......................................................................................................................8
2.7 Conclusion .....................................................................................................................8
3 Grid and AC configuration ..............................................................................................9
3.1 Point of connection (PC) ...........................................................................................9
3.2 AC configuration . ........................................................................................................9
3.3 Low voltage grid . ........................................................................................................9
3.3.1 Ancillary services for low voltage grid system . .........................................9
3.4 Medium voltage grid .................................................................................................9
3.4.1 Ancillary services in medium voltage grid system . ...............................10
3.5 Transformer station...................................................................................................10
3.6 System approval for connection to MV grid in Germany.............................10
3.7 Conclusion ...................................................................................................................10
4 Communication and monitoring ............................................................................... 11
4.1 Monitoring options . ................................................................................................. 11
4.1.1 Integrated Monitoring, Ethernet communication . ................................ 11
4.1.2 RS-485 communication . ..................................................................................13
4.1.3 GSM communication . .......................................................................................13
4.2 Web server ...................................................................................................................13
4.3 Master functionality .................................................................................................14
4.4 Comlynx Datalogger ................................................................................................14
4.5 System accessories . ..................................................................................................14
4.5.1 Router......................................................................................................................14
4.5.2 Sensor Kit . .............................................................................................................15
4.5.3 Energy Meter Sensor (S0) . ...............................................................................15
4.6 Conclusion....................................................................................................................15
5 Installation ......................................................................................................................16
5.1 Inverters locations . ...................................................................................................16
5.2 Cabling ......................................................................................................................16
5.2.1 AC............................................................................................................................16
5.2.2 DC............................................................................................................................16
5.2.3 Communication cables......................................................................................16
5.3 Conclusion ...................................................................................................................16
6 Service/reliability . ............................................................................................................17
2 | medium to large scale solutions based on TLX Pro | Application Paper | May 2011
Preface
PV systems ranging from several 100 kVA and up require a detailed system design to provide an optimum solution. With TLX
Pro string inverters there is no need to compromise on system performance. The flexibility of the inverters enables optimal
system planning even of very large systems by anyone possessing a standard understanding of PV systems.
All requirements from the distributed network operator (DNO), such as power level adjustment or reactive power exchange,
are fulfilled. The PV systems can be connected directly to the LV grid, or to the MV grid by using a standard MV transformer.
With integrated monitoring and communication functions external devices are only required for certain grid management
purposes. Master functionality means that data warehouse services can easily be utilised if desired.
TLX inverters provide the ideal solution for any PV system, free of extra cost or compromise.
medium to large scale solutions based on TLX Pro | Application Paper | may 2011 | 3
Summary
This paper is a part of a series whose purpose is to enable system designers to benefit from Danfoss’ system knowledge. The
knowledge collected in the papers, along with the inherent flexibility of the TLX inverters, will enable system designers to
utilise TLX Pro inverters in different applications ranging from residential installations to large commercial power plants.
The papers outline how PV Systems are optimally designed using the high efficiency TLX Pro string inverters, and how these
inverters contribute to the simplification of system communication, commissioning and service.
This particular paper describes installations with multiple TLX inverters of a total grid connection rating ranging from 100
kVA to more than 1 MVA, with the limit set at 100 inverters connected together.
Interconnecting systems of 100 inverters to form larger systems is possible but you must be aware that DNO or technical
