IEEE Std 3001.2 pdf download

IEEE Std 3001.2 pdf download

IEEE Std 3001.2 pdf download IEEE Recommended Practice for Evaluating the Electrical Service Requirements of Industrial and Commercial Power Systems
3. Common relationships with electric utilities The most common relationship that exists between the industrial or commercial facility and a connecting electric utility is that of a seller and buyer. That is, the electric utility supplies electric energy to the facility based on a rate typically regulated by a state agency as the utility will typically have a monopoly over serving a given geographic area. Considering this, the industrial or commercial user may be referred to as the customer. The relationship between a utility and its customer has become more complex based on the following developments.
— Wholesale power agreements that allow a user to purchase energy from entities other than the connecting utility. The connecting utility is not the direct seller of energy. However, the connecting utility will usually still be compensated for the use of their distribution system through wheeling charges that are added onto the user’s monthly energy invoice. — Community Choice Aggregation programs that allow users within the geographic boundaries of the program to secure alternative energy supply agreements by working in aggregate, typically through a city or county agency.
— The capability to generate power onsite, typcially through cogeneration or renewable energy sources such as wind turbines or photovoltaic panels. Diesel engine or gas turbine sources may be used. The onsite generation may simply reduce the overall facility demand, or the user may be permitted to export power when the user’s onsite source capacity is greater than the user’s own load demand. The utility should be consulted to determine whether they are willing to accept any exported power, and any special requirements they have for users who install onsite power sources that may be connected to the utility distribution system.
4. Planning for utility service
4.1 Introduction It is the responsibility of the engineer to understand the serving utility’s electric service requirements and service tariffs to develop an efficient and economical means of receiving electric power and distributing it to each area to be served. This function can be carried out in many ways. Selection of system arrangements, components, and voltages should be engineered to function reliably and safely, and to deliver the power at correct voltages without hazard to personnel or the facility.
4.2 Utility/designer communication Each utility differs in its service policies and requirements. Therefore, establish communications with the major account representative, or service design professional of the supplying utility so that their requirements can be incorporated in the facility’s plans, equipment specifications, and commissioning documents. This is a two-way path of communications. The utility needs information about the proposed loads to be connected (refer to 5.4). The facility’s electrical designers need information about the utility’s electrical distribution system characteristics (refer to 5.5). The designer should obtain from the utility company a range of possible available fault current at the point where the utility connects. Obtaining only the maximum theoretical value is not adequate for the eventual analysis of arc flash on the user’s distribution system. It is important to also know what is the possible minimum fault current available, as well as the maximum worst case available fault current.
4.3 Service availability
4.3.1 Service voltage The service voltage selected and its characteristics for primary or secondary service are based on the utility’s distribution standards and the voltage grids in the specific area of the facility. The utility should be contacted to determine the available voltages based on the load to be served and, in some cases, the geographic location of the load. The designer may become aware of service voltages provided to customers in the service area that are no longer available. Such services continue to be offered only to existing facilities and are not typically offered to new facilities. Service is usually available at the utilization voltages, such as 240 V delta (3-phase/3-wire), 120/240 V high- leg delta (3-phase/4-wire), 208Y/120 V, 480Y/277 V, or 600Y/347 V. Utilities may have kilowatt demand limitations for each specific voltage. When the facility’s load becomes too large to be supplied at the utilization voltage, due to excessive cost or excessive voltage drop, the facility should be supplied at a distribution voltage, typically, but not limited to, 4.16 kV, 12.47 kV, 13.2 kV, 13.8 kV, 26 kV, or 34.5 kV. In the case of large facilities, it may also be economically feasible to connect to the utility transmission line system. A primary substation is used to step the voltage down from transmission line levels to medium-voltage levels. Refer to 8.6 and Clause 11. If the customer owns the medium-voltage distribution system, then the associated equipment, including transformers, should be purchased and installed by the customer. The exception would be if the utility provides all or part of the medium-voltage distribution system, in return for the right to sell power directly to tenants, or when the utility and the authority having jurisdiction (AHJ) permit more than one service in the building. In the latter case, the utility may consider each service as a separate customer, and usually the bills will be higher than a single bill.
4.3.2 Service type The designer should discuss the type of services available in the service area supplying the facility with the utility service design professional. Services may be underground, open wire aerial, or lashed aerial cable. In addition, the utility may offer dual-service options or dedicated lines for special customer load requirements.

The previous

IEEE Std 2870 pdf download

The next

IEEE Std 3006.3 pdf download

Related Standards