Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition

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2 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Executive Summary Project Overview EPCOR Distribution & Transmission Inc. (EDTI), in its capacity as the legal owner of an electric distribution system (DFO), submitted a system access service request to the Alberta Electric System Operator (AESO) to reliably serve load growth in the northeast corner of the City of Edmonton, known as the Clover Bar area. The DFO s request for system access service includes a request for a Rate DTS, Demand Transmission Service, contract capacity increase of 12.1 MW (from 2 MW to.2 MW) at the existing Clover Bar substation, and a request for transmission development (collectively, the Project). Specifically, the DFO requested modifications to the existing Clover Bar substation. The scheduled in-service date (ISD) for the Project is May 31, This report details the engineering studies undertaken to assess the impact of the Project on the performance of the Alberta interconnected electric system (AIES). Existing System The Project is located in the AESO planning area of Edmonton (Area 60), which is in the AESO Planning Region of Edmonton. Edmonton (Area 60) is surrounded by the AESO planning areas of Fort Saskatchewan (Area 33), Athabasca/Lac La Biche (Area 27), Wabamun (Area 40), and Wetaskiwin (Area 31). From a transmission system perspective, Edmonton (Area 60) consists of 500 kv, 240 kv, 138 kv, and 69/72 kv transmission systems. The Clover Bar substation is connected to the Lamoureux 71S, East Edmonton 38S, and Ellerslie 89S substations by the 240 kv transmission lines 921L, 915L, and 947L, respectively. The Clover Bar substation is also connected: to the Hardisty substation by the 72 kv transmission lines and ; to the Kennedale substation by the 72 kv transmission lines and ; and to the Namao substation by the 72 kv transmission line 72CN10. Existing constraints in the AESO Edmonton Planning Region are managed in accordance with the procedures set out in Section of the ISO rules, Real Time Transmission Constraint Management (TCM Rule). Study Summary Study Area The Study Area for the Project consists of Edmonton (Area 60) and the tie lines that connect this planning area to neighbouring AESO planning areas. All transmission facilities within the Study Area were studied and monitored to assess the impact of the Project on the performance of the AIES, including any violations of the Reliability Criteria (as defined in Section 2.). 1

3 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Studies Performed Power flow studies were performed for the 2017 summer peak (SP) and the 2017 winter peak (WP) pre-project and post-project scenarios. Voltage stability studies were also performed for the 2017 SP and 2017 WP post-project scenarios. Results of Pre-Project studies The following is a brief summary of the pre-project studies results. Category A conditions No Reliability Criteria violations were observed under Category A conditions for the pre-project scenarios studied. Category B contingency conditions The pre-project power flow studies identified a number of system performance issues, namely thermal criteria violations, under certain studied Category B contingency conditions. These violations are described in Table E-1 below. Connection Alternatives Examined for the Project The AESO, in consultation with the DFO and the legal owner of transmission facilities (TFO), examined two transmission alternatives to meet the DFO s request for system access service. Alternative 1 East Industrial Substation Modification Alternative 1 involves modifying the East Industrial substation by adding one 25 kv circuit breaker and associated equipment. This alternative would involve adding a distribution feeder with a total length of approximately 10 kilometres. Alternative 2 Clover Bar Substation Modification Alternative 2 involves modifying the Clover Bar substation, including adding two 25 kv circuit breakers and associated equipment to accommodate the addition of one 25 kv distribution feeder. This alternative would involve adding a distribution feeder with a total length of approximately 5 kilometres. Alternatives Selected for Further Examination Alternative 2 is considered technically acceptable by the DFO and was selected for further study. Alternative 1 is considered technically acceptable by the DFO; however, this alternative involves increased distribution system development and hence, increased total cost compared to Alternative 2. Therefore, Alternative 1 was not selected for further study. Results of Post-Project Studies The following is a brief summary of the post-project studies results. 2

4 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Category A conditions No Reliability Criteria violations were observed under Category A conditions for any of the post- Project scenarios studied. Category B contingency conditions The post-project power flow studies identified the same thermal criteria violations under certain Category B contingency conditions that were identified in the pre-project power flow studies. No new Reliability Criteria violations were observed. As shown in Table E-1, under certain Category B contingency conditions, the observed thermal criteria violations were reduced marginally in the post-project studies when compared to the pre-project studies. For two of the Category B contingency conditions studied, the Reliability Criteria violations observed in the 2017 WP pre-project study scenarios were not observed in the 2017 post-project study scenarios. However, under four Category B contingency conditions, the observed thermal criteria violations were marginally worsened in the post-project studies when compared to the pre-project studies. Conclusions and Recommendations Analysis and Conclusions Table E-1, shown below, provides analysis of, and conclusions about, the impact of the Project on the identified Reliability Criteria violations. As shown in the table, the connection assessment identified pre-project and post-project system performance issues, namely thermal criteria violations under certain Category B conditions. The change in thermal criteria violations that were observed in the post-project assessment were marginal compared to the pre-project assessment. Real-time operational practices can be used to manage all of the identified system performance issues observed. Based on the study results, Alternative 2 is technically viable. 3

