Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R)
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Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R)
Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Information documents are for information purposes only and are intended to provide guidance. In the event of any discrepancy between the information document and the related authoritative document(s) in effect, the authoritative document(s) governs. 1 Purpose The AESO issues information documents to provide additional information and interpretations regarding certain subject matter set out in the AESO’s authoritative documents. The purpose of this information document is to provide additional information regarding the unique operating characteristics and resulting constraint conditions and limits in two (2) regions in the northwest area. In this information document the AESO has defined the northwest area as the area illustrated by the maps in Appendix 2 and 3. 2 Related Authoritative Documents The AESO’s authoritative documents consist of ISO rules, the ISO tariff and the Alberta Reliability Standards. Authoritative documents contain binding rights, requirements and obligations for market participants and the AESO. Market participants and the AESO are required to comply with provisions set out in authoritative documents. The AESO encourages market participants to review the related authoritative documents which include: (1) Section 302.1 of the ISO rules, Real Time Transmission Constraint Management. This section of the ISO rules sets out the general constraint management protocol steps the AESO uses to manage constraints in real time on the interconnected electric system. These steps are referenced in Table 1 of this information document as they are applied to the northwest area. 3 General The northwest area consists of long 144 kV and 240 kV bulk transmission lines, generally with a low degree of redundancy of transmission paths. The northwest area total generating capacity is substantially less than the area load, leading to inflows of energy under normal operation. Some of the 144 kV bulk transmission lines are heavily loaded. The outage of a single bulk transmission line or a generating unit may result in voltage depressions outside of the acceptable system operating limits set out in Alberta Reliability Standard TPL-002-AB-0 – System Performance Following the Loss of a Single BES Element. The AESO can partially mitigate this risk by ensuring a sufficient minimum amount of transmission must-run generating unit capacity is available under contract with the AESO. The availability of transmission must-run services reduces the risk of losing firm load due to low voltages and of a voltage collapse for certain critical transmission or generation contingencies. Two (2) maps of the northwest area are provided in Appendix 1 and 2. Appendix 1 provides a detailed geographical map of the northwest area indicating bulk transmission lines, substations and cutplanes. Appendix 2 provides a detailed view of the northwest area cutplanes including the generating units effective in managing the regional constraints through transmission must-run dispatch or directive. A cutplane is a common term used in engineering studies and is a theoretical boundary or plane crossing two (2) or more bulk transmission lines or electrical paths. The cumulative power flow across the cutplane is measured and can be utilized to determine flow limits that approximate conditions that would Information Document Effective: 2013-02-14 Page 1 Public Information Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) allow safe, reliable operation of the interconnected system. 4 Constraint Conditions and Limits When managing a transmission constraint in the northwest area of Alberta which results from the total generating capacity of the area being substantially less than the area load, the AESO uses regional cutplane inflow limits to manage area reliability. The AESO calculates the cutplane inflow limits for the Grande Prairie and Rainbow cutplanes in accordance with voltage requirements and bulk transmission line transfer limits. A further description of these limits is set out below. 