Investigating Particularities of Infeed and Fault Resistance Effect on Distance Relays Protecting Radial Distribution Feeders With DG

Abstract

The integration of distributed generation into distribution systems renders the reliable protection of these systems quite challenging. A solution being considered concerns the application of distance protection to distribution systems, due to its advantages compared to overcurrent protection. However, as distance relays (DRs) are principally designed for transmission systems, some of the factors affecting their operation in such applications have to be extensively studied, focusing on the particularities of these factors in distribution system applications. This paper examines the effect of intermediate infeed and fault resistance on the operation of DRs protecting radial distribution feeders. The investigation of these influencing factors is performed for phase and ground faults through theoretical analysis and simulations in a test distribution feeder, taking into consideration the concurrent effect of line load and zero-sequence compensation during single-line-ground faults. Moreover, the combined effect of intermediate infeed and fault resistance on distance protection is analyzed, and the resulting problems concerning proper relay operation are described. Potential solutions to these problems are proposed.

Keywords

• Distance protection
• distributed generation
• distribution systems
• infeed and fault resistance effect