DSP-Based Adaptive High impedance Ground Fault Subtransmission Feeder Protection

This paper presents a new, adaptive strategy for substation feeder protection implemented with state-of-the-art digital signal processing technology. This 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 is designed to significantly reduce this potentially fatal condition. This paper presents the design of this adaptive feeder protection. Several power system faults were simulated under varying load and system conditions. The results are analyzed to verify the design, to determine the improvement over a conventional static protection, and to verify the correct protection operation. Field tests were conducted in Runnymede Transformer Station in Ontario to validate this adaptive feeder protection