High-Resistance Grounding Design for Industrial Facilities: Providing Continuity of Service in Complex Distribution Systems

Continuity of service is crucial in most industrial facilities. Insulation failure due to a line-toground fault is the most prevalent cause of service interruption in such facilities. Solidly grounded systems create fatal and costly arc-flash hazards that cause substantial damage at the fault location. Resistance grounding limits the line-to-ground fault current. This practice has been in use for years and is widely applied in industry. This article explores the application of resistance grounding in hospitals, emergency power systems, and data processing facilities, where the distribution systems are complex and involve various sources, such as multiple transformers, generators, or a combination of both. It also proposes solutions for the integration of high-resistance grounding (HRG) in the distribution system design of various industries to increase the reliability and safety of these systems. Application examples are presented, and the concept of hybrid grounding in low-voltage (LV) and medium-voltage (MV) systems is discussed.