Development of Electric Shock Prevention Systems for Photovoltaic Solar Systems using Electromagnetic Relay

Photovoltaic systems (PVSs) have gained popularity as a clean recyclable source of energy because they generate electric power from light irradiation. However, this advantage of PVSs can lead to problems when they experience failures. For example, a fire in a building installed with PVSs can cause electric shock to firefighters working at the site. PV modules (PV-mdls) blown away during wind disasters are potentially harmful when the scattered PV-mdls are removed (e.g., from the ground), as they can cause electric shock to those who remove or clean up the scattered PV-mdls. Therefore, in this paper, we propose a system that can prevent the electric shock due to PVSs, which can cope with failures in case of fire and wind disasters. The proposed system uses an electromagnetic relay that causes a parallel disconnection and short-circuit along a PV-mdl string. The experimental tests show that the proposed system operates successfully, and the PVS voltage can be reduced to a level in which there is no risk of electric shock in case of emergencies.