This tutorial covers the errors in measurement from revenue meters due to the presence of harmonics at the metering point. The cause is the lack of adequate requirements or tests catering for non-sinusoidal conditions in most present meter specifications. Consequently meters can comply with specifications and yet give incorrect readings in the presence of harmonics.
The tutorial presents a practical example illustrating the problem, followed by a discussion on whether revenue meters should include harmonic energy or not. The tutorial then reviews power definition models and meter specifications and tests to identify harmonic power components. The definitions in the IEEE-1459 model were applied in a commercial Smart Meter by modifying the meter’s firmware, and the reprogrammed meter was tested against harmonics tests in the OIML R46 and IEC 62053-24 specifications. Finally, several reprogrammed meters were installed in the field for a year to determine the impact of the fundamental-only power definitions on meter readings and bills for various customers. The tutorial will conclude with a live demonstration of the reprogrammed meter applied to linear and nonlinear loads.
Andrew Berrisford was born in Cape Town, South Africa. He started work at Eskom in 1974, and after completing his National Diploma in Electrical Engineering (Light Current) he joined the Electrical Measurements Section of Eskom’s R&D Department, where he developed an interest in power definitions. Here he was exposed to the fact that two kWh meters could give significantly different readings in the field due to harmonics, while both complied with meter specifications and therefore were deemed to be correct. Mr. Berrisford started Eskom’s Load Research team in 1989 and spent several years developing load research applications in the Forecasting, Rates, IEP and DSM Departments. He completed his MSc in Electrical Engineering at the University of the Witwatersrand in 1997, left Eskom to start a consultancy, and immigrated to Canada in 2000. He has provided technical leadership to the Load Research team at BC Hydro in Vancouver, BC, Canada, since 2004. Mr Berrisford’s interest in power definitions for revenue metering has continued with his involvement in the IEEE-1459 Standard and the JWG between the CEA Metering Task Group and Measurement Canada. He has presented papers at local and international conferences on electrical metering, load research, and related topics.