5 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Table E-1: Summary of Reliability Criteria Violations, Project Impact, and Mitigation Measures Identified Reliability Criteria Violations Type Violation Contingency Occurrence (Pre-Project and/or Post- Project Scenarios) Project Impact Year/ Season Load Mitigation Measures (Pre-Project and Post-Project) 72RG7 (Rossdale - Garneau) 72RG1 (Rossdale - Garneau) Pre-Project and Post- Project Marginally reduced 2017 SP 2017 WP Real-time operational practices 72RG1 (Rossdale - Garneau) 72RG7 (Rossdale - Garneau) Pre-Project and Post- Project Marginally reduced 2017 SP Real-time operational practices (Clover Bar - Hardisty) (Clover Bar - Hardisty) Pre-Project and Post- Project Marginally increased Marginally reduced 2017 SP 2017 WP Real-time operational practices Thermal (Clover Bar - Hardisty) (Clover Bar - Hardisty) Pre-Project and Post- Project Marginally increased Marginally reduced 2017 SP 2017 WP Real-time operational practices (Clover Bar - Kennedale) (Clover Bar - Kennedale) Pre-Project and Post- Project Pre-Project Marginally increased Marginally reduced 2017 SP 2017 WP Real-time operational practices (Clover Bar - Kennedale) (Clover Bar - Kennedale) Pre-Project and Post- Project Pre-Project Marginally increased Marginally reduced 2017 SP 2017 WP Real-time operational practices Recommendations It is recommended to proceed with the Project using Alternative 2 as the preferred option to respond to the DFO s request for system access service. Alternative 2 involves modifying the Clover Bar substation by adding two 25 kv breakers and associated equipment. It is also recommended to continue to use real-time operational practices to manage the identified system performance issues. 4

6 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Contents Executive Summary Introduction Project Overview Load Component Generation Component Study Scope Objectives Study Area Studies Performed Report Overview Criteria, System Data, and Study Assumptions Criteria, Standards, and Requirements AESO Reliability Criteria ISO Rules and Information Documents Study Scenarios Load and Generation Assumptions Load Assumptions Generation Assumptions Intertie Flow and HVDC Assumptions System Projects Customer Connection Projects Facility Ratings and Shunt Elements Voltage Profile Assumptions Study Methodology Study Objectives Connection Studies Carried Out Power Flow Analysis Contingencies Studied for Power Flow Analysis Voltage Stability Analysis Contingencies Studied for Voltage Stability Analysis Pre-Project System Assessment Pre-Project Power Flow Studies Scenario 1 (2017 SP pre-project) Scenario 2 (2017 WP pre-project) Connection Alternatives Overview Connection Alternatives Examined Connection Alternatives Selected for Further Studies Connection Alternatives Not Selected for Further Studies Technical Analysis of Alternative Power Flow Studies Scenario 3 (2017 SP post-project) Scenario 4 (2017 WP post-project) Voltage Stability Studies Scenario 3 (2017 SP post-project) Scenario 4 (2017 WP post-project)

7 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition 7. Project Dependencies Conclusions and Recommendations Attachments Attachment A Attachment B Attachment C Pre-Project System Power Flow Plots Post-Project Alternative 4: Power Flow Plots Post-Project Alternative 4: Voltage Stability Analysis Plots Figures Figure 1-1: Study Area Transmission System... 9 Tables Table 2-1: Post Contingency Voltage Deviations Guidelines for Low Voltage POD Busses Table 2-2: Study Scenarios Table 2-3: Forecast Area Load (2016 LTO at Edmonton Planning Region Peak) Table 2-4: Local Generators in the Study Scenarios Table 2-5: Customer Connection Projects in the Study Area a Table 2-6: Key Transmission Lines in the Study Area (MVA on a 69/138/240 kv Base) Table 2-7: Summary of key transformer in the Study Area Table 2-8: Summary of Shunt Elements in the Study Area Table 2-9: Summary of the Voltage at Key Nodes in Study Scenarios Table 3-1: Summary of Studies Performed Table 4-1: Summary of Thermal Criteria Violations for Scenario 1 (2017 SP pre-project) Under Category B Conditions Table 4-2: Summary of Thermal Criteria Violations for Scenario 2 (2017 WP Pre-Project) Under Category B Conditions Table 6-1: Summary of Thermal Criteria Violations for Scenario 3 (2017 SP Post-Project) Under Category B Conditions Table 6-2: Summary of Thermal Criteria Violations for Scenario 4 (2017 WP Post-Project) Under Category B Conditions Table 6-3: Voltage Stability Study Results for Scenario 3 (2017 SP post-project) Table 6-4: Voltage Stability Study Results for Scenario 4 (2017 WP Post-Project) Table 8-1: Summary of Reliability Criteria Violations, Project Impact, and Mitigation Measures

8 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition 1. Introduction This report details the engineering studies undertaken to assess the impact of the Project (as defined below) on the performance of the Alberta interconnected electric system (AIES).. Project.1. Overview EPCOR Distribution & Transmission Inc. (EDTI), in its capacity as the legal owner of an electric distribution system (DFO), submitted a system access service request to the Alberta Electric System Operator (AESO) to reliably serve load growth in the northeast corner of the City of Edmonton known as the Clover Bar area. The DFO s request for system access service includes a request for a Rate DTS, Demand Transmission Service, contract capacity increase of approximately 12.1 MW (from 2 MW to.2 MW) at the existing Clover Bar substation, and a request for transmission development (collectively, the Project). Specifically, the DFO requested modifications to the existing Clover Bar substation. The scheduled in-service date (ISD) for the Project is May 31, Load Component The existing Rate DTS contract capacity for the system access service provided at the existing Clover Bar substation is 2 MW. The DFO requested a Rate DTS contract capacity increase of 12.1 MW, to.3 MW. The load type served by the Clover Bar substation is commercial and industrial. The Project load was studied assuming a power factor (PF) lagging. The DFO has indicated that it forecasts future growth in the area. The DFO will request a further Rate DTS increase at the Clover Bar substation when the target ISD is more certain..3. Generation Component There is no generation component associated with the Project Study Scope Objectives The objectives of the studies were as follows: Assess the impact of the Project on the performance of the AIES. 7

