Electric Plug-In Vehicle/Electric Vehicle Status Report Prepared by: Sanjay Mehta, Electrical Engineering Assistant August 2010
ABSTRACT The purpose of this report is to identify the various Electric Plug-in- Vehicle/Electric Vehicle (EV) charging processes and how Glendale Water & Power (GWP) is preparing its electrical infrastructure to carry EV load. This report evaluates the different types of charging, its levels and the need for electrical upgrades. This report analyzes the electrical infrastructure requirement for EVs in single family residential, multi-family residential, and commercial situations and the steps GWP staff is taking to handle EV deployment. ii
Table of contents 1. Introduction Background 1 2. Electric Vehicle Overview...1 3. Charging Systems Overview..1 3.1 Level 1 Charging...2 3.2 Level 2 Charging....2 3.3 Level 3 Charging...3 4. The Elements of EV Infrastructure....3 4.1 Electrical Vehicle Charging Equipment...4 4.1.1 Conductive Charging...4 4.1.2 On-Board Charging...5 4.1.3 Off-Board Charging...5 4.2 On-site Wiring....5 4.3 Electrical Services.....5 5. Codes, Standards and Recommended Practices for the installation of EVCE. 6 5.1 NEC 625 Electric Vehicle Charging System Equipment. 6 5.2 SAE-J1772 Electric Vehicle Conductive Coupling.....6 5.3 UL 2202 & UL 2231..7 6. EV Penetration and Electric Utilities...7 7. Planning Ahead..7 7.1 New Electrical Service and Upgrades...8 7.2 Transformer Loading.....8 7.3 Single Residential Customers....8 7.4 Multi Family Buildings/Commercial Locations.....9 7.5 Charging Stations........9 7.6 Battery Swapping Stations........9 7.7 Technology Plan....9 7.8 Time-of-Use (TOU) Metering for Electrical Service.....10 8. Installation Flowchart for Level 2 & 3...11 9. How GWP is prepared for EV deployment?...12 iii
1. Introduction Background When the automobile industry first introduced the battery powered electric vehicles they were quite popular. More than 360 electric recharging stations dotted the landscape in and around Boston alone! Despite the advantages of cleanliness, convenience, and virtual silence, electric vehicles fell from favor because of their slow acceleration, low speeds, and limited range between recharges. This is no longer the case with new Electric Vehicles (EVs). A new generation of EVs has come to market with the technical sophistication and performance able to serve the needs of many of today s drivers. As the EV industry reemerges, the development of an infrastructure to plug in EVs for recharging at home, at work, and at public locations has developed as an imperative need. Although electricity is available almost everywhere, the practical development of EV charging facilities is going to be necessary to support the growth of EVs. 2. Electric Vehicle Overview Electric vehicles are propelled by an electric motor powered by rechargeable battery packs. The capacity of the rechargeable battery depends on the model and the manufacturer. All EVs come with AC port for charging and an optional DC port 1 for fast charging. 3. Charging Systems Overview CHARGING TYPES LEVEL 1 LEVEL 2 LEVEL 3 VOLTAGE 120 VAC, Single 240 VAC, Single Up to 600 VDC Phase Phase ELECTRIC LOAD 2KW 8KW 150KW CHARGING TIME 8-16 Hours 4-8 Hours 10-50 Minutes 1 AC port is used for the Level 1 and Level 2 charging and DC port is for level 3 (fast) charging. Section 3 explains the different levels of charging. 1
3.1 Level 1 Charging Level 1 charging uses a standard electrical outlet NEMA 5-15R, which in the United States is 120 volt, single-phase, and grounded. The cord for Level 1 charging has plug NEMA 5-15P at one end, which plugs into 120 V outlet and J1772, which plugs into the AC port on the EV. Level 1 charging may take from 8-16 hours to fully recharge a battery depending upon the battery type and size. NEMA 5-15R NEMA 5-15P J-I772 3.2 Level 2 Charging Level 2 charging employs a permanently wired 2 and fastened EVCE sited at a fixed location. It requires grounding, ground fault protection for users, a no-load make/break interlock (which prevents vehicle startup while charging takes place), and a safety breakaway for the cable and connector. This charging also uses a J1772 plug to the vehicle. Depending on the battery type and capacity, Level 2 can recharge an EV in 4-8 hours. 2 NEC Article 625.13 Electric vehicle supply equipment rated at 125 volts, single phase, 15 or 20 amps or part of a system identified and listed as suitable for the purpose and meeting the requirements of 625.18, 625.19, 625.29 shall be permitted to be cord and plug connected. All other electric vehicle supply equipment shall be permanently connected and fastened in place. 2