limits may come into play. You should therefore contact Danfoss in order for us to help you find the best solution for your
large MW installation.
Using TLX inverters you are able to design a medium to large scale commercial PV system for every roof top or ground size
without special expertise in central inverter solutions. For this system size, several rooftop areas are usually required, and the
area is often subjected to partial shade. The design of the PV system is simplified significantly by using small inverter units
with a high number of MPPTs.
Ground based systems are usually very large, and require extra mounting equipment. TLX inverters with their inherent high
ratio of MPPTs allow you to accept shading situations during the winter months. This means that the rows may be placed
closer together, providing better utilisation of the area available. Additionally, surface space related costs for e.g. cabling, m2
rents, etc are also reduced due to the compact dimensions.
With a three-phase output on the AC side, and the very high maximum DC voltage, the user is provided with a high degree
of flexibility in selecting the ideal inverter mounting location. Long cable runs can be installed on both the DC and on the
AC sides without high cable losses.
The MV transformer station, required for MV grid connection can be a standard station. These are usually reasonably priced
and easily available. Due to the high number of independently working inverters, the system will only be limited affected
even if you experience partial failure of modules or inverters.
A detailed monitoring of module strings is possible without additional hardware. The high number of multiple power point
trackers (MPPT) combined with the high efficiency of the trackers allow for the best possible yield for every kind of roof,
even with shading. The combination of several 15 kVA inverters with other TLX inverters of different power ranges makes it
possible to select a total AC output power with the ideal ratio for PV power.
A data logging, monitoring and control system is integrated into the TLX Pro inverter. External sensors for temperature
and irradiation can be connected directly to a master inverter, enabling easy integration of the reference performance
monitoring. For systems requiring power level adjustment (PLA) or other ancillary features associated with systems
connected to medium voltage (MV) networks, a Grid Management Box is used to relay the input from the distributed
network operator (DNO) into the system. The master inverter will then ensure the system performs according to DNO
requirements. Thus a system based on TLX Pro comprises a complete verified system from a single manufacturer.
Any TLX Pro inverter can be set up as system master, and ordering a special unit is thus not necessary. The other inverters
in the system can be connected to the master via Ethernet LAN in star or daisy chain configuration according to installer’s
preference. Once connected, the IP address will be set up automatically. Installers can also use the inverter’s built-in
web interface to simplify installation, which includes parameter settings required for PLA or auxiliary features for the
MV network. Via the master inverter it is possible to replicate the setup parameters to every inverter in the plant. Thus
communication cabling and system setup is simplified, which reduces installation time and the potential for errors.
Unlike central inverters, special training is not required to be able to install, maintain or exchange string inverters. The local
electrician can maintain the string inverter installation, meaning that service contracts requiring specialists from the inverter
manufacturer are not required. For service purposes, backup of settings and data is available in the inverter display enabling
a quick exchange. Furthermore, by omitting junction boxes, no service on the DC side is required.
For monitoring you can use the built-in Web server interface, for easy overview of the installation, or the master inverter
can be set up to automatically send data to data warehouse services, using its built-in FTP upload feature. Through the
web interface of the data warehouse provider, it is possible to carry out standard plant monitoring down to detailed error
analysis. Data down to individual string level is transferred for central storage and monitoring of long term effects.
4 | medium to large scale solutions based on TLX Pro | Application Paper | May 2011
Introduction
1.
In a PV system the inverter links the DC based PV panels to the AC based grid with the purpose of transferring as much
power as possible from the modules to the grid. To be successful in this task the inverter must both draw out as much
energy from the modules as possible and feed in as much energy as possible.
In the following sections we will address how you can ensure that both the PV and grid side of your plant is optimised from
the point of view of the inverter.
To ensure maximum operation time and minimised down time a monitoring system is recommended. Depending on
preferences different solutions may be considered, a selection of solutions is therefore presented.
How the inverter is installed may also influence the system so this is also addressed.
Finally we will briefly mention considerations regarding service of the inverter.
medium to large scale solutions based on TLX Pro | Application Paper | may 2011 | 5
2.
Photovoltaic panels
and DC configuration
How much of the sun’s energy you can harvest will depend on the type of module and where and how they are installed.
Panels are available of different types and sizes, which lead to many different combinations of PV configurations being
possible. Selecting the optimal configuration to match the local installation conditions thus becomes relevant in order for
the inverter to optimise the amount of PV power for conversion into AC power.
In order to give you the widest possible range of solutions we have given the TLX inverters the following characteristic:

