Revise your NERC PRC-005 PSMP (Protection System Maintenance Program) by April 1, 2013

TULSA, Oklahoma-February 2012--The Federal Energy Regulatory Commission (FERC) has approved both a new definition of the term “Protection System,” to be included in the North American Electric Reliability Corporation’s (NERC) glossary of terms used in reliability standards, and also interpretations of the requirements of reliability standard PRC-005-1a, which sets forth requirements for the maintenance and testing of transmission and generation protection systems.

The revised definition primarily adds battery chargers to the categories of equipment that are deemed “Protection Systems” to ensure that batteries used to operate protection systems are in a continuous state of readiness. The revised definition of Protection System includes:

• Protective relays that respond to electrical quantities;
• Communication systems necessary for correct operation of protective functions;
• Voltage and current sensing devices providing inputs to protective relays;
• Station DC supply associated with protective functions (including station batteries, battery chargers, and non-battery-based DC supply); and
• Control circuitry associated with protective functions through the trip coil(s) of the circuit breaker or other interrupting devices.

The following interpretations, among others, also will be included within PRC-005-1a, effective 30 days after FERC’s order is published in the Federal Register:

• Maintenance and testing of auxiliary relays is not explicitly required, but should be addressed to the degree that a maintenance and testing program for DC control circuitry involves the maintenance and testing of imbedded auxiliary relays.
• Maintenance and testing of devices that respond to quantities other than electrical quantities (e.g., sudden pressure relays) is not required.
• Maintenance and testing of transmission line reclosing relays is not required, but FERC directed NERC to include certain reclosing relays in the next version of PRC-005.
• “Protective relays” refer to devices that detect and take action for abnormal conditions, and automatic restoration of transmission lines is not a protective function.
• “Associated communications systems” refer to communication systems used to convey essential Protection System tripping logic (e.g., pilot relaying or teleprotection), including, but not limited to, communications equipment involved in power-line carrier relaying or in various types of permissive protection system applications, and direct transfer-trip systems.

Implementation
Each entity subject to PRC-005-1a is required to modify its protection system maintenance and testing program description and basis documents under PRC-005-1a, R1, to reflect the revised Protection System definition by April 1, 2013. (Until this time, FERC clarified that battery chargers are not required to be maintained and tested under PRC-005-1a.) In addition, each responsible entity shall be required to implement any new or additional maintenance and testing under R2 by the end of the first complete maintenance and testing cycle described in its program documentation following the establishment of any program changes resulting from the revised definition.

Considerations
While there is a little more than a year to make changes necessitated by the new Protection System definition, responsible entities should soon start to identify which battery chargers must be included in the protection system maintenance and testing program, determine the appropriate testing interval, and identify what changes to program documentation are needed. This will allow ample time to identify, perform, and train on the changes necessitated by this new definition.
In addition, responsible entities should consider whether any of the approved interpretations would necessitate changes to their maintenance and testing program documentation or execution.

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