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MidAmerican Energy Company, the largest
utility in Iowa, is strategically located in the middle
of several major markets in the Midwest. The company’s
Riverside plant, located in Bettendorf, Iowa, serves
dual purposes – it supplies power to the surrounding
community as well as process steam to a nearby plant.
The Riverside plant has a total of four boilers. The
130-megawatt power side of the plant utilizes one boiler
installed in 1961, while the process steam side has three
boilers (two produce 250,000 lb. of steam per hour; one
produces 200,000 lb. of steam per hour) that supply process
steam to an outside customer, all installed in the 1940s.
Typically, the process steam side runs two boilers, with
the third serving as a backup. |
For years, the entire plant’s process control system
operated on a single network that controlled approximately
2,500 I/O. However, having the two sides of the plant integrated
in this way was not the optimum arrangement, according to
Eric Prybil, project manager. “We needed to keep the
process steam side of the plant running 24/7, which made
it more difficult when we needed to do maintenance on the
power side,” said Prybil.
Fortunately, the plant’s migration from Emerson’s
WDPF technology to the company’s Ovation expert control
provided the perfect opportunity to create separate networks
for the power and process steam sides of the plant. “We
have wanted to do this for a while, and it made sense to
tie the reconfiguration into the migration project,” Prybil
continued.
Emerson: The Logical Choice
When MidAmerican first considered updating the legacy
control system at its Riverside plant with the latest
technology, Emerson was the logical choice for a
number of reasons. First, Emerson has designed,
delivered and maintained WDPF systems for more than
two decades; the company was uniquely qualified
to perform the WDPF to Ovation migration.
Furthermore,
it always has been Emerson’s philosophy to design
products with an eye toward the future so that customers
have a fast, efficient and cost-effective way to migrate
to Ovation’s advanced
open architecture. This philosophy makes it possible for
WDPF users to replace aging platforms and gain functionality
with minimal re-engineering. For MidAmerican, this translated
into a migration solution that was technically compatible
with their legacy WDPF system and also preserved much of
the company’s investment in field cabling, terminations,
I/O, logic, graphics and the database.
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“We knew that by migrating to Ovation
we could reuse our cabinets, I/O and other components,” said
Prybil. “Because we were aware of the benefits of migrating
to Ovation, we knew it was the way we wanted to go.”
During the migration project, Emerson replaced the plant’s
existing 12 WDPF controllers with Ovation controllers. Under
the reconfiguration, seven controllers running the power
side of the plant were placed on one network, while the five
controllers allocated to the process steam side were placed
on a separate network.
Emerson also replaced three existing PLC data links and
added one more data link to a remote I/O on the power side.
In addition, three existing dual-screen operator consoles
were replaced with a total of six dual-screen consoles – three
dedicated to each side of the plant.
During the migration project, Emerson
replaced the plant’s existing 12 WDPF controllers with
Ovation controllers. Under the reconfiguration, seven controllers
running the power side of the plant were placed on one network,
while the five controllers allocated to the process steam
side were placed on a separate network.
Emerson also replaced three existing PLC data links and
added one more data link to a remote I/O on the power side.
In addition, three existing dual-screen operator consoles
were replaced with a total of six dual-screen consoles – three
dedicated to each side of the plant.
A Customized Installation
The power side
of the migration project was pretty basic, according to
Prybil, taking place during a one-month planned outage in
the fall of 2003. However, because the process steam side
needed to meet its steam-supply commitment to the outside
customer, this portion of the migration project, which took
place Sept. 22-30, 2003, was completed while the plant remained
online.
“We have redundancy built into the system, so we
would take out a controller, change it to Ovation, then power
it back up,” said Prybil. “At times, half the
plant was running on Ovation, the other half on WDPF.”
Beyond maintaining MidAmerican’s investment, the
migration to the Ovation expert control system yielded additional
benefits in terms of a faster learning curve for operators.
Operators of MidAmerican’s Riverside plant attended
three-day training sessions on site, while the maintenance
staff participated in maintenance-specific training at Emerson’s
Pittsburgh location.
“One of the benefits of migrating from WDPF to Ovation
is that you’re not starting from scratch with a new
system – the graphics have the same look and feel,
for example,” said Prybil, who is pleased with both
the advanced technology of the Ovation control solution and
the technical expertise of the Emerson team that implemented
the project.
“The project went well – we’re happy
with it,” he said.
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