Small Range Searching Method Of Dynamic Security Region For Calculating Probabilistic Insecurity Index

Modern electrical power systems characterized as high voltages, large capacity generators and highly inter connected grids, they will cause great expense to national economy and people's life once some serious faults happen. So, stability and security of power system are important research aspects for a long period of time.Dynamic Security Region (DSR) is based on modern nonlinear differential dynamic system and stability boundary theory. The"Region"method has developed a lot and become a comparatively mature method using for dynamic security analysis and assessment in electrical power system recently. The characteristics of DSR also show it is more available and practicable for on-line application.Probabilistic Security Evaluation (PSE) of composite generation and transmission system is one of academic frontier of the research on power system reliability. Without accounting for uncertainty factors in power system, the security measure of traditional deterministic security assessment is uncertainty itself, so the traditional deterministic security assessment should be replaced by probabilistic security evaluation.Power system dynamic security region (DSR) provides a powerful tool for power system probabilistic security assessment. It can often cause obvious deviations when calculate power system probabilistic insecurity index using present DSR searching method in large range. To solve this problem, a small range searching method of DSR, based on the fast attenuation characteristics of standard normal distribution function, is presented. A preliminary DSR boundary hyper-plane is estimated at first, and then a small range is determined, in which an approximate DSR boundary hyper-plane is calculated. This method improved present popular methods using in calculating power system probabilistic insecurity index whose results are either optimistic nor pessimistic, it supply feasible means of calculate probability insecurity index accurately and estimate the probability security of power system.The demonstration results of New England 10-generator 39-bus system indicate that the presented small area searching method is effective and feasible.