Device and method for measuring bus voltage phase of capacitor voltage transformer

The invention relates to a device and method for measuring a bus voltage phase of a capacitor voltage transformer. The device comprises a first current transformer, a second current transformer and a current vector collection and computation unit. The method comprises the following steps: connecting the first current transformer and the second current transformer into a ground terminal of a middle voltage capacitor and a ground terminal of a middle transformer of the capacitor voltage transformer respectively, respectively feeding coupled current signals into the current vector collection and computation unit by the first current transformer and the second current transformer, conducting processing such as amplification and filtering on collected current signals, converting the current signals into digital signals, and computing the numerical value to obtain the instantaneous phase of the bus voltage of the capacitor voltage transformer. The device and method are accurate in measuring, good in real-time performance, simple in wiring, small in influence on the capacitor voltage transformer, safe and reliable.