9 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Identify any violations of the relevant AESO criteria, standards or requirements, both pre-project and post-project. Recommend mitigation measures, if required, to reliably connect the Project into the AIES Study Area Study Area Description The Project is located in the AESO planning area of Edmonton (Area 60), which is in the AESO Planning Region of Edmonton. Edmonton (Area 60) is surrounded by the planning areas of Fort Saskatchewan (Area 33), Athabasca/Lac La Biche (Area 27), Wabamun (Area 40), and Wetaskiwin (Area 31). From a transmission system perspective, Edmonton (Area 60) consists of 500 kv, 240 kv, 138/144 kv, and 69/72 kv transmission systems. The Clover Bar substation is connected to the Lamoureux 71S, East Edmonton 38S, and Ellerslie 89S substations by the 240 kv transmission lines 921L, 915L, and 947L, respectively. The Clover Bar substation is also connected: to the Hardisty substation by the 72 kv transmission lines and ; to the Kennedale substation by the 72 kv transmission lines and ; and to the Namao substation by the 72 kv transmission line 72CN10. The Study Area for the Project consists of Edmonton (Area 60) and the tie lines that connect this planning area to neighbouring planning areas. All transmission facilities within the Study Area were studied and monitored to assess the impact of the Project on the performance of the AIES, including any violations of the Reliability Criteria (as defined in Section 2.). The existing transmission system in the region is shown in Figure

10 72RS5 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition P Area Transmission System This diagram contains a simplified version of the system configuration. Technical detail has been simplified for illustration purposes. It does not indicate geographical locations of facilities. 739L (to Carvel 4S) 739AL 905L (to Wabamun 19S) 40 - Wabamun BILBY 105S 1043L (to Keephills 0P) STONY PLAIN 434S Harry Smith 367S 1045L/909L (to Sundance 310P) 1202L (to Keephills 0P) 1209L (to Genesee 330P) NORTH ST.ALBERT S 712L 677L 712L 667L SPRUCE GROVE 595S 898L (to Clyde 150S) 930L ACHESON 305S 739L 6L (to Buford 538S) N.W. CARDIFF 191S VISCOUNT 92S 747L 1139L 739L 838L Figure 1-1: Study Area Transmission System INLAND CEMENT 792L 898L POUNDMAKER 1098L 1045L 1044L 711L JASPER 805S MEADOWLARK (Normally Open Point within Substation) 1044L 909L DEVON 14S 838L 6L 31 - Wetaskiwin NORTH CALDER 37S WOODCROFT (Normally Open Point within Substation) 72JM18 72JW19 PETROLIA 1044L 739L ROSSDALE University of Alberta (UOA1-UAO2) 908L 72RW3 72MG16 LEDUC 5S 72NW15 72RG1 240CV5 72RV6 72RV2 GARNEAU STRATHCONA (Normally Open Point within Substation) 908L 909L 72RV4 72RG7 BLACKMUD 155S 60 - Edmonton 604L 1055L BELLAMY DOME NISKU 149S KENNEDALE NAMAO 72NK23 72VN21 908L 511S 909L 240BA2 908L 909L 1055L ELLERSLIE 89S 72CN10 240BA3 1056L 910L 914L (to Bigstone 86S) CASTLE DOWNS ARGYLL 72LS L 1057L 908L 72LH8 HARDISTY AT PLASTIC 5RS STELCO EDMONTON 133S LAMBTON 1058L SUMMERSIDE 657S Saunders Lake 289S 858L (to Wetaskiwin 40S) IMPERIAL OIL EDMONTON 95S AT PLASTIC 4RS EAST INDUSTRIAL 1057L 908L 920L 738AL 822L 822AL 946L 947L 1059L 174L (to Bardo 197S) 737L 915L 738L EAST EDMONTON 38S 1059L 908L 908AL 1059AL 915L 947L Cloverbar #1-3 (ENC1-3) P1757: EPCOR Clover Bar 25kV Breaker Addition CLOVER BAR 987S FIBERGLASS 761L 746AL 215L 947L 921L YASA 286S KNIGHTSBRIDGE 216S 736L 780L 897L 865L Gas Generator 33 - Fort Sask. 605L BASELINE 317S 741L 731L BERNESE 293S 897L 920L/921L (to Lamoureux 71S) 705L BRETONA 45S 780L 606L BRETVILLE 185S PETRO-CANADA EDMONTON 184S Future 240 kv Substation 69 or 72 kv Substation 138 or 144 kv Substation 240 kv Substation 500 kv Substation Future 138/144 kv Future 138/144 kv Double Circuit Future 240 kv Double Circuit 746BL 746L 1206L/1212L (to Heartland 12S) BROADMOOR 420S 874L 636L 726L (to Lamoureux 71S) 761L (to Lamoureux 71S) 746L 700L (to Westwood 422S) CANADA LIQUID AIR 337S 700L SHERWOOD PARK 746S COOKING LAKE 522S 174L (to Bardo 197S) Currency Date: Normally Open Line 69/72 kv 138/144 kv 138/144 kv Double Circuit 240 kv 240 kv Double Circuit 500 kv 500 kv Double Circuit P1757 Project Area AESO Planning Areas Existing Constraints Existing constraints in the Edmonton Planning Region are managed in accordance with the procedures set out in Section of the ISO rules, Real Time Transmission Constraint Management (TCM Rule) AESO Long-Term Transmission Plans The approved South and West Edmonton Area Transmission Development ( Edmonton) transmission developments is expected to be in service by December 31, The AESO 2015 Long-term Transmission Plan (2015 LTP) 2 includes the following transmission developments that are in the vicinity of the Study Area in the near term (by 2020): 3 1 The South and West of Edmonton Area Transmission Development Needs Identification Document was originally approved by the Alberta Utilities Commission on May 5, 2014 in Approval No. U and Decision

