IEEE P3006.2-D5 pdf free download
IEEE P3006.2-D5 pdf free download.Draft Recommended Practice for Evaluating the Reliability of Existing Industrial and Commercial Power Systems.
5. Evaluation methodology – overview
Evaluation of the reliability of an existing electrical system should include review of the system at a number of levels, each of which will be discussed in more detail in subsequent sections of this standard:
5.1 Utility supply
The 1974 survey of electrical equipment reliability in industrial plants (see IEEE Committee Report [B7])4, parts of which are available as Annex A and Annex B of IEEE Std 493, and subsequent investigations showed the utility supply to be the largest single component affecting the reliability of an industrial plant. A power quality survey of 112 industrial and commercial sites in North America conducted in 1995 [B6] identified supply interruptions as likely responsible for the majority of adverse impacts to computers and other electronic equipment within the facilities.
Most customers simply “hook up” to the utility system and do not fully recognize that their reliability requirements may impact how the utility supplies them. A utility is constrained by the system available at the customer site and the investment that can he made per revenue dollar. However, most utilities are willing to discuss the various supply options that arc available to their customers. Many times, an option is available (sometimes with financial sharing between the user and the utility) that will meet the reliability needs of a specific facility.
5.2 Configuration
The system configuration, as determined from the one-line diagram, determines the inherent reliability that can be obtained from the system without adding or rearranging components. This should be the first level of analysis, in which vulnerabilities due to single paths, single points of failure, capacity shortfalls, etc., can be identified.
Many facilities have on-site generators to back up utility power. This will raise the availability of electrical power for part of the facility that is backed up by the generator. It niay also raise the reliability, depending on what is considered a failure for the facility. For example, if loss of power while the generator starts and transfers to pick the load back up is acceptable, the facility would have increased availability and reliability for the loads backed up by the generator. If loss of power while the generator starts would cause a failure, such as with most IT equipment rooms, an Uninterruptable Power Supply (UPS) system would also be needed to improve the reliability.
As seen from the example above, improving the reliability of the existing power system may include analysis of several systems and ensuring that all of the loads are connected to the proper system. As obvious as it may seem, a real world example is to make sure that the fuel transfer system for the standby generator is backed up by generator power.
When evaluating critical facilities, such as data centers, it is often worthwhile to compare the one-line drawing for the critical systems in the facility with examples given in IEEE Std 3006.7. IEEE Recommended Practice for the Determining the of Reliability of 7×24 Continuous Power Systems in Industrial and Commercial Facilities to see how well the critical systems have been designed. If there appears to be concern, a company that specializes in reliability can be brought in to do reliability analysis of the critical systems.IEEE P3006.2-D5 pdf download.
