DFO STATEMENT OF NEED REPORT

Transcription

1 APPENDIX E DFO STATEMENT OF NEED REPORT

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3 Table of Contents 1.0 Executive Summary Description of the Area Geographic Study Area System Configuration Area Loading & Risk Assessment Load Growth Development Load Forecast Current Configuration Risk Assessment Load at Risk Magnitude Area Supply Deficiency No. 39 Substation Transformer Overloading During Contingency (Table 4) Feeder Overloading During Contingency (Table 5) Transformer Overloading During Normal Operation (Table 2) Alternatives Considered to Address Deficiency Alternative 1: Do nothing Alternative 2: Load Transfer to Adjacent Substations Alternative 3 (Preferred): 2 nd Transformer Addition at No. 162 Substation Alternative 4: Transformer Upgrade at No. 39 Substation Alternative 5: New Distribution Point of Delivery Substation Capital Cost Estimates Alternative 1: Do nothing Alternative 2: Load Transfer to Adjacent Substations Alternative 3 (preferred): Transformer Addition at No. 162 Substation Alternative 4: 25kV Transformer Upgrade at No. 39 Substation Alternative 5: New kV Distribution Substation to the East Proposed System Development - Preferred Alternative Preferred Alternative Transmission Scope of Work 2017 (Figure 6): Preferred Alternative Distribution Scope of Work Preferred Alternative Future Distribution Considerations Load Forecast Preferred Alternative 3 Implemented In-Service Date Potential Future System Changes... 26

4 1.0 Executive Summary ENMAX Power Corporation (EPC) is seeking endorsement from the Alberta Electric System Operator (AESO) and approval from the Alberta Utilities Commission (AUC) for the addition of a second kV 30/40/50MVA transformer at No. 162 Substation. The requested transformation capacity upgrade and associated 25kV switchgear is necessary to supply two [2] new 25kV distribution feeders to accommodate 80MVA of load growth and to maintain restoration capability in the northeast area of Calgary over a ten year timeframe. No. 162 Substation, scheduled for completion in 2015, is comprised of one [1] kV 30/40/50MVA transformer to supply the residential developments of Redstone, Skyview Ranch, Saddleridge, Cornerstone and Cityscape and the industrial & commercial developments of Northeast Industrial, Calgary International Airport, Stoney Industrial, Northpoint Industrial and Nose Creek. Through system analysis it was determined that the loss of the single transformer at No. 162 Substation will result in 5 MVA of unsupplied load (Load at Risk) in the area during winter 2017/2018, increasing to 43MVA by winter 2023/2024. The addition of a second kV 30/40/50MVA transformer at No. 162 Substation and construction of two [2] new 25kV distribution feeders was determined as the most viable and cost effective long term engineering solution to address the identified deficiency and support the expected load growth. The estimated Transmission cost for the new kV 30/40/50MVA transformer and associated bus work is approximately $5,300,000 (+/-50%). The estimated Distribution cost for the two [2] new 25kV distribution feeders is approximately $2,500,000 (+/-50%), for an expected total project cost of $7,800,000 (+/-50%). The Transmission cost estimate includes the cost of four [4] new 25kV distribution breakers which is EPC s standard practice with a new transformer addition. Installing four [4] breakers minimizes compatibility issues in the future and provides capacity at No. 162 Substation to accommodate the 10 year forecasted growth. The requested in-service date for the second kV 30/40/50MVA transformer addition at No. 162 Substation and two [2] new 25kV distribution feeders is Q4 of This Statement of Need complies with the EPC Planning Guidelines and Criteria. Page 1 of 26

5 2.0 Description of the Area 2.1 Geographic Study Area The geographic study area discussed in this Statement of Need covers 25kV facilities supplying the following industrial, residential and commercial communities: Redstone Skyview Ranch/Cityscape Saddleridge Saddleridge Business Park Cornerstone Freeport Jacksonport Nose Creek Stoney Industrial Northeast Industrial Park Northpoint Industrial Park Calgary International Airport Reference Figure 1 25kV System Configuration (2016) System Configuration The 25kV residential, industrial and commercial load in the northeast corner of the ENMAX service area is currently proposed to be supplied by the following EPC Infrastructure (Figure 1): No. 162 Substation [1] (Figure 2) consisting of: One [1] kV 30/40/50MVA transformer (162.4TR) Four [4] 25kV feeders on 162.4TR supplying the following areas: o Redstone, Skyview Ranch/Cityscape o Stoney Industrial, Nose Creek, Northpoint Industrial o Calgary International Airport (New Terminal) o Northeast Industrial, Saddleridge, Cornerstone (In Service Date 2016) [1] No. 162 Substation is both a kV step down station and a kV POD source (by 2015). This Statement of Need addresses the kV substation component only. Page 2 of 26

