Research on the Adaptive Protection Method for Distribution Networks With Inverter‐Type Distributed Power Supplies: Based on Short‐Circuit Impedance Calculation

Abstract

ABSTRACT In order to solve the problem of the influence of large‐scale inverter distributed power supply access to the distribution network on the reliability of distance and current protection of the traditional distribution network, an adaptive protection scheme applicable to the access of inverter power supply is proposed. In this paper, the control strategy of the inverter distributed power supply is analyzed to derive the mutual influence relationship between various electrical parameters. The fault characterization method of iterative correction is used to extract the fault characterization factors of the distribution network containing IIDG and construct the distribution network model containing IITG. Combined with the complex plane relationship of impedance under fault, the short‐circuit impedance corresponding to the fault location of the line is calculated, and the method of solving the actual short‐circuit impedance is obtained to realize the design of the adaptive protection scheme for distribution networks. The experimental results show that the proposed method can correctly and accurately reflect the fault distance and the size of the actual line impedance, and the error value of the short‐circuit current at the moment of fault produced by this design method is small, and the maximum value of the error is 3.01. It verifies that the design method is of good reliability and selectivity, and realizes the accurate prediction of the short‐circuit flow at the moment of fault of the distribution network, and the prediction effect has real‐time stability.

Keywords

• adaptive distance protection
• distribution network
• fault current
• inverter‐based distributed power supply