ABSTRACT
Voltage transients are created in distributed photovoltaic grid transformers (DPV-GTs) due to changing weather conditions. The amount of irradiance that impinges on the photovoltaic (PV) panels is inversely proportional to the cloud coverage. In a few more words, insulation coordination is a series of steps used to select the dielectric strength of equipment in relation to the operating voltages and transient over-voltages that can appear on the system for which the equipment is intended. Any dramatic change in current will cause a dramatic change in voltage. This can occur whenever the generator main breaker opens, or during clouding. Mitigation of voltage fluctuation can be achieved with storage devices that may be an option especially in cable grids with a high series resistance. In mainly inductive grid circuits with interconnecting DPV-GTs, this can be achieved by injection of reactive power by the inverter circuit.
