基于两相电源的高压直流输电线路分布参数计算方法及直流工程的应用研究

Calculation Method of Distributed Parameters and Application of DC Projects in HVDC Transmission Lines Based on Two Phase Power Resource

为解决高压直流输电线路单位长度分布参数的测量问题,建立了双极直流线路的分布参数模型,在线路末端分别处于对地开路和短路接地的边界条件下采用两相电源系统测量线路阻抗参数,在此基础上推导了高压直流输电线路单位长度分布参数计算的新方法。在等效直流输电线路1 000 km的实验模型上对比分析了不同干扰信号下测量结果的最大误差为1.89%,验证了方法测量精度的有效性;通过普洱至广东特高压直流输电线路及接地极线路、牛寨至广东同塔双回直流线路现场参数测试结果表明:耦合参数小于导线自参数,零序电阻、零序电感分别大于正序电阻、正序电感,但零序电容小于正序电容。线路实验模型和工程实践应用验证了基于两相电源的高压直流输电线路分布参数计算方法的正确性和有效性。

In order to solve the distributed parameters measurement problem of HVDC transmission lines, we proposed the distributed parameters model and measured impedance parameters by the two-phase power resource system while the boundary conditions for the end of transmission lines were open circuit or short circuit to the earth. Furthermore, the maximum relative error with the different frequency interfering signals is 1.89% for the equivalent length 1 000 km of HVDC transmission lines. Moreover, the proposed method has been applied to the UHVDC transmission lines, grounding polar transmission line for Puer-to-Guangdong project and double circuit HVDC transmission lines on the same tower for Niuzai-to-Guangdong project, the measurement results demonstrate that coupling parameters are less than the self-parameters, the resistance and reactance of zero sequence are greater than those of positive sequence while the capacitance has opposite relationship. Therefore, the validation and feasibility of the proposed method can be verified through the transmission line experimental model and engineering practice application.