Control Engineering Online Update for July 16, 2004

By Control Engineering Staff July 16, 2004
Highlights Sponsored by Dice
Constellation Energy employs a two-step approach to its control system migration at three of its plants—replacing operator stations and controllers during planned outages.

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Constellation Energy employs two-step control system migration

In a migration program that began in 2002 and runs through 2005, Constellation Energy Group is migrating legacy process control systems at a total of six units at three of its Maryland plants.

By keeping a constant focus on growth and improvement, Constellation Energy Group has kept its doors open for more than 185 years. These two, long-held business strategies are also the principal drivers of Constellation’s ongoing program to migrate its older process control systems at several plants in Maryland.

When the migration program is completed next year, Constellation will have upgraded legacy control systems at a total of six units at three of its Maryland plants with the Ovation Expert Control System from Emerson Process Management Power & Water Solutions. At each unit, Constellation is migrating Emerson’s WDPF control systems to Ovation, a system utilizing commercially available (non-proprietary) off-the-shelf hardware, communications, and software applications. The Ovation system is design to provide a straightforward migration path for users of WDPF systems, allowing them to keep existing I/O cards, field cabling, terminations, and cabinets, as well as their control logic, graphics, and database.

Planning maximizes plant availability

Constellation is maximizing plant availability by installing the new controllers and operator workstations during regularly scheduled outages that occur on an every-other-year basis. Preparation for the onsite installation begins months in advance as WDPF graphics and logic codes are converted to Ovation’s advanced open architecture.

In its first WDPF-to-Ovation migration project, Constellation upgraded the process control system at Unit 1 of its coal-fired C.P. Crane power plant in Baltimore County. During a scheduled outage in June 2003, eight controllers, two data link servers, and eight operator workstations were replaced at the 190-megawatt unit. The new Ovation system was up and running in a few days, according to William Collins, Constellation control system analyst. “C.P. Crane Unit 2 is scheduled for a Fall 2004 migration, during which Constellation will replace eight operator stations, 11 controllers, and three data links, and upgrade its six-level DEH turbine control to Ovation,” Collins says.

Ovation controller integrates with existing I/O cards, field cabling, terminations and cabinets.

In the C.P. Crane Plant Unit 1 migration, all hardware (controller and operator stations) was replaced during one scheduled outage. At two other plants—H.A. Wagner Units 3 and 4 (with a combined capacity of 740 megawatts) and Brandon Shores Units 1 and 2 (with a combined capacity of 1,300 megawatts)—Constellation is taking a two-step approach to migration, in which operator stations were replaced during outages in 2002 and 2003 (Phase One) and controllers are installed during outages taking place in 2004 (Phase Two).

Two-phased approach details

Constellation is using Emerson’s System Life Assessment Program methodology (designed to develop short- and long-term process automation strategies) to direct the two-step migration plan at H.A. Wagner and Brandon Shores.

At H.A. Wagner Units 3 and 4, Emerson replaced 12 operator stations (six per unit) in 2002, while 13 controllers (Unit 3) and 10 controllers (Unit 4) were replaced during overlapping planned outages in March 2004.

At Brandon Shores, 12 operator stations (six per unit) were upgraded in 2002 and 2003. In October 2004, Emerson will replace 18 controllers on Brandon Shores Unit 2; replacement of Unit 1’s 16 controllers is scheduled for October 2005.