LS-Solar-PV System Impact on Line Protection

Large-scale photovoltaic power station access to the grid will profoundly change the fault current characteristics of the power station’s outgoing lines. This change results in adaptive problems in traditional protection phase selection components, which may cause incorrect actions in reclosing, protection ranging, and distance protection. Based on the fault current characteristics of the large-scale photovoltaic power station transmission line, this paper analyzes the adaptability of the phase current difference mutation and the sequence component phase selection component in protecting the Photovoltaic (PV) power plant side of the transmission line. Based on the fault current analytical formula, the phase relationship between the phase current difference and the current sequence component under different control targets, such as suppressing negative sequence current, suppressing the active power fluctuation, and suppressing the reactive power fluctuation, is derived. The operational performances of the phase–phase current difference of the abrupt phase selection component and the sequence component phase selection component of the power station side are degraded, which may cause incorrect operation of the phase selection component. Based on the actual engineering parameters of a PV power plant, a simulation model was built in Power System Computer Aided Design (PSCAD) to verify the correctness of the theoretical analysis.