Optimal transmission planning based on quantitative security risk in uncertain environment

The present status of transmission planning is reviewed from various viewpoints and the new requirements of transmission planning resulting from development of electricity markets are discussed. In the deregulated electricity market, there is no longer centrally coordinated planning of new generation or closure of existing generation, which are basically at the generation companies´ own discretion, and price bidding of electricity market results in more uncertain injection power. Transmission system planning in the electricity market environment has to be confronted with much more uncertain factors. In order to ensure a flexible transmission system, this paper extends the transmission planning model, which considers both static security risk and dynamic security risk, to deal with uncertain injection power at the buses. A global optimization framework is developed to resolve the problems caused by the multi-object mathematical model and uncertain power injections. A numerical example is presented to illustrate the validity of the method.