Frequency Control in Competitive Electricity Market Dispatch

The dynamic and inertial characteristics of electricity systems are evolving with consequences for system frequency control. This issue is particularly important for smaller, more isolated electricity systems, where simple heuristic reserve targets may no longer be sufficient to ensure the security of the system. In a market environment, this issue needs to be dealt with in a systematic way that is compatible with the method of market dispatch to ensure least-cost operation of the system. This paper describes how frequency control constraints can be derived and included into a market dispatch algorithm. Comparisons are made with a conventional reserve target dispatch approach for a real isolated power system. The impact on market prices, cost, and the number and size of problem contingencies is assessed. The effect of increasing amounts of wind capacity is also examined.