HYBRID CHAMBER WITH VACUUM AND GAS INTERRUPTERS FOR HIGH-VOLTAGE CIRCUIT-BREAKERS

摘要

SF{sub}6 technology for high-voltage circuit-breakers was introduced during the 1960's in the transmission voltages range. In the 1970's SF{sub}6 soon became the dominant medium in this range due to its excellent arc quenching and dielectric withstand capabilities. In spite of continuous researches for alternative gases, some are conducted at the present time, no other gas has been found yet that could combine both the arc quenching capability required for high voltage applications and the dielectric withstand necessary to have a reduced number of chambers per pole. Among the alternative technologies for high-voltage circuit-breakers, the application of vacuum technology has already been investigated and several contributions were presented during the CIGRE session of 2002. This report intends to present another interrupting principle were a vacuum interrupter is combined in series with a gas blast chamber to provide the required performances. During interruption of high breaking currents, the withstand of the initial part of TRV (thermal phase) is given by the vacuum interrupter and the withstand of the peak TRV (dielectric phase) is mainly provided by the gas blast interrupter. Both interrupters contribute to the dielectric withstand required for switching tests and for the insulation level. After a brief history on the matter, the report explains the interrupting principle and shows some examples of geometry where this principle has been implemented for testing. It is preferable in practice that both interrupters are operated by the same operating mechanism. Special arrangements had to be designed in order to obtain ratios of 10 or more between the strokes and velocities of the two interrupters. Tests results obtained on a full scale mock up are presented, showing the potential and limitations for the main type test duties. Comparisons are made with present interrupting techniques for high-voltage circuit-breakers. The possible uses of the hybrid technique are given in the report. It is shown that this technology allows to reduce the size and the operating energy of high-voltage circuit-breakers, and can be an alternative to present technologies in some high-voltage applications.