11 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Convert Hardisty substation in east Edmonton to 240/15 kv from 72/15 kv. Add new 240 kv loop from Lambton substation in southeast Edmonton to Hardisty substation and onto Bellamy substation at Rossdale. Discontinue use of 72 kv lines from Rossdale substation (Bellamy) to Strathcona substation to Lambton substation. Replace existing 240/72 kv transformer at Clover Bar substation in northeast Edmonton with larger units. Add new 240/72 kv substation near Namao in northeast, cut into 240 kv line between Castle Downs substation and Victoria substation on north edge of downtown Edmonton. Add new 72 kv line from new substation to existing Namao substation Add new 240/72 kv transformer at Castle Downs substation in the northeast Add new 72 kv transmission lines from Castle Downs substation to Kennedale substation, and onto Namao substation Discontinue use of 72 kv lines between Clover Bar and Hardisty substations, and Hardisty and Lambton substations Discontinue use of existing 72 kv lines that connect Clover Bar, Victoria, Namao, Kennnedale, and Woodcroft substations Convert Victoria substation from 240/72/15 kv to 240/15 kv Add new 240 kv line from Victoria substation to Bellamy substation Discontinue use of 72 kv lines between Rossdale and Victoria substations Studies Performed The following studies were performed for the pre-project scenarios: Power flow studies The following studies were performed for the post-project scenarios: Power flow studies Voltage stability studies 2 The 2015 LTP document is available on the AESO website. 3 The 2015 LTP identifies the near-term transmission developments in the City of Edmonton area on page

12 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition. Report Overview The Executive Summary provides a high-level summary of the report and its conclusions. Section 1 provides an introduction of the Project and the Study Area. Section 2 describes the criteria, system data, and study assumptions used in the studies. Section 3 presents the study methodology used in the studies. Section 4 presents the pre-project study results. Section 5 presents the connection alternatives that were examined. Section 6 presents the post-project study results for the alternative that was selected for further study. Section 7 identifies project dependencies, if any. Section 8 presents the conclusions and recommendations of the project connection assessment. 11

13 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition 2. Criteria, System Data, and Study Assumptions 2.1. Criteria, Standards, and Requirements 2.. AESO Reliability Criteria The Transmission Planning (TPL) Standards, which are included in the Alberta Reliability Standards, and the AESO s Transmission Planning Criteria Basis and Assumptions 4 (collectively, the Reliability Criteria) were applied to evaluate system performance under Category A system conditions (i.e., all elements in-service) and following Category B contingencies (i.e., single element outage), prior to and following the studied alternatives. Below is a summary of Category A and Category B system conditions. Category A, often referred to as the N-0 condition, represents a normal system with no contingencies and all facilities in service. Under this condition, the system must be able to supply all firm load and firm transfers to other areas. All equipment must operate within its applicable rating, voltages must be within their applicable range, and the system must be stable with no cascading outages. Category B events, often referred to as an N-1 or N-G-1 with the most critical generator out of service, result in the loss of any single specified system element under specified fault conditions with normal clearing. These elements include a generator, a transmission circuit, a transformer or a single pole of a DC transmission line. The acceptable impact on the system is the same as Category A. Planned or controlled interruptions of electric supply to radial customers or some local network customers, connected to or supplied by the faulted element or by the affected area, may occur in certain areas without impacting the overall reliability of the interconnected transmission systems. To prepare for the next contingency, system adjustments are permitted, including curtailments of contracted firm (non-recallable reserved) transmission service electric power transfers. The TPL standards, TPL-001-AB-0 and TPL-002-AB-0, have referenced Applicable Ratings when specifying the required system performance under Category A and Category B events. For the purpose of applying the TPL standards to the studies documented in this report, Applicable Ratings are defined as follows: Seasonal continuous thermal rating of the line s loading limits. Highest specified loading limits for transformers. For Category A conditions: Voltage range under normal operating condition per AESO Information Document # RS, General Operating Practices Voltage Control (ID # RS). ID # RS relates to Section of the ISO rules, Maintaining Network Voltage. For the busses not listed in ID # RS, Table 2-1 in the Transmission Planning Criteria Basis and Assumptions applies. 4 Filed under a separate cover 12

14 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition For Category B conditions: The extreme voltage range values per Table 2-1 in the Transmission Planning Criteria Basis and Assumptions. Desired post-contingency voltage change limits for three defined post event timeframes as provided in Table 2-1, below. Table 2-1: Post Contingency Voltage Deviations Guidelines for Low Voltage POD Busses Parameter and reference point Voltage deviation from steady state at POD low voltage bus Post Transient (Up to 30 sec.) Time Period Post Auto Control (30 sec. to 5 min.) Post Manual Control (Steady State) ± 10% ± 7% ± 5% ISO Rules and Information Documents AESO ID # RS was used to establish system pre-contingency voltage profiles in the Study Area. The TCM Rule was followed in setting up the study scenarios and assessing the study results. In addition, due regard was given to the AESO s Connection Study Requirements Document and the AESO s Generation and Load Interconnection Standard Study Scenarios The scheduled ISD for the Project is May 31, Therefore, the studies were performed using the 2017 summer peak (SP) and 2017 winter peak (WP) scenarios. Table 2-2 provides a list of the study scenarios. The post-project scenarios reflect the requested Rate DTS contract capacity increase of 12.1 MW. The Clover Bar substation load was assumed to have a power factor of lagging. Scenario No. Table 2-2: Study Scenarios Year/Season Load Pre-Project system Clover Bar Substation Load (MW) SP WP 2 Post-Project system SP WP.2 13

