Research On Distribution Feeder Automation

Distribution automation is the requirement of the development of smart grid. Feeders’ automation is the most important part of distribution automation system; its operation directly affects the realization of power distribution. Therefore, improving the feeder automation operation level is of great significance to improve the reliability of power supply, protect the distribution network safe and economic operation.Depicturing from the concept of distribution automation, this paper introduces the feeder automation concept, significance and main functions of the main problems facing the distribution network feeder automation, discusses the necessity and urgency of feeder automation in smart grid construction. On this basis, the distribution feeder automation mode, the feeder fault line selection method, distributed power feeder automation and other key technical problems are focused researched.The common ways to achieve the existing feeder automation are summarized. According to the distribution network fault isolation; recovery of non-fault regional load power supply, feeder automation system is divided into four modes, namely local control mode, centralized control mode, distributed intelligence mode and network protection mode. The characteristics of each mode feeder automation system and applicable occasions are analyzed and compared.A feeder grounding fault line selection method is proposed based on the analysis of the characteristics of transient and steady state of the small current grounding system. When the feeder line has occurred ground fault, the feeder line zero sequence make a difference between each feeder firstly. Then the first half of the cycle and1.5cycle of the feeder line’s zero sequence difference are sent to wavelet decomposition based on the frequency characteristics of wavelet transform, and then calculate the coefficient of each layer of wavelet energy in the main fault frequencies, then choose the max of wavelet energy’s decomposition layer as the decomposition layer. The determine fault line is chosen by comparing the proportion of each feeder transient zero sequence current differential energy on all feeders transient zero sequence current differential energy based on the choose decomposition layer, and then adaptive analysis is made. The simulation results show that the algorithm can not only automatically adapt to the system operation mode, but also unafford by the grounding resistance, fault distance, and the fault switching angle and, has higher sensitivity and reliability, it has important application value.The influence and the access of distributed generation are elaborated. The power flow changes in the distribution which contains distributed generation can be different when ground fault occurs in different location. Therefore, the feeder automation’s improvement program is proposed based on local control mode.