The Research Of Fault-section Location For Distribution Network With Distributed Generation

With the society’s development and people’s living standard improvement, the scale and capacity of electric system is increasing, and there’s an increasing high demand for power supply reliability. The access of distributed generator (DG) makes the distribution network a two-way flow grid, the characteristics of fault current change greatly, too, causing the existing distribution network fault location don’t match with its protection configuration. Thus, it’s necessary to study the fault section location containing DG for distribution network.Firstly, this paper makes a description of the traditional fault location strategy and calculation methods for DG fault current; and analyzes the impact of DG access to traditional distribution network fault section location strategy, it proposes a maximum capacity of DG access to distribution network which can ensure the original applicable fault section location, and based on this, this paper further studies the maximum access capacity and the longest power supply distance for DG.Then, this paper studies the distributed power failure location algorithm improved by directional elements. First, it divides DG distribution network into different parts, defines a T connection area with the installation of directional element and set the short-circuit current direction provided by the main power source as positive direction and based on this, establishes a distribution network description matrix and fault identification matrix, and then analyzes the fault judgment matrix, gets T connection and non-T connection area’s fault location criterion, through the fault location algorithm analysis this paper determines the final feeder switch which need to be installed with directional element and proposes specific localization process.Finally, this paper studies the process strategy for phase short circuit current fault location in distribution network, analyzes the structure and function of the master station and the terminal in the location system, designs the computer program for phase short circuit fault location, makes a simulation analysis of the actual line by RTDS, and verifies the accuracy and speed of designed location strategy.