Predistortion Phenomenon of the Field Distortion Switch at High Repetition Frequency

The testing experiment on the field distortion switch shows that there is a predistortion phenomenon when it operate sunder electrical trigger at high repetition frequencies (>= 100 Hz),that is, the potential of the trigger electrode is much lower than the expected equipotential surface potential determined by its location during the charging stage, which makes the gap electricfield significantly distorted before triggering. This is caused by the distributed capacitance of the switch and the coupling capacitor connected between the trigger circuit and the trigger electrode. The minimum repetition frequency of predistortion is tested to be 10 Hz. Predistortion reduces the maximum operating voltage(V-max)of the switch. V-max of the test switch (static self-breakdown voltage at full insulation recovery is approximately 30 kV) is only 18.04, 17.33, 16.94, and 15.04 kV at repetition frequencies of 100 Hz, 500 Hz, 1 kHz, and 1.3 kHz, respectively, when blowing. In order to restrain the predistortion phenomenon and improve V-max, two methods are proposed: adding a compensation capacitor and adjusting the resistance of gap voltage divider. For the former, V(max)can be increased to 28.02, 26.96, 21.85, and17.06 kV, while for the latter, V-max can be increased to 25.17,21.81, 17.53, and 16.34 kV, respectively