15 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition 2.3. Load and Generation Assumptions Load Assumptions The load forecast used for the studies is shown in Table 2-3 and is based on the AESO 2016 Long-term Outlook (2016 LTO). Table 2-3: Forecast Area Load (2016 LTO at Edmonton Planning Region Peak) AESO Planning Area or Region Name and Year/Season Forecast Peak Load (MW) Edmonton (Area 60) Edmonton Planning Region 2017 SP 2, WP 1, SP 2, WP 2, Generation Assumptions The generation assumptions for the studies are described in Table 2-4. The Cloverbar #3 generating unit was identified as the critical generating unit, and was assumed to be out of service to represent the N-G condition for all studies. Existing/Future Table 2-4: Local Generators in the Study Scenarios Unit Name Bus Number Area Pmax (MW) 2017 SP 2017 WP Unit Net Generation (MW) Unit Net Generation (MW) Existing Cloverbar # Existing Cloverbar # Existing Cloverbar # Offline Offline Existing University of Alberta Intertie Flow and HVDC Assumptions The Alberta-BC, Alberta-Montana, and Alberta-Saskatchewan intertie points were deemed to be too far away from the Study Area to have any material effect on the results of the studies. Therefore, the AESO planning base case intertie flow assumptions were used for the study scenarios. The Western Alberta Transmission HVDC Line (WATL) and the Eastern Alberta Transmission Line (EATL) assumptions were expected to have minimal effects on the results of the studies. Therefore, HVDC dispatches based on the minimum system loss assessment were used, which aligns with the AESO planning base case assumptions. 14

16 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition 2.4. System Projects The approved South and West of Edmonton Transmission Development transmission developments were included in the system topology for all study scenarios. The near-term transmission developments listed in Section were not included in the system topology for the study scenarios because these transmission developments are not expected to be in service before the Project ISD Customer Connection Projects Customer connection projects within the Study Area that have passed Gate 2 of the AESO Connection Process as of March 2017 were modelled in the study scenarios based on their positions in the AESO Connection Queue unless otherwise indicated. Table 2-5 summarizes the customer connection project assumptions that were used in the studies. Information in this table is subject to change as projects progress. Table 2-5: Customer Connection Projects in the Study Area a AESO Planning Area Queue Position* AESO Project Number Project Name Genesee Generating Units 4 (G4) and 5 (G5) Fortis New Anthony Henday Substation Scheduled ISD Modelled in the study cases (Y/N) Q No c Q Yes EPCOR Garneau Area Upgrade Q No b EPCOR Strathcona Capacity Increase Fortis Cooking Lake 522A Capacity Increase Q No b Q Yes EPCOR Riverview Substation New POD Q No b EPCOR Victoria Substation E511S Breaker Addition Q No b Notes: a Per the AESO Connection Queue posted in March The projects in the Study Area, if any, that have queue positions after Project 1757 are not listed in this table and were not modelled in the study cases. b This project is deemed to be too far away from the Project to have any material effect on the assessment of the Project s impact on the performance of the AIES. c Including this project in the customer connection assumptions would result in less stressed study cases for this connection assessment. Therefore, for the purpose of assessing the impact of the Project on the performance of the AIES, this project was not included in the customer connection project assumptions. 15

17 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition 2.2. Facility Ratings and Shunt Elements The legal owner of transmission facilities (TFO) provided the seasonal continuous thermal ratings and the emergency ratings for the transmission lines in the Study Area. The seasonal continuous thermal ratings and the short-term emergency ratings for the key transmission lines in the Study Area are shown in Table 2-6. Line ID Table 2-6: Key Transmission Lines in the Study Area (MVA on a 69/138/240 kv Base) Line Description Voltage Class (kv) Seasonal Continuous (MVA) 5 Line Thermal Ratings Emergency (MVA) From To Summer Winter Summer Winter 1202L Keephills 0P Ellerslie 89S L Genesee Ellerslie 89S L Genesee Sunnybrook 510S L Genesee Sunnybrook 510S L Keephills 0P Sunnybrook 510S L Heartland 12S Ellerslie 89S L Heartland 12S Ellerslie 89S L Clover Bar Lamoureux 71S L Clover Bar East Edmonton 38S L Clover Bar Ellerslie 89S CV5 Victoria Castle Downs AL East Industrial 908AL tap point L Summerside Ellerslie 89S L Petrolia Ellerslie 89S L Dome Keephills 0P L Ellerslie 89S Dome L 1059L tap point Lambton L Lambton Summerside L 908AL tap point East Edmonton 38S L 1059AL tap point East Edmonton 38S Ratings for the 72 kv transmission lines are provided on the system base voltage of 69 kv. 16

