A Micro-grid Fault Section Positioning Method Based On Fault Steady State Component

Abstract

After the micro-grid is connected to the distribution network, the unidirectional power flow in the original network is transformed into a bidirectional flow, and the original protection device cannot meet the current safe operation of the micro-grid. Due to the complex structure of the micro-network, it is necessary to study the fault location and identification methods in the network when a fault occurs.In this paper, in order to solve the fault section location problem, the phase-to-phase short circuit model of the micro-grid under the state of distributed power grid-connected faults was established, and the positive sequence currents amplitude at the upstream and downstream of the fault point are extracted using the symmetrical component method.The fault section is determined by the amplitude of the positive sequence current at the adjacent detection point on the fault branch. It solves the problem of increasing the difficulty of fault detection due to changes in the access of conventional power electronic devices and changes in short circuit types. The distribution network model was built by MATLAB to simulate and verify the feasibility of fault-based steady-state component section positioning method.