Technology Research And Application Of Fault Location In Single-phase Ground Distribution Network

Nowadays,6kV-35kV medium-voltage(MV) grids in our country often adopt neutral non-grounding or neutral grounding via arc suppression coil. With the development of urban construction, people pay more and more attention to cable lines of MV distribution network, also most distribution lines are overhead lines and cable lines mixed structure. Consider this feature of the distribution network, the author describes the development status of fault-locating technology of single-phase grounding in small current grounding system and accordingly proposed a new fault location technique based on signal injection method in this paper.First, inject the high-voltage DC signal into fault line and then detect signal in the overhead line. If there is a signal existed in overhead lines in front of the test section while the overhead lines at the back of test section have no signal, the test section is the fault section, therefore we can determine the fault in a certain period of overhead lines or cables.Second, inject the high-voltage pulse signal and AC signal into fault section with the overhead line or cable still put in, and detect the signal along the overhead line or cable. If there have a signal before the test position in the fault section while not after, It shows that the test position is the point of failure.Furthermore, we designed a new multi- functional high-voltage signal generator to achieve the above fault location technology based on injecting signal. This mode of fault location device has been put into use in the field and running well. Also its reliability and feasibility have been fully verified.