4 power sizes (8 kVA, 10 kVA, 12.5 kVA, 15 kVA)

2-3 individually regulated MPP Trackers of each:
 1000 VDC open circuit
 250-800 V MPP range
 12 A input current
Selecting the PV panels is one of the first tasks to be performed.
2.1 Monocrystalline panels or Polycrystalline panels
Two types of crystalline standard solar cells are available: the less expensive polycrystalline cells and the monocrystalline
cells with slightly higher efficiency. A vast majority of polycrystalline cells are produced in 6.inch units (156 mm × 156 mm)
with a maximum power of 4 Wp. Standard monocrystalline cells are available in 5-inch units (125 mm × 125 mm) with up to
2.8 Wp, or in 6-inch units with up to 4.2 Wp. New efficiency records for mass production solar cells were recently published,
though these cells are not yet widely available.
2.1.1 Standard polycrystalline panels
The most common application of polycrystalline cells are modules with 48, 54 or 60 cells. There are also large, 72-cell
modules on the market, though these are less common. According to the cell power these modules yield up to 190 Wp (48
cells), 215 Wp (54 cells), 240 Wp (60 cells) or 290 Wp (72cells). The DC input parameters of the TLX inverters are optimised to
connect one string of these modules to one input with its own MPPT.
2.1.2 Standard monocrystalline panels
Modules with 6-inch monocrystalline cells are increasingly available on the market. These are available with the same
number of cells per module as those mentioned above with polycrystalline panels. The power values of monocrystalline
panels can reach up to 200 Wp (46 cells), 225 Wp (54 cells) 250 Wp (60 cells) or 300 Wp (72 cells). Here it is also the most
useful to connect one string to one input with its own MPPT.
Five-inch units are primarily used in modules with 72 or 96 cells. These modules yield up to 200 Wp (72 cells) or 270 Wp
(96 cells). The maximum possible power per string compatible with the TLX inverters amounts to 3.8 kWp. The installer
must therefore connect a higher number of strings to the inverters to obtain the usual layout factor, when compared to
modules with 6-inch cells; e.g. five stings to a TLX 15k.
2.2 Thin film panels
All thin film panels that do not require grounding on the DC side are compatible with TLX inverters. Modules based on CIS
or CIGS technology, in particular, are used for residential PV systems and can also be used with transformer-less inverters.
One important challenge brought about by using thin film panels is the high module voltage. This reduces the maximum
number of modules per string; hence, the maximum power per string is limited to around 1.5 kWp. Often less than 1 kWp
power per string can be reached with thin film panels. This means that the installer must connect a greater number of
parallel strings to obtain the recommended PV power of any inverter. Here the multiple MPPT of the TLX inverters come
into play. With three to eight strings per DC input/MPPT in many cases, it is not necessary to use string diodes or string
fuses. This reduces the installation costs and eliminates additional potential for error.
Having chosen the panels, the configuration of strings to utilise the area available and accommodate for the installation
location is of importance.
2.3 Layout factor
A plant which utilises power via high-efficiency inverters located in Central Europe should not exceed a layout factor of
Psolar/Pinverter = 1.12, as indicated by Dr Bruno Burger1.
Due to better Pmpp temperature coefficients and a better low light performance for thin film modules, it is advisable to
use a lower layout factor of maximum 1.1 for thin film modules.
1 Inverter sizing for grid connected PV plants: Dr.-Ing. Bruno Burger, Fraunhofer-Institut für Solare Energiesysteme ISE Heidenhofstraße 2, D-79110 Freiburg.
6 | medium to large scale solutions based on TLX Pro | Application Paper | May 2011
For crystalline modules with standard solar cells, different options are available with the TLX 15k at optimal orientation:
Standard Crystalline modules with 6-inch solar cells:

1 string of up to 24 modules with 60 cells on each of the three inputs

1 string of up to 26 modules with 54 cells on each of the three inputs

1 string of up to 30 modules with 48 cells on each of the three inputs
Standard Crystalline modules with 5-inch solar cells:

5 strings of up to 20 modules with 72 cells divided on the three inputs

5 strings of up to 15 modules with 96 cells divided on the three inputs
Thin film modules as examples First Solar FS-377 and FS-277:

