Related Files | 2008-02.2 Phase 2 of Undervoltage Load Shedding (UVLS): Misoperations
UVLS Status - PRC-010-1
Board Adopted: November 13, 2014
Filed with FERC: February 6, 2015
Order Effective:
Enforcement Date:
UFLS Status - PRC-006-2
Board Adopted: November 13, 2014
Filed with FERC: December 15, 2014
Order Effective: March 4, 2015
Enforcement Date: October 1, 2015
UVLS information
Purpose/Industry Need:
To establish an integrated and coordinated approach to the design, evaluation, and reliable operation of undervoltage load shedding programs used to mitigate undervoltage conditions leading to voltage instability, voltage collapse, or Cascading impacting the Bulk Electric System (BES)
Background:
In January 2010, NERC posted the Project 2008-02 Undervoltage Load Shedding (UVLS) SAR for public comment. The SAR cited NERC technical reports and assessments of UVLS programs and standards, along with the FERC Order No. 693 directive that approved PRC-010-0 but requested that it be modified to require that an integrated and coordinated approach be included in all protection systems on the Bulk Power System, including generators and transmission lines, generators’ low voltage ride-through capabilities, and underfrequency load shedding (UFLS) and UVLS programs.
Concurrently with the SAR posting, nominations were accepted for a drafting team. Work was deferred due to prioritization for the 2011–2013 Reliability Standards Development Plan (RSDP) and the effort was restarted as part of the 2013–2015 RSDP. A formal drafting team was appointed on May 21, 2013. Its members are tasked with reevaluating and revising the SAR and subsequently proceeding with standard development. The team’s objective is to ensure that Project 2008-02 addresses NERC’s existing UVLS standards such that they are results-based, address the appropriate regulatory directives, coordinate with present reliability standard efforts (e.g., Paragraph 81, the Independent Expert Review Panel, and Five-Year Reviews), and consider current reliability issues associated with UVLS.
UFLS information
Purpose: The purpose of the UFLS project is to address an outstanding FERC directive and review PRC-006-1 to determine if any steady state modifications are appropriate (i.e., Paragraph 81 criteria and recommendations of the Independent Expert Review Panel). Specifically, the standard drafting team will revise PRC-006-1 to address the directive included in FERC Order No. 763 and to provide for clear, unambiguous design and documentation requirements for automatic UFLS programs.
Background:
The UFLS work will be done in concert with the current efforts underway by the UVLS standard drafting team in order to ensure overall consistency and alignment for these protection systems programs. The revised SAR was posted on May 23, 2014 for a 30-day informal comment period, which concluded on June 23, 2014.
