HVDC换流站PLC滤波器设计中的噪声源模型

Model of Noise Source for the Design of PLC Filter in Converter Station

为设计好HVDC换流站载波噪声滤波器,研究了换流站载波噪声源模型。在分析了换流阀换相产生高频噪声的基本原理后,采用带缓冲回路的换流阀等效模型,用PSCAD/EMTDC仿真贵广工程,得到噪声源的频谱曲线,确定了影响噪声强度的主要因素;修正并验证了确定噪声源强度的经验模型,给出了修正后经验模型中各物理量的计算方法。以贵广工程为例,将修正经验频谱、仿真频谱与文献中给出的实际频谱对比,结果表明,修正经验模型能较为准确地得出换流站噪声源的频谱特性。

For the design of PLC filter in HVDC converter station, the model of the noise source which causes interference with PLC was studied. Firstly, based on the deep analysis of the basic principles by which the high frequency noise in PLC band is produced during the commutation process, the equivalent model of HVDC valve with snubber circuit was applied to the simulation of the GUI-GUANG HVDC project in PSCAD/EMTDC. Then spectra plots of the noise source in the frequency domain were obtained by FFT analysis of the voltage waveforms gained from the former simulation. By analyzing the spectrum characteristics of the noise source in various operating modes, the main factors influencing the level of PLC noise were found. Secondly, a model from experience used to calculate the level of the noise source was modified and verified with particular explanation of the physical quantities used in the model. Finally, based on the GUI-GUANG HVDC project, the spectra of the noise source gained from experiential model and simulation were compared with the real spectrum given in reference, and a conclusion is drawn that the model from experience can meet the requirements of the PLC filters.