Relay 81 Frequency Test

Data records

• Relay 81 Frequency Test is specified for electromechanical and solid-state protective relays in acceptance testing at clause 7.9.1.B.3.23 of ANSI/NETA ATS-2025. Value: electromechanical and solid-state protective relays. Source: ANSI/NETA ATS-2025, clause 7.9.1.B.3.23. Verified 2026-10-13. Record tests.relay-81-frequency-test.equipment.relay.acceptance
• Relay 81 Frequency Test is specified for electromechanical and solid-state protective relays in maintenance testing at clause 7.9.1.B.3.23 of ANSI/NETA MTS-2023. Value: electromechanical and solid-state protective relays. Source: ANSI/NETA MTS-2023, clause 7.9.1.B.3.23. Verified 2026-10-13. Record tests.relay-81-frequency-test.equipment.relay.maintenance
• Relay 81 Frequency Test is addressed in ANSI/NETA ATS-2025. Source: ANSI/NETA ATS-2025, clause 7.9.1.B.3.23. Verified 2026-10-13. Record tests.relay-81-frequency-test.governed-by.ansi-neta-ats
• Relay 81 Frequency Test is addressed in ANSI/NETA MTS-2023. Source: ANSI/NETA MTS-2023, clause 7.9.1.B.3.23. Verified 2026-10-13. Record tests.relay-81-frequency-test.governed-by.ansi-neta-mts
• The overfrequency and underfrequency trip type tests in clauses 5.5.1 and 5.5.2 of IEEE 1547.1-2020 use the rate-limited step of Annex A.4 with frequency as the parameter under test: other control functions are disabled or set so as not to interfere, frequency droop is set to its widest deadband and maximum droop, the magnitude and duration settings start at the minimum of the adjustable range, the source is moved to a starting point and held, then stepped past the set point and held, and the trip frequency and clearing time are recorded, with repeats at the maximum magnitude, at the maximum duration and for each trip region. Source: IEEE 1547.1-2020, clause 5.5.1, 5.5.2. Verified 2026-10-24. Record tests.relay-81-frequency-test.ieee1547-1.type-test
• Clause 5.5.1.5 of IEEE 1547.1-2020 requires that the rate of change of frequency during the test transitions stay below the category limit of IEEE 1547-2018 Table 21 or within the unit's demonstrated capability, and that the power level be high enough to separate the trip response from the frequency droop response; the pass criterion has the same form as the voltage trip criterion, and tripping inside the regions where IEEE 1547-2018 Annex H.3 allows either ride-through or trip is accepted. Source: IEEE 1547.1-2020, clause 5.5.1.5, 5.5.2.5. Verified 2026-10-24. Record tests.relay-81-frequency-test.ieee1547-1.type-test-requirements
• For distributed energy resources, clause 6.5.1 and Table 18 of IEEE 1547-2018 set mandatory frequency tripping through two overfrequency functions and two underfrequency functions, with one set of defaults and allowable ranges shared by all three abnormal performance categories; the area electric power system operator specifies the settings after coordinating with the regional reliability coordinator, and the function applies only while the fundamental voltage exceeds a threshold the clause states. Source: IEEE 1547-2018, clause 6.5.1, Table 18. Verified 2026-10-24. Record tests.relay-81-frequency-test.ieee1547.trip-requirements
• Clause 9.1 of IEEE 2800-2022 does not require frequency protection on an inverter-based resource plant; where a frequency element is applied it must allow the frequency ride-through of clause 7.3.2 and be coordinated with the transmission system's underfrequency load shedding. Source: IEEE 2800-2022, clause 9.1. Verified 2026-10-24. Record tests.relay-81-frequency-test.ieee2800.frequency-protection
• Clause 9.2 of IEEE 2800-2022 does not require rate-of-change-of-frequency protection; where it is applied it must permit the rate-of-change-of-frequency ride-through of clause 7.3.2.3.5, and clause 7.3.2 with its footnote 111 has frequency computed with filtering under clause 4.4 and cautions against letting a frequency measured during a fault decide a trip. Source: IEEE 2800-2022, clause 9.2, 7.3.2. Verified 2026-10-24. Record tests.relay-81-frequency-test.ieee2800.rocof-protection
• The test method is named Relay 81 Frequency Test. Value: Relay 81 Frequency Test. Source: Electrical Testing Reference editorial taxonomy, 2026-10 edition. Verified 2026-10-13. Record tests.relay-81-frequency-test.title