A Local Protection and Local Action Strategy of DC Grid Fault Protection

Abstract

Fast detection and isolation of direct current (DC) faults are key issues for DC grids. Therefore, it is very necessary to study the fault protection principle for DC grids. This paper firstly presents the main difficulties in DC fault protection. Then, a local protection and local action strategy for isolating the DC faults is proposed. To illustrate the performance of the proposed protection strategy, a four-terminal DC grid with the hybrid high voltage direct current (HVDC) circuit breakers (HVDC CBs) is constructed in the time-domain simulation software PSCAD/EMTDC as the test system. The systematical comparison between the ordinary protection strategy and the proposed strategy is carried out. The protection selectivity of the proposed local detection and local action strategy is thoroughly studied through complete DC line fault scanning of the test system. The simulation results show that the proposed strategy is of high protection selectivity and speed. In addition, the current rating and the voltage of HVDC CB could be greatly reduced with the proposed strategy, which proves the economic benefits of the proposed strategy.

Protection of Future Electricity Systems

“…Both HVDC and LVDC systems are being developed, and the protection of such networks has a separate set of challenges in terms of ultra-fast fault detection and classification requirements, fault-ride through capabilities, and DC fault current breaking. Therefore, we are pleased to present four papers [3][4][5][6] that tackle various aspects of DC network protection.…”

“…This issue is no exception. You will find some fine examples of unconventional thinking and innovation in most of the presented papers (e.g., [3,5,7,8], to highlight a few).…”

Hybrid HVDC circuit breakers with an energy absorption branch of a parallel arrester structure

“…The conventional operation principles of hybrid DCCBs are shown in Figure 4 [18]: During the steady state, the UFD and the LCS are closed, whereas the MBs are open. The DC current only flows through the normal current path. When a fault occurs on the DC side at t 0 , the dc current starts to increase.…”

Locating Natural Frequency Faults in HVDC Transmission Systems Based on the Rotation-Invariant Technology Signal Parameter Estimation Algorithm and the Total Least Squares Method

“…Common faults include single-pole faults, bipole short-circuit faults, and single-level faults. Identifying the faults that most frequently occur [5][6][7], quickly remotely locating the fault, and eliminating the fault to ensure the reliability of the power supply are particularly important tasks. e HVDC fault location scheme mainly uses two classification standards based on the distance measurement principle and the source of fault information extraction.…”