Research On Fault Point Location Method Based On WMAS In Power Grid

Nowadays, with the development of high speed communication network techniques, using the precise time scale of GPS, in order to realize the rapid operation state monitoring of power network, many areas of our country have installed the wide-area measurement system (WAMS)in power grid. In order to make full use of the function of WAMS, the research of fault location method in power grid based on wide-area measurement system has an important significance to implement the strategy of fast automatic stability control after fault taking place in power grid. Contraposing the sparseness characteristic of the measurement data of WAMS, in order to achieve rapidly detecting the disturbance point in grid, this paper puts forward an extraction method of disturbance variable in grid and a location method of using the waveform similarity of fault disturbance variable multi-point extracted in power grid to determine the fault place, and it has verified the accuracy and correctness of the methods through simulation results.The main research contents and results are as follows:1) An extraction method of fault disturbance variables in power grid is put forward, and the detailed practice is:using the measuring units that installed in different positions of power grid to separately measure the maximum and minimum values and the corresponding time of voltage variable during each period, and then sent the data to the monitoring center; In the monitoring center, with the data interpolation method, respectively fitting out the maximum voltage curve and the minimum voltage curve, then adding them, it will get the fault disturbance variable that can reflect the fault disturbance characteristics.2) According to the propagation characteristics of fault disturbance traveling wave in power grid, use the definition of the subsequence wave similarity function of disturbance wave between adjacent measuring units, a location method is put forward that using the waveform similarity of fault disturbance variable multi-point extracted in power grid to determine the fault place.3) Using the Matlab simulation software, simulation analysis models of single phase earth fault, three-phase short-circuit, the resistance ground fault and load shedding disturbance are respectively built, then did some simulation experiment analysis and the simulation experiment results have demonstrated the correctness of the presented positioning method.The theory analysis and simulation results show that the method needs few measuring unit numbers, which can not only save the investment and can quickly and automatically locate the fault point. In order to improve the WAMS fast detection function of fault in the power grid, it is helpful and valuable to ensure the safety of the power network operation.