Faulty Line Selection Study Based On Improved Transient Energy Method

The safety of the power system is to ensure the safety of the country and the stabilityof the society and people’s happiness basis of life. In our country, to ensure safety andstability of the system, small current grounding mode has been used widely in thedistribution network. In small current grounding mode when one-phase ground faulthappened, it’s very important to select the fault line out accurately. Since the existing faultyline selection methods don’t work well in industry scene, the research of the faulty lineselection has important practical significance.Firstly, this paper analyzes the domestic and foreign existing faulty line selectionmethods, and the existing main problems of the methods the main impacting reasons.Secondly, this paper analyzes the fault transient components of the parameters in thesmall current grounding mode when one-phase ground fault happened, and the parameterswhich influence the fault transient components were analyzed. Based on the above analysis,this paper proposed the main existing problems of the traditional energy method. Forsolving these problems, this paper introduces the instantaneous active power method intothe traditional faulty line selection method based on power energy. Then, a new faulty lineselection method based on instantaneous active power is proposed. Theory analysis showsthat the new method can accurately select out the fault line and identify the fault typeincluding permanent fault, transient fault and intermittent fault type regardless of theneutral point ground mode, fault initial angle and the fault resistance. PSCAD simulationsverified the effectiveness and practice of the proposed method.Finally, this paper reviews and summarizes of the main research work in this paper, andpoints out the problems which needed to be solved in the future research work.