Abstract: Disclosed is a base agent for electrical insulating oils, which mainly contains an esterified product of glycerin and a linear or branched, saturated or unsaturated fatty acid having 6-14, preferably 8-12 carbon atoms. This base agent for electrical insulating oils is excellent in electrical characteristics, oxidation stability, cooling characteristics, flame retardance and safety. In particular, this agent for electrical insulating oils can meet energy/environmental problems by using an edible oil and fat, which is obtained by using a fatty acid derived from a vegetable oil as a raw material, as the linear or branched, saturated or unsaturated fatty acid having 6-14 carbon atoms.

Abstract: Disclosed is a base agent for electrical insulating oils, which mainly contains an esterified product of glycerin and a linear or branched, saturated or unsaturated fatty acid having 6-14, preferably 8-12 carbon atoms. This base agent for electrical insulating oils is excellent in electrical characteristics, oxidation stability, cooling characteristics, flame retardance and safety. In particular, this agent for electrical insulating oils can meet energy/environmental problems by using an edible oil and fat, which is obtained by using a fatty acid derived from a vegetable oil as a raw material, as the linear or branched, saturated or unsaturated fatty acid having 6-14 carbon atoms.

Abstract: A control circuit for an inverter for converting DC voltage to AC voltage, operable in an individual mode and an interconnection mode, and including a synchronous compensating circuit in which, when the inverter is operating in a power system synchronous operation mode under control of a synchronous-interconnection control system, a quantity of an instantaneous voltage variation component occurring in the power system is separated, in order to detect respectively, a quantity of the variation of the component in same phase with a reference voltage vector of the output voltage of the inverter, and a quantity of the variation of the component orthogonal to the reference voltage vector. The detected variation quantities are respectively added to the outputs of a voltage adjuster and a phase adjuster in the synchronous-interconnection control system. The circuit is capable of compensating an instantaneous variation of the power system without a decrease of circuit stability.