Let's Talk Design: Solidly Grounding vs. High Resistance Grounding

There are two basic types of system grounding substations in power systems: solidly grounding and high resistance grounding (HRG). Solidly grounding is the most diverse and can handle 3 phases, line to line, and line to neutral loads. Unfortunately, it has high line to ground fault currents and can cause large feeders to trip in line to ground fault conditions. This makes it hard to troubleshoot and may cause reliability issues. HRG only supports 3 phases and line to line loads, but it is more reliable than solidly grounding. During ground fault conditions, the ground fault current is reduced to 5 amps. According to the IEEE Gold Book, 98% of all system faults originate as a line to ground fault conditions which means that 98% of system faults can be controlled by HRG. This creates a more reliable, safer system and allows you to address the problem without having to experience an unplanned shutdown. If you are looking at system grounding approaches, consider leveraging high resistance grounding. #LetsTalkDesign #grounding #powersystems #powersystem #ieee