World-first electricity monitoring device developed

The market for measuring energy use in the home is huge and is set to grow further as we increase smart meter use. All home energy management systems rely on power measurement, usually by a single core current clamp sensor on the incoming live wire.

However, this only gives the user a reading for the total electricity use and does not provide information on which parts of the house use most power. Individual monitors on each appliance can provide this data, but require access to sockets and the appliance to be powered down for fitting and removal.

Dr Reuben Wilcock, Enterprise Fellow at the University of Southampton, and PhD student Robert Rudolf have developed a multicore clamp sensor that can measure current flowing in any accessible mains cable, giving a more detailed picture of electricity usage in the home. Through extensive modelling and analysis, they have shown that they can calibrate the device and accurately measure mains cable current to a full scale of 16 amps with an accuracy of better than 1%.

“This is a world first,” said Dr Wilcock. “Many people have tried to do this but non-invasive measurement of current in two- or three-core mains cables is extremely challenging because an equal and opposite current flows in the live and neutral wires, cancelling out the field you are trying to measure. Our system addresses this challenge by using state-of-the-art sensors and elegant calibration and measurement algorithms.”

The new clamp is also suitable for industrial power monitoring. Many industrial machines are permanently wired in and have no plug to accommodate a conventional energy monitor. The system will also be invaluable for office energy audits, reducing the need to turn off equipment for fitting and removal, and for electrical test equipment to help electricians find faults.

“There is a £50 billion market for energy management systems in the residential sector alone,” said Don Spalinger, Director Research and Innovation Services at the University of Southampton. “Reuben and Robert’s invention has the potential to significantly impact not only the home, but also the office and industrial sectors. The innovation of a non-invasive device to measure the power utilisation of individual equipment will add a whole new approach to the markets, and we see commercialisation of this being done very quickly.”

Dr Wilcock and Rudolf now have the opportunity to take their multicore current clamp to market as joint winners of this year’s Royal Academy of Engineering ERA Foundation Entrepreneurs Award. The award was established by the ERA to identify entrepreneurial researchers in UK universities, working in electrotechnology and at an early stage of their careers, and to enable them to commercialise their research.

Dr Wilcock and Robert will receive the award at the academy’s awards dinner in London on 17 July.