14 strings of 15 modules FS-377 divided on the three inputs

21 strings of 10 modules FS-277 divided on the three inputs
The farther away from optimal orientation and inclination, the higher the layout factor should be. For example, a roof with
a 45° inclination and a westward orientation may have a layout factor of around 1.18, because the roof will not be exposed
to the sun the whole day, and the sun will have less power when it hits the roof perpendicularly. On the other hand, a roof
with a 6° inclination and westward orientation should have a maximum layout factor of around 1.25, because the roof will
be exposed to the sun almost the whole day, however always at an oblique angle.
Northwest
West
Southwest
South
Southeast
East
Northeast
North
Inclination°
125
125
118
118
118
125
125
125
<10
125
118
112
112
112
118
125
125
10
125
118
112
112
112
118
125
125
20
125
118
112
112
112
118
125
125
30
125
118
112
112
112
118
125
125
40
125
118
112
112
112
118
125
125
50
125
118
112
112
112
118
125
125
60
125
125
118
118
118
125
125
125
70
125
125
118
118
118
125
125
125
80
125
125
125
125
125
125
125
125
90
Table 1: Layout factor in % relative to orientation of modules – Central Europe
For installations in southern Europe, where a lower layout factor is recommended, power can easily be reduced by
connecting fewer modules to each string when using crystalline modules or fewer strings to the inverter when using thin
film modules
2.4 Maximum DC voltage and operating voltage
The negative temperature coefficient for open circuit voltage (Uoc) of solar modules has to be considered when
determining the maximum number of modules per string. For Central Europe, the current practice is to calculate the
maximum DC voltage at -10°C. At this temperature solar modules can theoretically reach Uoc values of up to 13% higher
than Uoc at standard test conditions (STC). Although lower module temperatures can occur normally it is not necessary
to take this into consideration This is due to the fact that the voltage decrease rate, at lower sun irradiation only result in
around 10% lower Uoc values at a radiation of 200 W/m², as compared with 1000 W/m² radiation. Furthermore even at 200
W/m² there is a module temperature increase resulting in a significantly higher temperature than the ambient.
In order to determine operating voltage values under realistic conditions, these conditions have to be defined. For this
reason, the NOCT was developed. NOCT stands for ‘nominal operating cell temperature’. This value is also stated on the
datasheet of a module and it stands for the typical cell temperature over the course of one year (for crystalline modules
around 45°C).
The everyday operating DC voltage range is important for determining inverter efficiency. Unlike most single-phase
inverters, highly efficient three-phase inverters reach operating voltage values near their nominal DC voltage. This means
the inverters actually function with the datasheet efficiency. As a result, the following rule of thumb comes into play: to
reach the best possible inverter efficiency you should aim for the maximum number of modules per string. If there is a
single string with a lower number of modules and lower DC voltage level, the corresponding lower efficiency only affects a
share of all modules connected to the inverter, with reduced effect on the total efficiency.
medium to large scale solutions based on TLX Pro | Application Paper | may 2011 | 7
2.5 Maximum Power Point Tracker (MPPT)
It is not easy to find a spacious roof area that experiences no shading situations, where a PV system installation with one
or more central inverters can be installed. You therefore often compromise between maximum use of the roof and the DC
design possibilities of central inverters. This problem is further complicated when designing a PV system on several roofs
with different orientations and/or inclinations. String inverters with multiple MPPTs allow for the optimum use of every
roof; not only because you can build up a PV system with maximum power, but because the string MPPT brings out the
best possible yield from every part of the roof. It is also possible to use different types of solar modules if this is deemed to
be helpful in installing the system
For large ground mounted PV power plants, central inverter solutions are generally preferred. As a result, you must accept
a poor ratio of PV power to MPPT: the higher the PV power per MPPT, the lower the tracking accuracy due to mismatched
string MPP voltages between the parallel connected strings. Furthermore, the highly recommended string monitoring
requires expensive additional installations.
In most cases, by using inverters with several MPPTs you can operate every string of crystalline modules with its own
MPP voltage. The string MPPT also includes power data collection whereby no additional string monitoring is needed.
This ultimately results in lower costs by abandoning additional monitoring hardware, and better yields due to better MPP
tracking accuracy.
2.6 Cable loss
Cables in the PV plant will contribute to losses, -how much depends on the cable resistance. For equal amounts of power
transferred on a wire you can reduce the losses either by choosing a cable with a larger cross section or by increasing the
voltage. In general it is advisable to keep the total cable loss below 1%.
Having a module configuration with a nominal DC voltage in the 700 V range you will in most cases be utilising the 1000 V
open circuit limit of the system and thus be running at the highest possible voltage. This means you can save cable costs
by using a smaller cable cross section. Typically 4mm² can be used in most installations with up to app. 200 m total DC
cable length. For installations with up to 300 m total cable length a 6 mm² cable will still keep the loss below 1%. With the
DC voltage being significantly higher than the AC voltage it is also advisable to make the longer cable runs on the DC side
as this will contribute to keeping the overall cable losses low.
2.7 Conclusion
The TLX inverter offers a large degree of flexibility in PV layout design, due to the strengths of 1000 VDC, 2-3 independently
regulated MPP trackers and 2-3 DC inputs. All crystalline panels can be connected to the inverter, thinfilm panels may be
used and as the TLX inverters come in different power sizes the PV to AC ratio can be optimised ensuring that you always
get the most efficient system for the area available.
Having ensured the optimum configuration for PV input, it is important to likewise consider the conditions for output.
8 | medium to large scale solutions based on TLX Pro | Application Paper | May 2011
Grid and AC configuration
Despite ongoing harmonisation, delivery of the produced energy to the grid is no simple task. It is linked to both the size of
your installation and to the type of grid. Different countries do not just have different requirements but within the country
grid requirements may also depend on the amount of power supplied.
The characteristics of the TLX inverters regarding the AC side are:

