IEEE C37.95-2014 pdf free.IEEE Guide for Protective Relaying of Utility-Consumer Interconnections.
The supply that is selected should satisfy the consumer’s load requirements. Available utility supply options in the area as well as the Utility’s design standards and operation and maintenance practices should also bc considcred.
4.1.1 Consumers load requirements
Prior to meeting with utility personnel, the consumer should define the present and future load requirements including thc conncctcd kVA, thc avcragc load, and pcak demand powcr requirements (both real and reactive). The effect of interruptions and voltage dips on plant operation, the required dependability and security of the utility’s electrical service, and any other needs that may be unique to the operation should be determined. The consumer’s engineer should be prepared to discuss these requirements in detail with utility engineers to ensure that there is a clear understanding of the consumer’s requirements.
4.1.2 Utility service availability
The utility should describe the supply voltages available in the area and estimate the initial and total costs of the various alternatives. Most utilities establish nominal limits on the load that can be supplied at diflrcnt voltage levels. The number of utility supply lines available and the performance level of each line should be discussed in detail. In addition, the utility should intbrm the consumer of any required studies, unusual problems, or future plans that may affect the quality or continuity of service. Some utilities publish standard intuirmation booklets detailing the requirements for service.
When the consumer has identified critical power requirements. the utility engineer should investigate these requirements and be certain that both parties have a clear understanding of the etTeci of interruptions and voltage dips. The utility may then be able to suggest a supply system that will meet these requirements, or suggest plant control changes to make the operation more successful.
4.2 Information exchange
Once the supply method is established, a further exchange of intbrmation is required so that the station design can be completed and the utility can make the necessary preparations to supply the scrvicc By establishing good communication between the utility and the consumer as early as possible, specific requirements for either a new or modified supply can be identified and included in the initial design before equipment is ordered.
4.2.1 TypIcal information furnished by utility
a) Available utility short-circuit current including values for normal and alternate supply facilities, as well as any anticipated future values (i.e., range of single- and three-phase-to-ground fault currents, and associated XJR ratios, at the consumer’s point of service.)
b) Expected minimum, maximum, and nominal voltage at the consumer’s point of service for available voltage levels
C) System neutral grounding on customer supply circuit
d) Outage history of the supply including both forced and maintenance outages
c) Estimated &cqucncy, duration, and magnitude of momentary voltage dips at the consumer’s point of service
1) Operating requirements and restraints
g) Specific protection requirements to coordinate with the utility system
h) Specific reclosing practices on both normal and alternate supply facilities
I) Harmonic content, voltage fluctuation, maximum allowable voltage sag during interconnection transformer energization, and current unbalance limits imposed by the utility
j) Estimates of voltage harmonic distortion and harmonic current injection from other sources on the utility system, if requested by the consumer.IEEE C37.95 pdf free download.