4.1 Studied Constraints and Limits Cutplane Inflow Limits There are two (2) cutplanes in the northwest area; one (1) for the Grande Prairie region and one (1) specific to the Rainbow Lake region. These cutplanes are reflected on the maps in Appendix 2 and 3. As mentioned above, the northwest area generation capacity is substantially less than the area load, which leads to inflows of energy into the northwest area under normal circumstances. The specific contingency conditions and inflow limits are set out in Appendix 4 and 5 of this information document. The limits in Appendix 4 are not absolute limits as certain generating units operating at or above minimum stable generation can provide a slight increase to the limits. The scenarios that provide an increase to the limits are set out in Appendix 5 of this information document. Generation Capacity Limits Due to angular stability and voltage concerns associated with outages of the 7L03, 7L07 or 7L22 transmission lines on the Elmsworth loop, there is a need to limit generation capacity of the generation pool assets PH1 (Poplar Hill) and NPP1 (Northern Prairie Power Project). Please refer to Appendix 7 of this information document to review the specific conditions and limits. Operating Modes and Limits If the Poplar Hill or Valley View # 1 generating units are either generating MW or operating in synchronous condenser mode, the AESO increases the Grande Prairie cutplane inflow limits by the amount specified in Appendix 5 of this information document. The increases contemplated in Appendix 5 are only applicable when there is a net power transfer-out of the northeast area as measured on the Dover - Ruth Lake cutplane in the northeast area under N-0 and N-1 conditions. Due to angular stability and voltage concerns, there is a need for the AESO to issue directives or dispatches for transmission must-run in the northwest area to ensure that the system operating limits and dynamic reactive reserve requirements for the Rainbow region are met. These reactive reserve requirements are set out in Appendix 6. 5 Transmission Constraint Management While the AESO manages transmission constraints in all areas of Alberta in accordance with the provisions of section 302.1 of the ISO rules, not all of those provisions are effective in the northwest due to certain unique operating conditions that exist in that area. This information document represents and clarifies the application of the general provisions of section 302.1 to the northwest area. The Fort Nelson connection is unique and the curtailment of Fort Nelson load requires additions steps which are set out below. The protocol steps which are effective in managing transmission constraints are outlined in Table 1 below, followed by additional steps which may be required. Information Document Effective: 2013-02-14 Page 2 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Table 1 Transmission Constraint Management Sequential Procedures for the Northwest Area Section 302.1 of the ISO rules, subsection 2(1) protocol steps Applicable to the Grande Prairie cutplane inflow? Applicable to the Rainbow cutplane inflow? (a) Determine effective pool assets Yes Yes (b) Ensure maximum capability not exceeded No No (c) Curtail effective downstream constraint side export service and upstream constraint side import service No No (d) Curtail effective demand opportunity service on the downstream constraint side No No (e)(i) Issue a dispatch for effective contracted transmission must-run Yes Yes (e)(ii) Issue a directive for effective noncontracted transmission must-run Yes Yes (f) Curtail effective pool assets in reverse energy market merit order followed by pro-rata curtailment No No (g) Curtail effective loads with bids in reverse energy market merit order followed by pro-rata