Research on the Influence of Low-Voltage Ride-through Strategy of Distributed Photovoltaic Power Supply on the Relay Setting Calculation of Distribution Network

With the rapid development of distributed photovoltaic power supply industry, its impact on the distribution network rectification calculation is also increasing. In the traditional calculation mode, the influence of the LVRT strategy of distributed PV power supply on the fault current is not considered, which may lead to the calculation result of the calibration being larger than the actual value, and then affect the action effect of the protection device. In order to improve the accuracy of the calibration calculation of distribution networks, this paper studies the specifications and standards of the LVRT strategy of distributed photovoltaic power supplies and its influence on the fault current calculation, and points out that under its influence, the fault current required for the relay protection calculation will change from a static value to a time-varying value, thus making the calibration value smaller. A time-varying model of LVRT strategy considering distributed photovoltaic power sources is proposed, and the matrix calculation method is used to divide the fault current into several time periods for multiple calculations according to different time definite values, which effectively improves the accuracy of the distribution network rectification calculation.