This section is maintained by the drafting team during the development of the standard and will be removed when the standard becomes effective.

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1 Standard Development Roadmap This section is maintained by the drafting team during the development of the standard and will be removed when the standard becomes effective. Development Steps Completed: 1. NPCC Regional Standards Committee (RSC) authorized posting UFLS RSAR development on August 20, UFLS RSAR posted on NPCC website on August 25, NPCC Reliability Coordinating Committee (RCC) approved the Task Force on System Studies (TFSS) as the lead task force to initiate drafting a UFLS Regional Standards on September 4, NPCC UFLS Regional Standard Drafting Team initial meeting on January 27, Formatted: Indent: Left: 0.25", Hanging: 0.38", Numbered + Level: 1 + Numbering Style: 1, 2, 3, + Start at: 1 + Alignment: Left + Aligned at: 0.25" + Tab after: 0.5" + Indent at: 0.5", Tab stops: 0.63", List tab + Not at 0.5" Description of Current Draft: This is the first draft of the proposed standard which will be submitted to the NPCC Regional Standards Committee with a request to post the proposed standard for industry comment. Future Development Plan: Anticipated Action 1. Post the initial draft of the standard for 45 day comment period. 2. Respond to comments on the first posting and post revised standard and implementation plan for a 45 day comment period. 3. Respond to comments on the draft of the proposed standard and implementation plan. Anticipated Date July 10, 2009 September 30, 2009 November 30, Obtain Regional Standards Committee December 7, 2009 approval to move the standard forward to balloting. 5. Post the standard and implementation plan December 14, 2009 for a 30-day pre-ballot review. 6. Conduct an initial ballot for ten days. January 15, Respond to comments submitted with the January 31, 2010 initial ballot. 8 Conduct a recirculation ballot for ten days February NPCC Membership approval March 2010 Draft 1 Page 1 of 12

2 Definitions of Terms Used in Standard This section includes all newly defined or revised terms used in the proposed standard. Terms already defined in the NERC Reliability Standards Glossary of Terms are not repeated here. New or revised definitions listed below become approved when the proposed standard is approved. When the standard becomes effective, these defined terms will be removed from the individual standard and added to the NPCC Glossary. In the standards, defined terms are indicated with its first letter capitalized. Draft 1 Page 2 of 12

3 A. Introduction 1. Title: Automatic Underfrequency Load Shedding Program 2. Number: PRC-006-NPCC-1 3. Purpose: Ensure the development and maintenance of an effective coordinated automatic underfrequency load shedding (UFLS) program to preserve the security and integrity of the interconnected bulk power system during declining system frequency events. 4. Applicability: a.4.1. Generator Owner b.4.2. Planning Coordinator c.4.3. Distribution Provider with 25 MW or more of end-use load connected to its facilities d.4.4. Transmission Owner with 25 MW or more of end-use load connected to its facilities 5. (Proposed) : To be established. Formatted: Outline numbered + Level: 2 + Numbering Style: 1, 2, 3, + Start at: 1 + Alignment: Left + Aligned at: 0.65" + Tab after: 1" + Indent at: 1" B. Requirements R1. The Planning Coordinators shall conduct system studies or use information available from actual system operations to identify anticipated islands within the NPCC region to be used for establishing locational requirements for entities aggregating their UFLS programs in Requirement R2 and locational requirements for compensatory load shedding in Requirement R10. R2. Each Distribution Provider and Transmission Owner in the Eastern Interconnection portion of NPCC with end-use load connected to its facilities shall implement an automatic UFLS program for its facilities or shall collectively implement by mutual agreement with one or more Distribution Providers and Transmission Owners within the same island, identified in Requirement R1, an aggregated automatic UFLS program that sheds load based on the following frequency thresholds, total nominal operating time 1, and amounts specified in one of the following sub-requirements: 1 The total nominal operating time includes the underfrequency relay operating time plus any interposing auxiliary relay operating times, communications time, and the rated breaker interrupting time. The underfrequency relay operating time is measured from the time when frequency passes through the frequency threshold set point, using a test rate of frequency decay of 0.2 Hz per second. Draft 1 Page 3 of 12

