The accuracy of 10 kV synchronous vacuum circuit breaker consists of two aspects:the measurements accuracy and the phase accuracy. Little research has been focused on the measuring accuracy problem of power system acquisition device

which results in error between measurements and actual value. In this paper

a novel voltage measuring circuit with capacitor is designed

and the error of this acquisition device is analyzed in terms of numerical precision and phase accuracy. The calculation errors of switching phase angle and power value caused by temperature variation are discussed as well. The voltage acquisition system features small size

light weight

low cost

and small power consumption

and satisfies the demands of engineering.