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7 Figure 2: Existing No. 162 Substation kV Configuration (2016) PLANNING SCOPE ONLY. Not to be used for final design or switching purposes. Page 4 of 26

8 3.0 Area Loading & Risk Assessment 3.1 Load Growth Development The northeast corner of the ENMAX service area is expecting a significant amount of load growth within the next 10 years. The major subdivisions and associated forecasted load growth for the area are listed in Table 1 below. This load growth includes all sectors such as Industrial, Residential and Commercial. The load growth listed in Table 1 below has been integrated into the overall area load forecast, indicated in Section 3.2 Load Forecast. Table 1 - Major Area Load Addition Expectations ( ) Description of New Load Addition Forecasted Load [MVA] Redstone 4 Skyview Ranch/Cityscape 5 Saddleridge 4 Cornerstone 10 Jacksonport 5 Saddleridge Business Park 2 Nose Creek 5 Northeast Industrial 28 Stoney Industrial 4 Freeport 2 Northpoint Industrial 2 Calgary International Airport 12* Total Area Load Growth (Non-Diversified) 83 Refer to Figure 3 Expected Area Load Growth for a geographic reference of the new load growth. *The Calgary International Airport (YYC) is undergoing a significant expansion including a new terminal, runway system (completed and operational as of June 28 th, 2014), and hotel. Distribution System Planning s current forecast includes 12MVA of load growth within the next 10 years. Page 5 of 26

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10 3.2 Load Forecast Current Configuration Table 2 outlines the 25kV transformer load forecast at No. 162 Substation. Table 2 Transformer 162.4TR Load Forecast - Existing System (MVA) Installed S/W Actual Load [MVA] Diversified Forecasted Load [MVA] Transformer Capacity [MVA] Peak S ² 59² 65² 162.4TR¹ 50 W ² 63² 71² 79² 50 S POD³ 50 W Note: 1. Transformer 162.4TR in service date Transformer at or exceeds nameplate rating and is at risk of overloading under normal operation 3. Non-diversified POD peak only includes 25kV sources. This Statement of Need addresses the 25kV system facilities only. Table 3 outlines the 25kV feeder load forecast at No. 162 Substation. Table 3 Feeder Load Forecast - Existing System (MVA) S/W Actual Load [MVA] Non-Diversified Forecasted Load [MVA] Feeder* Peak S W S W S W S W *Feeder cable ratings for 25kV feeders is 25.9MVA Note: 1. Feeder proposed in service date Feeder proposed in service date Feeder at or exceeds the thermal rated capacity of the cable (25.9MVA) under normal operation Page 7 of 26

11 4.0 Risk Assessment 4.1 Load at Risk Magnitude Load at Risk is defined as customer load that cannot be returned to service within an acceptable timeframe. The Load at Risk highlighted in Table 4 & 5 represents the maximum unsupplied customer load under peak loading conditions in the event of the loss of the single kV 30/40/50MVA transformer at No. 162 Substation. Table 4 Customer Load at Risk During Winter Peak (MVA) Loss of 162.4TR Peak TR¹ Transformer Loading W Total Tie Away Capacity² (Adjacent Feeders) W Load at Risk W Note: 1. Transformer 162.4TR in service date Tie Away Capacity: max load adjacent feeders can restore Table 5 Feeder Load at Risk - Peak Conditions (MVA) Feeder* Peak Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk *Feeder cable ratings for 25kV feeders is 25.9MVA Note: 1. Feeder proposed in service date Feeder proposed in service date Load at Risk on feeder is due to insufficient feeder backup capacity from No. 162 Substation. Page 8 of 26

12 4.2 Expected Frequency of Load at Risk Occurring During Contingency An analysis was completed based on the data in Table 5, to determine the number of days over the winter peak season (October 1 to April 30) that EPC customers would be exposed to a potential loss of supply due to the limited restoration capability in the event of a transformer outage at No. 162 Substation (162.4TR). The analysis is based off of historical loading profiles applied to identify the frequency and magnitude of customer Load at Risk. Figures 4 & 5 represent a graphical display of the anticipated magnitude of the load at risk along with the identified possible days at risk over the winter peak season from years Table 6 summarizes the data from the graphs of Figure 4 & 5, which represent the number of days that customer loads would be at risk throughout the winter peak season, during a contingency. Table 6 Frequency of Risk (Days) Peak Days at Risk* Winter *Days at risk: Number of days throughout the winter season customers are exposed to risk of un-restored load. Page 9 of 26

