210 MW Siemens Gas Turbine Power Plant1. Introduction The plant comprises of two oil fired gas turbines each rated at 105 MW each. The plant was commissioned in 1982 to 1983 and from 1995 to 2004 both units were mainly used for peaking and fast start purposes. The GT2 was decommissioned in 2005 and GT1 still operates as a fast start unit. The gas turbine has a nominal generation capacity of 105 MW each at site condition (average temperature of about 30 degree C) and has been operated with distillate-oil as the only fuel. It generates at 10.5 kV, and transmits electrical power at 66 kV via a generator step-up transformer (a new or re-used step up transformer will be installed to suit the local transmission voltage and vector group requirement). The station’s auxiliary voltage is 6 kV and it can receive its incoming power either through back-feed from the grid or a separate station transformer depending on the requirement and grid connection. It is also equipped with black-start diesel engine generator to allow for total black-start conditions (as an option). The main equipment is listed in Figure 1. 2. Gas Turbine and Generator The GT is a Siemens V94.2 heavy-duty gas Turbine. It is of single-shaft, single casing design, equipped with 2 silo-type combustion chambers, a 16-stage compressor and a 4-stage turbine. An air-cooled generator, rated at 125 MVA and generating at 10.5 kV is driven from the cold (compressor) end of the GT unit. The unit is currently installed with dual fuel Siemens diffusion-type burners, capable of operation on distillate-oil liquid and natural gas. Currently the gas turbines operate primarily on distillate-oil liquid fuel but with minor modification, it is able to operate on natural gas. Figure 1: Main Equipment Fuel Specification The GT currently operates only on distillate-oil liquid fuel. Figure 2 illustrates the typical distillate-oil fuel specification that the GT unit currently operates on. Figure 3 illustrates the typical natural gas fuel specification that the GT unit can also operate on. It has further been confirmed by Siemens that this class of gas turbine can operate on 100% bio-diesel (i.e. B100) 3. Overview of Past Operation and Maintenance As the units were meant for providing quick power during an emergency, the maintenance on the GT units have therefore been performed to achieve consistently high levels of availability, peaking capability and reliable start-up. Most of the scheduled inspections on the GT unit is typically performed at 18-month intervals or 4000 EOH, whichever is earlier, and cover the following scope: General inspections of GT thermal block Renewal of air filter elements Inspection and renewal of flame tube tiles (where required) Inspection and repairs to air-filter house and exhaust diffuser/stack A major overhaul on PPGT2 was carried out in October 1992. 4. Overview of Performance GT2 An overview of the performance of GT2 is described in this section. The GT unit has been operated primarily as peaking unit to meet the peak electrical load demands from local electricity pool. Even though the plant was commissioned in 1983, its total service hours and equivalent operating hours (‘EOH’) to date are considered low for plant of its age. Figure 4 summarizes the total service hours, EOH and number of starts performed by the GT unit during the period from Financial Year 1997/1998 to Financial Year 2005/2006. There is no differentiation between hot, warm or cold starts from the stand point of equivalent operating hours. Figure 5 and 6 highlight the historic availability and forced outage rate achieved by the GT unit.
Report "210 MW Siemens V94.2 Gas Turbine Power Plant"