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PRC-005-6
Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance
PRC-005-6 requires Transmission Owners, Generator Owners and Distribution Providers to establish a Protection System Maintenance Program for the Protection Systems, Automatic Reclosing and Sudden Pressure Relaying listed in the standard's Facilities section, and to maintain those Components under that program. Time-based programs follow the minimum activities and maximum intervals in the standard's tables, performance-based programs follow Attachment A, and the entity must demonstrate efforts to correct identified Unresolved Maintenance Issues.
Who it applies to
- Transmission Owners, Generator Owners and Distribution Providers, for:
- Protection Systems and Sudden Pressure Relaying installed to detect Faults on BES Elements; Protection Systems for underfrequency and undervoltage load-shedding systems as described in the standard; and Protection Systems installed as a Remedial Action Scheme for BES reliability.
- Protection Systems and Sudden Pressure Relaying for generator Facilities that are part of the BES, except generators identified through BES Inclusion I4, including protection that trips the generator directly or via lockout or auxiliary tripping relays, protection for generator step-up transformers, and protection for station service or excitation transformers on the generator bus that trips the generator.
- For dispersed power producing resources identified through BES Inclusion I4: Protection Systems and Sudden Pressure Relaying for Facilities used to aggregate dispersed BES generation from the point where it aggregates to greater than 75 MVA to a common point of connection at 100 kV or above.
- Automatic Reclosing at generating plant substations, and at substations one bus away, meeting the criteria in Section 4.2.7, and Automatic Reclosing applied as an integral part of a Remedial Action Scheme.
- Category 2 Generator Owners of non-BES inverter-based resources are not subject to PRC-005-6, whose Facilities are Protection Systems, Automatic Reclosing and Sudden Pressure Relaying for BES Elements and BES generator Facilities, unless a later revision of the standard includes them.
Key dates
- January 1, 2016: effective date.
- Phased compliance: Automatic Reclosing Components, Sudden Pressure Relaying Components and dispersed generation resources were phased in from the regulatory approval of PRC-005-6 (FERC order of December 18, 2015). The final step, 100 percent compliance for maintenance activities with 12 calendar year maximum intervals, falls on the first day of the first calendar quarter 156 months after that approval (January 1, 2029).
- March 31, 2027: PRC-005-1.1b, PRC-008-0, PRC-011-0 and PRC-017-1 (named PRC-017-0 in the PRC-005-6 implementation plan) are retired at midnight. Until then they stay enforceable for maintenance activities not yet transitioned to PRC-005-6.
Source
NERC PRC-005-6 (standard page)October 29, 2026
Requirements
What each requirement asks for, in plain English.
R1 · Establish a Protection System Maintenance Program
What it means. Establish a Protection System Maintenance Program (PSMP) that identifies, for each Protection System, Automatic Reclosing and Sudden Pressure Relaying Component Type, whether maintenance is time-based, performance-based per Attachment A, or a combination. All batteries associated with the station dc supply Component Type must be in a time-based program. Where monitoring is used to extend intervals beyond the unmonitored ones, the PSMP includes the monitored Component attributes the tables require.
Evidence an auditor expects. The documented PSMP showing the maintenance method for each Component Type and the station batteries in a time-based program, and, where monitoring extends intervals, evidence such as manufacturer's specifications or engineering drawings of the monitored attributes.
R2 · Performance-based intervals
What it means. An entity that uses performance-based intervals follows the Attachment A procedure to establish and maintain them. Attachment A works on Segments of at least 60 Components, keeps them on time-based intervals until results exist for at least 30 Components, and sets each Segment's maximum interval so that Countable Events occur on no more than 4 percent of its Components. Ongoing use requires maintaining the greater of 5 percent of a Segment's Components or 3 Components each year, and an action plan when Countable Events reach 4 percent or more.
Evidence an auditor expects. Component lists, dated maintenance records, and dated analysis records and results.
R3 · Time-based maintenance
What it means. Maintain Components in a time-based program to the minimum maintenance activities and maximum maintenance intervals in Tables 1-1 through 1-5, Table 2, Table 3, Tables 4-1 through 4-3 and Table 5. For example, an unmonitored protective relay has a 6 calendar year maximum interval, which includes verifying its settings are as specified.
Evidence an auditor expects. Dated maintenance records, maintenance summaries, check-off lists, inspection records or work orders.
R4 · Follow the performance-based program
What it means. An entity that uses performance-based maintenance under R2 implements and follows its PSMP for the Components in that program.
Evidence an auditor expects. Dated maintenance records, maintenance summaries, check-off lists, inspection records or work orders.
R5 · Correct Unresolved Maintenance Issues
What it means. Demonstrate efforts to correct identified Unresolved Maintenance Issues, meaning deficiencies found during maintenance that cause a Component not to meet its intended performance, cannot be corrected during the maintenance interval, and require follow-up corrective action.
Evidence an auditor expects. Work orders, replacement Component orders, invoices, project schedules with completed milestones, return material authorizations or purchase orders.
For inverter-based plants
For dispersed power producing resources identified through BES Inclusion I4, PRC-005-6 covers the Protection Systems and Sudden Pressure Relaying on the Facilities that aggregate the dispersed generation from the point where it exceeds 75 MVA to a common point of connection at 100 kV or above, not the individual generating units.
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