| Abstract: | A comparative analysis made in 1, 2] of different types of regulable high-voltage dischargers with liquid insulation showed that trigatrons are currently the most promising for use in high-voltage pulse-operated devices due to their simplicity and reliability. Two basic mechanisms of discharge initiation can be realized in trigatrons — initiation by intensification of the field in the region of the control electrode 2, 3], and triggering by a spark in the ignition gap 4, 5]. The first type of trigatron has been studied sufficiently only for short voltage periods 3, 6, 7], so it is used mainly in switching the pulse-shaping lines of powerful nanosecond pulse generators with  rapid (0.5–1.5  sec) charging 8, 9]. Almost no use is now made of the second type of trigatron switch in high-voltage pulse technology due to its unsatisfactory time characteristics. Here we report results of a study of the time characteristics of both types of oil-filled trigatrons operating in a regime whereby they form the leading edge of rectangular voltage pulses with amplitudes up to 800 kV and durations of 1–100 sec. The goal is to find the optimum conditions for triggering of trigatron dischargers with liquid insulation in the region of microsecond voltage discharges. Experiments were conducted on the unit in 10]. The test discharger was placed in a cylindrical chamber 45 cm in diameter and 27 cm in length. The high-voltage electrode of the discharger was in the form of a cylinder 20 cm in diameter positioned coaxially inside the chamber. The 10-mm-diameter ground electrode was positioned radially in a branch pipe 8 cm long. The control electrode was placed in a 2-cm-diameter hole in the center of the ground electrode. The chamber with the test discharge was filled with transformer oil with a breakdown voltage of about 50 kV. The oil was not replaced or cleaned during the experiment. We did not find that contamination of the oil by discharge products had any effect on the time characteristics of either type of discharger. The results were analyzed by the least squares method, with 50 measurements to a point (it was found that time lag of the discharger triggering conforms approximately to a normal distribution law for both types of discharger).Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 6, pp. 26–31, November–December, 1986. |
