Research on Relay Protection of Active Distribution Network Based on Innovation Graph

The large scale integration of new energy leads to great changes in the characteristics of power flow and fault characteristics of traditional radial distribution network, which has a great impact on the correct action of relay protection devices. The influence of different types of short circuit faults on the protection device is analyzed when the distributed power is connected to the starting bus and the intermediate bus. A current protection scheme using the innovation graph to calculate the correct estimate ratio of lines is proposed. In this scheme, the innovation graph parameters are calculated by the current innovation before the fault and after the fault, and the fault is judged only by comparing the correct estimate ratio of each line in the region. Compared with the conventional method of current protection, the scheme has lower requirements for communication system and improves the complex coordination between contiguous lines. A simplified distribution network model is established in PSASP software to verify the effectiveness of the proposed protection scheme.