Enhanced security-constrained OPF with FACTS devices

The features of the new electricity market with the presence of many different operators lead to a new interest in the congestion management. The changes to the market-clearing point schedules required by the presence of bottlenecks in the electric grid can be strongly reduced if flexible ac transmission system (FACTS) devices are suitably installed in the transmission system with the aim of redistributing real and reactive power flows. Their optimal setting and operation mode can be determined by the use of customized security-constrained optimal power flow (SCOPF) programs. This paper deals with the use of FACTS devices as control variables in a compact and reduced SCOPF formulation, focusing on the definition of their control regions and on a new procedure implemented to find a global solution without sticking on local minima. The application of the new SCOPF procedure to a real system is also presented.