A Novel Whole-line Fast Protection Scheme Based on Single-end Line Current for HVDC Transmission Lines

The performance of HVDC transmission line protection is closely related to the operation of power system. The currently single-ended protections, configured as primary protection in HVDC projects, have inadequate sensitivity with high resistance faults. To overcome these shortcomings, a novel protection scheme using single-ended line current from already existing measurement unit in HVDC projects is proposed in this paper. With current fluctuation extracted, floating threshold current criterion is proposed to distinguish internal and remote external faults. Based on variable current, fault direction and faulty line can be reliably identified. RTDS simulation results verify that the proposed protection scheme can act sensitively and quickly. The action time is not more than 1.2ms and 3.2ms when faults with $0\Omega$ and $800 \Omega$ resistance respectively occur in the range of the whole line. Compared with other single-ended protections, the proposed method has advantages of detecting the high resistance fault, small operation time.