Online Early Warning Model for Cascading Failure in Complex Power Grid Under Severe Weather
Jianli Zhang · Power System Technology · 2012
Even though the main sturctures of power grids are strengthened increasingly,due to complex weather conditions of the partial corridors for main transmission lines of regional power networks the severe weather leads to the phenomena of 'failure aggregation' that makes the probability of occurring cascading failure in power grid greatly increased.By means of analyzing the meachnism leading to cascading failures under severe weather and combining with the small world theory,an online early warning model for cascading failures in complex power grid under severe weather was proposed.Through the analogy of sandpile model with powr system a concept of 'critical line' was put forward,and utilizing self-organized criticality of power system the constraint to judge whether a transmission line was in a critical state was given,and by means of examining the change of partial components cluster status of power system it could be prejudged whether there was the trend that the whole system might enter into self-organized critical status.Analysis results showed that the long range connectivity line was the main path along which the cascading failure was propagaeted,and it was proposed that the long range connective line could be defined by line betweenness.Both the correctness of the proposed method and the effectiveness of the proposed early warning model were verified by simulation results of a certain regional power grid in China.The proposed early warning model can search out the long range connectivity line in critical line set and deliver early warning to the dispatcher to prevent the occurrence of cascading failure.