SYSTEM CONTROL ORDERS

Transcription

1 IMO-Public IMO_SCO_S_0423 SYSTEM CONTROL ORDERS Inadvertent Interchange - Terminology, Calculation and Management Public SCO S-0423 Version 01 Issued: May 10, 2001 This SCO defines the terminology associated with uncontrolled exchange of energy between systems, and outlines the methods to calculate and manage inadvertent interchange.

2 Disclaimer The posting of documents on this web site is done for the convenience of IMO market participants and other interested visitors to the IMO web site. Please be advised that, while the IMO attempts to conform all posted documents to the original, changes can result from the original, including changes resulting from the programs used to format the documents for posting on the web site as well as from the programs used by the viewer to download and read the documents. The IMO makes no representation or warranty, express or implied, that the documents on this web site are exact reproductions of those documents listed. In addition, the documents and information posted on this web site are subject to change. It is solely your responsibility to ensure that you are using up-to-date documents and information. Viewing access of these SCOs during the Uncoupled Operational Dry Run test period is limited to the 20 Market Participants who are registered for Uncoupled Operational Dry Run and are not to be published, posted or distributed until the IMO completes its full review process which is expected before the commencement of Operational Dry Run. Document ID IMO_SCO_S_0423 Document Name Inadvertent Interchange - Terminology, Calculation and Management Issue Version 01 Reason for Issue SCO 23-5 superceded by SCO S Effective Date May 10, 2001

3 Table of Contents Table of Contents Table of Changes Related Reference Documents 1. Scope Definitions Final Schedule Setting Equipment Error Inadvertent Interchange Managing Inadvertent Interchange Billing...6 Appendix A: On-Peak and Off-Peak Periods For Inadvertent Accounting Appendix B: Seasonal Time Changes Appendix C: Procedure for Daily Control Error Correction Appendix D: CNP Inadvertent Appendix E: HID Adjustments for Ramps Across the Hour Appendix F: Dealing With Abnormal Inadvertent Accumulations SCO S-0423 Version 01 May 10, 2001

4 Table of Changes Date Version Reference Section & Paragraph May 8, 2001 SCO S Appendix E Appendix F Description of Change Appendix added to include HID adjustments for Ramps Across the Hour (formerly OGI C-11). Appendix added for new procedure dealing with abnormal inadvertent accumulations. April 26, 2001 SCO S SCO 23-5 superceded by SCO S November 23, 2000 SCO Eliminate reference to Canadian Niagara Power (CNP) 60 Hz load and (retired) CNP-TP trunk from the 25 XPT quantity definition. - Incorporate OGI C5, OGI C6, OGI C7 and OGI R6 as attachments, to consolidate Inadvertent Interchange related procedures and instruction into one document. - Reflect organizational changes. SCO S-0423 Version 01 May 10, 2001

5 Related Reference Documents Ref. # Document ID Document Title 1 NERC Policy 1 2 NERC Policy NERC Training Document NPCC Reference Manual 5 SCO S-0402 NERC Operating Manual Generation Control & Performance NERC Operating Manual Interchange Inadvertent Interchange Accounting Training Document NERC Glossary of Terms 6 DACS Guideline DG A1- AGC Frequency Control, Time Error Correction, and Equipment Calibration 7 DACS Guideline DG H1 Hourly Interconnection Data SCO S-0423 Version 01 May 10, 2001

6 1. Scope This SCO defines the terminology associated with uncontrolled exchange of energy between systems, and outlines the methods to calculate and manage inadvertent interchange. SCO S Version 01 May 10, 2001

7 2. Definitions Some of the following terms are described in the NERC Glossary of Terms, however their definitions are expanded here to highlight how they are used within ICR and HID. ICR is the Interchange Control Record; DACS switch matrix Level 9 Button 76. HID is the Hourly Interconnection Data; DACS switch matrix Level 9 Button Final Schedule Setting The final schedule setting (MW) is the sum of four components: Final Schedule Setting = Interchange Schedule (NYISO, MECS, MAN, MP&L) +Inadvertent Payback +Control Error Correction +Time Error Correction Each of these components is described below. The final schedule setting is recorded in the ICR. It is used in the calculation of Control Deviation (Section 2.2). Interchange Schedule An interchange schedule is the sum of the planned interchanges between the IMO and each of its synchronously tied interconnected systems; New York, Michigan, Manitoba and Minnesota. Energy transfer between Ontario and Quebec is accomplished by switching generators from one control area to another. Inadvertent with Quebec is kept track of separately. All schedule changes are to be considered as taking place instantaneously in spite of the fact that some time is required to ramp the schedule (typically 10 minutes). The instantaneous schedules are recorded in ICR, while the average hourly schedules are recorded on HID. Inadvertent Payback Inadvertent payback is the pre-arranged transfer of energy for the purpose of reducing the cumulative inadvertent energy balance. Payback is not included in the interchange schedule, but added to the final schedule setting. It is recorded on ICR and HID. Control Error Correction SCO S Version 01 May 10, 2001

