Research on Temporary Overvoltage of AC Transmission System for Long Distance Offshore Wind Farm

Abstract

To accurately select the insulation level of submarine cables, an in-depth study should be conducted on the problem of temporary overvoltage attributed to long AC cables used in offshore wind power transmission. This study selected the offshore wind farm connected by single circuit submarine cables as the research object. In combination with the relevant current source characteristics and overvoltage protection strategy, this study theoretically analyzed the temporary overvoltage characteristics exhibited by submarine cables under no-load and load rejection conditions. In addition, the effects of submarine cable length, system short-circuit capacity, transmission capacity and overvoltage protection delay on the amplitude of temporary overvoltage were investigated. The voltage amplitude of load rejection temporary overvoltage showed a positive correlation with the transmitted power and the overvoltage protection delay of the fan converter. Shunt reactor could effectively suppress temporary overvoltage, and its installation position slightly affected the suppression effect.