Expert control unifies plant systems

Emerson Process Management has upgraded and unified combustion, turbine control and burner management systems at Pagbilao power station Units 1 and 2 with its Ovation expert control system.

Emerson Process Management has completed a project to upgrade and unify combustion, turbine control and burner management systems at Pagbilao power station Units 1 and 2 with its Ovation expert control system.

The 750MW plant, operated by Mirant Pagbilao Corp, is located in Quezon, Philippines.

Unifying the control systems has resulted in a number of operational and economic benefits for Mirant Pagbilao, including a more than 1% increase in plant reliability; a significant improvement in data acquisition, alarm monitoring and report management; and the prevention of forced outages and/or load restrictions that could have resulted in a potential energy loss of 16,800MWh per day.

Prior to the upgrade, the control architecture at Pagbilao Units 1 and 2 consisted of two primary control systems - Emerson's previous-generation WDPF distributed control system for boiler and turbine control, and a Diasys-UP system for burner management.

Mirant considered two options for the controls upgrade: Replacing both of the existing systems with an entirely new control system or migrating the existing WDPF system to the Emerson Ovation expert control system and replacing the existing burner management controls with the new Ovation system.

Mirant chose a WDPF-to-Ovation migration because of its successful experience with Emerson, the reliability of the existing WDPF system, and Emerson's history of long-term product support.

Designed specifically to meet the needs of the power generation industry, Emerson's Ovation system boasts a number of industry-leading advanced technologies.

These include the incorporation of embedded advanced control algorithms; a mission-critical, Fast Ethernet network for high-speed communication of plant information; the industry's most powerful controller with the fastest duty cycle available to optimise plant performance; and a full line of analogue, digital and special-purpose turbine and boiler I/O modules; among others.

From the beginning, Emerson designed the Ovation system to allow a straightforward migration path for users of its WDPF systems.

Emerson's migration path allows WDPF customers to retain much of their investment by allowing them to keep existing I/O cards, field cabling, terminations and cabinets; as well as their system engineering investment in control logic, graphics and the database.

This enables users to increase the functionality of their control systems in a cost-effective way.

"One of the many good things about the new Ovation system is that our operators have the opportunity to view and understand the SAMA-built control logic of individual operations", said Juanito M Sainz Jr, Technical Specialist, Mirant Pagbilao power plant.

"This feature, when thoroughly used, can prevent a major outage that both directly and indirectly impacts operations and maintenance costs".

Furthermore, the new Ovation Historian offers flexibility in the way in which data is presented, and enables process data to be presented in report format or communicated to several other plant systems via OPC-based connectivity.

With the OPC Server, process data from the historian is sent to Mirant's eDNA system which, in turn, broadcasts process data to remote stations and Mirant's headquarters in Manila, Philippines, and Atlanta.

The OPC server also exchanges information with the plant's Bently Nevada system, which is used for the turbine vibration monitoring system.

Data can be extracted from the Bently Nevada system and converted into an Ovation historical report.

Finally, the OPC server is also connected to a Wonderware system, allowing data exchange between the Ovation system and Pagbilao's sootblower system.

The new Ovation system has essentially centralised the functionality of several independent systems for data broadcasting, logging and reporting.

"Previously, data communication between the two control systems increased the level of risk involved in operation because of too many communication devices and protocols", explained Sainz.

"Now, operating the units is a lot easier".

"Nothing is better than having a single brand of control system".

"We know that no two power plants are alike, and so we work closely with our customers to develop migration strategies tailored specifically to their operational and financial objectives", said Bob Yeager, President of Emerson's Power and Water Solutions division, who notes that more than 200 WDPF systems have been migrated to Ovation technology.

"The benefits Mirant has experienced, coupled with the ease of the migration process itself, mirror the experience of other Emerson customers who have decided to take advantage of the latest control technologies".

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