ERA has invested in new state of the art equipment for monitoring the condition of HV electrical equipment. The HVS Longshot instrument from IPEC and HV Solutions measures partial discharge activity generated within high voltage insulation in cables, switchgear and transformers.

Partial discharges are small electrical discharges within insulation which do not bridge the gap between two electrodes. The partial discharge activity is detected using high frequency current transformers,acoustic sensors and capacitive couplers. These devices can be attached to earth bonds and metallic enclosures without having to de-energise the HV equipment.

	ERA's investment also includes a portable transponder/pulse booster so that partial discharges can be located in cables over 5km in length. This is a powerful technique where partial discharge pulses sent from a remote location are detected at the far end of the cable and a large 100V pulse is sent back down the cable to the monitoring position.

In this way small discharges which would in time cause a cable failure can be accurately
detected. The new equipment was demonstrated in the 11kV susbstation at ERA on the 14th May 2004 with representatives from IPEC, HV systems and Red Phase Instruments.