Upgrade of Eraring Power Station Turbo Generators from 660 MW to 750 MW

摘要

Eraring Power Station is a black coal fired power station 130 km north of Sydney Australia. Commissioned in the early 1980's with four 660 MW units, the power station has maintained very high availability with mid-merit output loadings. As the plant approached 25 years old, asset reviews focused on options for life extension and potential for up-rating the installed plant, also taking account of obsolescence in installed systems and plant. It was apparent that the majority of original electronic/electrical systems required upgrading or replacement with new technology. The majority of common station plant had sufficient capacity for increased output. Major engineering studies determined the potential up-rating possible and work scope for the unit plant. There was an iterative process of examining the major areas of Boiler and Turbine plant to match steam production and steam handling capability, and to increase plant capacity and efficiency. Unmodified plant limitations were reviewed against the new upgraded limits. Existing plant condition was also considered for mid life refurbishment or replacement. Modelling of major electrical power systems was performed for plant upgrade proposals, focusing on capacity, voltage drops and fault levels. The generator stator winding was redesigned and replaced in-situ to give 750 MW, 833 MVA, 0.9 pf capability. The existing generator was 660 MW, 776 MVA, 0.85 pf. The increase in MW output has been achieved with a reduction in MVAR capability due to economic considerations in avoiding an upgrade of the existing generator rotor and generator transformers. There were significant mechanical upgrades to Turbine and Boiler plant which have increased unit maximum continuous rating from 660 MW to 720 MW, with peaking to 750 MW possible. Generator excitation, protection and transformer coolers were also upgraded.