Equipotential shielding voltage sensor for contact measurement of transient voltage in EHV/UHV power grids

In this study,an equipotential shielding voltage sensor is proposed to achieve contact measurement of transient voltage in extra-high voltage(EHV)/ultra-high voltage(UHV)power grids.Two design versions of the voltage sensor for engineering application are described.One version of the sensor is designed as a miniaturized sensor for non-dis-turbing measurement of potential distribution along power electronic equipment under transient voltage.The other version is designed for online measurement and monitoring in alternating current EHV/UHV power grids.Based on the design parameters,the performance of the sensor is evaluated,including stability of measurement,shielding effect against the interference from adjacent objects and frequency bandwidth.In order to verify the performance of this sensor,an experimental comparison between this sensor and a standard capacitive voltage divider used in high voltage laboratory was carried out and the results of comparison are presented.The results show that the difference of measured peak voltage between the two devices is no more than±5%,and the difference of measured time parameters between the two devices is no more than±15%.