Washington Energy Report > Troutman Sanders LLP

FERC Approves Interpretations of Transmission Operations Reliability Standards

On September 15, 2011, FERC issued two final rules approving NERC’s interpretation of the Transmission Operations Reliability Standard, TOP-001-1, and the Transmission Planning Reliability Standard, TPL-002-0.

Final Rule on TOP-001-1

In this Order, FERC adopted a final rule approving NERC’s interpretation of Transmission Operations Reliability Standard TOP-001-1 (Reliability Responsibilities and Authorities), Requirement R8, that the balancing authority is responsible for restoring real power balance and the transmission provider is responsible for restoring reactive balance during a system emergency.

On July 16, 2010, NERC submitted a petition requesting that FERC approve NERC’s interpretation of Requirement R8 of Reliability Standard TOP-001-1 in response to a request from Florida Municipal Power Pool.  On April 21, 2011, the Commission issued a NOPR proposing to approve NERC’s interpretation.  In this Order, the Commission adopts the NOPR proposal and approves NERC’s interpretation of TOP-001-1, R8, as follows:

Question: Balancing real power is not a function of a [Transmission Operator] and balancing reactive power is not a function of a [Balancing Authority]. For Requirement R8 is the Balancing Authority responsibility to immediately take corrective action to restore Real Power Balancing and is the [Transmission Operator] responsibility to immediately take corrective action to restore Reactive Power Balance?

Response: The answer to both questions is yes. According to the NERC Glossary of Terms Used in Reliability Standards, the Transmission Operator is responsible for the reliability of its “local” transmission system, and operates or directs the operations of the transmission facilities. Similarly, the Balancing Authority is responsible for maintaining load-interchange-generation balance, i.e., real power balance. In the context of this requirement, the Transmission Operator is the functional entity that balances reactive power. Reactive power balancing can be accomplished by issuing instructions to the  Balancing Authority or Generator Operators  to alter reactive power injection. Based on NERC Reliability Standard BAL-005-1b Requirement R6, the Transmission Operator has no requirement to compute an Area Control Error (ACE) signal or to balance real power. Based on NERC Reliability Standard VAR-001-1 Requirement R8, the Balancing Authority is not required to resolve reactive power balance issues. According to TOP-001-1 Requirement R3, the Balancing Authority is only required to comply with Transmission Operator or Reliability Coordinator instructions to change injections of reactive power.

A copy of the final rule is available here.

Final Rule on TPL-002-0

In this Order, FERC adopted a final rule approving NERC’s interpretation of Transmission Planning Reliability Standard TPL-002-0 addressing system performance following loss of a single bulk electric system element.

On November 17, 2009 NERC submitted a petition requesting that FERC approve NERC’s interpretation of Requirement R1.3.10 of Reliability Standard TPL-002-0 (System Performance Following Loss of a Single Bulk Electric System Element). In March 2010, FERC issued a NOPR proposing to reject NERC’s interpretation.  However, after evaluating comments received in response to the NOPR, FERC declined to adopt the NOPR and adopted NERC’s interpretations of TPL-002-0 in response to three questions from PacifiCorp, as follows:

Question 1:  Does TPL-002-0 R1.3.10 require that all elements that are expected to be removed from service through normal operation of the protection systems be removed in simulations?

Response 1:  TPL-002-0 requires that System studies or simulations be made to assess the impact of single Contingency operation with Normal Clearing. TPL-002-0, R1.3.10 does require that all elements expected to be removed from service through normal operations of the Protection System be removed in simulations.

Question 2: Is a Category B disturbance limited to faults with [N]ormal [C]learing where the protection system operates as designed in the time expected with proper functioning of the protection system(s) or do Category B disturbances extend to protection system misoperations and failures?

Response 2: This standard does not require an assessment of the Transmission System performance due to a Protection System failure of Protection System misoperation. Protection System failure of Protection System misoperation is addressed in TPL-003-0—System Performance following Loss of Two or More Bulk Electric System Elements (Category C) and TPL-004-0—System Performance Following Extreme Events Resulting in the Loss of Two or More Bulk Electric System (BES) Elements  (Category D).

Question 3: Does TPL-002-0, R1.3.10 require that planning for Category B [C]ontingencies assume a [C]ontinency that results in something other than a [N]ormal [C]learing event even though the TPL-002-0 Table I-Category B matrix uses the phrase “SLG or 3-Phase Fault, with Normal Clearing?”

Response 3: TPL-002-0, R1.3.10 does not require simulating anything other than Normal Clearing when assessing the impact of a Single Line Ground (SLG) or 3-Phase (3Ø) Fault on the performance of the Transmission System.

In addition, the Commission directed NERC and Commission Staff to initiate a process to identify any reliability issues. The Commission also directed NERC to make an informational filing within 6 months of the date of the issuance of the Final Rule on whether there is a further system protection issue, how it should be addressed, and what priority it should be accorded relative to other reliability initiatives planned by NERC.

A copy of the final rule is available here.