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UL 9741 Ed. 2-2021
Outline of Investigation for Electric Vehicle Power Export Equipment (EVPE)
1 Scope 1.1 These requirements cover both unidirectional and bidirectional equipment that is connected to an electric vehicle. Unidirectional equipment exports power from the vehicle to off board loads including an electric power system such as the electric utility grid. Bidirectional equipment serves the same function but additionally provides power to the electric vehicle for recharging of the on board electric vehicle battery. Some bidirectional equipment may be configured to operate only in a unidirectional mode. The products covered by these requirements are intended to be installed in accordance with the National Electrical Code, NFPA 70. 1.2 Some examples of equipment covered by this outline have functionality as described below: a) The equipment can be supplied by DC from the vehicle and acts as a standalone piece of equipment provided with an inverter for converting to AC power and terminating in receptacles for the connection to external loads; b) The equipment can be supplied by AC from the vehicle and acts as a standalone piece of equipment provided with optional voltage conditioning equipment and terminating in receptacles for the connection to external loads; c) The equipment can be supplied by DC from the vehicle and is provided with an inverter for converting to AC power and is permanently connected to the premise to provide power to receptacles that are not connected to the building wiring system; d) The equipment can be supplied by AC from the vehicle and is provided with optional voltage conditioning equipment and is permanently connected to the premise to provide power to receptacles that are not connected to the building wiring system; e) The equipment can be supplied by DC from the vehicle and is provided with an inverter for converting to AC power and is permanently connected to the premise to provide power to receptacles that are interconnected with building wiring systems through a transfer switch; f) The equipment can be supplied by AC from the vehicle and is provided with optional voltage conditioning equipment and is permanently connected to the premise to provide power to receptacles that are interconnected with building wiring systems through a transfer switch; g) The equipment can be supplied by DC from the vehicle and is provided with an inverter for converting to AC power and is permanently connected to the premise wiring system with grid interaction power export but is prevented from export to the utility grid by PCS control; h) The equipment can be supplied by AC from the vehicle and is provided with optional voltage conditioning equipment and is permanently connected to the premise wiring system with grid interactive power export but is prevented from export to the utility grid by PCS control; i) The equipment can be supplied by DC from the vehicle and is provided with an inverter for converting to AC power and is permanently connected to the premise wiring system for interactive power export including backfeed to the utility grid; j) The equipment can be supplied by AC from the vehicle and is provided with optional voltage conditioning equipment and is permanently connected to the premise wiring system for grid interactive power export including backfeed to the utility grid. k) The equipment can be supplied by DC from the vehicle and is provided to an output to connect to other inverter/converter/power conditioning equipment (such as UL 1741 or UL 62109) and / or loads. All of the equipment type, (a) through (k) may also provide power to the electric vehicle for the purpose of charging the on board battery. All equipment is provided with a function that will cause a disconnect between the vehicle and the load if power from the vehicle exceeds specific limits. Some products may be able to operate in multiple modes and will comply with the requirements for the functions it performs. 1.3 For the purposes of this outline, the term "electric vehicle", designated throughout by the initials "EV", is considered to cover electric vehicles, hybrid electric vehicles, and plug-in versions of these vehicles. 1.4 For grid interactive equipment, these requirements are intended to be used in conjunction with UL 1741 which addresses the grid interconnection compliance. UL 1741 provides guidance and options for evaluation and testing in accordance with specific utility grid interconnection requirements and standards such as the Standard for Interconnecting Distributed Resources With Electric Power Systems, IEEE 1547, the Standard for Conformance Test Procedures for Equipment Interconnecting Distributed Resources with Electric Power Systems, IEEE 1547.1, California Rule 21, Hawaii 14H, etc. 1.5 The power export functionality will include enable and disable functions to limit or prevent export to the utility grid for locations that are not capable of or permitted to receive backfed power. This functionality is addressed using the UL 1741 Power Control System (PCS) requirements. 1.6 The equipment includes off board equipment only. Equipment may be considered for indoor use only or indoor/outdoor use. 1.7 This outline covers equipment that perform power conversion and Interconnection Systems Equipment (ISE) functionality. These functions may be located within one piece of equipment or within multiple pieces of equipment. 1.8 Equipment that is not a complete assembly and depends upon installation in an end product for compliance with the requirements in this outline is investigated under the requirements of this outline and the standard for the end product. 1.9 These requirements do not cover battery chargers covered by the Standard for Battery Chargers for Charging Engine-Starter Batteries, UL 1236, or the Standard for Industrial Battery Chargers, UL 1564. 1.10 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; Part 1: General Requirements, UL 2231-1, and the Standard for Personnel Protection Systems for Electric Vehicle (EV) Supply Circuits; Part 2: Particular Requirements for Protective Devices for Use in Charging Systems, UL 2231-2. 1.11 Equipment covered by this outline may additionally be evaluated to SAE J3072. 1.12 Equipment covered by this outline may communicate with other equipment and systems via standardized communications protocols such as but not limited to IEEE 2030.5, IEEE 1815, Sunspec Modbus, etc. 1.13 Equipment covered by this outline may include connections to alternative power sources including but not limited to: photovoltaic, wind turbine, fuel cell, energy storage, etc.
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Underwriters Laboratories [ul]
