Development Of Distribution Feeders Single Phase Fault Location Device Based On Embedded System

Rapid distribution and location of distribution network line fault can reduce user outage time effectively and improve the reliability of power supply. Therefore, it has very important significance. In MV system, the faults are mostly single phase to ground faults and the neutral ineffectively grounded systems are mostly adopted, it is generally difficult to detect the fault automatically. After many years of research and practice, earth fault identification has succeeded in projects, and fault location off-line method has made substantial progress and has been applied, but this method required off-line, so it has a bad influence on reducing the reliability of users. With the proposal and forward of smart grid, on-line fault location has on the agenda.This paper deals with research on neutral point non-grounded system. At first, summarized the zero sequence current of on and off fault line, and studied the theory’s effectiveness and feasibility of zero-sequence power direction method. Subsequently, key technologies and related algorithms involved in the fault location are discussed, and designed a small current fault location new device. This device based on ARM Cortex-M3processor, uses GPS technology and software achieve frequency technology for accessing zero sequence phase of wide-area, and communicates through the CSD network. This paper focused on the design of hardware and software.Using two designed location devices, experiments were carried out on the10Kv physical model. In the zero-sequence current measurement node side, compares zero sequence voltage and zero sequence current phase. Through zero-sequence power direction method, accurately determine the fault location. the experiment results shows that the device can measure the zero-sequence signal better, and it will be used for single phase ground fault detection and location.Through analyzing of experimental results, obtained that used the location devices can be done with simultaneous measurement signal and transmission function better, and can detect and locate ungrounded system single phase to ground fault effectively. At last, this paper validated the effectiveness of fault location device.