load curtailment Yes Yes Applicable Protocol Steps The first step in managing constraints in any area is to identify those generating units effective in managing the constraint. All generating units and loads operating in the northwest area are indicated in Appendix 3 (single line diagram), the generating units effective in managing constraints are identified in Appendix 1. Step (a) in Table 1 The effective pool assets are as shown in Appendix 1. Step (b) in Table 1 Ensuring maximum capabilities are not exceeded is not applicable to the northwest due to the deficiency of generation and inflow scenario. Step (c) in Table 1 Information Document Effective: 2013-02-14 Page 3 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) There is no effective export or import opportunity service to curtail for either the Grande Prairie or Rainbow cutplane. Step (d) in Table 1 There is no demand opportunity service load in the area to curtail. Steps (e)(i) and (ii) in Table 1 Issue dispatches to effective contracted pool assets or directives to effective non-contracted pool assets for transmission must-run. Step (f) in Table 1 Reverse merit order curtailment is not effective and therefore not required because the constraint is caused by not having enough in-merit generation in the downstream constrained area. Step (g) in Table 1 Curtailing effective loads with bids in reverse energy market merit order followed by pro-rata load curtailment is available for both Grande Prairie and Rainbow cutplanes. Additional Steps Due to the operating characteristics of the northwest area, when managing a transmission constraint on the Rainbow cutplane, the AESO may utilize the following additional procedures: (i) curtail applicable load in accordance with the provisions of the contract between the AESO and the British Columbia Hydro and Power Authority (addressing Fort Nelson operation), after implementing step (e)(i) in Table 1 set out in subsection 3(1); and (ii) if necessary to maintain Rainbow area voltage levels, follow the Grande Prairie cutplane curtailment procedure. 6 Project Updates As necessary, the AESO intends to provide information in this section about projects underway in the northwest area that are known to have an impact on the information contained in this information document. 7 Appendices to this Information Document Appendix 1 – Effective Pool Assets Appendix 2 – Geographical Map of the Northwest Area Appendix 3 – Northwest Area Cutplanes Single Line Diagram Appendix 4 – Grande Prairie Cutplane Limits Appendix 5 – Grande Prairie Cutplane Inflow Limits and Operating Mode Appendix 6 – Rainbow Lake Cutplane Requirements Appendix 7 – Generation Capacity Limits – Poplar Hill and Northern Prairie Power Project Revision History Version Effective Date 1.0 2011-06-30 2.0 2012-03-03 3.0 2012-06-14 Information Document Effective: 2013-02-14 Description of Changes Initial Release Updated to reflect transmission upgrades in the area Updated to include material content from existing section 302.4 of Page 4 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) 4.0 5.0 6.0 2012-08-31 2013-01-01 2013-02-14 Information Document Effective: 2013-02-14 the ISO rules, Northwest Area Transmission Constraint Management Updated to include minor drafting edits Updated to include Table 4 which reflects changes to the Rainbow Lake Cutplane limits and Dynamic Reactive Reserve requirements. Updated Table 4 to reflect changes to the Rainbow Lake Cutplane limit and Dynamic Reactive Reserve requirements. Minor drafting edit to geographical map. Page 5 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Appendix 1 - Effective Pool Assets 1 The effective generation pool assets for the Grande Prairie cutplane , listed alphabetically by their pool IDs, are: BCR2 BRCK DAI1 GPEC NPC1 NPP1 PH1 ST1 ST2 VVW1 The effective generation pool assets for the Rainbow cutplane, listed alphabetically by their pool IDs, are: FNG RB1 RB2 RB3 RB5 RL1 1 An operational study in this area is being conducted and the