| Popis: |
Aiming at the phenomenon that the arcing time is different when SF6 circuit breaker interrupts capacity current under the conditions of positive and negative polarity. So the capacity current breaking test by SF6 circuit breaker is used to study it, which can provide reference for the optimization of SF6 arc extinguishing chamber. In this paper, the interrupter structure of test prototype is introduced. Electrode reversal is analyzed when the static parts of SF6 circuit breaker is connected with capacitive loads. According to CB2 in GB 1984–2014, The back-to-back switching capacitor group test is completed in the 40.5kV SF6 self-circuit breaker prototype. Opening speed of test prototype is 3.85m/s. The main test parameters are as follow, closing surge peak is 26kA, inrush frequency is 4050Hz, the valid values of opening current is 826A. In the condition of positive and negative polarity, 83 times CO operations are completed in test prototype. The test result is that restrike did not occur. When the static part of breaker is connected with capacitive loads, the short arc time under the negative polarity condition is longer than that of the positive polarity. And the short arcing time is 0.9ms and 1.6ms, respectively. The results indicate that the 40.5kV self-energy SF6 circuit breaker can meet the requirements of power system to switch capacitor group. The polarity effect is existed in slightly uneven electric field inside of arc chamber. The short arcing time is longer when static arc contact is cathode during current-zero zone. |
