The LG Fault Location System Based On Distributed Wireless Communication In Distribution Network

The small-current-to-earth system is mainly used in the medium distribution network in China, the probability of line-to-ground (LG) fault is very high, almost80%of all fault in the system. Because of the complex structure of the distribution network and weak fault current, the LG fault detection in non-solidly earthed network is a technical problem which has not been well solved in the actual project. Seriously affected the distribution network reliability and improving the level of automation.Firstly analyzed the steady-state and transient single-phase ground fault feature, On this basis, it is necessary to make full use of the features of zero sequence fault curre nt component. The zero-sequence current ratio of amplitude, phase and zero-sequence c urrent transients could be used to determine the fault branch of distribution network wit h different grounding ways, and then use the impedance method for fault location. Dynamic simulation experiments and PSCAD electromagnetic transient simulation fully verify the correctness and effectiveness of multi-criterion fusion method of fault location, and analyzed the effects of the fault resistance and the load variation on the proposed method, and discusses the technology that need further research and solution.In this paper, the integration of multi-criterion distribution network of single-phase ground fault location method, presented a LG fault location system based on the wireless communication in distribution network, including line measuring units, data transfer station and master station. The line measuring units are installed on the main buses of distribution network, data transfer station installed near the line measurement unit, while the master station placed inside the substation. The system realizes the communication lines between line measuring units and the data transfer station via a Bluetooth module, the data transfer station and the master station communication through the GPRS module, the whole network using GPS to achieve synchronous sampling.This paper also design a self-powered module for line measurement unit, using the principle of electromagnetic induction from the bus line access to energy, and with super capacitor energy storage, the charge and discharge times, and life are better than batteries, maintenance-free features, reducing hardware costs.The system is applicable to a variety of fault location method and possesses the functions such as electrical synchronized measurement, wireless communication, data storage, line status monitoring and fault locations. This monitoring and fault location system has flexible configuration, the number of the measuring units and the installing places can be determined according to the distribution network topology and fault location requirements, can perform online fault location, improve the reliability of distribution network, online monitor of operational status of the main lines, and provide the basic information for the optimal operation and fault isolation and post-fault reconfiguration of the distribution network.