Power Quality in Islanded Microgrids supplied by Vehicle-to-Grid: Norwegian Pilot Study

Abstract

This paper presents vehicle-to-grid (V2G) tests performed in the microgrid at university Campus Evenstad, Norway. The purpose of the tests was to investigate the power quality in the connection point to the grid during transitions to/from island mode. These transitions are generated by disconnecting and reconnecting the microgrid from the surrounding distribution grid. During the short islanding period, the energy in the microgrid is supplied by an electric vehicle (EV) battery, in interaction with battery energy storage systems (BESS). The frequency, voltage variations, and voltage harmonics are measured and found to be within the Norwegian regulatory limits. However, high current spikes (500-800 A) and irregular current and voltage waveforms are observed during the transitions. The test results show that an EV battery, in interaction with BESS, can supply a microgrid within the regulatory limits of power quality. Hence, V2G can contribute to supplying loads in microgrids during supply interruptions.