Resonant Grounding as an Alternative to Resistance Grounding


Mr Doug Hay (Engineering Consultant - Stantec Consulting)

Douglas Hay, B.Sc., P.Eng.ConsultantStantec Consulting, 200-147 McIntyre Street West, North Bay, Ontario, P1B 2Y5Tel – 705.494.8255 Ext 1333Fax – 705.474.2652 douglas.hay@stantec.comABSTRACT: The main goals of power system grounding are to provide personnel safety, minimize voltage and thermal stresses on equipment, and assist in rapid detection and elimination of ground faults. As a result of very long haulage distances for a large Canadian mining project, an alternative grounding system design that minimized grounding system impedance and the resultant Ground Potential Rise (GPR) was proposed.The original grounding system design proposed for the project utilized resistance grounding but was elaborate in terms of arrangement. The system required an extensive network of ground bonding cables and segmenting transformers to meet the requirements of CSA M421 -Use of Electricity in Mines. An alternative solution to dealing focusing on a Resonant grounding systems was sought to maintain employee safety and system reliability at reduced costs with less complex installation methodologies, yet able to adapt to changing system topologies and charging current requirements.Resonant grounding systems, used extensively in Europe, Australia and New Zealand, offer a multitude of benefits over resistance grounding systems. Of greatest benefit is the very limited ground fault current that is permitted thus limiting GPR during a ground fault. A well-tuned resonant grounding system compensates for the fault-current and most arcing faults become self-extinguishing. This offers a significant improvement to employee safety and greatly reduces potential damage to electrical infrastructure when a fault does occur.