Induced Components in HVDC Transmission Lines Caused by Same-Tower AC System Faults

摘要

It's significant to consider building ac and dc transmission lines in the same corridor or even on the same tower to solve the difficulties of getting the new right of way and improve the power transfer capability of an existing power system. Due to the proximity between ac and dc overhead lines, the problem of electromagnetic coupling effect between those circuits may be of great concern. This paper firstly presents a theoretical analysis for the coupling effect and calculate the induced components in dc lines. Moreover, factors such as tower configuration, the location and length of the parallel part of the hybrid system and conditions including DC power transfer capacity, system strength, fault type and fault location are discussed. The impacts of these factors are considered and the solution for seeking the boundary value is presented. Simulation results demonstrated the correctness of the method. At last some constructive proposals on protection scheme from the aspect of safe operation of ac and dc system were recommended.