25 th International Conference on Electricity Distribution Madrid, 3-6 June 2019 Paper 1170 CIRED 2019 1/5 AN EVALUATION OF V2G FOR DISTRIBUTION NETWORK HARMONIC SUPPRESSION Preye IVRY Jin YANG Jim SCOTT Nortech Management Limited – UK Aston University – UK Grid Edge Limited – UK preye.ivry@nortechonline.co.uk j.yang8@aston.ac.uk jim.scott@gridedge.co.uk Zhengyu LIN Clara SERRANO Graham GISSING Aston University – UK Aston University – UK Aston University – UK z.lin5@aston.ac.uk c.serrano@aston.ac.uk gissingp@aston.ac.uk ABSTRACT Vehicle-to-Grid (V2G) is an emerging application of plug- in electric vehicles communicating with power grids to provide energy or ancillary services. Power quality improvement is one of the possible benefits of V2G systems. In this paper, V2G is evaluated as a means to improve distribution network power quality via harmonic suppression. Based on a V2G trial project, simulations were conducted with practical power quality parameters monitored and collected from installed charging points with V2G functions. Both the simulation and practical results revealed an improvement in voltage rms value but an increase in current harmonics during V2G operation. On the other hand, V2G had no significant effect on voltage harmonics. Lastly, potential solutions on how to suppress current harmonics were proposed. INTRODUCTION The drive to decarbonise electricity, heat and transport is currently transforming electric power systems globally as large amounts of distributed energy resources (such as PV, wind turbines, battery storage and plug-in electric vehicles – PEVs) are connected at the distribution network level. These distributed energy resources can export power back to the distribution network and when PEVs are used for this, it is called Vehicle-to-Grid (V2G). V2G is a concept where energy stored in the battery of a PEV is used to provide grid support or other ancillary services with the consent of the PEV owner and in return for financial incentives. V2G application can provide benefits such as the increased use of localised renewables, energy arbitrage, peak shaving, load balancing, demand response, frequency response and voltage support [1]. Another benefit of V2G is that it can be used to improve power quality on the grid by reducing the harmonics on the network when operated as active power filters [2, 3] but as most Power Electronic Converters (PEC) generate harmonics [4] it may be difficult to justify this approach. Refs [2, 3] carried out simulation studies and showed how harmonics generated from non-linear loads and Electric Vehicle Supply Equipment (EVSE) may be suppressed when the EVSEs are operated in the V2G mode. However, they did not consider this for different OEM’s V2G. In the real world, different OEM’s V2G unit s will have different PEC and harmonic filter configuration. This means each V2G unit will have different harmonic profiles when charging (Grid-to-Vehicle – G2V) or discharging (V2G) an EV. The net effect of this cannot be easily predicted via simulation or via a demonstration using only one OEM’s V2G. In this paper, we aim to evaluate the effect of V2G operation on distribution network harmonics using realistic power networks at two sites in Aston University’s campus and as part of the VIGIL (VehIcle to Grid Intelligent controL) project. Both sites have a mix of different OEM’s EVSE with V2G capability. The paper will look at the current and voltage individual harmonics, total harmonic distortion (THD) and total demand distortion (TDD) at several points on the network, and compare this to several international standards (IEEE 519 [5], ENA ER G5/4 [6], IEC 61000-3-2/12 [7]). The paper will explore methods for improving power quality and reducing harmonics on a distribution network via proper sizing of active power filters and/or adapting control schemes of EVSEs in V2G mode. The outline of the paper is as follows: An introduction is given for the VIGIL project and the two V2G trial sites used for the practical studies on live networks. Then it presents and analyses the MATLAB/Simulink simulation results of the two sites, followed by the presentation of the live trial results for one of the sites. Lastly, it discusses how V2G and active power filters can be used to improve the power quality on a distribution network. VIGIL PROJECT AND TRIAL SITES The VehIcle-to-Grid Intelligent controL (VIGIL) project aims to develop, build and trial an off-vehicle control platform (see Figure 1) that aggregates energy at different substations and controls the bidirectional flow of power from Electric Vehicle (EV) batteries with respect to the local substation network constraints and the EV/building energy requirements.