effective pool assets will be updated following the study. Information Document Effective: 2013-02-14 Page 6 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Appendix 2 – Geographical Map of the Northwest Area Zama Lake 795S 7L72 Sulphur Point 828S Rainbow Lake 791S 1L359 7L81 Fort Nelson 852S High Level 786S 7L133 7L93 Arcenciel 930S 7L122 Blumenort 832S 7L76 7L109 Melito 890S SVC Bassett 747S 7L59 SVC 7L64 7L113 Chinchaga 779S Haig River 748S Keg River 789S Ring Creek 853S Kemp River 797S 7L58 Rainbow Lake cutplane (RLC) 7L62 7L82 Hamburg 855S 7L63 Hotchkiss 788S Meikle 905S 7L120 7L138 783S 878S Kidney Lake 7L63 7L51 7L131 861S Eureka River 812S 7L106 839S 7L94 830S 6L16 SVC 827S Cranberry Lake 724S 869S 7L12 7L27 6L37 7L75 Lubicon 9L11 7L48 858S 720S 865S 9L56 7L68 7L07 811S Clairmont 728S 749S 7L03 823S 734S 7L32 798S 6L57 7L57 794S 808S 845S Big Mountain 6L73 7L162 844S 745S 729S 7L49 732S 727S 23 Valleyview 862S 722S 758S 6L99 6L91 787S 6L68 7L22 739S 7L45/7L46 736S Little Smoky 813S 854S 809S 9L02, 9L05 733S 7L80 HR Milner 740S 7L199 741S Fox Creek 9L938 234S 69S 9L939 72kV 199L 720L 236S 77S 397S 854L To Bickerdike 39S Page 7 7L230 824S 347S 24 Fox Creek 857S 9L913 743S 851S 738S 26 Swan Hills 810S Dome 9L40 7L56 7L40 7L90 735S 744S 742S 725S SVC 7L20 Information Document Effective: 2013-02-14 Grande Prairie cutplane 7L23 784S 730S Rycroft 790S Poplar Hill 731S Elmworth 9L15 7L61 882S 815S Goodfare To Britnell 876S 796S 7L73 7L10 Wesley Creek 834S 793S West Peace 800S Fredenstal 829S 754S Ksituan 780S To Whitecourt 323S 144kV 240kV Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Appendix 3 – Northwest Area Cutplane Single Line Diagram FNG1 RB1, RB2, RB3, RL#1, RB5 7L81 Rainbow Lake 791S 7L122 7L109 NPP1 Arcenciel 930S 7L113 PH1 Ring Creek 853S Poplar Hill 790S DAI1 Keg River 789S 7L82 Rainbow Lake Cutplane (RLC) M BRCK BCR2 Hotchkiss 788S 7L38 7L120 ST1 ST2 7L58 7L62 M M Meikle 905S NPC1 7L106 7L131 GPEC Wesley Creek 834S GOC1 M 9L11 HRM1 VVW1 VVW2 Kinuso 727S M 9L15 M M Little Smoky 813S M M 6L57 Mitsue 732S M M M Grande Prairie Cutplane 876S 9L56 7L56 7L90 Louise Creek 809S 9L02 9L913 720S 69S 9L05 9L40 725S 240 kV 144 kV 741S 72 kV Electrical Path Rainbow Lake Cutplane Grande Prairie Cutplane Information Document Effective: 2013-02-14 Page 8 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Appendix 4 – Grande Prairie Cutplane Limits Table 1 Grande Prairie Cutplane Limit for a Northeast area Export Grande Prairie Cutplane Limit for a Northeast area Export Contingency Conditions Maximum Grande Prairie area load studied 860 MW To increase the Grande Prairie import limit add the synchronous condenser mode effect (Table 3) HR Milner = 70MW 70 MW < HR Milner < 140 MW HR Milner ≥140 MW X = HR Milner output – 70 MW No contingencies 585 585 – (0.71 * X) 535 GPEC or BCR2 steam 590 590 – (0.79 * X) 535 9L11 610 610 – (0.93 * X) 545 9L15 585 585 – (0.57 * X) 545 9L02 or 9L05 485 485 485 919L or 989L 470 470 – (0.21 * X) 455 9L938 or 9L939 485 485 485 9L40 570 570 – (0.93 * X) 505 9L56 600 600 – (0.79 * X) 545 9L913 545 545 – (0.79 * X) 490 7L56 600 600 – (0.57 * X) 560 7L90 600 600 – (0.57 * X) 560 7L23 575 575 – (0.71 * X) 525 7L61 595 595 – (0.57 * X) 555 6L57 610 610 - (0.79 * X) 555 590 590 590 565 565 – (1.29 * X) 475 595 595 – (1 * X) 525 HR Milner < 70 MW Little Smoky static VAr compensator Cranberry static VAr compensator Information Document Effective: 2013-02-14 Page 9 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Examples to assist with interpretation of Table 1: 1. If HR Milner is generating at 70 MW and transmission line 9L15 is out of service then the power flow limit into the northwest is 585 MW. 2. If HR Milner is generating at 100 MW and the region load is less than 860 MW, and transmission line 9L15 out of service then the power flow limit into the northwest is calculated as 585 – (0.57*(100 – 70)) = 567.9 MW. 3. If HR Milner is generating at 140 MW and transmission line 9L15 is out of service then the power flow limit