8 Control error correction is a parameter set into the AGC software to compensate for any known errors in the control or telemetering equipment. An effective offset can be determined as per instruction in Section 3, Item 3. Control error correction offset is recorded on ICR and HID. Time Error Correction Time error correction is a megawatt offset designed to reduce the accumulated inadvertent energy, while reducing an existing time error. Typically this time error correction is applied via schedule frequency offsets or automatic time error correction. Refer to SCO S-0402 for further information on time error correction. It is recorded on ICR and HID. 2.2 Equipment Error Equipment error may be caused by errors in telemetering and load control equipment. It is defined as the difference between the control deviation and the bias effect. Control Deviation Equipment Error = Control Deviation - Bias Effect Control deviation is computed by the difference of metered net and the final schedule setting, both quantities are displayed on Page 3 of HID. Where: Control Deviation = Metered Net - Final Schedule Setting Metered net is the algebraic sum of all energy flows between Ontario and the connected systems over synchronous tie lines, which are in control. Final schedule setting is the hourly average of the final schedule setting. For the purposes of control deviation calculation, the number does not get recomputed if manual corrections to interchange schedules are applied after the fact. Bias Effect Bias effect is the amount IMO owes, as part of our contribution to time error accumulation over the last hour, calculated using our frequency bias characteristic, or bias setting, as follows: Where: 60 Hz BiasEffect = BiasSetting x x T sec/hr { } { } BiasSetting x AvgFreqOffset BiasSetting is the control area s frequency response characteristic, expressed in MW/0.1 Hz. The current value is displayed on DACS under AGC ADJUSTMENTS picture (#1017). SCO S Version 01 May 10, 2001

9 AvgFreqOffset is the average scheduled frequency, taking into account any frequency offsets. T is the change in time error accumulation during the hour, expressed in seconds. Example: BiasSetting T AvgFreqOffset BiasEffect for the hour = 292 MW/0.1 Hz = -0.2 seconds = 0.0 Hz = { -(292/0.1)x(60/3600)x(- 0.2) } - {292x0.0} = 10 MW 2.3 Inadvertent Interchange Inadvertent Interchange is defined by the algebraic sum of the inadvertent interchange of all the synchronous ties between Ontario and its interconnects. Inadvertent = Inad NYISO + Inad MECS + Inad MAN + Inad MP&L Where: Inad NYISO = Metered Net (NYISO) - Interchange Schedules (NYISO) Hydro-Quebec inadvertent is accounted for separately. A distinction is to be made between "on peak" and "off peak" inadvertent. Details are provided in Appendix A. SCO S Version 01 May 10, 2001

10 3. Managing Inadvertent Interchange 1. It is desirable to keep the hourly inadvertent interchange at a minimum and the accumulated total as close to zero as possible. At times when persistent high or low frequency exists on the interconnection, it is desireable to allow the offsetting inadvertent to accumulate. If the on-peak or off-peak balance exceeds 2500 MWh, follow the procedure outlined in Appendix F. 2. Inadvertent interchange is minimized when every control area involved in a transaction: a) Changes its schedule setting at the same time. b) Selects the same rate of change. c) Consistently uses the same period of change. d) Has accurate and responsive system controls and telemetering. NERC Policy 3, Subsection B requires control areas to confirm the details of an interchange prior to the commencement of the same. 3. Supervise the equipment error and check for errors in the control or telemetering equipment. Equipment error should be compensated, by using a Control Error Correction. This correction is for equipment error and NOT to compensate for inadvertent. Do not use Auto Control Error Correction. The Procedure for Daily Control Error Correction is outlined in Appendix C. 4. Supervise the 25 XPT quantity used by AGC. It represents the energy delivered to CN for their loads at the CNP power plant. 25 XPT = CNP-NF1 + BSH106 Where: CNP-NF1 =Trunk used by CNP, between CNP and Niagara TS within Ontario. Further details on CNP inadvertent are provided in Appendix D. 5. Scheduled frequency or scheduled net tie line flows may be offset to reduce inadvertent when such action will also reduce the existing time error. This time error inadvertent correction has been detailed in SCO S Correcting the inadvertent balance may be performed any time a time error exists except during an Eastern Interconnect scheduled time error correction. During a scheduled time error correction, no inadvertent interchange would theoretically be returned since all control areas would have the same frequency offset. 6. Reduction of the inadvertent accumulation through payback is achieved by scheduling inadvertent payback with another interconnected system, which has an inadvertent accumulation of opposite sign. Any mutually acceptable amount may be scheduled. SCO S Version 01 May 10, 2001

