【摘要】 换流阀塔作为柔性直流输电技术的核心设备，内部寄生电容参数直接影响其暂态绝缘性能与运行安全。以±500 kV柔性直流换流阀塔为研究对象，建立了其简化三维模型。首先，采用单源激励法提取了阀塔屏蔽罩系统的主要寄生电容参数，量化了水平、层间及对地三个方向的耦合强度，结果表明对地寄生电容普遍超过100 pF，显著高于其他类型。然后，建立了子模块的宽频等效电路，在穿墙套管对地闪络产生的过电压下，仿真分析了各类寄生电容对端口电压的影响，发现对地寄生电容会显著放大端口电压的振荡幅值并引入丰富的高频谐波；层间寄生电容主要加剧电压波形纹波，而水平寄生电容影响甚微。最后，综合稳态电场仿真结果，提出了以抑制暂态过电压为核心、优先优化高场强区域寄生电容的工程策略，并明确了对地电容的优化区间。更多还原

【Abstract】 As a core component of VSC-HVDC, the converter valve tower contains inherent parasitic capacitance that critically influence its transient insulation and operational safety. Taking the ±500??k V VSCHVDC valve tower as the research object, a simplified three-dimensional model is established. The single-source excitation method is firstly employed to extract the key parasitic capacitances of the shielding cover, and to quantify coupling strength in horizontal, inter-layer, and ground directions. Results show that ground capacitances generally exceed 100??p F, which is markedly higher than those of other types. Then, a wideband equivalent circuit model for the sub-module is established to simulate the transient overvoltage stress induced by a ground flashover of the wall bushing. The simulation analysis reveals that ground capacitance greatly amplifies port voltage oscillation and introduces high-frequency harmonics; inter-layer capacitance mainly increases waveform ripple, while horizontal capacitance has negligible impact. Finally, based on the simulation results of steady-state electric field, an engineering strategy focusing on suppressing transient overvoltage and optimizing parasitic capacitance in high-field areas is put forward, and the optimization interval of capacitance to ground is defined.更多还原