Research On Transient Risk Assessment Of Power System Integrated With Large Wind Farm

Nowadays, Energy Conservation and Emission Reduction is encouraged in power system. As the development of wind power generation technology become more and more mature, wind power connecting to the grid has become the trend of The Times. However, due to the randomness and intermittent of wind power, we have to consider risks for power system brought by the wind power connecting to the grid. In particular, the transient security problem of power system can also not allow to be ignored. Therefore, in this paper, transient security risk problem of the power system with wind farm is studied.Risk assessment of the power system is to comprehensively consider the fault probability and the effect of system fault. Based on the definition of risk assessment, this paper studied operating state probability model of the power system with wind farm. Based on the Monte Carlo simulation method, operating state of the power system is sampled. With the purpose of improving the sampling efficiency and making full use of computing resources, this paper adopts the Monte Carlo parallel algorithm for sampling system operating state. Taking the IEEE 14 Node power system integrated with wind farm for example, this paper has proved that the Monte Carlo parallel algorithm could improve the sampling efficiency and reduce the simulation time.To judge the effect of system fault, in this paper, based on extended equal-area criterion(EEAC method), by transferring the influence of a wind farm on the power system into system operation parameters, the calculation method of transient energy margin of power system integrated with wind farm is given. The application range of EEAC method has been expanded. Based on the IEEE 39-node power system integrated with wind farm, this paper has compared critical clearing time between the motified EEAC method and time-domain simulation when the system operates in the same fault. The accuracy of the method in this paper has been proved.Considering transient energy margin of power system integrated with wind farm in a operating state as the index of system transient stability level and at the same time considering the processment of the sampling, the calculation system of average transient security risk indicators of the power system integrated with farm including the calculation and classification of the risk indicators is given in this paper. Based on the definition of power system risk assessment and IEEE 39-node system, the Monte Carlo parallel algorithm is applie in the sampling of the power system operating state and the motified EEAC method is applied in calculatin the transient energy margin of power system integrated with wind farm.According to the result of simulation, the influence of wind farm capacity, the branches and wind farm types on the power system transient security risks is studied. At the same time, based on the classification of the risk indicators, the level of power system transient security is given and system administrator can make right decision on the operation of power system. It turns out that the result in this paper is accurate and disirable.