A coupling voltage based adaptive reclosing scheme for flexible DC grid

The total electric field around the DC line is composed of both the ion flow field produced by coronae and the electrostatic field produced by the conductor charge. Under the effect of the total electric field, the disconnected pole will generate a coupling voltage. Therefore, based on the coupling voltage, this paper proposes an adaptive reclosing scheme for flexible DC grid to prevent power supply interruption caused by temporary fault. First, the disconnected pole coupling voltage (DPCV) under the total electric field is analysed when single pole to ground fault (SPGF) and pole to pole fault (PPF) occur respectively. Then, according to the DPCV difference between permanent fault and temporary fault, a fault property identification (FPI) criterion is constructed. The scheme is very simple and not affected by the transition resistance, fault position and wiring mode which has high reliability. Compared with the non-selective reclosing strategy, the adaptive reclosing scheme can avoid the secondary impact on the system from the permanent fault. Extensive simulations and experiments verify the effectiveness of the proposed adaptive reclosing strategy.

Automated summary

This paper proposes an adaptive reclosing scheme for flexible DC grids to prevent power supply interruption caused by temporary faults. The scheme analyzes the disconnected pole coupling voltage under the total electric field and constructs a fault property identification criterion based on the difference between permanent faults and temporary faults. Extensive simulations and experiments verify the effectiveness of the proposed strategy.