Three phased output 3x400 VAC L-L

Grid settings for 17 countries including ancillary service functionalities
In larger systems with several inverters considerations into inverter location also becomes relevant, taking AC cabling
versus DC cabling into account.
3.1 Point of connection (PC)
The point of connection (PC) is where the PV system is connected to the public electricity grid.
The PC is evaluated and selected by the DNO under consideration that the selected point should not affect the
performance, and the generated power should not interfere with the grid, power supply or the connected power
consumption device.
This is to electrically isolate the PV power generation system and the power consumption circuit. More PV systems can be
connected to the common point, though the total power generation capacity should be taken into consideration.
3.2 AC configuration
TLX inverters are designed to receive a high DC voltage level. It is thus possible to span long distances with standard PV
cables, increasing the flexibility in terms of finding the optimum position for mounting the inverters. Generally, the lowest
costs for DC and AC cabling can be obtained by concentrating larger numbers of inverters in one place, ideally near the MV
transformer or the low voltage feed-in point.
When installing a PV system on several buildings, the installer can choose to install the inverters in groups per building or
utilise the high DC voltage of TLX inverters to unite all inverters in one place. This flexibility minimises cable losses, cable
installation costs and AC sub-distributions.
Beyond the standard AC cable for connecting the inverters to the AC sub-distribution, no (or only one) additional AC cable
type is need to connect the transformer. The reduced number of AC sub-distributions also contributes to the cost-saving
potential of string inverters.
3.3 Low voltage grid
For system output power levels of between 400 kVA and 600 kVA AC, it is often possible to connect the inverters directly to
the low voltage grid. The low voltage (LV) distribution system carries fewer requirements compared to the medium voltage
(MV) grid. However, there is a clear tendency that regulations for the MV grid become increasingly adapted in the LV grid,
thus grid support functions are now also required in the LV grid to some extent.
3.3.1 Ancillary services for low voltage grid system
An example of required grid support (ancillary services) is found in Germany, where as of July 2011, requirements will take
effect concerning active power reduction and the control of reactive power.
Power reduction must be carried out at excess frequencies for all installations. Reduction based on input from the DNO is
only relevant for systems over 100 kVA. The remote control device for power management provided by the DNO can be
connected to the Danfoss Grid Management Box. This box controls the output power reduction of the TLX Pro inverter PV
system The power can be reduced by 0%, 30% or 60%, or it can be restored to 100% according to the needs of the utility
company to keep the grid stable.
Additionally TLX Inverters will able to control reactive power, either as a fixed value of Cos(φ), or as a function of the
generated power when selecting the country setting Germany LV by 1-7- 2011.
3.4 Medium voltage grid
PV systems with more than 400 kVA AC output power typically have to be connected to MV grid. Therefore you need a MV
transformer as interface to the grid. The German BDEW has compiled a technical guideline for energy generating systems
connected to the MV grid. Other countries have (or will have) similar directives. In this directive it is stated how PV systems
have to contribute to the grid management.
medium to large scale solutions based on TLX Pro | Application Paper | may 2011 | 9
3.
3.4.1 Ancillary services in medium voltage grid system
The requirements from grid suppliers have recently been expanded in several countries. For all PV power plants connected
directly to the MV grid, it is now commonly seen that there is a requirement to support the grid stability. Thus for counties
with such requirements it is possible to select a country setting, (indicated by “MV”) during inverter setup. Once selected
the relevant ancillary services will be activated. Depending on the type of ancillary service required you may need external
input to control them. For this purpose the Grid Management Box must be connected. The Grid Management Box is an
interface between the DNO’s equipment and the inverter network communication system, through which the parameters
and settings are controlled. To date, Germany is the country having implemented the largest number of support
requirements, including active power reduction, control of reactive power and support during grid faults.
Power reduction must be carried out both at excess frequencies and based on input from the DNO. Input from the DNO
to control the amount of power reduction is transmitted via a remote control signal, which ends in four relay outputs
determining whether 0%, 30%, 60% or 100 % of the nominal power will be allowed to be delivered.
Support of reactive power may be based on different schemes, which range from the most basic, with a fixed value of
power factor [fixed PF] or reactive power [fixed Q] to the power factor being automatically controlled as function of the
power [PF(P)] or as a function of the grid voltage [Q(U)].
To help the gird during error situations, the inverter must be capable of remaining on grid for a defined period, despite
the absence of grid voltage. During this period the inverter will continue to deliver reactive current, which will help to reestablish the grid voltage once the grid error begins to clear. The TLX Pro + inverters are able to support all the different
requirements when connected to the Grid Management Box.
3.5 Transformer station
When connecting to the MV grid a transformer station is needed. If there is adequate room available a stand-alone
transformer station can be placed centrally within the installation area. It can also be required or recommended to use
a compact transformer station outside the building carrying the PV system. For ground mounted plants this will be the
preferred solution. The transformers or compact stations are available in various standard sizes and are among the most
commonly used. They usually have short lead times. The stations can be ordered prefabricated, which will also reduce
installation effort and cost.
The use of a low-loss transformer reduces the nightly power consumption of the transformer to below 0.4% of yearly
production. Consequently, short circuit losses in the transformer have little effect on overall yield. In the medium voltage
area of transformers of up to 1000 kVA, outgoing feeder panels with HH-fuses can be inserted instead of the more
expensive power switches.
3.6 System approval for connection to MV grid
Generally you need approval to connect to the MV grid. You therefore need to contact your DNO for the procedure.
As an example, the procedure for connecting to the MV grid in Germany is explained.
In order for a PV plant to be connected to the MV grid in Germany a four-step procedure must be followed. The procedure
is outlined in the technical guideline from BDEW. First, the Plant Owner must apply to the DNO. The application must
include a data sheet and unit certificate for the inverter. Based on the application, the DNO will then inform the plant
owner about the amount of power that may be connected [SKV, ΨK]. Based on this information the owner can then erect
the plant, and a plant certificate can be prepared by a plant certification office. The plant certificate will include a grid
simulation of the plant. For this purpose the plant certifier will require a simulation model of the inverter, which can be
obtained directly from Danfoss, should the certifier not have one already.
3.7 Conclusion
The TLX inverters will ensure that the energy produced is supplied to the grid in accordance with all standards and
legislation without causing trouble in installation.
The inverter will always deliver a symmetrical output, and includes setting functionalities for compliance with all grid
regulations in the range of 17 countries.
Having designed the best solution for the application it is of interest to include monitoring of overall system performance
and status in order to verify that the investment performs as expected and to enable you to act before potential problems
escalate.
10 | medium to large scale solutions based on TLX Pro | Application Paper | May 2011
Communication and monitoring
Having spent time on optimising your PV system, refining it to harvest as much as possible of the energy from the PV
modules and feeding it into the grid you will also want to ensure the system continues to do so. Thanks to modern
hardware and sophisticated software, the TLX inverter range includes detailed data logging functionalities supporting
the desired monitoring. Whether you want to use a built-in or external solution TLX inverters provide multiple ways of
interaction:

