On-site Waveform Characterization at Static Meters Loaded with Electrical Vehicle Chargers

Abstract

For assessing the underlying problem behind the static meter misreadings, a measurement technique must be developed for characterizing the currents that static meters are usually exposed to. In previous studies it was shown that misreadings of the static meters occur when impulsive currents are drawn from the net, even with standalone commercial off the shelf equipment. Time domain electromagnetic interference (EMI) measurements create a novel opportunity for analyzing these noisy waveforms and identifying their fundamental parameters. The next step is extending this measurement approach to on-site scenarios in which these kind of waveforms coexist in superposition with other components that are properly measured by the static meter when they occur alone. This especially holds for up and coming technologies like electric vehicle (EV) charging stations. The characterization is intended in the future for describing realistic waveforms that can be used as new standardized type-testing signals, which will be employed to produce novel standards. Time Domain Electromagnetic Interference Measurement and Post-processing System (TEMPS) software is used in conjunction with a low cost baseband digitizer to measure the waveforms of EV chargers on four different lines, that is the three phases (L1, L2, and L3) and the neutral line (N) simultaneously. To distinguish the impulsive nature of the waveforms a statistical approach is performed in the form of an amplitude probability distribution (APD) diagram. Furthermore the multichannel capability of the low cost digitizer is utilized to achieve a frequency range extension by using two probes simultaneously with different frequency ranges.