The Study Of Steady State Voltage Stability And Control Strategy Of Microgrid For Multiple Virtual Synchronous Generators

Energy crisis and environmental pollution is worsening, so that people’s eyes turn to new and renewable energy sources. Currently, it is recognized that a single centralized power system can not meet the needs of human development because there were several major blackouts. Under the dual pressures, microgrid power industry becomes a new trend of development. The study of microgrid voltage stability has become one of the hot issues.Firstly, this paper discusses the type of distributed power and analyses the node type of inverter which use virtual synchronous generator control strategies in the microgrid power flow calculation. Then shows a typical microgrid model with multiple distributed power which use VSG(Virtual Synchronous Generator) control strategy.Secondly, this paper derived the voltage stability index based on power flow calculation of each branch. This criterion needs not calculate equivalent’s network loss. Proved this criterion is necessary but not sufficient condition. Then it derived a voltage-stability discrimination based on V-I characteristic and proved this criterion is sufficient condition. Discuss the relationship between these two voltage stability index and proposed processes for microgrid static voltage stability discrimination.Finally, because of the randomness of wind speed, light intensity and load, the paper introduces a stochastic model of wind power generation system, photovoltaic cell and load. And stochastic power flow is calculated by Monte Carlo simulation in this paper.Then tatic voltage stability is analyzed in this paper. Through the analysis DG(Distributed Generation) used different VSG control and DG access different locations. The paper proposes a method to effectively improve static voltage stability of microgrid branch.