Integrated Web server

External products
Depending on your preferred type of interaction different ways of communication may be relevant:

Ethernet communication

RS-485 communication

GSM communication
To aid both the interaction and communication processes in systems having multiple inverters various supporting
functionalities have been collected in what is know as Master Functionality.
Ancillary services requiring central control and input also use the communication system for distribution of the required
control signals.
In the following we will initially describe the communication possibilities that form the foundation for the different
interaction possibilities. These are subsequently described. Additionally the web server and master functions are covered
before accessory products are mentioned.
4.1 Monitoring options
For a power plant with an output level of several hundred Kilowatts, it is common practice to connect to the medium
voltage grid. Therefore a power plant system of this size must enable all grid support functionalities for medium voltage
grids. If the power plant is to be connect to the low voltage grid, only some grid supportive functions for low voltage are
required, i.e. power level adjustment (PLA).
The TLX Pro includes a cost-efficient solution to get logging and monitoring functionalities as it includes an extensive
web interface accessible via Ethernet. All individual and accumulated system parameters are accessible through the
master inverter, providing a single point of access to the entire inverter communication network where control and grid
management parameters can be set-up.
4.1.1 Integrated Monitoring, Ethernet communication
The TLX Pro is equipped with high logging capacity (Storage capacity is 34 days at 10-minute intervals). Logging intervals
may be changed (Every minute, 10 min or every hour).
The data logged in the inverter is accessed via a LAN connection to the inverter. The LAN network can be configured in
two ways:
a)
Direct access
Connect you computer directly to the TLX Pro master inverter via LAN:

Automatic Addressing (APIPA), no router, no DHCP

Local access from computer through Explorer or Firefox,
Providing you with an extensive administration and monitoring interface through the integrated Web server
b) Internet access
Connect a TLX Pro master inverter via LAN to a router, then to Internet; see figure.

Router with DHCP assigning IP addresses to hosts (inverters and computers)

Local access to inverters from local computer through Explorer or Firefox

Access to inverters from the Internet through Explorer or Firefox

Requires configuration of router NAT tables
Providing you with an extensive administration and monitoring interface through the integrated Web server, and allows
for data to be sent via FTP to a data warehouse service, or as e-mail to specified recipients
medium to large scale solutions based on TLX Pro | Application Paper | may 2011 | 11
4.
Data
warehouse
PV input
www
Inverter
Web user interface
3 × MPPT
LAN connection
LAN connection
Router
LAN connection
Grid
Management Box
Grid connection
3 × MPPT
Remote control device
K1-K4
Grid
3 phase
LAN connection
3 × MPPT
LAN network
Network Structure
✔
Daisy chain
✔
Star connections
✘
No rings!
Network structure
12 | medium to large scale solutions based on TLX Pro | Application Paper | May 2011
4.1.2 RS-485 communication
As alternative to the integrated monitoring a data logger or web logger (Comlynx range or a third-party unit) can be
connected to the inverter through RS-485 communication. These units are then accessible through a computer, for
monitoring. The RS-485 ComLynx protocol is open and free for download if you want to write your own communication
solution.
Data
warehouse
PV input
www
Inverter
Web user interface
3 × MPPT
RS-485 connection
LAN connection
WEB logger
Router
RS-485 connection
Grid connection
3 × MPPT
Grid
Remote control device
K1-K4
3 phase
RS-485 connection
3 × MPPT
RS-485 network
4.1.3 GSM communication
A TLX inverter may be upgraded with a GSM modem. This allows data to be transmitted through GSM to external data
warehouses or as SMS.
Note: In inverter networks with TLX Pro inverters only the defined master inverter need upgrading with the GSM Modem
4.2 Web server
Through the Ethernet network the logged data can be accessed by using the Web server, which is included in all TLX Pro
inverters. Once the network has been established, all you need it to do is to open a browser (Explorer or Firefox) and type
in the inverter name in the address field. Via the Web server, you can access all relevant parameters, however, faster, easier
and more illustrative than through the display.
The Web server allows you to monitor or change:

Inverter/plant setup

Power plant status

Show graphics and curves (yield, or reduced CO2 emission, etc.)