18 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Line Thermal Ratings Line ID Line Description Voltage Class (kv) Seasonal Continuous (MVA) 5 Emergency (MVA) From To Summer Winter Summer Winter 1056L Ellerslie 89S Argyll L Petrolia Argyll BA2 Argyll Bellamy BA3 Argyll Bellamy L Ellerslie 89S 908AL tap point L Petrolia Jasper L Jasper Sundance 310P RS5 Rossdale Strathcona LH8 Lambton Hardisty LS24 Lambton Strathcona JM18 Meadowlark Jasper JW19 Jasper Woodcroft RW3 Woodcroft Rossdale RG7 Garneau Rossdale RV2 Victoria Rossdale RG1 Garneau Rossdale RV4 Victoria Rossdale RV6 Victoria Rossdale VN21 Victoria Namao Clover Bar Hardisty Clover Bar Hardisty NW15 Woodcroft Namao NK23 Namao Kennedale CN10 Namao Clover Bar Kennedale Clover Bar Kennedale Clover Bar The TFO also provided the details of the substation transformer elements in the Study Area. The key transformers in the Study Area are shown in Table 2-7. Table 2-7: Summary of key transformer in the Study Area Substation Transformer Rating (MVA) 17

19 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Substation Transformer Rating (MVA) T5 240/72 kv 45 T1 72/14.4 kv 66.7 Victoria T2 72/14.4 kv 66.7 T3 72/14.4 kv 66.7 T4 72/14.4 kv 66.7 Jasper T1 240/72 kv 30 Lambton T3 240/72 kv 8 Bellamy T1 240/72 kv T2 240/72 kv The TFO also provided the details of the shunt elements in the Study Area, as shown in Table 2-8. No shunt reactors are present in the Study Area. Table 2-8: Summary of Shunt Elements in the Study Area Station Name and Number Voltage Class (kv) Capacitor (MVAr) East Edmonton 38S x Nisku 149S x 30 Leduc 5S x Acheson 305S x Jasper x Rossdale 69 2 x 45 Clover Bar 69 1 x Stelco Edmonton 133S Voltage Profile Assumptions The AESO ID # RS was used to establish the pre-contingency voltage profiles for key area busses prior to commencing any studies. Table 2-1 of the Transmission Planning Criteria Basis and Assumptions applies for all the busses not included in ID # RS. These voltages were used to set the voltage profile for the study base cases prior to performing the power flow studies. The key bus voltages for the Study Area for the Project are shown in Table

20 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Table 2-9: Summary of the Voltage at Key Nodes in Study Scenarios ID # RS Substation Name and Number Nominal Voltage (kv) Minimum Operating Limit (kv) Desired Range (kv) Maximum Operating Limit (kv) East Edmonton 38S Bigstone 86S Left Blank * Acheson 305S Ellerslie 89S Petrolia Clover Bar Lambton Bellamy 240 Left Blank * Left Blank * 255 Jasper * This value was intentionally left blank, per ID # RS. 3. Study Methodology The studies for this connection assessment were completed using PTI PSS/E version Study Objectives The objectives of the studies were as follows: Assess the impact of the Project on the performance of the AIES. Identify any violations of the relevant AESO criteria, standards or requirements, both pre-project and post-project. Recommend mitigation measures, if required, to reliably connect the Project to the AIES Connection Studies Carried Out Table 3-1 summarizes the studies that were carried out. 19

21 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Table 3-1: Summary of Studies Performed Scenarios Studied Pre-Project Post-Project Studies Performed System Conditions Studied 1, 2 3, 4 Power flow Category A and Category B - 3, 4 Voltage stability Category A and Category B 3.3. Power Flow Analysis Pre-Project and post-project power flow studies were performed to identify thermal and voltage criteria violations as per the Reliability Criteria, and any deviations from the limits listed in Table 2-1. The purpose of the power flow analysis is to quantify any incremental violations in the Study Area after the Project is connected. For the Category B power flow studies, the transformer taps and switched shunt reactive compensating devices such as shunt capacitors and reactors were locked and continuous shunt devices were enabled. Point-of-delivery (POD) low voltage bus deviations were assessed for both the pre-project and post-project networks by first locking all tap changers and area shunt reactive compensating devices to identify any post transient voltage deviations above 10%. Second, tap changers were allowed to move while shunt reactive compensating devices remained locked to determine if any voltage deviations above 7% would occur in the area. Third, all the taps and shunt reactive compensating devices were allowed to adjust, and voltage deviations above 5% would be reported Contingencies Studied for Power Flow Analysis The power flow studies included all Category B contingencies (69 kv facilities and above) within the Study Area. All transmission facilities in the Study Area were monitored for voltage criteria violations and thermal criteria violations under Category A conditions and under Category B contingency conditions Voltage Stability Analysis The objective of the voltage stability analysis is to determine the ability of the network to maintain voltage stability at all the busses in the system under Category A and Category B conditions. The power-voltage (PV) curve represents voltage change as a result of increased power transfer between two systems. The reported incremental transfers are to the collapse point. As per the AESO requirements, no assessment based upon other criteria such as minimum voltage were made at the PV minimum transfer. Voltage stability studies were performed for post-project scenarios. For load connection projects, the load level modelled in post-project scenarios is the same or higher than in pre- Project scenarios. Therefore, voltage stability analysis for pre-project scenarios would only be performed if the post-project scenarios show voltage stability criteria violations. 20

22 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition The voltage stability analyses followed the Western Electricity Coordinating Council (WECC) Voltage Stability Assessment Methodology. WECC voltage stability criteria states, for load areas, post-transient voltage stability is required for the area modeled at a minimum of 105% of the reference load level for Category A and Category B conditions. For this standard, the reference load level is the maximum established planned load. Typically, voltage stability studies are carried out assuming worst case loading scenarios. For the Project s worst case scenario, load was increased in Edmonton (Area 60) and corresponding generation was increased in Fort McMurray (Area 25) Contingencies Studied for Voltage Stability Analysis The voltage stability studies were performed for the Category A condition and all Category B contingencies (69 kv facilities and above) in the Study Area to determine the system voltage stability margin in the area. 21