4 R2.1. Distribution Providers and Transmission Owners with 100 MW or more of end-use load connected to its facilities shall implement a UFLS program with the following attributes: UFLS Stage Frequency Threshold (Hz) Total Nominal Operating Time (s) Load Shed at Stage as % of TO or DP Load Cumulative Load Shed as % of TO or DP Load Anti-Stall R2.2. UFLS Stage Distribution Providers and Transmission Owners with 50 MW or more and less than 100 MW of end-use load connected to its facilities shall implement a UFLS program with the following attributes: Frequency Threshold (Hz) Total Nominal Operating Time (s) Load Shed at Stage as % of TO or DP Load Cumulative Load Shed as % of TO or DP Load > 14 > > 14 > 28 R2.3. UFLS Stage Distribution Providers and Transmission Owners with 25 MW or more and less than 50 MW of end-use load connected to its facilities shall implement a UFLS program with the following attributes: Frequency Threshold (Hz) Total Nominal Operating Time (s) Load Shed at Stage as % of TO or DP Load Cumulative Load Shed as % of TO or DP Load > 28 > 28 Draft 1 Page 4 of 12

5 R3. Each Distribution Provider and Transmission Owner in the Québec Interconnection portion of NPCC shall implement an automatic UFLS program that sheds load based on the following frequency thresholds, slopes, total nominal operating time 2, and amounts specified in the following table: Rate Frequency (Hz) MW at peak Mvar at peak Total Nominal Operating Time (s) Threshold Stage * Threshold Stage * Threshold Stage Threshold Stage Threshold Stage 5 (anti-stall) Slope Stage Hz/s Slope Stage Hz/s * Slope Stage Hz/s * Slope Stage Hz/s * Load must be fixed at all times R4. Each Distribution Provider and Transmission Owner shall set their underfrequency relays with the following minimum time delay: R4.1. Eastern Interconnection 100 ms R4.2. Québec Interconnection 200 ms R5. Each Distribution Provider and Transmission Owner that utilizes undervoltage inhibit on their underfrequency relays shall set this function at or below 70 percent of nominal voltage. R6. Each Transmission Owner and Distribution Provider shall report to its Balancing Authority no later than 24 hours after the forced removal or disabling of an UFLS relay. Planned outages of relays for maintenance do not compromise the objectives of the NPCC automatic UFLS program because of the distributed nature of the load shedding protection. 2 The total nominal operating time includes the underfrequency relay operating time plus any interposing auxiliary relay operating times, communications time, and the rated breaker interrupting time. The underfrequency relay operating time is measured from the time when frequency passes through the frequency threshold set point, using a test rate of frequency decay of 0.2 Hz per second. Draft 1 Page 5 of 12

6 R7. Each Transmission Owner and Distribution Provider shall annually verify, and provide documentation to its Planning Coordinator according to the schedule specified by the Planning Coordinator, the net amount of load its UFLS relays were armed to shed at each UFLS stage coincident with their integrated hourly peak during the previous year. R8. Each Generator Owner with a generating unit that will trip directly or indirectly for underfrequency conditions above the generator tripping threshold curve in Figure 1 shall: Generating units are required to trip directly or indirectly for underfrequency conditions below the generator tripping threshold curve in Figure 1. R8.1. For new generators that are scheduled to be in service on or after the effective date of this Standard, each generator owner shall: R Verify auxiliary system(s) or devices used for the control and protection of auxiliary system(s) necessary for the generating unit operation will not force the generating unit out of service during under-frequency conditions above the generator tripping threshold curve in Figure 1.prior to the generator unit under-frequency protection. R Transmit the generator under-frequency trip setting and time constant to the Planning Coordinator. If an auxiliary system or device is found to trip at a higher frequency than the generator under-frequency trip setting, the tripping point (frequency and time) of that auxiliary system or device shall also be reported to the Planning Coordinator. R8.2. Generator Owners with existing non-nuclear units in service prior to the effective date of this Standard which have underfrequency tripping that is not compliant with R8, illustrated in Figure 1, shall verify that the existing compensatory load shedding is adequate to compensate for the loss of their facility. [Placeholder for RSDT: Consider addressing FERC s stated recommendation to use DSM or DSM-type arrangements as the preferred load for compensatory load-shedding.] R Set the protection to operate at as low a frequency as possible in accordance with the plant design and licensing limitations, and R Transmit the setting and the technical basis for the setting to the Planning Coordinator. A new transmittal is required whenever the setting is changed. R These Generator Owners shall file an annual report with their Planning Coordinator identifying the generating units, and associated compensatory load shedding. The report shall include the information detailed below. R Unit name and generating capacity. R Underfrequency tripping protective settings, including frequency set point and time delay. R Name of UFLS entity providing compensatory load shedding for the unit. Formatted: Strikethrough Formatted: Font: Italic Formatted: Bullets and Numbering Formatted: Font: Italic Formatted: Font: Times New Roman Formatted: Font: Times New Roman, Strikethrough Formatted: Font: Times New Roman, 12 pt, Italic, Strikethrough Formatted: Font: Times New Roman Formatted: Font: Times New Roman Formatted: Font: Italic Formatted: Indent: Left: 1.2" Formatted: Bullets and Numbering Formatted: Font: Italic Draft 1 Page 6 of 12

