On February 3, 2012, FERC interpreted a key reliability standard to clarify what types of relay and communication equipment should be subject to internal testing and audit procedures. FERC directed NERC to do further work regarding the inclusion of the certain reclosing relays and DC control circuitry in maintenance, testing, and internal audit programs.

FERC issued an interpretation of requirement R1 for the reliability standard PRC-005-1, Transmission and Generation Protection System Maintenance and Testing.  FERC accepted the North American Electric Reliability Corporation’s (“NERC”) proposals to exclude from PRC-005, requirement R1:

  1. Maintenance and testing of battery chargers;
  2. Auxiliary relays and any other devices that responds to quantities other than electrical quantities (e.g., sudden pressure relays);
  3. Transmission line re-closing relays;
  4. Any additional requirements for DC control circuitry that is extraneous to:
    • Addressing DC control circuitry within an entity’s program;
    • Having a basis for addressing that program; and
    • Executing the program.

FERC also accepted the following examples of “associated communications systems” that are part of a “protection system” to be included in an entity’s maintenance and testing program:

  1. Communications equipment involved in power-line-carrier relaying;
  2. Communications equipment involved in various types of permissive protection system applications;
  3. Direct transfer-trip systems;
  4. Digital communication systems.

In 2007 the Commission directed NERC to modify 56 of its reliability standards, including PRC-005-0.   NERC is designated under section 215 of the Federal Power Act as the Commission’s Electric Reliability Organization (“ERO”).  The ERO drafts the mandatory reliability standards and submits the standards to FERC for final approval.  Once approved the reliability standard can be enforced by the Commission or by NERC.  Any person affected by the Bulk-Power System can request an interpretation, and NERC will conduct a ballot-process to draft an interpretation and submit that to FERC to be appended to the actual reliability standard.  In asking the Commission to accept its currently-proposed interpretation to PRC-005, NERC anticipates extensive revisions by the end of the second quarter 2012.

In approving the reliability standard interpretation, the Commission also directed NERC to require maintenance and testing of reclosing relays that may affect the Bulk-Power System.  NERC is currently in the process of drafting revisions to PRC-005-2, but the initial attempt to draft modifications to the standard failed the ballot-process.  Further, Project 2007-17 will address “extensive, specific maintenance activities (with maximum maintenance intervals) related to the DC control circuits.”  Therefore, interested utilities should track NERC’s Project 2007-17 to understand when inclusion of the certain reclosing relays and DC control circuitry must be included in maintenance, testing, and internal audit programs.

A copy of the Commission’s interpretation of PRC-005-1 is available here.