The utility model provides the utility model discloses a high tension switchgear partial discharge detector's TEV sensor including the shell, is provided with the magnetic base, capacity coupler, signal processing module, wireless transmission module and power module in the shell, the said capacity coupler differential coupling capacitance structure that two coupling capacitance pole pieces constitute of serving as reasons, two coupling capacitance pole pieces set up respectively at the both ends of shell bottom surface, and signal processing module's input is connected to the electrode of coupling capacitance pole piece, and power module's output is still connected to signal processing module's input, and wireless transmission module is connected to signal processing module's output, the magnetic base sets up on the coupling capacitance pole piece. The utility model discloses can guarantee that the sensor can closely adsorb the transient state voltage-to-ground that detects the partial discharge production at the cubical switchboard on the surface when detecting, have higher accuracy