Adaptability Analysis of Three-Stage Current Protection in Distribution Networks with Distributed Generation Integration

Abstract

With the widespread integration of Distributed Generation (DG), conventional single-source radial distribution networks have transitioned into multi-source power systems. This transformation significantly alters fault current distributions and power flow patterns, thereby affecting the operating characteristics of traditional three-stage current protection. Focusing on Inverter-Interfaced Distributed Generation (IIDG), this paper investigates the influence of DG location, penetration capacity, and fault current characteristics on protection measurements and operating performance. The analysis reveals that the shunting and infeed effects of DGs cause variations in protection sensitivity, coverage zones, and selectivity. Under severe conditions, protection dead zones or sympathetic misoperations may occur, rendering traditional fixed-setting principles inadequate for modern active distribution networks. The conclusions obtained in this study offer a solid theoretical foundation for subsequent research on setting methods for three-stage current protection in distribution networks with high DG integration.