Alleviation of the transients induced in large photovoltaic power plants by direct lightning stroke

Abstract

Lightning strokes are considered the most common passively effective cause on the photovoltaic (PV) power plants compared to the other internal faults. In this paper, a 1 MW solar PV grid-connected power plant was studied. Lightning strikes were applied at different positions in the grid to test its effect on the PV farm’s components with the variation of the strike’s position. Also, it was studied the effect of lightning on the PV plant elements with the variation of lightning characteristics. Different mitigation techniques are applied such as choosing of metal oxide surge arrester (MOSA) with a suitable rating, designing high voltage filter (HVF), and parallel combination between them. The modeling and analysis were implemented by using PSCAD/EMTDC software. The results show that when the lightning stroke had been applied nearby the grid’s inverter position, it negatively harmed the PV farm by about a 16.1 % increase in peak voltage. As, either of the lightning characteristics increase, their effect appears negatively over all the system’s components especially the tail time parameter when it increases from 50 µs to 300 µs, it caused an increase in the peak voltage value at the striking position by 71.7%. Finally, the parallel combination between using MOSA and HVF represents an efficient mitigation technique for the lightning stroke over the solar farm totally with a reduction percentage of 96.3% than using MOSA only and 95% than using just HVF. Therefore, it effectively reduces the maintenance and replacement cost for the expensive components in the PV grid-connected plant.

Keywords

• Photovoltaic grid-connected system
• voltage source converter(VSC)
• Lightning stroke
• MOSA
• HVF