Improving Network Fault Protection at 20/0.4 kV for General Hospital Operations through ETAP Simulation-Based Protection Relay Re-Setting

Fires caused by electrical disturbances are a major cause of material loss and safety risk in hospital buildings, particularly from short-circuit faults that are not selectively isolated by the existing protection system. This study evaluates the performance of the 20/0.4 kV distribution network protection system in a type-B general hospital and formulates a re-setting of the Over Current Relay (OCR) and Ground Fault Relay (GFR) to satisfy the principles of selectivity, sensitivity, reliability, and speed. A quantitative method with an ETAP 19.0.1 simulation approach was used, supported by field observation and historical fault data. The results show that the existing protection coordination has a grading margin of less than 0.2 seconds between relay levels, resulting in non-selective operation, consistent with a laboratory fire incident that was not isolated quickly. After re-setting based on short-circuit simulation and Time Current Characteristic (TCC) curve analysis, the protection coordination becomes selective, with a total clearance time on the priority feeder below 1.5 seconds and a considerably narrower outage area. This study recommends implementing the new settings together with primary injection testing and standardized documentation procedures for the hospital's electrical team.