Methodology of security region and practical results

Some superiority of security regions is illustrated. Then we define the so called practical dynamic security region (PDSR) in power injection space which guarantees transient stability and the practical security region to guarantee static voltage stability (CVSR) in cut-set power flow space. Based on the above definitions, two important facts for practical applications are given. Finally, the paper explained why, based on the hyper-plane descriptions of the boundaries of the PDSR and CVSR, the computation burden of probabilistic security assessment of power system can be reduced dramatically and the difficulties of dealing with stability constraints in the problems of solving for optimal power flow and ATC can be overcome easily.