3.3 Level 3 Charging This type of charging may take 5-50 minutes depending on battery size and type. Level 3, will not be ideal for residential area due to the cost of on-site upgrade to the panel and wiring system. This requires a minimum voltage of 440V, thus a 3- phase service. This type of charging may be located at parking garages, shopping mall areas, etc., where customers can charge vehicle while performing other business. Currently there are no standards for the DC plug. The society of Automobile Engineering (SAE) is working on standardizing the plug for DC charging. 4. The Elements of EV Infrastructure Generally, EV charging infrastructure consists of three components: o Electric Vehicle Charging Equipment (EVCE) 3 o On-site wiring o Electrical service 3 EVCE is required for Level 2 and Level 3 Charging. 3
Electrical Service On-site Wiring EVCE 4.1 Electric Vehicle Charging Equipment The Electrical Vehicle Charging Equipment (EVCE) can be conductive or inductive 4. EVCE consists of a power supply device, power cord and connector, with some variations in equipment specifications. 4.1.1 Conductive Charging Conductive charging systems use metal to metal contact between the EV connector and the EV s charge inlet (or charge port) similar to most household appliances that use metal-to-metal contact between a power outlet and plug/connector. This type of charging is available on all EVs such as Nissan Leaf, Chevy Volt, and Tesla Roadster. Power supply device - must be a polarized, non-interchangeable, grounded electric vehicle coupler to comply with Article 625 Electric Vehicle Charging System, Section 9, Paragraph (a) through (f) of the National Electric Code 2008 5 : (a) Polarization- The electric vehicle coupler 6 shall be polarized unless part of a system identified and listed as suitable for the purpose. (b) Non interchangeability- The electric vehicle coupler shall have a configuration that is non interchangeable with wiring devices in other electrical systems. Non grounding type electric vehicle couplers shall not be interchangeable with grounding-type electric vehicle couplers. 4 Inductive Charging - This is another type of charging and involves the transfer of power magnetically between the EVCE and EV. It relies on the magnetic induction of electricity rather than metal to metal contact. Currently no standards have been set for this type of charging and EVs are not compatible with this type of charging. 5 National Electrical Code-625 NFPA 70 6 EV coupler A mating electric vehicle inlet and electric vehicle connector set. 4
(c) Construction and Installation- The electric vehicle coupler shall be constructed and installed so as to guard against inadvertent contact by persons with parts made live from the electric vehicle supply equipment or the electric vehicle battery. (d) Unintentional Disconnection- The electric vehicle coupler shall be provided with a positive means to prevent unintentional disconnection. (e) Grounding Pole- The electric vehicle coupler shall be provided with a grounding pole, unless part of a system identified and listed as suitable for the purpose in accordance with Article 250. (f) Grounding Pole Requirements. If a grounding pole is provided, the electric vehicle coupler shall be designed so that the grounding pole connection is the first to make and the last to break contact. 4.1.2 On-Board Charging The On-board charger gets alternating current (AC) and converts to direct current (DC) for replenishing the EV battery. Level 1 and Level 2 use onboard charger to charge the battery. 4.1.3 Off-Board Charging Power supply device - includes a rectifier to convert alternating current to direct current (DC) for replenishing the EV battery. Level 3 uses an Offboard charger to charge the battery. 4.2 On-Site Wiring On-site wiring is the premise wiring that runs from the service panel to the EVCE. The facility owner/operator is responsible for providing the on-site wiring necessary to install the EVCE for level 2 & level 3 charging in the desired location in compliance with NEC Code 625, Electric Vehicle Charging System Equipment. Although level 1 charging utilizes a 120V residential standard plug, it is not advisable to plug in an EV because the load is going to be much higher than any typical residential appliance. 4.3 Electrical Service Electric Service includes the utility distribution lines and the customer s electric meter. This equipment is owned and controlled by the local electric utility. Any EVCE installations requiring new or upgraded electrical service must be coordinated with the local utility and approval from the building safety inspector. 5
