Study On Risk Assessment Of Power System Based On Monte Carlo Method

The modern power system is large-scale, complex in the structure. Because of power system probability characteristic, both of the equipment components fault rate and the load will increase the uncertainty of the grid operating state. At the same time achieve better economic efficiency, the power system will be under enormous risks. In the recent decades, many voltage instability and voltage collapse incidents occurred in the worldwide. They are not only had great impact on the people’s life, but also caused tremendous economic losses. So the Risk assessment of power systems has been drawn great attention by researchers.First, this paper discusses the risk assessment of power system based on Monte-Carlo method. From the possibility and severity of accidents, it puts forward the risk assessment indexes. By using random sampling of Monte-Carlo method, it calculates the fault probability of branches for N-1 scanning; it carries out the N-1 fault scanning and risk assessment of power system based on Monte-Carlo method and continuation power flow method. It presents the maximum load power margin differences between the normal operation system and branch N-1 fault cases as the severity index of the voltage collapse risk, and the fault probability of the branches as the probability index. By considering the severity index and the probability index, it obtains the voltage collapse N-1 risk assessment indexes.Second, by random sampling on the running state of the transmission lines, it can determine the fault branch based on the math model of N-1 fault selecting randomly based on Monte Carlo method. It collects the fault branch randomly, then carries reactive power optimization, and works out the line voltage stability indexes LSI. According to the operation state of the lines, it not only can determine whether to carry out line maintenance measures and repair solutions, but also can eliminate hidden dangers of transmission lines promptly.Finally, it can provide decision support and information to make trading plan and risk prevention by analyzing the trading risk of the optimal power flow integrated with wind farm by using Monte-Carlo method.It takes IEEE 30-bus system and IEEE 39-bus system for an example. the simulation results show the effectiveness of the model and method.