Abstract: A synthetic test circuit for testing a metal-encapsulated high voltage circuit breaker of a type which is grounded on one side and which includes several switching gaps arranged in series. The testing circuit includes a high voltage source and a high current source for stressing the switching gaps during testing and, in addition, a high voltage means for applying a high voltage to the encapsulation simultaneously with the application thereto of a further voltage from the high voltage source. The high voltage is chosen to be of opposite polarity to the further voltage and the encapsulation is insulated from ground potential during application thereof.

Abstract: A surge voltage arrester contains a series circuit arrangement of spark gaps and voltage-dependent resistors. The voltage-dependent resistors include a semi-conductive material having an exponent .alpha. of voltage dependence which is at least 10. The surge voltage arrester makes it possible to manufacture high-capacity surge voltage arresters with spark gaps exhibiting a very simple construction. This effect is based on the fact that the voltage-dependent resistors assume the actual arrester function and the spark gap, therefore, are essentially only used for switching the arrester on and off. The arrester is particularly suitable for application in networks for electrical power distribution.