5. Codes, Standards and Recommended Practices for the installation of EVCE 5.1 NEC 625 Electric Vehicle Charging System Equipment Standards for installation and functionality requirements of electric vehicle infrastructure are provided in the NEC Article 625, published by the National Fire Protection Association (NFPA). Key requirements of Article 625 include the following: Wiring methods, including electric vehicle coupler design, construction, and functionality. EVCE coupler requirements, including polarization, noninterchangeability, construction and installation, unintentional disconnection, and grounding pole requirements. EVCE construction requirements, including rating, markings, means of coupling, cable, interlock, and automatic deenergization of the charge cable. EVCE control and protection, including overcurrent protection, personnel protection, disconnecting means, loss of primary source, and interactive systems. EVCE location requirements, including hazardous (Classified) locations, indoor sites and ventilation requirements for indoor installations (where applicable), and outdoor site requirements. 5.2 SAE-J1772 Electric Vehicle Conductive Coupling This SAE Recommended Practice covers the general physical, electrical, functional and performance requirements to facilitate conductive charging of EV vehicles in North America. This document defines a common EV and supply equipment vehicle conductive charging method including operational requirements and the functional and dimensional requirements for the vehicle inlet and mating connector. J-1772 6
5.3 UL 2202 Charging Station Safety & UL 2231 Personal Protection Device (i.e. ground fault hardware) These requirements cover conductive and inductive charging system equipment intended to be supplied by a branch circuit of 600 volts or less for recharging the storage batteries in over-the-road electric vehicles (EV). The equipment is located on- or off-board the vehicle. Off-board equipment may be considered for indoor use only. The equipment is intended to be installed in accordance with the National Electrical Code, NFPA 70. The requirements for devices or systems intended to reduce the risk of electric shock to the user in grounded or isolated circuits for charging electric vehicles are covered in the Standard for Personnel Protection Systems for Electric Vehicle (EV) Supply Circuits. 6. EVs Penetration and Electric Utilities Charging EVs present an opportunity but interesting challenge to the electric utility. The Promoting Electric Vehicle Act of 2010, was approved by Energy and Natural Resources Committee on July 21, 2010 7. The Promoting Electric Vehicle Act of 2010, approved by the Committee, includes initiatives to increase the introduction of electric cars and trucks throughout the country to reduce gas consumption and create domestic jobs. If passed by the Congress and signed into law, the Promoting Electric Vehicle Act of 2010 would cause a rapid EV penetration into the market. Also, the president s five-year goal is quite ambitious, and it may take another two to four years to reach the target of 1 million vehicles sold. It is projected that 20 to 25 % EV penetration will occur within a few years. The mature market development and expansion period is assumed to begin in 2017. 7. Planning Ahead GWP will need to conduct a thorough study to see the impact of EVs on feeders, transformers, transmission lines, generation and energy imports. A complete study of EVs' impact on GWP s system will provide key information on feeders, transformers and line upgrades. EV load on the utility system will depend on the number of EVs, the charging voltage, and the time period that the vehicle is charging. The total energy required to charge the batteries depends on the miles driven and the vehicle energy consumption per mile. EVs can be connected at any time of day. Whether or not they are charging depends on the battery state of charge. 7 http://www.chattanoogan.com/articles/article_180374.asp 7
7.1 New Electrical Service and Upgrades Most homes may not have sufficient electric service capacity for either a Level 1 or a Level 2 charging system. When using Level 1 charging, a new, dedicated circuit is recommended because existing 120 VAC branch circuits typically include multiple outlets served by a single circuit breaker that provides overload protection. This can result in other appliances or more than one electric vehicle using the same branch circuit, often resulting in the circuit breaker tripping from an overload condition. Additionally, level 1 takes longer to charge an EV, majority of vehicle owners will desire Level 2 charging because of its shorter charging times. In some cases, EV owners may desire Level 3 charging, but the installation expense of Level 3 will be prohibitive for residential installation. With the rising popularity of large household electrical appliances, many multifamily buildings have very little electrical capacity left to accommodate new, large electrical loads such as EV, which equal the average energy use of an entire household. If electrical service is near capacity, the utility may have to upgrade service wires and transformers serving the location. EV charging stations at locations such as shopping centers and parking lots may require upgraded electrical service, including new feeder lines and on-site equipment such as service panels, sub-panels, and transformers. Some factors that determine the need for electrical service upgrades include: Number and Type of Charging Units: This depends on the anticipated number of vehicles for the location, vehicle usage schedules, and the desired charging level. Electrical Capacity Considerations: Some sites may be at or near their electrical load capacity. 