Research On The Adaptive Distance Protection Algorithm For Large-scale Photovoltaic Station

Large-scale photovoltaic power grid connection has a profound impact on power quality,grid frequency regulation and economic operation,power grid stability control and relay protection of the power grid.At present,the analysis of relay protection in photovoltaic power systems is mainly focused on current protection and distributed photovoltaic power systems.There is relatively little research on distance protection,especially in the case of boosting the PV power plant into the 110 kV power grid to make the transition resistance grounding distance.The measured impedance of protection cannot accurately reflect the location of the fault.This paper analyzes the relationship between the power generation P of the photovoltaic power plant and the transitional resistance tilt angle ?,and introduces the adaptive parameter ka to reflect the information of the influence of the power generation amount P of the photovoltaic power plant on the gradient of the transition resistance.A new algorithm of adaptive distance protection against photovoltaic characteristics is proposed,and the influence of the protection distance in the action characteristics of adaptive distance protection is analyzed,and the adjustment range of ka is given.The PSCAD software simulation verifies that the criterion can well eliminate the influence of the transition resistance on the distance protection.