Study On Fault Line Selection Plan Of Huianbao Transformer Substation

Indirectly grounded power system is widely used in medial and low voltage distribution networks in the world (including the neutral point is not grounded, by the Petersen-coil or by high resistors), which is benefit to improve the reliability of power system, because its characters that fault current is low and the system can continue to provide power to load while single-phase ground fault occurs. There isn't existed an effective method to select the fault line nowadays, which has been an important task for the relay protection researchers of power system. It is difficult to detect the signals while single-phase ground fault occurs, because the fault current is small and the electricity arc is instability. With the research and development of power automation, it has become more and more important to verdict the fault line correctly and promptly by auto-mechanism.We usually break and closing each line in short-time to find the fault line traditionally, but it exist many unfavorable factors. Such as harmonic pollution, mechanical effects and so on. With the development of electronic technology and computer technology, people began to use computer to find fault line, put forward many fault line selection principles, and development auto selection device. The correct rate is very low because of many causations, it is hardly meet the requirements.A wealth of transient current component information are contains after the Power system fault. The characteristic components can not only improve the currency of line selection, but also ignore the influence of arc suppression coil. The wavelet theory can accurately analysis the discontinuous, weak and precarious fault signal, it can analysis the transient process and draw the fault characteristic. So the wavelet analysis theory is introduced to selecting fault in this article. We put up the system model of Huianbao transformer substation using MATLAB software and verify the theory's correctness and feasibility. In a detailed analysis of the operation of the device is inevitable after the interference, we draw a large number of simulation data under various factors and summed up that the simulation results consistent with the theoretical analysis. We educe that the max frequency band energy method is better than the zero sequence current method, and we give the line selection device design process.Because of its special geographic position and complex running environment, this paper chooses Hui Anbao transform station as the research object. This commodiously distinct lives little persons. The load's distributing is not equal, transmission line is too long and running environment is bad. The successful use of line selection theory brings an economization on both human resource and financial resource.