The main form of electrical discharge in long air rod-rod gaps is broken down by leader mechanism. The leader development in rod-rod gaps under positive switching impulse was investigated by using two high-speed CMOS cameras. The clearer and more particular colorized physical morphology of the leader propagation process than the traditional image converter cameras was recorded and the leader development parameters were also obtained. As a comparative study, an improved simplified model for the rod-rod configuration was performed to simulate the leader development. The numerical simulations of leader development characteristics were in a close agreement with that of experimental measurements. From the experimental measurements and simulated results, it is obtained that the negative upward leader is incepted at the beginning of the final jump stage and develops to the positive downward leader. Moreover, the propagation velocities of both leaders are almost equal and keep gradually increase with the decrease of the distance of the rest gap. The length of the negative upward leader is almost half of the final jump distance.
KEY WORDS :positive discharge;switching impulse;leader development;rod-rod air gap;simulation;
图8
3m棒-棒间隙自由发展阶段先导发展特性(仿真条件同Fig. 8
Discharge characteristics for the 3m rod-rod configuration (same conditions as Fig. 2) during the free development stage
图9
3m棒-棒间隙约束发展阶段先导发展特性 (仿真条件同图2,施加电压1150kV)
Fig. 9
Discharge characteristics for the 3m rod-rod configuration (same conditions as Fig. 2) during the constrained development stage
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