23 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition 4. Pre-Project System Assessment This section provides the results of the pre-project power flow studies Pre-Project Power Flow Studies The pre-project power flow diagrams are provided in Attachment A. 4.. Scenario 1 (2017 SP pre-project) Category A condition No Reliability Criteria violations were observed under the Category A condition. Category B contingency conditions No voltage criteria violations were observed under Category B contingency conditions. Thermal criteria violations were observed under certain Category B contingency conditions. The thermal criteria violations are shown in Table 4-1. Table 4-1: Summary of Thermal Criteria Violations for Scenario 1 (2017 SP pre-project) Under Category B Conditions Line Thermal Ratings Study Results Contingency Limiting Facilities Seasonal Continuous (MVA) Short-term Emergency (MVA) Load Flow (MVA) % Loading* 72RG7 (Rossdale - Garneau) 72RG1 (Rossdale - Garneau) (Clover Bar - Hardisty) (Clover Bar - Hardisty) (Clover Bar - Kennedale) (Clover Bar - Kennedale) 72RG1 (Rossdale - Garneau) 72RG7 (Rossdale - Garneau) (Clover Bar - Hardisty) (Clover Bar - Hardisty) (Clover Bar - Kennedale) (Clover Bar - Kennedale) * All line flows are reported as percentage loading relative to seasonal continuous line rating. 22

24 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Scenario 2 (2017 WP pre-project) Category A condition No Reliability Criteria violations were observed under the Category A condition. Category B contingency conditions No voltage criteria violations were observed under Category B contingency conditions. Thermal criteria violations were observed under certain Category B contingency conditions. The thermal criteria violations are shown in Table 4-2. Table 4-2: Summary of Thermal Criteria Violations for Scenario 2 (2017 WP Pre-Project) Under Category B Conditions Line Thermal Ratings Study Results Contingency Limiting Facilities Seasonal Continuous (MVA) Emergency (MVA) Load Flow (MVA) % Loading* 72RG7 (Rossdale - Garneau) 72RG1 (Rossdale - Garneau) (Clover Bar - Hardisty) (Clover Bar - Hardisty) (Clover Bar - Kennedale) (Clover Bar - Kennedale) (Clover Bar - Hardisty) (Clover Bar - Hardisty) (Clover Bar - Kennedale) (Clover Bar - Kennedale) * All line flows are reported as percentage loading relative to seasonal continuous line rating. 5. Connection Alternatives 5.1. Overview The AESO, in consultation with the DFO and the TFO, examined two transmission alternatives to meet the DFO s request for system access service. 6 6 These alternatives reflect more up to date engineering design than the alternatives identified in EPCOR Distribution & Transmission Inc. s Distribution Deficiency Report (DDR) for Breakers Addition (14C and 24C) at Clover Bar, which is filed under a separate cover. 23

25 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition. Connection Alternatives Examined The examined transmission alternatives are listed below. Alternative 1 East Industrial Substation Modification Alternative 1 involves modifying the East Industrial substation by adding one 25 kv circuit breaker and associated equipment. This alternative involve adding a distribution feeder with a total length of approximately 10 kilometres. Alternative 2 Clover Bar Substation Modification Alternative 2 involves modifying the Clover Bar substation, including adding two 25 kv circuit breakers to accommodate the addition of one 25 kv distribution feeder. EDTI has advised that Clover Bar substation relies on a cubicle farm configuration, requiring the addition of two 25 kv circuit breakers to add one distribution feeder. This alternative involves adding a distribution feeder approximate 5 kilometres in length..1. Connection Alternatives Selected for Further Studies Alternative 2 is considered technically acceptable from a DFO perspective and was selected for further study..2. Connection Alternatives Not Selected for Further Studies Alternative 1 is considered technically acceptable from a DFO perspective. However, this alternative would involve increased overall development and hence, increased total cost compared to Alternative 2. Therefore, Alternative 1 was not selected for further study. 24

26 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition 6. Technical Analysis of Alternative 2 This section provides the analysis of the post-project power flow and voltage stability studies Power Flow Studies The post-project power flow diagrams are provided in Attachment B. 6.. Scenario 3 (2017 SP post-project) Category A condition No Reliability Criteria violations were observed under the Category A condition. Category B contingency conditions No voltage criteria violations were observed under Category B contingency conditions. Thermal criteria violations were observed under certain Category B contingency conditions. The thermal criteria violations are shown in Table 6-1. Table 6-1: Summary of Thermal Criteria Violations for Scenario 3 (2017 SP Post-Project) Under Category B Conditions Contingency Limiting Facilities Line Thermal Ratings Seasonal Continuous (MVA) Short-term Emergency (MVA) 2017 SP Pre-Project (Scenario 1) Load Flow (MVA) Study Results % Loading 2017 SP Post- Project (Scenario 3) Load Flow (MVA) % Loading Difference % Loading Between Pre- Project and Post- Project Scenarios 72RG7 (Rossdale - Garneau) 72RG1 (Rossdale - Garneau) (Clover Bar - Hardisty) (Clover Bar - Hardisty) (Clover Bar - Kennedale) (Clover Bar - Kennedale) 72RG1 (Rossdale - Garneau) 72RG7 (Rossdale - Garneau) (Clover Bar to Hardisty) (Clover Bar - Hardisty) (Clover Bar - Kennedale) (Clover Bar - Kennedale)

