Transient analysis of a combined cycle power plant (CCGT) connected directly to the distribution network

Distribution networks in the UK have been designed in order that electrical power is provided by large scale generating stations via the transmission network. A distribution network typically operates at voltages up to and including 132 kV with the end customers directly connected. Legislations introduced by the present UK government state that 10% of the total UK energy should be provided from renewable sources, and 10GWe of combined heating power (CHP) should be provided by 2010. This will inevitably lead to a large increase in distributed generation in the UK by 2010. Distributed (embedded) generation is defined as that generation connected directly to the distribution network. The gas turbine is used extensively in these new schemes. It is commonly used in CHP schemes where use is made of the waste heat present in the gas turbine exhaust gases for industrial processes or domestic heating. A far more beneficial practice with respect to the distribution network is to utilize the gas turbine in a combined cycle gas turbine (CCGT) plant. This paper presents the results of the transient performance of a CCGT plant when connected to the distribution network (Chilvers (1)).