高压直流输电直流侧谐波电流计算

Calculation of DC Side Harmonic Currents for HVDC Transmission

为计算高压直流输电工程的等效干扰电流,详细描述了给定两侧三脉动谐波电压源情况下如何计算沿线各次谐波电流的一套计算流程,包括直接流过直流极导线、接地极线路的谐波电流和感应到直流线路、接地极线路地线中的谐波电流。该计算流程分为2步:第1步,将直流侧系统作为一个整体用求解一般性电网络的节点分析法计算,在计算节点导纳矩阵时,直流输电线路作为一个网络元件采用全相耦合模型;第2步,在求得直流输电线路端口上的谐波电压之后,将直流线路分解为正序与零序网络,分别计算沿线各次谐波电流的正序与零序分量,然后再将正序与零序分量合成为整体谐波电流。在同等条件下,比较该算法的结果与电磁暂态仿真程序PSCAD/EMTDC的结果,两者基本一致,验证了所提算法的正确性。

Based on the three-pulse harmonic voltages of the rectifier side and the inverter side, this paper described an approach to calculate the DC side harmonic currents in HVDC systems, including the harmonic currents flowing directly in the DC line and the grounding electrode line, as well as the harmonic currents induced in their screening wires. The approach included two steps as follows： Firstly, the DC side system was treated as a general electric network and was analyzed by the nodal analysis method; the DC transmission line was treated as a network element, and its coupled phase model was used to form the network nodal admittance matrix. Secondly, because the harmonic voltages on both DC line ports were known, the harmonic currents along the DC line were calculated in positive and zero sequence respectively; then the whole harmonic currents along the DC line were synthesized by the two sequences. In the same conditions, the results were compared with those of PSCAD/EMTDC simulation, and the validity of the approach was verified through the comparison.