Set up communication (e-mail or SMS to recipients)

Dynamic language selection between eight languages
In addition, the data can be exported in different forms, and data analyses and comparisons can be performed.
medium to large scale solutions based on TLX Pro | Application Paper | may 2011 | 13
4.3 Master functionality
TLX Pro inverters feature a Master/Follower function. Every TLX Pro inverter can be defined as a master inverter with
unidirectional control over one or more inverters.
With master functionality, setup, commissioning, monitoring will be significantly simplified, as it allows you to:

Collect and summarize data from entire inverter communication network

Upload data to data warehouse service

Distribute emails or SMS

Replicate data from Master inverter to followers (inverter/plant set-up)
4.4 Comlynx Datalogger
For extra storage capacity the PV installation may be equipped with external logging units, using the RS-485
communication network.
You thereby obtain between 1.5 – 4 years of storage capacity and communication based on the RS-485 protocol.
Danfoss offers a range of data and web loggers in the ComLynx range.

ComLynx Datalogger and ComLynx Datalogger +, which is equipped with a sensor interface

ComLynx Weblogger with a matching sensor interface
The Comlynx range translates and transmits all important parameters (yield, inverter events, etc) from the inverter to a
computer or a modem for remote access.
In addition to Danfoss Comlynx range, several other monitoring solutions are compatible with Danfoss solar inverters.
Consult your supplier for the proper application.
4.5 System accessories
4.5.1 Grid Management Box
The Danfoss Grid Management Box is designed to support the master functionality of the TLX Pro and TLX Pro+ inverter
to meet today’s dynamic grid requirements. After receiving the control signal from grid (DNO), the Grid Management Box
translates the commands to the master inverter, which then perform the following as needed:

Reactive power exchange

Power level adjustment
Note: The Danfoss Grid Management Box is only applicable with TLX Pro and TLX Pro+, and the grid management function
of TLX Pro and TLX Pro+ can only be used through the Danfoss Grid Management Box.
The following schema shows the position of the grid management box:
Remote control device
K1-K4
Danfoss Grid
Management Box
Ethernet
Grid Management Box Network
14 | medium to large scale solutions based on TLX Pro | Application Paper | May 2011
Ethernet
Ethernet
4.5.1 Router
In order to enable communication between the internet and inverters, a router should be used for “traffic directing”
functions, i.e. a router with DHCP assigning IP addresses to hosts (inverters and computers). A configuration of the router
NAT tables should be performed.
Home or small office routers are insufficient for medium and large scale commercial installations due to the amount of data
traffic. A professional router must be employed, which is capable of handling the data amount. In order to properly match
the application and ensure correct set-up you need to involve a network or IT specialist.
4.5.2 Sensor kit
Sensors can be connected directly to the sensor interface integrated in the TLX Pro master inverter. External sensors are
used to provide sophisticated monitoring of ambient conditions for accurate calculation of performance.
Danfoss offers a sensor kit including:

Irradiation sensor

Module temperature sensor

Ambient temperature sensor
4.5.3 Energy Meter Sensor (S0)
Input from an energy meter is supported according to EN62053-31, Annex D. S0 is a logical count input.
The energy meter input is presented via the display, Web server or external monitoring solution.
4.6 Conclusion
The monitoring options allow you to actively follow the PV installation, whereby potential problems can be identified
quickly. If service is required, troubleshooting is easy to perform as the detailed system overview allows you to narrow
down the potential causes. With integrated monitoring solutions you get the advantages of a full monitoring system,
without the hassle of having to connect more units.
All grid management tasks are also handled through an integrated solution from a single supplier.
Easy installation and as simple cabling and handling as possible, is something, which is always top of mind
medium to large scale solutions based on TLX Pro | Application Paper | may 2011 | 15
5.
Installation
The low weight and small dimensions of string inverters allow for easy positioning of the unit within the space already
available in/on the building or ground mounting structure.

