Siemens helps JEA keep the waters flowing in Northeast Florida

Siemens helps JEA keep the waters
flowing in Northeast Florida
Electricity, water and sewer services for the
residents and businesses of Northeast Florida are
served by the municipal-owned utility called JEA.
Established by the City of Jacksonville in 1895, JEA
grew from a department of city government to an
independent energy authority created by the
consolidation of city and county governments in
1967. Thirty years later, the water and sewer
systems operated by the city since 1880 also
became part of JEA’s service offerings.
Today, JEA is the largest community-owned utility in
Florida and the eighth largest in the U.S. With a total
generating capacity of about 3,050 megawatts, JEA
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serves more than 417,000 electric customers in
Jacksonville and parts of three adjacent counties.
JEA’s water system serves more than 305,000
water customers and 230,000 sewer customers
in Northeast Florida. Its water system consists of
134 artesian wells that tap the Floridian Aquifer,
one of the world’s most productive aquifers.
Water is distributed through 35 water treatment
plants and 4,208 miles of water lines. More than
3,760 miles of collection lines and seven regional
and eight non-regional sewer treatment plants
make up the JEA sewer system.
Challenge:
Modernizing an
outdated pumping
control system for
JEA’s waste water
collection system’s
lift stations and
treatment centers
According to Darren Hollifield, JEA’s manager of Access and Control
Systems, the existing pumping control system for the 1,273 lift
stations that keep waste water flowing through 14 treatment
centers was simply outdated. “The current system was designed and
engineered in the middle 1990s,” he said, “and technology has
changed a lot since.”
The data concentrators are Modbus master pollers, each featuring
eight master channels. Each master channel, in turn, can poll up to
100 Modbus slaves. The communication path uses inverse
multiplexing over fiber equipment on each end from JEA’s Systems
Operations Control Center (SOCC) to each remote station’s master
radio over narrowband, spread spectrum radio.
JEA uses the lift stations throughout its sewage system to manage
storm water flows and pump wastewater from homes and
businesses to its treatment centers. Also, JEA continues to acquire
adjacent water systems and work with current septic tank owners to
connect to JEA’s system. As a result, they will need to add more
pumping capacity and communications capabilities in the future
among its existing and any newly built remote lift stations.
Pat Harwood, the control system’s technician, explained that with
the current system, verifying communication between the data
concentrators and the remote lift stations is primitive. “We do it by
checking a counter which is always changing and incrementing or
resetting the counter, if a certain value changes or does not
change.”
Hollifield explained that JEA’s current SCADA (Supervisory Control
And Data Acquisition) pump control system consists of multiple
operator interfaces; two input/output servers (primary and backup);
seven data concentrators using Siemens S7 416-2 PLCs; and 32
master radio sites. Most of JEA’s remote lift stations use Siemens S7
200-series PLCs, while about two dozen lift stations use the Siemens
S7 300-series PLCs.
Such limited, one-way communications prevents Pat and his team
from conducting remote diagnostics or doing remote programming.
As a result, each time a lift station has a problem or needs a
software fix, patch or upgrade, a technician needs to be dispatched
at a typical cost of several hundred dollars.
Pat Harwood also noted that communications are only updated
when the Modbus polling device requests data and the more
Remote Terminal Units (RTUs) on a channel, the slower the update
times are. If communications with the RTU is lost, the RTU has no
buffering capacity to hold its data until communication is restored.
Solution:
A Siemens
SIMATIC S7-300
PLC with SINAUT
Telecontrol
and SIMOCODE
pro motor
management
and WinCC HMI
Working both with its distributor AWC as well as with Hollifield, Pat
Harwood and other JEA team members, Siemens developed an
advanced and comprehensive solution based on the proven SIMATIC
S7-300 PLC platform and the SINAUT ST7 telecontrol system using
Profibus. Each lift station’s PLC is also integrated with Siemens
SIMOCODE pro intelligent motor management system.