7 R8.3. R The compensatory load shedding provided by the Distribution Providers or Transmission Owners shall be in addition to the amount they are required to shed in Requirement R2 or R3 R The amount of compensatory load shedding shall be equivalent (±5%) to the two-year average net generator megawatt output plus expected station loads to be transferred to the system upon loss of the facility. R The compensatory load shedding shall be provided at the UFLS program stage with the frequency threshold setting closest to and at or above the frequency at which the subject generator will trip. R The compensatory load shedding shall be within the smallest island identified by the Planning Coordinator in Requirement R1 within which the generator may operate. sset the protection to operate at as low a frequency as possible in accordance with the plant design and licensing limitations, and ttransmit the setting and the technical basis for the setting to the Planning Coordinator prior to when the generating unit is placed in service and prior to when the setting is changed. Recognizing the underfrequency trip settings at existing boiling water reactor nuclear generating plants have, as part of their licensing design basis, effective underfrequency relay threshold settings above the generator tripping curve given in Figure 1, these units are required to adhere to the following: R Set the protection to operate at as low a frequency as possible in accordance with the plant design and licensing limitations, and R Transmit the setting and the technical basis for the setting to the Planning Coordinator. A new transmittal is required whenever the setting is changed. R9. Each Generator Owner with a generating unit that will trip directly or indirectly for underfrequency conditions above the compensatory load shedding curve in Figure 1 shall arrange for compensatory load shedding with Distribution Providers or Transmission Owners with end-use load customer(s) connected to their facilities. [To be removed.] Formatted: Bullets and Numbering Formatted: Font: Italic Formatted: Indent: Left: 1.2" Formatted: Bullets and Numbering Formatted: Font: Italic Formatted: Indent: Left: 1.2" Formatted: Strikethrough Formatted: Font: Italic, Strikethrough The compensatory load shedding provided by the Distribution Providers or Transmission Owners shall be in addition to the amount they are required to shed in Requirement R2 or R3. R7.1. The amount of compensatory load shedding shall be equivalent (±5%) to the two-year average net generator megawatt output plus expected station loads to be transferred to the system upon loss of the facility. Formatted: Indent: Left: 0.63" Formatted: Indent: Left: 0.25" Draft 1 Page 7 of 12

8 R7.2. R7.3. The compensatory load shedding shall be provided at the UFLS program stage with the frequency threshold setting closest to and at or above the frequency at which the subject generator will trip. The compensatory load shedding shall be within the smallest island identified by the Planning Coordinator in Requirement R1 within which the generator may operate. R8.R10. Each Planning Coordinator shall develop and maintain its UFLS program data base. This data base shall include the following information: R8.1.R10.1. Location of the UFLS relays. R8.2.R10.2. Amount of load shed by each relay and the corresponding frequency threshold and time delay settings. R8.3.R10.3. The buses at which the load is modeled in the NPCC library power flow case. R8.4.R10.4. A list of all generating units that may be tripped directly or indirectly for underfrequency conditions above the compensatory load shedding curve in Figure 1, including the frequency trip threshold and time delay for each protection system. R9.R11. Each Transmission Owner and Distribution Provider shall provide its UFLS program data to its Planning Coordinator for inclusion in the Planning Coordinator s data base annually on the schedule specified by the Planning Coordinator. Draft 1 Page 8 of 12

9 Figure 1 Requirement R8 and R9 Thresholds for Setting Underfrequency Trip Protection for Generators Frequency (Hz) Compensatory Load Shedding Eastern Interconnection Generator Tripping Quebec Interconnection Generator Tripping Time (seconds) C. Measures M1. Each Planning Coordinators shall file provide evidence, such as electronic or hard copies, with NPCC of studies performed and other information used to identify anticipated islands within the NPCC region. Comment [pjt1]: Gerry and Phil will confirm standard format and assumptions regarding to whom evidence is provided. M2. Each Distribution Provider and Transmission Owner and Distribution Owner in the Eastern Interconnection portion of NPCC shall provide evidence that it has implemented an automatic UFLS program for its facilities as specified in Requirement R2 to its Planning Coordinator either through an annual survey (refer to M7) or otherwise demonstrating that it s installed, in-service UFLS facilities meet R2. M3. Each Distribution Provider and Transmission Owner in the Québec Interconnection shall file provide evidence, such as electronic or hard copies, that it has implemented an automatic UFLS program for its facilities as specified in Requirement R3with its Load Serving Entities of their procedure to ensure the aggregated UFLS program that shed load based on the frequency thresholds and slopes. M4. Each Distribution Provider and Transmission Owner shall file provide evidence, such as electronic or hard copies, with its Planning Coordinator of their procedure to ensure that their underfrequency relays have been set with the following minimum time delay: Comment [a2]: Because some stages required the exact load to be shed at any time, LSE must prepare dynamically the right quantity based on their forecast ready to be shed. M4.1 Eastern Interconnection 100 ms M4.2 Québec Interconnection 200 ms Draft 1 Page 9 of 12