into the northwest is 545. Information Document Effective: 2013-02-14 Page 10 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Table 2 Grande Prairie Cutplane Limit for a Northeast area Import Grande Prairie Cutplane Limit for a Northeast area Import Maximum Grande Prairie area load studied 860 MW Contingency Conditions HR Milner=70 MW 70 MW < HR Milner < 140 MW HR Milner ≥140 MW X = HR Milner output – 70 MW No contingencies 565 565 – (0.36 * X) 540 GPEC or BCR2 steam 555 555 – (0.21 * X) 540 9L11 590 590 – (0.64 * X) 545 9L15 545 545 545 9L02 or 9L05 440 440 440 919L or 989L 405 405 405 9L938 or 9L939 460 460 460 9L40 530 530 – (0.71 * X) 480 9L56 575 575 – (0.29 * X) 555 9L913 550 550 – (1.43 * X) 450 7L56 570 570 570 7L90 570 570 570 7L23 550 550 – (0.36 * X0 525 7L61 560 560 560 6L57 580 580 – (0.29 * X) 560 HR Milner < 70 MW 560 560 560 Little Smoky static VAr compensator 540 540 – (1.14 * X) 460 Cranberry static VAr compensator 570 570 – (0.86 * X) 510 Information Document Effective: 2013-02-14 Page 11 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Examples to assist with interpretation of the Table 2: 1. If HR Milner is generating at 70 MW and transmission line 9L11 is out of service then the power flow limit into the northeast is 590 MW. 2. If HR Milner is generating at 100 MW and the region load is less than 860 MW, and transmission line 9L11 out of service then the power flow limit into the northeast is calculated as 590 – (0.64*(100 – 70)) = 570.8 MW. 3. If HR Milner is generating at 140 MW and transmission line 9L11 is out of service then the power flow limit into the northeast is 545 MW. Information Document Effective: 2013-02-14 Page 12 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Appendix 5 –Grande Prairie Cutplane Inflow Limits and Operating Mode Table 3 below sets out the power flow limits if the Poplar Hill or Valley View (VVW1) generating units are operating in either synchronous condenser mode or MW generation mode: Table 3 Increase to Grande Prairie Transfer Limit IF the Northeast area is Exporting System Conditions PH1 in synchronous condenser mode or 1 generating MW VVW1 in synchronous condenser mode or either VVW generating unit is 1 generating MW Both PH1 and VVW1 in synchronous condenser mode or both generating 2 stations are generating MW System normal +30 +20 +45 HR Milner contingency +10 +0 +20 Note: 1. Generating units are considered in generating mode if they are above their minimum stable generation. 2. It is accepted that any combination of the following meets this requirement: a. PH1 is on synchronous condenser mode/generating MW; or b. VVW1 is on synchronous condenser mode or either VVW1 or Valley View 2 generating units are generating power. Examples to assist with interpretation of Table 3: 1. For any limit calculated in Appendix 4 and when VVW1 is in synchronous condenser mode or is generating MW, for system normal conditions, the limit calculated from Appendix 4 is increased by 20 MW. 2. For any limit calculated in Appendix 4, if PH1 is generating at some level or in synchronous condenser mode, and HR Milner is out of service, the cutplane limit is increased by 10 MW. Information Document Effective: 2013-02-14 Page 13 Information Document Northwest Area Transmission Constraint Management ID# 2011-004(R) Appendix 6 – Rainbow Lake Cutplane and Dynamic Reactive Reserve Requirements Table 4 sets out the Rainbow Lake cutplane and the dynamic reactive reserve requirements. Table 4 Rainbow Lake 1 Cutplane Limit Operating State 3 Minimum Dynamic Reactive 2 Reserve (MVAr) Rainbow Lake 1 Cutplane Limit Minimum Dynamic Reactive 2 Reserve (MVAr) No Either Synchronous Condenser or Rainbow unit on line A Synchronous Condenser or a Rainbow unit is on line Summer 130 “N-0” System Normal 103 MW 30 MVAr Summer 103 MW 30 MVAr Summer 103 MW 30 MVAr N-1: 7L131 or 7L106 Out 83 MW 20 MVAr Winter / 155 30 MVAr (See Note 1) 130 N-1: High Level SVC Out 30 MVAr (See Note 1) 130 N-1: Arcenciel SVC Out Winter / 155 Winter / 