A NIST Testbed for Examining the Accuracy of Smart Meters under High Harmonic Waveform Loads
Richard L. Steiner, Michael P. Farrell, Shannon Edwards, Thomas L. Nelson, Joni Ford, Sumaiyah Sarwat
Household and industrial electrical energy measurements are advancing into a Smart Grid stage, using solid-state watthour meters with communication capability, called Smart meters. As electrical products become heavily based on solid-state designs, such as LED lighting and dimmers, electrical loads are not purely resistive, but contain voltage and current spikes, introducing relatively high harmonic power to the grid. This paper describes a testbed laboratory that attempts to model LED household lighting loads, measure the energy by Smart meter and power analyzer, and correlate offsets to the waveform variations. Preliminary results show that, with large current crest factors up to about 10, two meters (same manufacturer) out of eight tested show an error near 4%. Three meters showed no variation outside a 0.07% standard deviation that was typical for their normal repeatability.