Arc Collection And Characteristic Analysis Of DC Circuit Breaker Transferring Current

In recent years, with the rapid development of the high-voltage DC transmission project, the application of DC becomes more and more widely, the demand of the DC circuit breakers becomes larger and larger, the requirement of the reliability become more and more strict. DC transmission has huge advantages in long-distance and large-capability transmission, which reflects the importance of DC circuit breakers. The interruption of DC circuit is difficult because of having no zero-crossing point in comparison with the interruption of AC circuit. The method of current transfer achieves the interruption of DC circuit by rejecting a reversed current on the normal DC current to create the zero-crossing point.The Mayr arc model was established by Matlab/Simulink to simulate the process of current transfer, and the variation of the current and the voltage across the fracture were analyzed in the article. ATMEGA16L was used as main control chip to design time schedule controller and speed setting controller in the control system. The sequential control was achieved by exploiting keyboard and LCD12864on the time schedule controller. The speed adjustment of main breaker was achieved by collecting the voltage of capacitor and exploiting PWM control principle and designing bridge circuit of IGBT. The speed setting controller passed electromagnetic compatibility tests successfully and realized control of the experimental circuit successfully.In order to imitate DC interruption, we obtained the oscillating current by the oscillation circuit which was composed of capacitors and inductors, and the reversed current was generated by high-frequency circuit. The form and feature of DC arc was received by analyzing the arc images which were collected by high-speed camera during the interruption process by digital picture processing technique. The preferable arc images were collected by adjusting the parameters after the dispersion test and sequential control test and speed regulation control test on the experimental facilities. The curve of arc area was obtained by the binaryzation of arc images by Matlab. Compared with ordinary AC arc, the feature of change of the arc area during the DC interruption was obtained. It turned out that the arc can be extinguished more easily with a higher speed by research on the variation of the arc area at different speed within limits.