The S7-300 PLC system provides local logic as well as data collection
for the SINAUT ST7. It is also the PROFIBUS master for two
SIMOCODE pro systems. The two SIMOCODE pro systems provide
motor overload protection, local I/O to read in the analog well level
and the digital floats’ signals. If the PROFIBUS connection is lost
between the SIMOCODE pro and the PLC, the SIMOCODE pro
provides redundancy and can take over full control of the pumping
operation until the network is restored. SIMOCODE pro also provides
key diagnostic and operational data that is eventually sent to the
control center. This includes power measurement data that is
recorded and sent to the SCADA system, which is used to evaluate
energy savings projects and control strategies.
The SINAUT ST7 extends the SIMATIC S7 automation system by
integrating special hardware and software components that enable
remote data transmission. This interconnects the SIMATIC S7 CPUs
with one another through a Wide Area Network (WAN) and with the
SINAUT ST7sc Control Center System that provides fully automatic
monitoring and control of the lift stations from the master control
center.
The SINAUT software in each lift station provides event-driven
process data transmission between each lifting station PLC’s CPU
and with the control center. Now, for example, Harwood and his
fellow technicians can see connection failures, disrupted CPUs or a
disrupted control center on PC displays via the Siemens WinCC PCbased SCADA software. It updates data automatically after a
problem is corrected or after an RTU’s CPU or the control center is
restarted.
Date and time throughout the network’s CPUs and control center
can be synchronized via a DCF77 radio clock or a GPS (Global
Positioning System). Either way the systems always have the exact
time of day. Also daylight-saving/standard time is switched
automatically. Time stamped data messages or automatic
scheduling of program starts are therefore standard features of the
system.
A Siemens DC UPS system also provides backup power to retain
communications to the lift station if 480VAC power is lost for
example during storm conditions.
Results:
Much improved
communications,
lower operating
costs and lots of
scalability for
the future
The Siemens SIMATIC S7 solution has helped Hollifield and Pat
Harwood realize their goal of designing new control cabinets for the
lift stations that cost the same or less as the old ones but with a lot
more capabilities, especially communications. Their deployment
plans involve migrating a lift station’s cabinet controls to the new
Siemens SIMATIC S7 platform when an existing unit fails; when
upgrading selected stations; or when building new remote stations.
One of the most beneficial aspects of the solution comes from the
SINAUT ST7 telecontrol system. “Now that we have two-way
communications capabilities with the SINAUT ST7, we can get
exception reports when something goes wrong,” said Hollifield. “We
also can do remote diagnostics, software upgrades and other fixes
and maintenance that would otherwise have to be done onsite by a
technician. And we can do it without losing communications with
any other RTU on the system.”
Energy savings is realized by optimizing hydraulic control. Pump
stations are controlled so that they run in concert and not pumping
against each other. SIMOCODE pro can measure motor current,
voltage, apparent power(kVA), active power(kW), power factor(%)
and power consumption(kWh).
The system automatically compiles complete diagnostic logs of all
communications between the central control system and the remote
lift station along with details of the type and time of any failures,
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which helps shorten troubleshooting times. Updating the remote
PLCs is much improved because individual messages can be
automatically triggered by an exception report or by a predetermined event or time parameter.
He added that if a problem does require a technician’s visit, remote
diagnostics can provide a much better idea of what the problem is,
so they can dispatch a technician with the right skill set and with the
right parts and tools. This can save the monetary costs of “truck rolls”
as well as the environmental costs of burning gasoline.
Inside JEA’s remote stations, the intelligent SIMOCODE pro motor
management system can keep the pumps working even if the PLC
control network goes down. “SIMOCODE pro provides us with peaceof-mind because those pumps need to be working 24x7,” said Pat
Harwood. “With SIMOCODE pro, there’s also a lot less wiring costs
and its power management features can help us cut our energy
usage up to 20 percent.” In fact, less wiring brought down the overall
project costs by 30 percent, almost enough to pay for the upgraded
system.
Going forward, Hollifield and Pat Harwood are confident that the
Siemens S7-300 platform’s scalability will meet JEA’s growing needs
to build more remote lift stations and upgrading existing ones. At
the same time, they both are excited about the potential to optimize
their control system’s operations to achieve greater efficiencies,
lower costs and save energy.
Subject to change without prior notice
Order No.: GCCS-JEAWW-0211
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© 2011 Siemens Industry, Inc.
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