Safety issues related to the connection of MV and HV grounding systems outside substations

Hydro-Quebec conducted a research program aimed at specifying a method of feeding loads in HV (high voltage) lowers and more specifically, whether the HV and MV (medium voltage) grounding systems should be connected. Field measurements were made at three sites and the results were used to validate a MATLAB-based computer model. The main results of a sensitivity analysis identifying the key system parameters that influence touch voltages on LV (low voltage) and MV networks during faults on the HV system are presented. Finally, a method for feeding loads in HV towers is proposed