The North American Electric Reliability Corp. (NERC) Reliability Standards are under constant revision even while new requirements are under active development. As noted in the last NERC Critical Infrastructure Protection (CIP) update (“Lessons Learned in Reliability Standards Compliance,” October 2010, available in the POWER archives at, the standards are constantly undergoing revisions, updates, and requests for interpretations. Three important regulatory definitions are currently being contested.

BES Definition

On November 18, 2010, Federal Energy Regulatory Commission (FERC) Order 743 directed NERC to revise the definition of the bulk electric system (BES) so that it encompasses all the “Elements and Facilities” necessary for the reliable operation and planning of the interconnected bulk power system. NERC believes that this additional specificity in the definition will reduce ambiguity and establish consistency across all NERC regions in distinguishing between BES and non-BES elements and facilities.

NERC includes electrical generation resources, transmission lines, interconnections, and associated equipment in the BES. An “element” is “any electrical device… connected to another electrical device, such as a generator, circuit breaker, bus section, or transmission line.” A “facility” is a “set of electrical equipment that operates as a single BES element.” Examples include generators, power lines, and transformers.

In addition, NERC was directed to develop a process for identifying any elements or facilities that should be excluded from the BES. NERC is working to address these directives in two ways. First, it is modifying the definition of BES through the standard development process. NERC’s second approach is to develop a BES Definition Exception Process as a proposed modification to the NERC Rules of Procedure. One particular problem is FERC’s preference for including all transmission facilities rated at 100 kV and above in the definition of BES. This approach contradicts certain regional criteria that currently consider facilities on a case-by-case basis for inclusion in BES, regardless of operating voltage.

On the surface, revising the definition of BES to include all systems rated at 100 kV and above appears to be an easy fix. However, the devil is always in the details. In this situation the uncertainty lies with the exception process that identifies facilities operating at or above 100 kV that have minimal or no system reliability impact and therefore are not part of BES.

You can follow future developments by watching NERC project 2010-17 on the NERC website ( on the Standards Under Development page. Industry members potentially affected by the new definition should watch these developments closely and submit comments.

PRC-005-1 Interpretation

In a Notice of Proposed Rulemaking (NOPR) released December 16, 2010 (Docket No. RM10-5-000,, FERC accepted an interpretation submitted by NERC to clarify the scope of equipment to be addressed in standard PRC-005-1 (Transmission and Generation Protection System Maintenance and Testing). Although FERC accepted the interpretation that clarified (in part) that equipment such as battery chargers, auxiliary relays and sensing devices, and line reclosing relays are not included in the scope of PRC-005-1, it then expressed disagreement with the exclusion of such devices and proposed to “direct NERC to develop modification to the PRC-005-1 Reliability Standard… through its Reliability Standards development process to address gaps in the Protection System maintenance and testing standard.”

NERC responded with a request that it be allowed to address FERC’s concerns rather than having FERC issue directives. The NOPR drafting team is currently working on PRC-005 Version 2 to reflect a complete framework for maintenance and testing of equipment. This unanticipated FERC comment will alter PRC-005-2, which was posted for ballot for May 3 through May 12, 2011. Now the drafting team will either have to revise the draft standard for the upcoming balloting or quickly produce a version 3 that will answer FERC’s concerns. Registered entities should closely monitor the ongoing PRC-005 proceedings and be prepared to comment on whichever approach is finally selected.

CIP-002-4 “Bright Line” Criteria and FERC Request for Additional Data

Version 4 of the CIP Standards is currently under review by FERC. The key change in Version 4 is CIP-002-4, which seeks to eliminate the current risk-based assessments. Registered entities must apply annually to determine asset criticality and replace risk-based assessements with a set of “bright line” criteria that will be used to make the determination. The bright line criteria are a series of thresholds and attributes that BES equipment is measured against to determine its criticality. They include, for example, a 1,500-MW threshold for generators, the inclusion of black-start resources in a restoration plan, and the ability to produce over 1,000 MVARs of reactive power. There are also thresholds for transmission facilities of 300 MW or higher and for control centers.

On April 12, FERC issued a data request asking NERC what the consequences would be of applying the Version 4 bright line criteria to the BES. For example, how many generators would be deemed critical, how many transmission facilities, and how many control centers? NERC advised FERC that it is able to respond within the allotted 45 days on roughly half of the questions, while the remainder would require a survey of registered entities to compile the data. An extension was requested and granted on these specific questions.

CIP standards and their development and revision will remain very high-profile issues for the power industry for some time. Regulators and registered entities continue to work through the details of protecting our bulk electric system against an ever-changing cybersecurity threat.

—Contributed by James Stanton (, principal adviser, regulatory services, Quanta Technology.