155 (See Note 1) 30 MVAr 128 MW Summer 71 N-1: 7L82 or 7L113 Out Summer N-1: 7L58 or 7L62 Out 71 20 MVAr 83 MW 75 Summer / 80 (See Note 1) N-1: 7L64 Out N-1: 7L59 or 7L93 Out Winter Winter (See Note 1) 83 MW Summer 75 20 MVAr 38 MVAr Winter / 80 30 MVAr 30 MVAr (See Note 1) 20 MVAr / 86 83 MW (See Note 1) 20 MVAr Winter / 86 (See Note 1) 83 MW 20 MVAr 38 MVAr Notes: Information Document Effective: 2013-02-14 Page 14 Public Information Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) 1. The Rainbow Lake cutplane operating limits are based on voltage stability and thermal limits. Thermal limits are illustrated when summer and winter limits have been identified. 2. The dynamic reactive reserve units are: Arcenciel Static Var Contoller (desired range: 0 to -5), Arcenciel Synchronous Condenser, High Level Static Var Contoller (desired range: 0 to -5), Rainbow generators. 3. An unstudied state occurs when two elements in the above table are out of service. Real time limits are determined using the energy management system advanced applications contingency analysis or voltage stability application. Information Document Effective: 2013-02-14 Page 15 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Appendix 7 – Generation Capacity Limits – Poplar Hill and Northern Prairie Power Project Tables 5.1 and 5.2 below set out the generation limits for Poplar Hill and Northern Prairie Power Project generating units under certain conditions. When reading the tables: (1) (2) (3) (4) HRM refers to the HR Milner generating unit. NPP1 refers to the Northern Prairie Power Project generating unit. PH1 refers to the Poplar Hill generating unit. Generation limit refers to the sum of the MW generation plus any operating reserves for which the AESO issued a dispatch. Table 5.1 Poplar Hill Unit Generation Capacity Limits PH1 Generation Limit (MW) = the sum of energy and operating reserve for which the AESO has issued dispatches for the generating unit NPP1 and HR Milner Generator Status A. HR Milner on-line and ≥ 70 MW, and A.1. NPP1 is on-line when the sum of energy and operating reserves for which the AESO has issued dispatches > 1MW 42 A.2. NPP1is off-line and not issued dispatches for operating reserves 48 B. HR Milner off-line or generating < 70 MW, and B.1. NPP1 is on-line when the sum of energy and operating reserves for which the AESO has issued dispatches > 1 MW 41 B.2. NPP1 is off-line and not issued dispatches for operating reserves 48 An example to assist with interpretation of the table directly above: If the HRM generating unit is on-line and generating seventy (70) MW or more; and the NPP1 generating unit is on-line; then the generation limit for the PH1 generating unit is forty two (42) MW. Information Document Effective: 2013-02-14 Page 16 Information Document Northwest Area Transmission Constraint Management ID # 2011-004(R) Table 5.2 Northern Prairie Power Project Generation Capacity Limits NPP1 Generation Limit (MW) = the sum of energy and operating reserve for which the AESO has issued dispatches for the generating unit PH1 and HR Milner Generator Status A. HR Milner on-line and ≥ 70 MW, and A.1. PH1 is on-line when the sum of energy and operating reserves for which the AESO has issued dispatches > 1 MW 81 A.2. PH1 is off-line and not issued dispatches for operating reserves, or 82 A.3. PH1 is operating in synchronous condenser mode and not issued dispatches for operating reserves 93 B. HR Milner off-line or generating less than 70 MW, and B.1. PH1 is on-line when issued dispatches for energy > 1 MW. 79 B.2. PH1 is off-line, or 76 B.3. PH1 is operating in synchronous condenser mode and not issued dispatches for operating reserves 93 An example to assist with interpretation of the table directly above: If the HRM generating unit is on-line and generating more than seventy (70) MW or more; and the PH1 generating unit is on-line; then the generation limit for the NPP1 generating unit is eighty one (81) MW. Information Document Effective: 2013-02-14 Page 17