13 Figure 4 Winter Load at Risk Duration Existing system Page 10 of 26

14 Figure 5 Winter Load at Risk Duration Existing system Page 11 of 26

15 5.0 Area Supply Deficiency With an expected load growth greater than 80MVA over the next ten years the existing Substation and Distribution infrastructure supplying the residential, commercial and industrial loads in the surrounding area of No. 162 Substation will be unable to maintain the EPC planning criteria requiring full mutual backup capacity over peak loading over the 2017/2018 winter peak season. By the 2019/2020 & 2020/2021 winter peak seasons feeder and transformer 162.4TR will be loaded above their rated capacity, respectively. The identified system deficiencies include: 5.1 No. 39 Substation Transformer Overloading During Contingency (Table 4) By the winter of 2017/2018, 39.4TR transformer will exceed nameplate rating and cannot provide restoration to No. 162 Substation feeders during a transformer contingency of 162.4TR. 5.2 Feeder Overloading During Contingency (Table 5) By the winter of 2017/2018, feeder can no longer be restored during a contingency due to transformer 39.4TR exceeding its nameplate rating (through feeder tie to ). Also, in the winter of 2018/2019 feeder can no longer be restored during a contingency due to an exceeded thermal capacity of the 25kV feeder cables (26MVA) on Transformer Overloading During Normal Operation (Table 2) By the winter of 2020/2021, 162.4TR transformer will be overloading under normal operation TR transformer has a maximum nameplate rating of 50MVA which will be exceeded by 5MVA during winter peak conditions in 2020/2021. Page 12 of 26

16 6.0 Alternatives Considered to Address Deficiency 6.1 Alternative 1: Do nothing Alternative 1 was dismissed as it does not address the identified system deficiencies and results in a violation of EPC loading and reliability criteria policy statements as detailed in the Distribution System Planning Guideline. Alternative 1 is not a viable solution. 6.2 Alternative 2: Load Transfer to Adjacent Substations Adjacent substations do not have the capacity to offload No. 162 Substation. The areas with major growth and future load at risk are in proximity to No. 162 Substation. Supplying these areas from adjacent substations would result in longer feeders which is an ineffective use of distribution infrastructure. Advantages: None Disadvantages: Would result in longer feeders to supply the areas of growth. Would shift the system deficiencies in the area to adjacent substations Alternative 2 was dismissed as it does not address the identified system deficiencies and was not considered to be the best engineering solution. Alternative 2 is not a viable solution. 6.3 Alternative 3 (Preferred): 2 nd Transformer Addition at No. 162 Substation Installation of a second kV 30/40/50MVA transformer and construction of two [2] new 25kV distribution feeders to service the loads to the south of No. 162 Substation. Advantages: System upgrade meets EPC Planning Criteria through addressing the risk of transformer and feeder overloads during normal operation and under contingency. Meets long term reliability and capacity needs for forecasted growth ( ). No. 162 Substation can accommodate the installation of a second transformer and is central to the area of major load growth. Disadvantages: No material disadvantages noted Alternative 3 is considered to be the preferred option as it is the best long term, cost effective solution to address the identified system deficiencies. Page 13 of 26

17 6.4 Alternative 4: Transformer Upgrade at No. 39 Substation Upgrade the two [2] existing kV transformers at No. 39 Substation from 30/40/50MVA to 50/67/83MVA providing additional capacity to this substation. Construction of two [2] new 25kV distribution feeders to service the loads to the north of No. 39 Substation. Advantages: System upgrade meets EPC Planning Criteria through addressing the risk of transformer and feeder overloads during normal operation and under contingency. Provides an efficient solution to supply load growth to the east of Stoney Trail due to existing infrastructure from No. 39 Substation. Disadvantages: An additional cost of $6,700,000 compared to Alternative 3 associated with upgrading two [2] kV transformers. New load growth is geographically close to No. 162 Substation. Due to the geographic location supplying this new load growth from No. 39 Substation would result in long distribution feeders. This alternative was dismissed due to the limited advantages it provides given the associated higher cost. 6.5 Alternative 5: New Distribution Point of Delivery Substation Construction of a new kV 30/40/50MVA substation to the east of Stoney Trail and construction of two [2] new 25kV distribution feeders to serve the loads to the West of the new substation. Advantages: System upgrade meets EPC Planning Criteria through addressing the risk of transformer and feeder overloads during normal operation and under contingency. Provides flexibility to serve the load growth in the area and improves reliability due to the addition of a new Point-of-Delivery substation. Provides an established source for potential future development east of Stoney Trail. Disadvantages: An additional cost of $15,700,000 compared to Alternative 3 Constructing a new substation without utilizing the established infrastructure at No. 162 Substation (i.e. provision for a second transformer) is not a prudent use of system infrastructure. New transmission lines would be required to supply the new substation. This alternative was dismissed due to the limited advantages it provides given the associated higher cost. Page 14 of 26

