Fault Line Selection And Location Of Dayabay Substation

Indirectly grounded Power system is widely used in medial and low voltage distribution networks in the world,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.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 Dayabay transformer substation using 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.Because of its special geographic position and complex running environment,this paper chooses Dayabay transform station as the research object.