Studies On Complicated Distribution Network Fault Location Method

In the distribution network of our country, the probability of small grounding current faults is very high, and within which fault location is almost rather difficult. For distribution circuit fault, especially the single-phase to earth fault, fast and accurate location not only has great help to line repairing and reliable power supplying, but also has the extremely vital significance to security, stability and economic operation of the whole power system. This paper firstly focuses on the current research status of fault location in transmission system and distribution system home and abroad. Then, based on these research works, and combining with the characteristics of fault in distribution network, many theories of fault location in distribution network have been studied, such as basic theories of AC signal injection method and its effective positioning distance, DC injection method and pulse injection method, theory of traveling wave method, fault transient traveling wave propagation process, the basic theory of wavelet analysis, the signal singularity detection theory and the wavelet analysis used in traveling wave method of fault location principle, and so on. Using the electromagnetic transient simulation software PSCAD/EMTDC, based on the IEEE 34 node benchmark model, some distribution network simulation models have been established for the research of signal injection method and traveling wave method of fault location. The effectiveness and applicability of signal injection method and traveling wave method are analyzed, and therefore, some important conclusions are obtained. Moreover, this paper proposes a fault location method based on both on-line and off-line method, namely, primarily using Type A and Type B traveling wave method and supplemented by Type C traveling wave method to conduct on-line fault location; then, using signal injection method to carry out accurate fault location and remove the faults, consequently, there easily realizes fast repairing and power supply recovering. Finally, due to the fault location methods studying in this paper, some suggestions are put forward on self-healing control and rapid power supply recovery of smart distribution network.