VSC-HVDC换流站电磁辐射计算

Calculation of Electromagnetic Radiation of VSC-HVDC Converter Stations

为分析电压源换相直流输电(VSC-HVDC)换流站对站外电磁辐射,建立了基于偶极子理论的赫兹偶极子和磁偶极子模型;利用IGBT1模型分析换流阀器件开通和关断的瞬态特性;通过对换流站整体仿真求得了换流站开关场内主设备与大地构成的等效电流环路中的电流;改变偶极子模型参数得到影响VSC-HVDC换流站电磁辐射强度的因素。计算证明,换流阀开关暂态电压变化频率以及各频率对应的电压幅值直接决定阀体产生电磁辐射强度,换流站内设备布置的紧凑程度也直接影响了其对外电磁辐射强度;通过紧凑布置站内设备,减小谐波尤其是高频段谐波电流能够有效地抑制VSC-HVDC换流站电磁辐射。

Hertzian dipole model and magnetic dipole model based on dipole theory were established to analyze electromagnetic radiation of VSC-HVDC converter stations. Transient characteristics of converter valves during switching were analyzed with IGBT1 model. Current through equipment other than valve in converter stations can be extracted by system simulation. Factors that affect electromagnetic radiation of VSC-HVDC converter stations are obtained by varying these parameters of the magnetic dipole models. Transient vohage＇s frequencies of valve and their corresponding voltage amplitudes tend to have obvious effects on electromagnetic radiation of valves according to calculation, and the compact extend of equipments inside the station would also affect electromagnetic radiation directly. Electromagnetic radiation from VSC-HVDC converter station can be restrained effectively by retrenching devices and decreasing harmonic, especially harmonic current at high frequencies.