11 4. Billing Ontario, Michigan, New York and Manitoba bill each other for scheduled tie line flow rather than the actual metered energy flow. This type of billing is known as "Scheduled Billing". The agreements with Michigan, New York and Manitoba are such that the net inadvertent interchange is carried forward from month to month. SCO S Version 01 May 10, 2001

12 Appendix A: On-Peak and Off-Peak Periods For Inadvertent Accounting The On-Peak and Off-Peak periods for Inadvertent Interchange Energy accounting purposes within the Eastern Interconnection during 2000 and 2001 are as follows: The On-Peak periods consist of Hour Ending 08:00-23:00 EST when EST is in effect (note: the inadvertent ON PEAK time will be hours ending 8-23 on the HID sheet), and Hour Ending 07:00-22:00 EST when EDST is in effect (note: the inadvertent ON PEAK time will be hours ending 7-22 on the HID sheet), Monday through Saturday, excluding the six NERC mandated holidays listed below. The Off-Peak periods consist of Hour Ending 24:00-07:00 EST when EST is in effect and Hour Ending 23:00-06:00 EST when EDST is in effect, all hours on Sunday and all hours on the following holidays. 2001: Holiday Date Day New Year s Day January 1 Monday Memorial Day May 28 Monday Independence Day July 4 Wednesday Labor Day September 3 Monday Thanksgiving Day November 22 Thursday Christmas Day December 25 Tuesday 2002: Holiday Date Day New Year s Day January 1 Tuesday Memorial Day May 27 Monday Independence Day July 4 Thursday Labor Day September 2 Monday Thanksgiving Day November 21 Thursday Christmas Day December 25 Wednesday Ref: NERC Policy 1, Appendix 1F, SubSection F, On-Peak and Off-Peak Periods SCO S-0423 A-1 Version 01 May 10, 2001

13 Appendix B: Seasonal Time Changes Ontario and Michigan operate on Eastern Standard Time all year round. In order to ensure that misunderstandings do not occur with adjacent jurisdictions, the following reference information is provided: Eastern Standard Time The time change from Eastern Daylight Saving Time to Eastern Standard Time occurs at 02:00 on the last Sunday in October. During the Eastern Standard time period, Ontario's operating time will be identical to Quebec, New York, and Michigan's operating time. Manitoba will be one hour behind Ontario. Eastern Daylight Saving Time The time change from Eastern Standard Time to Eastern Daylight Saving Time occurs at 02:00 on the first Sunday in April. During the Eastern Daylight Saving time period, Ontario's operating time will be one hour behind Quebec and New York's operating time. Manitoba and Michigan will be identical to Ontario. SCO S-0423 B-1 Version 01 May 10, 2001

14 Appendix C: Procedure for Daily Control Error Correction The procedure for daily Control Error Correction (C.E.C.) that started on April 27, 1993 helped to keep total inadvertent lower but did not help the split between on and off peak totals. Every night when HID is printed, the C.E.C. may be applied using Method A or B as described below. Do not use the AUTO Control Error Correction. Method A: This calculation is easier and is appropriate when equipment error is distributed evenly between on and off peak hours. Divide the 24-hour accumulation of Equipment Error by negative 24 and apply as a manual Control Error Correction for the next 24 hours. Method B: This calculation will take more time but will allow the Exchange Coordinator Markets to better balance on and off peak inadvertent accumulations. Calculate the average On and Off peak Equipment Error. Apply the negative of these values as a manual Control Error Correction for the on and off peak hours over the next 24 hour period. Inform subsequent shifts of the method used and the C.E.C. value (two numbers if method B is selected). Method A must be used to apply a C.E.C to a Sunday or Holiday. Method B may be used to apply a C.E.C to a Monday (or a day after a holiday) but there will only be an off peak C.E.C and it will be the total 24 hour Equipment Error divided by negative 8. Weekend adjustments are no longer to be applied. These were based on how closely the C.E.C. matched the equipment error. The subject matter expert (SME) will monitor inadvertent performance and will inform the control room if the difference between C.E.C. and equipment error appears to be greater than would result from normal operation. SCO S-0423 C-1 Version 01 May 10, 2001

15 Appendix D: CNP Inadvertent As of May 2, 2000, following the transfer of the CNP 60 Hz load to the IMO Control Area, IMO is not required to keep track of the CNP Inadvertent on OPG s behalf. The Assistant Exchange Coordinator - Markets will no longer enter into HID the amount of next hour's CNP Estimated Replacement (which was scheduled with the NYISO based on information received from OPGI and confirmed with the NYISO). CNP Actual Replacement value in HID will no longer be required. The value should always be zero. The CNP inadvertent energy value in HID should be manually zeroed daily for all 24 hours. This instruction along with its requirement for manual adjustment will no longer be required upon in-service of the new EMS. SCO S-0423 D-1 Version 01 May 10, 2001

