Network-integrated DSP-based adaptive high impedance ground fault feeder protection

This paper presents a practical adaptive strategy for live substation feeder protections with new implementations using state-of-the-art digital signal processing (DSP) technology and modern computer networking technology. This network-integrated DSP-based feeder protection adapts its trip settings to provide improved selectivity and speed of fault detections for varying power system configurations and loadings. This protection accurately senses and de-energizes downed conductors that often could not be detected by conventional non-adaptive feeder protections. Several people are killed every year by contacting with live downed conductors. This adaptive protection can significantly reduce this potentially fatal condition. This paper presents the design of this adaptive feeder protection. Several power system faults were studied under varying load and system conditions. Results were analyzed to verify the design, to determine improvement over conventional static protections, and to verify correct protection operations. Field tests were conducted in a substation in Canada to validate this adaptive feeder protection.