Abstract: An overvoltage protection device for metal-encased, gas-insulated high-voltage lines is disclosed. The device includes a low pass filter which comprises an inductance connected in series with the inner conductor of the high voltage line, and a capacitance connected between the inner conductor and the grounded casing. The inductance and capacitance form the low-pass filter which serves as a trap for high-frequency traveling waves. The invention is especially suited for protection of metal-encased and gas-insulated high-voltage lines and installations in conjunction with a conventional overvoltage arrester.

Abstract: A contact system for a high-voltage power circuit breaker wherein the contact system includes first and second hollow contacts which have end faces which rest against one another under pressure in the "on" position or condition of the breaker and which separate to form a gap in the "off" position of the breaker. In accordance with the invention, the contact system is further provided with a number of spring-loaded contact means arranged at the end face of one of the contacts for forming with the current path of that contact current loops for aiding the spring force provided by the contact means.

Abstract: The invention is directed to a contact arrangement in a compressed-gas circuit breaker such as a blast-piston breaker. The contact arrangement includes two base contacts and a bridging contact member. One of the base contacts is movable as a function of the current to be interrupted and the motion is controlled by two electrodynamic coil systems. One coil system causes a shortening of the gap and the other coil system causes a reverse motion shortly before the zero crossing to establish the quenching distance.

Abstract: An arrangement for testing metal-clad, high-voltage installations includes an equipment unit having a separate encapsulation for accommodating the apparatus for making the tests. The separate encapsulation can be flanged as a unit to the installation to be tested. The arrangement is particularly suited for detecting partial discharges in metal-clad, high-voltage installations which are filled with an insulating gas, such as sulfur hexafluoride.