Method of Judgment and Control Decision of Voltage Instability in Electromechanical Transient of Power System

Electromechanical transient process of power system was one of the important problems threatening the safety and stability of power system. The judgment of transient voltage instability and the automatic search of control measures for voltage problems were important for the actual operation of power system. Combined with the dynamic characteristics of transient voltage instability in power system and artificial experience in simulation analysis, a method of voltage instability judgment and control decision-making were proposed based on oscillation center identification, low-voltage area identification and bus voltage shape analysis. Firstly, the local topology of the power grid was analyzed to find the load area. Secondly, the voltage of load node was statistically analyzed to find out the low-voltage region, and the voltage shape of the load node in the low-voltage region is analyzed. At the same time, the oscillation center of the power grid was calculated, and whether it is voltage instability was judged according to the voltage form and oscillation center of the load low-voltage region. Then, the low-voltage area of load related to voltage instability was handled, and the auxiliary control measures to be selected were formed by adding dynamic reactive power compensation device or cutting off load. Finally, the feasible auxiliary control measures are determined by simulation. It was shown by the simulation based on the actual power grid that the method could simply and practically provide effective auxiliary control measures, which put forward a new idea in the automatic judgment and decision-making of transient voltage problems in power system.