C I R E D 22 nd International Conference on Electricity Distribution Stockholm, 10-13 June 2013 Paper 1500 CIRED2013 Session 5 Paper No 1500 DISTRIBUTION NETWORK PLANNING IN PRESENCE OF FAST CHARGING STATIONS FOR EV Gianni CELLI, Susanna MOCCI, Fabrizio PILO, Gian Giuseppe SOMA University of Cagliari – ITALY celli@diee.unica.it susanna.mocci@diee.unica.it pilo@diee.unica.it ggsoma@diee.unica.it Rocco CICORIA, Giuseppe MAURI RSE S.p.A. – ITALY rocco.cicoria@rse-web.it giuseppe.mauri@rse-web.it Enrico FASCIOLO, Gianfranco FOGLIATA A2A Reti Elettriche – ITALY enrico.fasciolo@a2a.eu gianfranco.fogliata@a2a.eu ABSTRACT The concept of electrical-mobility in opposition to the present oil-mobility is becoming even more attracting worldwide. Fast Charging Station (FCS) refers charging stations with nominal power equal or higher than 50 kW. Consequently, FCS requires high power and they must be connected to MV networks. For that reasons, it is crucial to analyze these situations and to model the impact of FCS on the electric network, in order to correctly plan the expansion of the MV system. In the paper, specific studies will be performed on a real MV distribution network of the A2A utility sited in the district of Brescia (Italy), in order to quantify the impact of the FCS and to identify the most suitable planning solutions needed to allow the effective integration of EV and boost electric mobility. INTRODUCTION The transport sector currently relies on fossil fuels, causing a significant part of greenhouse gas emissions. The passenger car is the major consumer of energy, accounting for more than half the total transportation energy. In this context, under the pressure of even more severe environmental constraints, the electrification of the transportation sector is becoming even more attractive worldwide, due to the dependency reduction form liquid fuels in this sector and the increment of primary energy sources diversity used in countries’ energy mixes. The electrical mobility is founded on the usage of battery powered electric vehicle (EV) and Plug-in Hybrid Electric Vehicle (PHEV) as the main future technology to combat greenhouse gas emissions [1]. Key questions are when and where drivers would recharge their vehicles. The primary source of charging will rely on normal charging boxes, located at home or in the parking at work and operated manually by the driver or, preferably, managed remotely by a suitable control system (of the local distributor or of an independent aggregator) [2]. In both cases, 3 kW AC slow chargers will be spread in the LV network (home chargers) or concentrated in some parking lots and connected to the LV or MV network. It should be observed that without controlled charging, large deployment of electric mobility could increase power flows in the distribution networks, particularly during peak electricity demand, causing critical network operation conditions (feeders overloading and voltage drops) [3]. Alternative to the slow charges, fast charges will occur when previous charging options are not available or when, in the middle of a trip, the battery approaches minimum SoC (State of Charge). Fast charging refers to DC charging stations with nominal power equal to or higher than 50 kW. Some European OEMs expect a charging rate of up to 100-120 kW for a typical EV battery as a realistic target for DC fast charging in year 2020. Consequently, a Fast Charging Station (FCS) will be characterised by high momentary peak power absorptions and they must be connected to MV networks. For those reasons, it is crucial the representation of the FCSs in order to assess their impact on the electric distribution network and to correctly plan the expansion of the MV system. The first step of this representation is the daily profile of the power demand absorbed by an FCS during the day. In the recent Literature, some models were proposed starting from real data of typical travel patterns [4]-[5]. In the paper, such models will be included in a specific distribution planning tool for MV distribution network, developed in the past years to deal with all the uncertainties that characterize the future scenario of the distribution system. Specific studies will be performed on a real MV distribution network of the A2A utility sited in North of Italy, in order to quantify the impact of the FCSs and to identify the most suitable planning solutions needed to allow the effective integration of EV and boost electric mobility. DISTRIBUTION NETWORK PLANNING Traditionally, distribution networks are sized to cope with the worst-case scenario of a given load forecast and in a way that minimum or no operation is required. This approach, known as ‘fit and forget’, is carried out in a deterministic way, i.e., without considering uncertainties (the loads are modelled with their peak demand). Each planning alternative considered is technically assessed taking account of the load conditions for the corresponding planning horizon and, if it is not technically feasible, network reinforcements are applied. The most cost-effective solution is the planning alternative likely to be adopted. While this passive way of