Experimental study on characteristics of post-arc current of high voltage gas circuit breaker

Post-arc thermal recovery property has a significant influence on the interruption capability of gas circuit breakers (GCB) and the influence of various factors on characteristics of the post-arc current was investigated experimentally in this paper. At first, a test circuit breaker was designed and produced based on a 126 kV puffer type SF₆ circuit breaker. A series of experiments under different current phase  (20°, 50°, 80°), current value I(12 kA, 18 kA) and filling gas pressure P(0.5 MPa, 0.6 MPa, 0.7 MPa) were carried out then. The high-frequency measuring system was employed to provide assistance for recording basic data on arc current during current-zero period. Comparison of the post-arc current under different conditions reveals that the probability of arc reignition grows with the increase of . Ascending speed of post-arc current is 1.03 A/s and 2.08 A/s respectively when  equals to 50° and 80° while breakdown doesn't happen when  equals to 20°; post-arc current and its ascending speed current becomes higher with increase of I. Ascending speed of post-arc current is 1 A/s and 2. 05 A/s respectively when I equals to 12 kA and 18 kA; post-arc current decreases with increase of P. The critical value of the post-arc residual current may be defined as the criterion of the thermal interruption due to the relevance between them.