7.2 Transformer Loading GWP needs to examine the load profile of each transformer. Whether a transformer needs an upgrade or not will depend on its loading history, anticipated EV load, EV Charging level and age of the transformer. As overloading leads to accelerated aging of transformer implementing an effective transformer load management system will be a key factor. Transformers currently operating at its capacity will need to be upgraded. 7.3 Single Residential Customers Residential customers desiring the level 2 charging at their premise must contact GWP and apply for building permit prior to using installation of any charging equipment for charging EVs. 8
7.4 Multi Family Buildings/Commercial Locations A level 2 or 3 charging station may be installed in multi family buildings and commercial locations. GWP may consider the installation of a charging station at a common shared location. This can be metered separately with the property owner having responsibility for bill payment. 7.5 Charging Stations Publicly available charging stations may also employ a mix of Level 2 and 3 charging stations. These charging stations will be placed at shopping malls, parking garages or where parking meters are already installed. These stations will be similarly arranged as the existing gas stations. Users will use credit cards for the charging and there will be different rate for different charging levels. Public charging stations will require electrical infrastructure, a rate schedule, and agreement with property owners. Level 3 Charging Level 2 Charging 7.6 Battery Swapping Stations Currently there are no standards set for battery swapping stations. We might see these stations in coming years. Battery swapping stations will charge the battery packs and stock them for swapping with discharged battery packs on the EVs. Swapping a battery is accomplished by automatic machines and may take few minutes to swap discharged battery packs.. 7.7 Technology Plan AMI will enable market penetration of EVS. GWP needs to develop a comprehensive plan for what type of demand limitation, control, and system automation technologies it will adopt to handle EVs loading. GWP will consider requiring a smart charging system for vehicle delivered in GWP territory so that charging of the vehicle batteries takes place via command and control signals from GWP s AMI network infrastructure. Smart charging would enable vehicle charging 9
to be delayed or temporarily interrupted or slowed depending on the loading on the electric system. 7.8 Time-of-Use (TOU) Metering for Electrical Service Below is a typical GWP residential feeder load profile. Heavy loading is between the hours of 3PM and 8PM. GWP needs to develop TOU rate to encourage vehicle charging during off-peak hours. TOU GWP s Load Profile Additionally, EVs with smart charging system can be programmed to not charge during peak hours. 10
8. Installation Flowchart Before Purchasing an EV 1. Contact EV Manufacturers - Inductive or Conductive - Charging Level - Ventilation Required - Special Requirements GWP - Service requirements - Rates Building and Safety Dept. -Local requirements - Obtain application form Current service adequate Install TOU meters 2. Hire Electrical Contractor -Special metering - Upgrade Electrical Panel - Ventilation Required - Charging level - Local requirements - Outdoor or indoor 3. Installation Plan 4. Obtain Building Permits If necessary upgrade feeder lines 5. Install charging station or upgrade service panel for Level 2 City notifies GWP that EVCE passed inspection 6. Permit Inspection Comply with change orders GWP energize new service 7. Charge Vehicle 11
9. How GWP is preparing for EV deployment? o Ask customers when they apply for new service or transfer if they have plans to purchase EV in near future and desired level of charging. o Work with EV dealers in setting up a demo site. The demo site may include a level 2 and 3 charging. o Work with EVCE service providers regarding the charging equipments, smart charging technology and charging stations. o Assess loading criteria for service wires, transformers and lines. o Establish a rate for TOU metering to minimize system impact during peak periods. o Provide step by step instructions to customers before purchasing EVs. 12