Transmission system congestion alleviation with consideration of bilateral contracts

This paper proposes a transmission congestion management by load shedding scheme altogether with adjustment of the transformer´s tap in the bilateral contract market. In this paper, it is assumed that an independent system operator (ISO) controls all transactions occurring in the system. It can curtail some transactions in case there exists a congestion problem in the power system, either voltage level violation or line overload. In the bilateral market, there is a special characteristic that is different from typical other power systems. When ISO curtails load, at the same time, it must consider reducing the generation of that transaction at the same amount. The proposed transmission congestion management method is based on the linearization and the quadratic programming techniques. It has been tested with the IEEE-RTS79 system. Satisfactory results were obtained.