A case study of medium voltage power system failures as a result of the loss of system grounding

Several 10 kV lightning arresters exploded in three substations while an electrical system was being tested at a new installation. The system was investigated for several weeks for possible causes. It was finally determined that the cause of the occurrence was from the loss of the electrical system grounding due to the switching arrangement of the system and the location of the emergency generator. This paper explores this occurrence and demonstrates the use of an artificial neutral and high resistance grounding system at 12.47 kV.<
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