ANSI device numbers

ANSI device numbers are standard numeric codes. In North America they are the usual way to name protective relays and other switchgear devices. The full list and definitions are in IEEE C37.2. Letters are sometimes added to a number to show the application. For grid protection of PV and storage systems, the common codes are 27 for an undervoltage relay, 59 for an overvoltage relay and 81 for a frequency relay. Utilities such as National Grid require these standard device numbers on functional single-line diagrams submitted for interconnection. The National Grid reference list of device numbers points to ANSI C37.2-1987.

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• sentence 1: support check: partial - Protective relays are generally named by device numbers in North America, but 'other switchgear devices' and 'numeric codes' are not explicitly stated.
• sentence 3: support check: partial - Codes 27, 59, 81 map to undervoltage, overvoltage, frequency relays, but the passages don't say they are the common codes for PV and storage grid protection.
• sentence 4: support check: partial - National Grid requires standard device numbers on functional single-line diagrams, but 'for interconnection' and 'these' specific numbers are not stated; also 'utilities such as' generalizes.
• sentence 1: review: partial - Passage says protective relays in North America are generally referred to by standard device numbers, but it does not mention other switchgear devices.
• sentence 4: review: partial - National Grid passages require industry standard device numbers on functional single-line diagram submittals, but they do not say the submittals are for interconnection, and 'utilities such as' generalizes beyond the source. -->