Research On Adaptive Protection For Distribution Network Containing Distributed Generation

The safe and stable operation of power system is the important foundation of the national economic and social livelihood of the people. The protection of the power system configuration as one of the important link of the stability of power system, determine the reliability, controllability and stability of the whole system. But with the development of distributed generation, more and more distributed generation penetration into the power distribution system, which change the traditional distribution network of single radius structure, this means that based on the traditional protection mechanism may fail. Therefore, research on adaptive protection in the application of the distributed power distribution network is of great importance.This paper introduces the concept, background, classification, and the grid method of DG. Secondly analyzes the impact of the type, capacity, and the location of distribution generation on relay protection of distribution network, meanwhile using the simulation of MATLAB verifies the conclusions. Adaptive protection can get its settings on-line on the basis of power system operation mode and fault type. the protection can adapt to changes of the power system and get the optimal protecting effect. Thus, Can well solve the problem of protection misoperation and refused to move.In order to realize the adaptive protection, this paper proposes a method of strong tracking filter to calculate the equivalent impedance of dorsal protection in real time. This method abandons the traditional way of fault component and can track the change of system parameters through the system parameter identification to achieve the online real-time identification of system equivalent impedance. Through the comparison with the fault component method based on the FFT, the simulation results prove that the method is not affected by the fault current decaying DC component, the power of initial phase angle and wind generator fault current, and can satisfy the real-time and accuracy requirements of the parameters are calculated. According to the characteristics of distribution network containing DG, the paper put forwards an adaptive protection scheme, and through the simulation results prove the correctness of the theory analysis.