抄録
In recent power systems in Japan, in some special districts, extremely high parallel capacitances have been connected, such as high capacity shunt capacitor banks for the purpose of voltage stability enhancement and EHV cables transmitting powers to large cities. As for short-circuit breaking currents for circuit-breakers, till now a days, only power frequency and dc components, both of which are supplied from the power sources, have been considered. Regarding the transient components due to the discharges of the parallel capacitances, because of relatively high frequencies and high damping rates, little attention has been paid. But due to the increase of the parallel capacitance values resulting higher amplitude and lower frequencies of the transient components, and also introducing facilities with low loss rates, the effect of the transient compo-nents on circuit-breakers' performances may not be possible to be disregarded
Introducing a model power system covering the conditions of today and near future, and applying EMTP, with reviewing the simulation accuracy comparing with field measuring data, some calculations have been performed. The results show the possibilities of cer-tain effect on circuit-breaker performances in the, especially, thermal mode of quench-ing phenomena such as breakings of short-line fault currents.