18 7.0 Capital Cost Estimates Cost estimates were prepared for viable alternatives 3, 4, and 5. Alternatives 1 & 2 were deemed not viable and dismissed. 7.1 Alternative 1: Do nothing No capital cost estimates were prepared for Alternative 1 as it does not address system deficiencies and was dismissed. 7.2 Alternative 2: Load Transfer to Adjacent Substations No capital cost estimates were prepared for Alternative 1 as it does not address system deficiencies and was dismissed. 7.3 Alternative 3 (preferred): Transformer Addition at No. 162 Substation Table 7 Cost Estimate (+/- 50%) Alternative 3 (Preferred): kV 30/40/50MVA Second Transformer Addition at No. 162 Substation Transmission: Installation of one [1] new kV 30/40/50MVA transformer, associated bus work and installation of four [4] new 25kV distribution breakers. Distribution: Construction of two [2] new 25kV feeders from No. 162 Substation. Capital Cost Estimate $ $ 5,300,000 2,500,000 Total: $ 7,800, Alternative 4: 25kV Transformer Upgrade at No. 39 Substation Table 8 - Cost Estimate (+/- 50%) Alternative 4: 25kV Transformer Upgrade at No. 39 Substation Transmission: Upgrading both existing kV 30/40/50MVA transformers to kV 50/67/83MVA transformers and any associated bus work. Installation of four [4] new 25kV distribution breakers. Distribution: Construction of two [2] new 25kV feeders from No. 39 Substation Capital Cost Estimate $ 11,000,000 $ 3,500,000 Total: $ 14,500,000 Page 15 of 26

19 7.5 Alternative 5: New kV Distribution Substation to the East Table 9 Cost Estimate (+/- 50%) Alternative 5: New kV 50MVA Point of Delivery Substation to the East of Stoney Trail Transmission: Construction of one [1] new kV substation with one [1] kV 30/40/50MVA transformer, associated transmission line and bus work and the installation of four [4] new 25kV distribution breakers. Distribution: Construction of two [2] new 25kV feeders from new substation and associated load transfers. Capital Cost Estimate $ 20,000,000 $ 3,500,000 Total: $ 23,500,000 Page 16 of 26

20 8.0 Proposed System Development - Preferred Alternative 3 The preferred solution (Alternative 3) addressing the identified deficiencies includes the installation of a second kV 30/40/50MVA transformer at No. 162 Substation and associated 25kV switchgear to support additional 25kV future feeders. Alternative 3 has been selected as the preferred solution for the following reasons: Provides a long term solution that addresses identified deficiencies. Provides improved reliability and operational flexibility at No.162 Point of Delivery Substation. Effectively makes use of provision for expansion at No. 162 Point of Delivery Substation. Provides sufficient capacity to accommodate forecasted load growth in the area over the next 8 years. Least cost viable solution Facilitates transformer maintenance at No. 162 Substation. 8.1 Preferred Alternative Transmission Scope of Work 2017 (Figure 6): Install second kV 30/40/50MVA transformer at No. 162 Substation complete with associated 25kV bus work. Install four [4] new 25kV distribution feeder breakers Add and modify protection and control equipment as required. The estimated cost of the required substation work is 5,300,000$ (+/- 50%). Page 17 of 26

21 Figure 6 Proposed No. 162 Substation 25kV Configuration Alternative 3 implemented PLANNING SCOPE ONLY. Not to be used for final design or switching purposes. Page 18 of 26