16 Appendix E: HID Adjustments for Ramps Across the Hour E.1 Introduction NERC Policy 3 requires control areas implementing interchange transactions to ramp the interchange equally across the start and end times of the schedule. Since the DACS scheduling software is not capable of this type of ramp, a manual workaround must be employed. This appendix describes the manual adjustments that are necessary to correct the Hourly Interconnection Data (HID) program. E.2 Rationale NERC Policy 3 now requires that standard, ten minute ramps for an interchange transaction be split across the start and end times of the transaction. This means that a transaction starting on the hour would require a ramp to begin at 5 minutes to the hour, and end at 5 minutes after the hour. DACS scheduling software must therefore be set to implement the schedule 5 minutes early. The DACS HID program, however, assumes that an interchange schedule is block loaded (unloaded) at the start of a ramping up (down) of a transaction. HID will therefore register inaccurate schedules. Manual adjustments to correct HID will be necessary after the fact. E.3 Adjustments Required SCO S-0423 E-1 Version 01 May 10, 2001

17 Figure 1 - HID Results When Transaction Profile Starts On the Hour 100 MW Interchange Transaction Profile Hour 1 Hour 2 Hour 3 t=1:00 0 MW t=2:00 HID schedule for Hour 1 = 0 MW Shaded area = HID schedule for Hour 2 = 100 MW HID schedule for Hour 3 = 0 MW Figure 2 - HID Results When Transaction Profile Crosses the Hour 100 MW Hour 1 Hour 2 Hour 3 Interchange Transaction Profile t=0:55 t=1:00 0 MW t=1:55 t=2:00 t=2:05 HID schedule for Hour 1 = 8 MW Shaded area = HID schedule for Hour 1 = 92 MW HID schedule for Hour 3 = 0 MW E.3.1 HID Adjustments Confirmation of hourly schedule data with OPG, New York, Michigan, Minnesota, and Manitoba, should be performed regularly during each shift, preferable every hour. Use data provided by OPG, NYISO, MECS, MP & MAN to cross-check IMO-adjusted schedules prior to correcting the schedule values in HID. In the example used in Figures 1 and 2, HID would be corrected from 8 MW, 92 MW and 0 MW, to 0 MW, 100 MW, 0 MW, respectively for hours 1, 2 and 3. Calculated corrections to HID Schedules should be performed for all affected hours, and for the daily total. The changes required are: NY Sched Net Mich Sched Net Man Sched Net MP Sched Net Time Error Correction (manually changed as req d) (manually changed as req d) (manually changed as req d) (manually changed as req d) (no changes req d) SCO S-0423 E-2 Version 01 May 10, 2001

18 Cntrl Error Correction Unallocated Scheduled Payback SUM = Final Schedule Setting (no changes req d) (no changes req d) (no changes req d) (no changes req d) For ramps incorrectly started on the hour, manual adjustments to net schedules should still be performed. In all cases, the Final Schedule Setting does not need to be calculated, as the difference is actual equipment error. The DACS Interchange Control Record should be checked to verify ramps used. E.3.2 E-tags E-tag Ramp start times indicated on interchange transaction tags may be inconsistent, and should be ignored. Correct ramp start and stop times on the e-tags indicate generator schedule alignment with NERC Policy 3. E.3.3 Hydro-Quebec Radial Generation Loading IMO is to coordinate interchange transactions with Hydro-Quebec to avoid large ACE swings. E.3.4 NY-ISO NY-ISO has deferred implementation of split ramps. Until such time as NY-ISO complies with NERC Policy 3 requirement for split ramps, IMO will nonetheless implement split ramps on interchange transactions with NY-ISO. This will result in frequency imbalance, which NPCC and NERC are aware of. SCO S-0423 E-3 Version 01 May 10, 2001

19 Appendix F: Dealing With Abnormal Inadvertent Accumulations As a normal practice, the IMO will utilize a manual control error correction to offset periods when persistent accumulation of inadvertent is encountered. To determine the proper control error correction to be used, please employ the following guidelines. The control error correction value to be used will normally be -0.2% (or ) of the existing inadvertent balance for the appropriate period. Control error correction values of less than 5 MW will not be used. This effectively cancels any correction for +/ MWh band of inadvertent accumulation for an on-peak or off-peak period. Due to the nature of our AGC software, this value will be placed into the DACS software as a manual T/E correction to account for the proper CPS calculation. The magnitude of this value may be changed at the discretion of the Exchange Coordinator - Resources to assist in low or high frequency events as they may occur, while still maintaining control within our CPS bounds. This value may stay in place during periods of frequency offset. This value may be disabled to allow DACS software to apply a time error correction when this value is more effective and appropriate. This value may be disabled as supply conditions warrant. End of Document SCO S-0423 F-1 Version 01 May 10, 2001