I. Introduction
Fujian Guangdong DC Interconnection Project as a Key Construction Project in the 14th Five Year Plan for National Electric Power Development [1]. It Adopts LCC-HVDC back-to-back wiring method, the rated DC voltage is ± 100kV and the transmission capacity is 2000MW. It has bidirectional power transmission capabilityº It builds two 500kV circuits on the Fujian side and connects with 500kV Donglin substation. Meanwhile it builds two 500kV circuits on the Guangdong side and connects with 500kV Jiaying substation. In the LCC-HVDC, the converter will produce a large number of characteristic harmonics and inject a large amount of harmonics into the AC power grid system [2]–[4], To ensure that the DC system limits the voltage distortion rate and current waveform distortion coefficient of the AC bus in the converter station within the specified allowable range under various operating conditions, a certain number of filters need to be configured at the converter station to achieve the filtering goal while also providing reactive power support for the converter station [5]–[7].