Ground fault over-voltage on sub-transmission and distribution circuit with high penetration of PV

Ground fault over-voltage (GFOV) study is an indispensable utility planning study for circuits with high penetration of PV. This paper presented mechanism of GFOV on sub-transmission circuit and distribution circuit caused by both rotating machine generation and PV inverter generation. GFOV on a real sub-transmission circuit with different penetration level of PV was modeled and simulated in PSCAD/EMTDC. Simulation results were analyzed according to the voltage arrester TOV curve as sub-transmission level study criteria and ITIC curve as distribution level study criteria. Based on comparing GFOV caused by rotating machine generation and by PV inverter generation, analysis results were discussed in detail. GFOV mitigation measures were also discussed in this paper.