22 8.2 Preferred Alternative Distribution Scope of Work 2017 (Figure 7): Construction of new 25kV distribution feeder to offload industrial load (Freeport) from Construction of new 25kV distribution feeder to sectionalize and offload The estimated cost of the required distribution work is $2,500,000 (+/- 50%). 8.3 Preferred Alternative Future Distribution Considerations Distribution System Planning has identified a future need for additional distribution infrastructure by A conceptual solution is presented in this document to outline a forecasted long term plan. Future system assessments will be performed along with the development of relevant business cases to address the need and timing. Distribution System Planning is not requesting approval at this time for the distribution infrastructure to be built by 2021 (Figure 8) outlined below (Figure 8): Construction of new 25kV distribution feeder to support growth in Northeast Industrial Park. Construction of new 25kV distribution feeder to support growth in residential developments. Cost estimates of the distribution infrastructure subject to the development of the appropriate business cases. [1] The in-service date of 2021 for the potential addition of two [2] new 25kV feeders from No. 162 Substation is a reflection of Distribution System Planning s current load forecast and long term plan. These feeders and their in-service dates are subject to further system assessments prior to commitment. Page 19 of 26

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25 9.0 Load Forecast Preferred Alternative 3 Implemented Table 10 outlines the 25kV transformer load forecast at No. 162 Substation with Alternative 3 implemented. Table 10 Transformer Load Forecast - Preferred Alternative Implemented (MVA) Installed S/W Diversified Forecasted Load [MVA] Transformer Capacity [MVA] Peak S TR 2 50 W S TR 1 50 W S POD W Note: 1. Transformer 162.4TR in service date Transformer 162.3TR proposed in service date Non-diversified POD peak only includes 25kV sources. This Statement of Need addresses the 25kV system facilities only. Page 22 of 26

26 Table 11 outlines the 25kV feeder load forecast at No. 162 Substation. Table 11 indicates that the implementation of the preferred alternative eliminates feeder overloading under normal operation. Table 11 Feeder Load Forecast - Preferred Alternative Implemented (MVA) Feeder* S/W Non-Diversified Forecasted Load [MVA] Peak S W S W S W S W S W S W S W S W *Feeder cable ratings for 25kV feeders is 25.9MVA Note: 1. Feeder proposed in service date Feeder proposed in service date Feeder proposed in service date Future conceptual feeders anticipated to be required in Subject to future system assessment and approval. Page 23 of 26

27 Table 12 indicates that during a specified transformer outage the implemented preferred alternative eliminates the load at risk. Table 12 Customer Load at Risk - Preferred Alternative Implemented (MVA) Loss of 162.4TR 162.4TR 1 Transformer Loading Total Tie Away Capacity 2 (Adjacent Feeders & Remaining Transformer) Load at Risk 4 Loss of 162.3TR 162.3TR 3 Transformer Loading Total Tie Away Capacity 2 (Adjacent Feeders & Remaining Transformer) Load at Risk 4 Peak W W W Peak W W W Note: 1. Transformer 162.4TR in service date Tie Away Capacity: max load adjacent feeders and/or remaining transformer can restore within thermal capacity of 25kV cable and transformer nameplate rating 3. Transformer 162.3TR proposed in service date Load at Risk is defined as the customer load that cannot be returned to service within an acceptable timeframe Page 24 of 26

28 Table 13 indicates that the implementation of the preferred alternative eliminates load at risk on the No. 162 feeders until Table 13 Feeder Load at Risk - Preferred Alternative Implemented Feeder* Peak Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk Loading Tie-Away Capacity W Load at Risk *Feeder cable ratings for 25kV feeders is 25.9MVA Note: 1. Feeder proposed in service date Feeder proposed in service date Feeder proposed in service date Future conceptual feeders 5. Forecast Load-at-Risk will be addressed through additional area system infrastructure appropriate at that time. Page 25 of 26

29 10.0 In-Service Date The requested in-service date for the kV 30/40/50MVA transformer addition at No. 162 Substation and two [2] new 25kV distribution feeders is Q4 of Potential Future System Changes Distribution As identified in Table 13, there will be a requirement for additional distribution infrastructure by 2021 in the northeast corner of the EPC service area. Distribution System Planning s current plan for the area includes building two [2] 25kV feeders out of No. 162 Substation as outlined in this Statement of Need. Future system assessments will be performed along with the development of relevant business cases to address the need and timing. Transmission/Substation Additionally, future development may include the possible installation of a new kV Point of Delivery (between No. 47 Substation and No. 162 Substation). The need for a future substation is conceptual at this time and represents Distribution System Planning s load forecast and long term plan to supply the area. Further assessment will be needed as the area develops. A separate Statement of Need document and AESO System Access Service Request (SASR) application will be prepared for this new substation when required. Page 26 of 26