27 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Scenario 4 (2017 WP post-project) Category A condition No Reliability Criteria violations were observed under the Category A condition. Category B contingency conditions No voltage criteria violations were observed under Category B contingency conditions. Thermal criteria violations were observed under certain Category B contingency conditions, as are shown in Table 6-2. Table 6-2: Summary of Thermal Criteria Violations for Scenario 4 (2017 WP Post-Project) Under Category B Conditions Contingency Limiting Facilities Line Thermal Ratings Seasonal Continuous (MVA) Short-term Emergency (MVA) 2017 WP Pre- Project (Scenario 2) Load Flow (MVA) Study Results % Loading 2017 WP Post- Project (Scenario 4) Load Flow (MVA) % Loading Difference % Loading Between Pre- Project and Post- Project Scenarios 72RG7 (Rossdale - Garneau) (Clover Bar - Hardisty) (Clover Bar - Hardisty) 72RG1 (Rossdale - Garneau) (Clover Bar to Hardisty) (Clover Bar - Hardisty) Voltage Stability Studies The voltage stability diagrams are provided in Attachment C Scenario 3 (2017 SP post-project) For Scenario 3, the reference load level for the Study Area is 2,009 MW. For Category B contingencies, the minimum incremental load transfer to meet the 105% load criterion is 5.0% of the reference load, or 10 MW (5 x 2,009 MW = 10 MW). Table 6-3 provides the voltage stability studies results under the Category A condition and for the five worst Category B contingency conditions. The voltage stability margin was met for all studied conditions. 26

28 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition Table 6-3: Voltage Stability Study Results for Scenario 3 (2017 SP post-project) Contingency From To Maximum incremental transfer (MW) Meets 105% transfer criteria? Category A >600 Yes 240 kv transmission line 947L 240 kv transmission line 921L Ellerslie 89S Clover Bar >600 Yes Clover Bar Lamoureux 71S >600 Yes 240 kv transmission line 915L Clover Bar East Edmonton 38S Clover Bar Transformer T1 >600 Yes Clover Bar Transformer T2 >600 Yes Scenario 4 (2017 WP post-project) For Scenario 4, the reference load level for the Study Area is 1,968 MW. For Category B contingencies, the minimum incremental load transfer to meet the 105% load criterion is 5.0% of the reference load, or 98.4 MW (5 x 1,868 MW = 98.4 MW). Table 6-4 provides the voltage stability studies results under the Category A condition and for the Category B five worst contingencies. The voltage stability margin was met for all studied conditions. Table 6-4: Voltage Stability Study Results for Scenario 4 (2017 WP Post-Project) Contingency From To Maximum incremental transfer (MW) Meets 105% transfer criteria? Category A >600 Yes 240 kv transmission line 947L 240 kv transmission line 921L Ellerslie 89S Clover Bar >600 Yes Clover Bar Lamoureux 71S >600 Yes 240 kv transmission line 915L Clover Bar East Edmonton 38S Clover Bar Transformer T1 >600 Yes Clover Bar Transformer T2 >600 Yes 27

29 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition 7. Project Dependencies The Project does not require the completion of any AESO plans to expand or enhance the transmission system prior to connection. 28

30 Connection Engineering Study Report for AUC Application: EPCOR Clover Bar 25 kv Breaker Addition 8. Conclusions and Recommendations The power flow studies results identified pre-project and post-project system performance issues under certain Category B conditions, which are shown in Table 8-1. As the table shows, under most of the Category B conditions, the thermal criteria violations observed in the pre- Project studies were reduced or eliminated in the post-project studies. For a few Category B conditions studied, the thermal criteria violations were worsened when comparing the results of the post-project study scenarios to the results of the pre-project study scenarios. All thermal criteria violations observed can be managed by using real-time operational practices. Table 8-1: Summary of Reliability Criteria Violations, Project Impact, and Mitigation Measures Reliability Criteria Violations Type Violation Contingency Occurrence (Pre-Project and/or Post- Project Scenarios) Project Impact Year/ Season Load Mitigation Measures (Pre-Project and Post-Project) 72RG7 (Rossdale - Garneau) 72RG1 (Rossdale - Garneau) Pre-Project and Post-Project Marginally reduced 2017 SP 2017 WP Real-time operational practices 72RG1 (Rossdale - Garneau) 72RG7 (Rossdale - Garneau) Pre-Project and Post-Project Marginally reduced 2017 SP Real-time operational practices (Clover Bar - Hardisty) (Clover Bar - Hardisty) Pre-Project and Post-Project Marginally increased Marginally reduced 2017 SP 2017 WP Real-time operational practices Thermal (Clover Bar - Hardisty) (Clover Bar - Hardisty) Pre-Project and Post-Project Marginally increased Marginally reduced 2017 SP 2017 WP Real-time operational practices (Clover Bar - Kennedale) (Clover Bar - Kennedale) Pre-Project and Post-Project Pre-Project Marginally increased Marginally reduced 2017 SP 2017 WP Real-time operational practices (Clover Bar - Kennedale) (Clover Bar - Kennedale) Pre-Project and Post-Project Pre-Project Marginally increased Marginally reduced 2017 SP 2017 WP Real-time operational practices Based on the study results, Alternative 2 is technically viable. It is recommended to proceed with the Project using Alternative 2 as the preferred option to respond to the DFO s request for system access service. Alternative 2 involves modifying the Clover Bar substation by adding two 25 kv circuit breakers and associated equipment. It is also recommended to continue to use real-time operational practices to manage the identified system performance issues. 29