10 M5. Each Distribution Provider and Transmission Owner that utilizes under voltage inhibit on their under frequency relays shall file provide evidence, such as electronic or hard copies, with its Planning Coordinator of their procedure to ensure this that the undervoltage inhibit function on its relays is set at or below 70 percent of nominal voltage. M6. Each Transmission Owner and Distribution Provider shall file provide evidence, such as electronic or hard copies, with its that it notified its Balancing Authority no later than 24 hours after the forced removal or disabling of an UFLS relay. M7. Each Transmission Owner and Distribution Owner Provider shall provide documentation annually to and as specified by its Planning Coordinator that indicates the net amount of load shed at each stage by its UFLS program coincident with the integrated hourly peak of the previous year and demonstrated compliance with R2. M8. Each Generator Operator Owner with a generating unit that will trip directly or indirectly for underfrequency conditions above the generator tripping threshold curve in Figure 1 shall provide evidence: M8.1 That the protection has been set to operate at as low a frequency as possible in accordance with the plant design and licensing limitations, and M7.1M8.2 That the setting and the technical basis for the setting has been transmitted to the Planning Coordinator as specified in Requirement R8.2 of its UFLS trip settings (direct or indirect) to the Planning Coordinator as requested and within 30 days. If these settings are above the curve in Figure 1 evidence shall be provided that they are set as low as possible in accordance plant design and license. Comment [pjt3]: Do we need to be more specific, or ask a question on the next comment form, as to what evidence would be provided given that the notification may be verbal. Formatted: Bullets and Numbering M8.M9. Each Generator Operator with a facility that trips above the compensatory load shed curve shall provide evidence of an agreement to provide compensatory load shedding. M9 The Distribution Providers or Transmission Owners shall provide evidence of compensatory load shedding over and above that required in R2 or R3. M9.2 The Generator Owner shall provide evidence of an agreement for compensatory load shedding within +/- 5% of two year average net generator megawatt output plus expected station loads. M9.3 The Distribution Providers or Transmission Owners shall provide evidence that the compensatory load shedding is at or above the frequency which the generator will trip. Draft 1 Page 10 of 12

11 M9.4 The Distribution Providers or Transmission Owners providing the load shedding shall identify the load shedding within the smallest island identified within R1 for each generator. M9.M10. Each Planning Coordinator shall file provide evidence, such as electronic or hard copies, with NPCC of its process to that it has developed and maintained the information required by its UFLS program data base as specified in Requirement R10. M10.M11. Each Transmission Owner and Distribution Provider shall file provide evidence of that it provided its UFLS program data, such as electronic or hard copies, with to its Planning Coordinator annually on athe schedule specified by its Planning Coordinator. D. Compliance 1. Compliance Monitoring Process 1.1. Compliance Enforcement Authority NPCC Compliance Committee a.1.2. Compliance Monitoring Period and Reset Time Frame Not Applicable b.1.3. Data Retention To be developed. c.1.4. Compliance Monitoring and Assessment Processes To be developed. d.1.5. Additional Compliance Information To be developed. 2. Violation Severity Levels To be developed. Formatted: Outline numbered + Level: 2 + Numbering Style: 1, 2, 3, + Start at: 1 + Alignment: Left + Aligned at: 0.65" + Tab after: 1" + Indent at: 1" Formatted: Outline numbered + Level: 2 + Numbering Style: 1, 2, 3, + Start at: 1 + Alignment: Left + Aligned at: 0.65" + Tab after: 1" + Indent at: 1" Formatted: Outline numbered + Level: 2 + Numbering Style: 1, 2, 3, + Start at: 1 + Alignment: Left + Aligned at: 0.65" + Tab after: 1" + Indent at: 1" Formatted: Outline numbered + Level: 2 + Numbering Style: 1, 2, 3, + Start at: 1 + Alignment: Left + Aligned at: 0.65" + Tab after: 1" + Indent at: 1" Draft 1 Page 11 of 12

12 E. Associated Documents Version History Version Date Action Change Tracking Draft 1 Page 12 of 12

Standard Development Roadmap

Standard Development Roadmap This section is maintained by the drafting team during the development of the standard and will be removed when the standard becomes effective. Development Steps Completed: