Upgrading aging units: OEMs vs. Independents

The retrofit market for gas turbine (GT) and compressor control systems is poised for a major boom. Systems sold during the GT bubble of the nineties and early 2000s are ready for an upgrade, not to mention even older systems equipped with analog controls or electromechanical governors.

Clark Weaver, Manager of New Product Introduction, Wood Group GTS said, “The average life cycle of many OEM controls are in a 10- to-15-year time frame. Some sites are one failure away from being down indefinitely and are not even aware of it.”

The battle to serve this burgeoning market is being waged by OEMs, such as GE and Siemens, looking to persuade users to upgrade their original control systems, and independent suppliers, such as Wood Group GTS, Invensys, Tri-Sen, Young & Franklin and Emerson, offering users the option of switching to open, flexible architectures and newly manufactured replacements.

OEMs urge users to stay with their controls for the life of the turbine or compressor. The basic logic is that the hardware and controls are designed to work in harmony. As turbine and controls engineers work together, OEM controls can be counted on to work best on their own machines.

No alternative to expensive spares

Independents, on the other hand, argue that users of OEM systems may be deprived of software logic, have no alternative to expensive spares and support, and may be forced to comply with programmed life cycle management. Whereas, the open philosophy lets them support their units as they desire. They also claim to provide users with functionality and upgrade options that the OEM either resists, charges more for, or refuses to provide. Users can modify control functionality, they say, particularly as it relates to operations criteria or auxiliary controls to improve flexibility or deal with site specific issues that are hindering operations.

This, they claim, can be achieved without jeopardizing turbine safety or critical control and protection logic. Wood Group GTS, for example, has released a control system upgrade for the GE LM6000. The market potential is significant:

More than 1,000 LM6000s have been shipped since the unit was introduced in 1991. The Wood Group GTS system can replace the original LM6000 hardware and software whether it employs NetCon, Micronet, GE Mark V or GE Mark VI platforms.

Wood Group GTS uses the Rockwell Plant PAx process automation system, which has been installed in over 500 installations. It operates in a similar fashion to a

PLC-based system and can be expanded to plant-wide controls.

Similarly, ABB’s Symphony controls system is being used to upgrade Pratt &

Whitney FT8 TwinPac turbines located at Iberdrola’s Klamath Cogeneration Facility. The retrofit included the design and implementation of enhanced control logic and graphics, development of the advanced surge protection module, startup and commissioning.

More in January/February 2013 issue of Turbomachinery International