Scientific paper ID 2285 : 2022/3

Cascade voltage multipliers are a useful teaching aid in conducting laboratory exercises in the discipline ”High Voltage Engineering”. ”Todor Kableshkov” Higher School of Transport has such a high-voltage generator, designed and implemented by a team from the department of “Electrical Power Supply and Electrical Equipment of Transport”. The generator provides symmetrical bipolar high voltage, which in about 15 seconds after switching on the power reaches 5.7 kV per arm (ie 11.4 kV). It is a useful addition to the relevant laboratory. With it, numerous laboratory exercises are carried out, illustrating some of the transient processes that occur during the operation of high-voltage equipment at DC current and voltage.

In some cases, when conducting laboratory exercises, it is necessary to make series of consecutive discharges, in which the time between two consecutive discharges is minimal and depends only on the charge time of the cascade. During the one-year operation of the multiplier in the laboratory, after the generation of one such series of discharges, a dangerous asymmetry of the residual charges in the stage capacitors was noticed, caused by a difference in the capacities of the ”accumulating” capacitors.

The paper describes the way in which the measurements were made to detect the problem, and a method was developed to solve it. An advanced version of the circuit diagram of the cascade multiplier is presented.