The paper presents a study of arc flash protection in a PV power plant connected to distribution network. It first put forward an approach applying relay protection and coordination to reduce arc flash hazard. An example of micro-grid with PV power plant connected is then proposed to verify the effectiveness of the approach. In recent years, the growing concern for environment preservation has caused the sustainable power and energy system gets more attention. The renewable energy integrated with traditional power system, such as the PV power plants connected to micro-grids, turns out to be lack of stability and more vulnerable to typical faults. Among many kinds of faults, the arc fault could result in serious arc flash accident, even terrible fire and explosion, leading to casualties and huge economic losses. In order to study the hazard of an arc flash accident and the way to protect the equipment from it, the paper uses a power system analysis software, named EasyPower, to simulate an arc flash accident happens in a PV power plant inside a micro-grid and makes an assessment of the hazard. After that, the time-current curves are plotted for the purpose of protection coordination among all the protective devices. The original relay settings are adjusted to satisfy the selectivity and backup protection.
Keywords PV power plant, arc flash analysis, protection coordination, relay settings