Analysis of Influence for AC Voltage Fluctuation in Converter Station on Discrete Equipment Operation

With the large-scale renewable energy centralized access to the power grid and the successive operation of UHVDC transmission projects, the frequent action of AC filters and converter transformer taps in converter station caused by random disturbance of AC system has attracted wide attention. It has become a key problem of voltage and reactive power control in AC/DC hybrid power grid on quantifying the operating range of converter bus voltage according to the specific operation mode of DC system in engineering. In view of the above problems, this paper analyzes the influence of AC voltage fluctuation on discrete equipment operation. Based on the voltage and reactive power characteristic equations of converter station, the sensitivity formula of reactive power absorbed by converter station to AC voltage is derived. In addition, under the operation mode of constant power at the sending converter station and constant voltage at the receiving end, the reactive power control mode of the converter station and the tap control mode of the converter transformer are considered. Meanwhile, the minimum filtering requirements of the converter station and the safe operation requirements of the converter control angle are also considered. Using the actual operation parameters as an example, the minimum fluctuation range of AC voltage causing the action of discrete equipment is obtained through simulation by MATLAB.