POWER October 2013 - 20

Replacing Multiple Turbine
and BOP Control Systems
with a Single Platform
Termoyopal, a utility based in Bogota, Colombia,
recently repowered its power plant
at Yopal, Colombia, by replacing three gas
turbines with refurbished units and upgrading
the remaining two turbines. The
repowering employed three GE Frame 5
gas turbine generators, which were relocated
to this site from the U.S. following
mechanical refurbishment. Termoyopal
had successfully operated the existing
units for many years and its staff were already
very knowledgeable in the operation
of the plant, as well as the advantages and
disadvantages of their existing turbine and
balance-of-plant (BOP) control systems.
The arrival of the replacement units
presented Termoyopal with the opportunity
to resolve issues its staff had
identified with the original units, while
rationalizing the control and operation
of the entire plant. Termoyopal especially
wanted to simplify its personnel training
and parts inventory requirements, while
at the same time gaining improved access
to plantwide data and maintaining
a high level of reliability and control.
Turbine Technology Services (TTS) undertook
a consolidation of a majority of the
disparate systems onto a single platform.
The goal was to modernize and simplify
the entire plant control, increasing the
available system data, while offering an
interface tailored to the operators' and
maintenance engineers' specifications for
plant operations.
Beginning in the fall of 2011, TTS began
the installation of what was to be the first
of five turbine control, generator control,
and BOP programmable automation controller
(PAC)-based systems.
The original control systems for these
units consisted of a mix of legacy GE MKIIs,
MKIV, and third-party Modicon-based
programmable logic controller (PLC) control
systems. In addition, each gas turbine
had its own gas conditioning skid with a
PLC-based controller that was not standard
between skids. To add further complication,
in the neighboring gas plant that
was the primary gas supply source for the
power plant, Termoyopal had a primary
gas-conditioning skid (for controlling the
gas supply pressure and removing liquid
condensate from the fuel) that also had
its own PLC system that was isolated from
the gas plant and power plant distributed
control systems (DCSs).
With this daunting variety of control
systems, Termoyopal's maintenance
personnel needed to be proficient with
several programming languages and
hardware platforms. They also had to
maintain an inventory of spares for each
system type.
System Upgrades
At the core of the system upgrade performed
by TTS was Rockwell Automation's
PlantPax system, which provides a scalable
architecture for easily adding process
components, both hardware and software.
Cybersecurity was a top priority for Termoyopal,
and the PlantPax system allows
for all of the Rockwell control products to
be easily integrated into the plant's secu1.
Unification. The upgraded HMI allowed a unified view of the upgraded system, such as the gas fuel system with electric valves shown
here. Courtesy: Turbine Technology Services
20
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POWER October 2013

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