G. Decision support
Information Must Support the Right Decision
An index can be technically correct and still be incomplete for a particular decision. Consider a prospective data-center location.
A prospective data-center owner should not rely solely on utility-wide or system-wide indices such as SAIFI or SAIDI to determine the reliability of a proposed site.
SAIFI and SAIDI are useful distribution-system performance measures. They may not, by themselves, represent reliability at a specific proposed supply point under the planned future system configuration.
What a site-specific view may need to consider
- Historical interruption performance at or near the supply point
- Supply configuration
- Number and independence of feeds
- Substation and transmission dependencies
- Common-mode exposure
- Restoration capability
- Planned network changes
- Load growth
- Maintenance practices
- Future operating conditions
What reliability can reasonably be expected at the proposed point or points of supply under the planned future system configuration?
Historical performance should support the assessment, but the decision should be forward-looking. Historical evidence alone does not automatically predict future performance.
If expected reliability does not meet the facility requirement, the utility and customer can discuss utility-side improvements, alternate supply arrangements, on-site redundancy, backup generation, UPS / BESS, operational flexibility, contractual or planning arrangements, and economic tradeoffs. This is a consultative process. Data sharing and study scope depend on applicable requirements, agreements, and what each party is prepared to make available.
Data-center power & grid reliability overview → · Reliability-constrained power utilization →