Risk-constrained congestion dispatch in deregulated power systems

Congestion dispatch is a very important issue in the operation of electricity markets, and up to now much research work on this problem has been done. Most of this work is based on the assumption that the load demand is unchanged. However, the error in load forecasting is often unavoidable. In electricity markets, the demand fluctuation has to be balanced in the realtime dispatch, which would lead to higher purchase price paid by the power users due to the higher power price in the real-time market. For more economical social benefits, a new model to deal with load-demand fluctuation in the generation dispatch, and thus decrease the power amount purchased in the real-time market, is necessary. A new generation dispatch model considering the demand fluctuation and its method of solution are therefore proposed in this paper. To handle the security constraints in the dispatch problem, a risk-based security assessment method instead of the conventional deterministic one, which is used in most of the existing dispatch models, is utilized in the proposed model. A case study in IEEE 30-bus system illustrates the basic feature of the proposed model and method.