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Gas Turbine Systems
Owners of gas turbine driven generators built in the 1960s and 1970s face the increasingly frustrating challenge of maintaining original equipment excitation systems that
are rapidly approaching obsolescence. Parts and services are becoming harder to find, while the costs of generation downtime continue to increase.
Basler offers prepackaged replacement voltage regulator systems, shunt static excitation systems and SSE-N-based voltage regulator systems, as well as other retrofit options for the Pratt and Whitney Single/Twin Pac, Westinghouse 191/251/501 and GE Frame 5.
Review the specifications of the DECS-400, DECS-300, DECS-200 and DECS-200N to choose the product that best fits your application.
Steam, Hydro or Engine-Driven Generators
As systems age, parts are more expensive and difficult to obtain, and it can be both expensive and technically challenging to find viable retrofit equipment options to
maintain a voltage regulator/exciter system on older steam, hydro or engine-driven generators.
Basler offers replacement options for the systems listed above that makes it simple to upgrade voltage regulator/exciter systems, supplied in either a NEMA 1 enclosure or engineered and factory tested panels for installation in existing cubicles.
Review the specifications of the DECS-400, DECS-300, DECS-200 and DECS-200N to choose the product that best fits your application.
For more information on system upgrades and retrofits, see the technical paper "Xcel Energy
Northern Region Experience with Excitation System Upgrades and Retrofits" from the EPRI Steam Turbine-Generator Workshop, August, 2005.
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Replacement of older equipment, such as this wire-wound rheostat, can reduce operating costs and produce gains in system
efficiency. |
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Rotating Exciter Systems
Increase reliability and flexibility while decreasing maintenance. See Application Note EX-RETRO for a summary of obsolete systems and the recommended replacement. Basler Electric can provide a static exciter regulator to replace difficult to maintain rotating exciters, including the systems listed above.
For applications that require negative field forcing, Basler offers the DECS-300 and DECS-400, that utilize
separate independent appropriately sized bridges.
Basler’s newest Negative Forcing Digital Excitation System, the DECS-200N, has been developed for machines with rotating exciters that
are brush or brushless, up to 30-40 MVA.
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Facilities with gas turbines requiring power system stabilizers benefit from Negative Field Forcing Voltage Regulators. |
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Unsupported Exciters and Regulators
After years of thermal aging, older excitation systems frequently develop cold solder joints on printed circuit boards, intermittent potentiometer misoperations, or other similar failures resulting in unwelcome
and unexpected forced outages. The cost of replacing the OEM circuit boards, if they are available at all - can approach or even exceed the cost of replacing the entire excitation system. Basler can help you
add a new digital AVR and retain the power SCR bridges, PPT, and AC or dc field breakers.
For a review of this option, read Selecting the Excitation System for the Additional Turbine Generator at the Port Wentworth Pulp Mill. This
paper covers the process involved in evaluating whether or not to reuse the generator's original compound excitation system and if replaced, the type of excitation system that should be installed, Compound
or Potential Bus Fed Type.
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Application Note EX-BRDG1 for details on upgrading high current static exciter systems
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Application Note EX-PUMP - The excitation requirements addressed by a subpanel or complete cabinet replacement for pump/generate units that include the rotating exciter.
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