JPS6465812A - Transformer protective device - Google Patents

Abstract

PURPOSE:To avoid a local concentration of potential by a method wherein a filter composed of an LC series circuit is connected between the terminals of a transformer, the resonance frequency of the filter is allowed to coincide with to the resonance frequency of the transformer winding, and the admittance value against the admittance of the transformer in the vicinity of the above- mentioned frequency is increased sufficiently. CONSTITUTION:An AC power source 5 is connected to a vacuum circuit-breaker 3 through the intermediary of a power cable 4, and the AC power source 5 is connected to the primary side winding of a transformer 1 through the interme diary of the filter 2 consisting of a capacitor 21 and a coil 22. In this constitu tion, the inductance of the coil 22 is set at LF, the capacitance of the capacitor 21 is set at CF, the equivalent resistance of the coil and the capacitor is set at RF, the equivalent impedance constituting the impedance in the vicinity of the resonance frequency of the transformer winding is set at Lr, equivalent capacitance is set at Cr, the product of LF and CF is made equal to the product of Lr and Cr when the equivalent resistance is indicated by the series circuit of Rr, and the LF is made smaller than the Lr, and the RF is also made smaller than the Rr.