Sensitivity Analysis of Corona Discharges Measuring Instruments Using Different Electrodes and High Voltage Supplies

Abstract

Corona discharge testing is critical to ensuring the safety, performance and reliability of high-voltage (HV) equipment and systems. Due to the high cost of shielded laboratories, many manufacturers test their components in unshielded laboratories for applications, such as product research and development or quality control. This letter compares the sensitivity of two corona detection instruments in an unshielded laboratory. The sensitivity of an electrical detector according to IEC 60270 in combination with a measuring impedance and a coupling capacitor is compared with that of a digital single lens reflex (DSLR) camera. In addition, needle-to-plane and sphere-to-plane electrode geometries are studied under different types of high-voltage power supplies, i.e., 50 Hz ac, positive dc, and negative dc. Experimental results performed in an unshielded high-voltage laboratory show that although the DSLR camera is not a standard method for partial discharge (PD) detection, it has similar sensitivity to the conventional electrical method according to IEC 60270 in all cases analyzed, and that the digital camera behaves much better in pulseless glow corona mode.