A definite reactive compensation devices are needed in photovoltaic power plants and shunt capacitor is a kind of main reactive compensation mode. In this paper

a kind of energy-saving thyristor switched capacitor（TSC） is proposed by the authors

which can reduce efficiently the power quality problems due to switching of capacitor by mechanical switch and also overcome efficiently such shortcoming of conventional high voltage TSC as low reliability and big loss. The key point of the energy-saving TSC is in the switch

among which any two of the three phases use thyristors and AC contactors in parallel to consist into composite switch and the rest one only uses AC contactor as switching switch. During the operation period

AC current flows only in the switching on and off period of the thyristor of energy-saving TSC’s and the active loss of the thyristor is reduced significantly without radiation device. It is proved by the digital simulation on the PSCAD/EMTDC platform that this energy-saving TSC is completely feasible.