The Effect Of Electronic Arc Suppression Coil On Transient Signals Method For Fault Line Selection In Non-solidly Earthed Network

With the enlargement of the distribution network’s scale, the operation mode, Neutral by Arc Extinction Coil Grounding, is used extensively. Compared with the traditional arc-suppression coil, the quick compensation, stepless adjustment, and the convenient operation and maintenance of the arc-suppression controlled by silicon controlled (electronic arc-suppression coil) make it used extensively. However, as a result of the compensation current adjusted by the on-off time of electronic arc-suppression coil, the harmful effects are that it will generate some transient and harmonic components, so the fault transient process become complex. And also it will affect the reliability of the fault line selection methods based on transient singles.In this paper, the operation principle and the characteristics of current generated by on-off of windings controlled by SCR (silicon controlled rectifier) are analyzed firstly. It is found that the current of winding contains a great deal of harmonic component. Among the 3rd,5th,7th,9th harmonic components, the 3rd component is the largest. Then, a filter circuit is designed to filter these special transient single.According to the characteristics of arc-suppression coil, the transient process generated by the on and off of SCR is analyzed and the transient current with different transition resistance is calculated. The smaller the transition resistance, the bigger the transient current is. And the transient component is in proportion to the harmonious degree of arc-suppression coil. The bigger the transition resistance, the smaller the transient current of electronic arc-suppression coil, the short the transient process.Through the calculation of equivalent circuit of distribution network compensated by electronic arc-suppression coil, the distribution of transient and harmonic single in the feeders can be obtained. The current on fault line is in proportion to distributed capacity of fault line and in inverse proportion to transition resistance. And the transient of electronic arc-suppression coil is so small, compared with fault transient, that it hardly affects the location methods.In this paper, the model of neutral by electronic arc suppression coil grounding network is established by PSCAD software. On the basic of the model, the transient process and the distribution of fault transient components are analyzed. Finally, combined with the fault line selection methods based on transient components, the reliability is analyzed, and the conclusions above are proved.The analysis of transient characteristics and the effects on fault location provide support for the fault line selection methods based on transient single. And it is benefit for the application and dissemination of electronic arc-suppression.