Mitton ElectroNet was chosen because of its specialist knowledge in Earthing Design, Modelling and Testing.

Project Overview & Design

The testing involves injecting 58Hz current into each earthing system to simulate an earth fault and create an earth grid voltage rise (EGVR). The EGVR is measured to determine the earthing system impedance, as well as touch and step voltages to determine if any hazardous voltages would be present in the event of a fault.

A number of the substations tested have been located in unique locations such as gold and coal mines providing our team with challenging and interesting working environments. Our test teams are fully equipped to handle challenging environments and most weather conditions- with the substations being located on the West Coast of the South Island, battling the ability to work in bad weather proved to be challenging.

Testing was carried out using low current off-frequency injection methods using a portable solid state injection unit and tuned voltmeters.

Project Outcome

All sites were tested successfully within the set time frame. Mitton ElectroNet provided a comprehensive report to Westpower Ltd detailing the earthing condition of their network and made recommendations regarding improvements  to mitigate any potential hazards deviations from industry standards and limits.