GT26 Operational Experience under Changing Market Condition

摘要

Combined cycle power plants (CCPP’s) are highly efficient and do have a high flexibility in fast load changes and large load ranges still keeping low exhaust emissions. Under changing market conditions, particularly in Europe, they are more often used for shifting and peaking applications in order to compensate changes in power demand, e.g. due to supply variations of regenerative energy sources. The modified operation characteristic requires an extended operation range at high efficiency while keeping emissions within the limits. Furthermore, reliable and fast start up schemes and high load ramps are required to follow the demands from the grid operators. Under these conditions the gas turbine and combined cycle power plant design is challenged in terms of minimized life time consumption under all operation conditions. The advantages of the sequential combustion of the GT24/GT26 gas turbine family become more important for the increasing demand on high operational flexibility in the market. Particular the capability to operate with low emissions over a wide load range and high part load efficiency is privileged by the sequential combustion system. Operational experience of the GT26 fleet is permanently observed with respect to wear and tear on the components in order to adapt the design and the operation concept for a robust and reliable operation. Furthermore maintenance intervals and durations of inspections are continuously optimized in order to increase the availability. This paper describes the GT26 gas turbine operational experience under the changing market conditions, improvements in the operational flexibility, in particular the extended turn-down ratio and adaptions to the design and operation concept to cope with the changed operation profile of the gas turbine. It is of high importance to keep the efficient CCPP’s as long as possible in operation as they have demonstrated to be the best alternative to compensate for the varying power supply of the regenerative energy source with the lowest environmental impact under the conventional power plant technologies while providing the highest operational flexibility.