Optimization Research on PLC Filter of HVDC Converter Station to Cancel Tuning Elements

In an HVDC system, the power line carrier noise filter, or the PLC filter for short, is mainly used to eliminate the interference of high-frequency harmonics generated by the converter valve to AC line carrier communication. There had been several burning accidents of PLC filter tuning elements in HVDC projects, which profoundly reduced the availability of the HVDC system. To solve this problem, in this paper, the operating parameters of PLC filter components were simulated and analyzed with the variation of harmonic power supply frequency firstly, with the fault weak points of tuned components being found. Then, according to the structures of the PLC communication filters and the tuning elements, three optimization schemes of the PLC filter were proposed. The feasibility of these schemes are compared by simulation and calculation from two aspects: the effect of reducing high-frequency harmonic interference and the influence on the running capacity of the equipment. Finally the risk of these schemes are pointed out.