Development of a high voltage sensor using a piezoelectric transducer and a strain gage

The authors describe the principle and design of an AC high-voltage sensor. When an electric stress is applied, this sensor accurately detects the mechanical strain of a piezoelectric transducer on which a foil strain gage is cemented. Two types of these sensors were designed, and a high-voltage measuring system using them was manufactured for trial. To confirm the frequency response of the trial sensors, an impedance of the trial piezoelectric transducer was performed using a YHP impedance analyzer, and the response-confirmation test of its vibration mode was carried out at the same time. Theoretical and experimental analyses are discussed in terms of the relation between the strain on the piezoelectric transducer and the applied sinusoidal AC voltage. It was ascertained that the strain was directly proportional to the voltage measured, and it was found that the measured percentage errors were less than ±2% for voltages up to 26000 V_p-p