Study On Relay Protection In Power Distribution Network With Distributed Generation

Nowadays,a noticeable trend in the new technology of electric power power source is the rising of the distributed generation. For efficiently making use of the dispersion energy and enhancing the effectively and reliability of power suppling, each kind of distributed generation(DG) obtains more and more widespread application in the electrical power distribution system. Its development will bring the tremendous influence to the traditional electrical power system and cause the electric power technology remarkable progress. But simultaneously distributional power source's turning on also brings some new technical difficult problem to the electrical network, because the majority electrical power distribution systems use the single power source radial network structure, and the traditional distributed network's relay protection is also take the radiating wire table structure as the foundation design movement. But after turning on the DG, not only causes the distribution network to become the double power source power supply by the single one, but also change nearby the node and the line fault level. That will brings new challenge to the traditional distribution network protection.In this paper, first studied about the influence of DG of different capacity joining on distribution network system by the different voltage class junction point to the distribution network line relay protection, and carried on the simulation confirmation in software DIgSILENT/PowerFactory. Second for DG turning on distribution network and has possibility to create the line protection misoperation, using the line latch-up protection to avoid. Third when the distribution network line breaks down, analyzing the DG its jitter time in the different turning on situation regarding the line tradition triad protection's influence, choosing the distribution network line comparison pilot protection to avoid, and taking the wind power as DG to carry on the simulation in software MATLAB/Simulink. Finally, for improving the installation method for the distribution network line protection, to carry on the preliminary analysis and the forecast based on the two-interphase-current distribution network line auto-adapted protection plan.