35 kg

700×525×250 mm
TLX inverters with IP54 enclosures are suitable for outdoor installations and need no extra shelter when mounted in the
shade. However, an inverter can also be mounted inside a building provided that it is in a well-ventilated room. If the plant
is located at an elevation above 1000 m, additional considerations must be taken into account regarding the layout factor
in order to compensate for the lower cooling effect, resulting from the thin air.
5.1 Inverters locations
For roof top systems an installation location inside the building that carries the PV system is often preferred. Using TLX
inverters you only have two or three pairs of DC cables throughout the building per inverter. However some types of solar
modules demand a higher number of strings. In such cases it is possible to connect pairs of strings in parallel by using
Y-connectors at the PV array. For ground mounted installations mounting the inverter under the modules is advisable, as
the modules can provide shelter from direct sun and rain.
5.2 Cabling
5.2.1 AC
Standard AC cables with cross-sections of up to 10 mm² can be connected directly to the inverter. This enables 15 kVA
inverters to span distances to the feed-in point of up to 60 m without increased cable losses. Smaller cables with crosssections of 6 mm² or 4 mm² can also be used. The cables must be 5-wire cables.
5.2.2 DC
In most cases, standard PV cable with a 4-mm² or 6-mm² cross-section is the best choice to connect the module strings
to the inverter. Reasonable cable losses are kept if you use 4 mm² or 6 mm² cables over total distances of up to 100 m or
300m respectively. Another cost-saving opportunity lies in the option of connecting all strings of one inverter in parallel.
After the parallel connection of the strings at the PV array, you can span distances of several hundred metres using a pair
of standard DC copper cables with cross-sections of 25 mm² or 35 mm². The inverter will subsequently operate in parallel
mode, once you divide the power between all DC inputs of the inverter
5.2.3 Communication cables
Ethernet connection requires:

Cat 5 cable

Between a TLX Pro inverter and a computer /internet

Between TLX Pro inverters
RS-485 connection requires:

Cat 5 cable

Between a web-logger and an inverter

Between inverters (note: no Pro functionalities)
5.3 Conclusion
The easy handling of the TLX inverters means full flexibility in installation location.
The complete system; perfectly designed, installed and monitored will be encompassed by the security of the Danfoss
service system.
16 | medium to large scale solutions based on TLX Pro | Application Paper | May 2011
Service/reliability
6.
String inverters have the benefit of being commercially available standard component. Unlike central inverters, special
training is not required to be able to install, maintain or exchange string inverters. The local electrician can maintain the
string inverter installation, meaning that service contracts requiring specialists from the inverter manufacturer are not
required. For service purposes, backup of settings and data is available in the inverter display enabling a quick exchange.
Furthermore, by omitting junction boxes, no service on the DC side is required.
The availability of the installation is very high as only a smaller part of the system will be affected if modules or inverters
should fail.
However, if any problems or issues arise Danfoss’ extensive service network ensures the installation is taken care of.
The service hotline is available during normal business hours. Service is offered in five languages – English, German,
French, Spanish and Italian – and the service personnel know exactly how to provide the technical support you need.
If an exchange inverter is required, we guarantee that it is shipped as soon as possible and within no more than 24 hours.
If the service issue cannot be solved by our Hotline guidance or by an exchange of inverter, On-Site service teams are
prepared for the task, which is initiated within 24 hours. The service teams consist of experienced technicians with special
training in solar inverters and PV systems.
The standard warranty is five-years extendable to ten years.
medium to large scale solutions based on TLX Pro | Application Paper | may 2011 | 17
18 | medium to large scale solutions based on TLX Pro | Application Paper | May 2011
medium to large scale solutions based on TLX Pro | Application Paper | may 2011 | 19
Functionalities
Relevant grid type
TLX
TLX+
TLX Pro
TLX Pro+
x
x
Ethernet communication
Master functionality
Distribution of settings
Software update from master inverter
Data upload
Inverter setings backup
Integrated logger
Storage capacity
Interface for sensors
x
x
3 days
3 days
34 days
34 days
x
x
x
x
x
x
Ethernet communication
Included monitoring
Web server
Alarms
RS-485 communication
Comlynx monitoring
Data upload
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
Alarms
RS-485 communication
3rd party monitoring
Data upload
Alarms
GSM modem
Ancillary services using
master functionality and
grid management box
Ancillary services
using none or
3rd party product
Data upload to FTP servier
Data upload through master inverter
PLA
LV/MV
P(F)
LV/MV
x
PF
MV
x
Q
MV
x
PF(P)
MV
x
Q(U)
MV
x
Fault Ride Through
MV
x
PLA
LV/MV
P(F)
LV/MV
x
x
PF
MV
x
x
x
Q
MV
PF(P)
MV
Q(U)
MV
Fault Ride Through
MV
x
x
x
x
x
x
x
x
Danfoss Solar Inverters A/S
Ulsnaes 1
DK-6300 Graasten
Denmark
Tel: +45 7488 1300
Fax: +45 7488 1301
E-mail: [email protected]
www.danfoss.com/solar
DKSI.PK.21.K1.02 Produced by PE-MMSC ©
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