Technical Justification and Rational WECC-0068 Modification of BAL-004-WECC-1 Automatic Time Error Correction Attachment G This filing is designed to meet the specific requirements of Order 723, clarify certain ambiguities, and meet the specific criteria for a Regional Variance as established by the Federal Energy Regulatory Commission (FERC). This filing was developed in accordance with the Process for Developing and Approving WECC Standards, as superseded by the Reliability Standards Development Procedures. In order to obtain a Regional Variance to a NERC Reliability Standard, the proposed documents must: 1) be an alternative methodology with the same reliability objective, 2) not be inconsistent with or less stringent than the NERC reliability standard, 3) be necessitated by a physical or difference. As illustrated below, the proposed documents meet criteria one and criteria two above. Although the proposed methodology is not necessitated by a physical difference, its implementation should enhance reliability within the Western Interconnection by lessening the need for manual calculations. Alternative Methodology with the Same Reliability Objective This filing represents a proposed alternative methodology for calculating Area Control Error (ACE). Specifically, it would replace the NERC raw ACE equation with the Automated Time Error Correction (ATEC) ACE equation thereby requiring WECC Balancing Authorities to use the ATEC ACE for control and Control Performance Standard (CPS) reporting. This approach has the same reliability objective as BAL-001-0.1a with the enhanced benefit of ensuring that Time Error Corrections and Primary Inadvertent Interchange (PII) payback are effectively conducted in a manner that does not adversely affect the reliability of the Interconnection. Using the ATEC ACE equation for CPS reporting is more appropriate because it is a more accurate measure of how well a Balancing Authority is controlling to its control performance target. Under the current NERC ACE equation, a Balancing Authority controls its frequency and Interchange to a target point of zero. By contrast, the proposed ATEC ACE allows the control to stay within a predefined range called (which is between 0.20 * |B| and ±L10) adjusted by Lmax the ATEC.
Technical Justification and Rational WECC-0068 Modification of BAL-004-WECC-1 Automatic Time Error Correction Attachment G This filing is designed to meet the specific requirements of Order 723, clarify certain ambiguities, and meet the specific criteria for a Regional Variance as established by the Federal Energy Regulatory Commission (FERC). This filing was developed in accordance with the Process for Developing and Approving WECC Standards, as superseded by the Reliability Standards Development Procedures. In order to obtain a Regional Variance to a NERC Reliability Standard, the proposed documents must: 1) be an alternative methodology with the same reliability objective, 2) not be inconsistent with or less stringent than the NERC reliability standard, or 3) be necessitated by a physical difference. As illustrated below, the proposed documents meet criteria one and criteria two above. Although the proposed methodology is not necessitated by a physical difference, its implementation should enhance reliability within the Western Interconnection by lessening the need for manual calculations. Alternative Methodology with the Same Reliability Objective This filing represents a proposed alternative methodology for calculating Area Control Error (ACE). Specifically, it would replace the NERC raw ACE equation with the Automated Time Error Correction (ATEC) ACE equation thereby requiring WECC Balancing Authorities to use the ATEC ACE for control and Control Performance Standard (CPS) reporting. This approach has the same reliability objective as BAL-001-0.1a with the enhanced benefit of ensuring that Time Error Corrections and Primary Inadvertent Interchange (PII) payback are effectively conducted in a manner that does not adversely affect the reliability of the Interconnection. Using the ATEC ACE equation for CPS reporting is more appropriate because it is a more accurate measure of how well a Balancing Authority is controlling to its control performance target. Under the current NERC ACE equation, a Balancing Authority controls its frequency and Interchange to a target point of zero. By contrast, the proposed ATEC ACE allows the control to stay within a predefined range called Lmax (which is between 0.20 * |B| and ±L10) adjusted by the ATEC.