Dynamic dielectric recovery performance of serial vacuum and SF₆ gaps in HVDC interruption and its regulation method

Abstract

Vacuum gaps have rapid dynamic dielectric recovery speed while SF 6 gaps have high insulation strength. The series-connected vacuum and SF 6 gaps are used as the main switch (MS), which combines their advantages. The work aims to verify the feasibility of serial vacuum and SF 6 gaps in mechanical HVDC interruption. The test circuit of the dynamic dielectric recovery performance (DDRP) is set up. The DDRP is tested under free recovery condition by the high voltage pulse source. The DDRP of the vacuum circuit breaker (VCB) and SF 6 gas circuit breaker (GCB) in DC interruption with active current injection is analyzed and compared. The test results indicate that the dielectric recovery duration of the VCB is below 30 μs while that of the GCB is above 100 μs. In order to achieve the cooperation between the VCB and GCB, a novel hybrid HVDC circuit breaker (CB) based on series-connected vacuum and SF 6 gaps is proposed. The 'voltage-zero' duration is created by introducing the follow current loop and there more recovery time for the dielectric recovery of the MS. The voltage distribution is controlled by the voltage dividing method so that the VCB undertakes the initial transient recovery voltage (TRV) and the later TRV is took by the GCB. The theoretical synergy characteristic of the novel HVDC CB is obtained. The paper supplies a new method to improve the custom mechanical HVDC CB, which is useful to achieve the HVDC CB with less serial breaks.

Factors and Underlying Mechanisms That Influence the Repetitive Breakdown Characteristics of Corona-Stabilized Switches

“…(1) distorting the re-applied electric field, and (2) affecting the initiation and development of streamers [30,31]. Therefore, this section analyzes the impact of switch parameters on repetitive breakdowns based on these two aspects as follows.…”

Research on the energy consumption mechanism and characteristics of the gallium indium tin liquid metal arcing process

“…With the development of higher-level DC transmission, the DC circuit breaker is required to consume huge energies within 10-20 ms. With the traditional energy consumption method, the number and volume of ZnO resistors need to be continuously increased. This leads to a significant increase in cost and cannot meet the development requirements of HVDC power grids in the future [1][2][3]. GaInSn liquid metal has the advantages of small size and fast energy consumption for use in DC circuit breakers and will become the focus of research in the future.…”