N-1Work Order - Redacted
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Summary of Related CIs +/- 2 years: Pursuant to Section 11.2 of the CEJC, related CIs for Distribution projects include Work completed on the same asset class (Padmount transformers, Breakers, etc.) or in the same location (feeder, Transmi...
AI summary The document outlines related Cost Items (CIs) for Distribution projects under Section 11.2 of the CEJC, specifying asset classes (e.g., Padmount transformers) and locations. No projects are listed for 2024–2028. Depreciation classes include Distribution Plant components, with an estimated asset life of 40 years.
JUSTIFICATION: Justification Criteria: Distribution System Sub Criteria: Overloaded Equipment
AI summary The justification focuses on the distribution system's 'Overloaded Equipment' sub-criteria, highlighting infrastructure challenges related to equipment capacity within the Nova Scotia Energy Board's regulatory proceedings.
Why do this project? The 92H-331 feeder at Tidewater substation is overloaded during periods of high load. The construction of the new three phase feeder section along Peggys Cove Road from 92H substation will allow for the offload of 92H-...
AI summary The 92H-331 feeder at Tidewater substation is overloaded, necessitating the construction of a new three-phase feeder along Peggys Cove Road to offload 92H-331, improve reliability, and reduce strain on the distribution system. A planning study (M-AREA-2025-002) outlines immediate and long-term solutions, including a new substation, to address capacity and reliability challenges in the area.
Why do this project this way? The proposed construction of a new three-phase feeder along Peggy's Cove Road provides the most effective nearterm solution in conjunction with CI C0071888 upgrading 92H-T61 with a larger 25 MVA transformer to...
AI summary The proposed construction of a new three-phase feeder along Peggy's Cove Road is presented as the most effective near-term solution to address loading and voltage constraints on feeder 92H-331, aligning with a staged infrastructure plan. Immediate feeder offloading is required before broader system upgrades, including future substation development and voltage conversion in the Hubley area. No viable alternative routes exist for the feeder.
Document No: XXX-XX-XXXX-XXXX Estimate Classification Class 4 Class 3 Class 2 Started or Preliminary Class 5 0% to 2% 1% to 15% 10% to 40% 30% to 75% 65% to 100% Maturity Level of Project Definition Deliverables Defined or Complete General...
AI summary The document outlines various project classifications, maturity levels, and deliverables for different project stages, including project location, requirements, technology selection, planning, and studies. It details the status of deliverables such as environmental monitoring, logistics plans, and regulatory approvals.
EXECUTIVE SUMMARY This study evaluates capacity constraints affecting the 92H-Tidewater and 137H-Hammonds Plains substations and identifies capital investments required to maintain compliance with NS Power planning criteria and accommodate...
AI summary This study identifies capacity constraints at 92H-Tidewater and 137H-Hammonds Plains substations, recommending capital investments to meet NS Power planning criteria and accommodate load growth through 2035. Key projects include transformer replacements, new feeders, and the Stillwater Lake substation. These upgrades aim to restore compliance, improve reliability, and address forecasted overloads.
TABLE OF CONTENTS EXECUTIVE SUMMARY TABLE OF CONTENTS i LIST OF APPENDICES ii LIST OF TABLES AND FIGURES ii 1.0 SCOPE 1 2.0 Existing System 2 2.1 Transmission 2 2.2 Distribution Ξ 2.2.1 92H-Tidewater ε 2.2.2 137H-Hammonds Plains Distributi...
AI summary The document outlines the existing electrical system in Nova Scotia, focusing on transmission and distribution infrastructure, load history, reliability concerns, and potential capacity alternatives. It details issues such as transformer overloads, voltage problems, and aging equipment in specific areas like Tidewater and Hammonds Plains, and presents various solutions to address these challenges.
1.0 SCOPE This study was initiated to address transformer and feeder overloads at the 92H-Tidewater and 137H-Hammonds Plains substations. Both substations have experienced sustained loading above planning criteria during recent winter peak...
AI summary This study addresses transformer and feeder overloads at 92H-Tidewater and 137H-Hammonds Plains substations due to sustained winter peak loading and forecasted residential growth. It evaluates alternatives to meet planning criteria (133% transformer loading, 325 A feeders) and contingency capacity (e.g., mobile transformers, load transfer) over a 15-year period, recommending capital investments to resolve overloads and ensure reliability.
3.1 Feeders Historical feeder loading was derived from peak load analyses based on AMI measurements from 2022 onward. Limited SCADA/PI data is available, and data prior to 2022 could not be validated. The load forecast is developed using a...
AI summary The historical feeder loading is based on AMI measurements from 2022 onward and uses linear regression to forecast future loads. The forecast includes a 90th-percentile deviation adjustment to account for variability and produce a conservative planning forecast.
3.2 Transformers Historical transformer loading was derived from peak load analyses based on AMI measurements from 2022 onward. There was limited historical data available, and data prior to 2021 (for 137H) and prior to 2022 (for 92H) coul...
AI summary The historical transformer loading analysis uses AMI data from 2022 onward, with limited data prior to 2021 and 2022. Load forecasts are based on linear regression trends and 90th-percentile deviation adjustments to account for variability, producing a conservative planning forecast.
5.0 OVERLOADS AND OTHER CONCERNS This section will highlight key findings from the analysis of the existing system and load forecasts for the Tidewater and Hammonds Plains areas. These findings are addressed in Section 6.
AI summary Section 5.0 outlines key findings from system and load forecasts analysis for Tidewater and Hammonds Plains, with further discussion in Section 6. The focus is on overloads and related concerns arising from infrastructure and demand planning.
5.1.1 92H Transformer Overload The transformer 92H‑T61 would have recorded a peak load of 20.5 MVA in 2025 without embedded hydro generation, exceeding 164% of its 12.5 MVA top nameplate rating. Historical loading on this transformer has i...
AI summary Transformer 92H-T61 is overloaded, exceeding 164% of its 12.5 MVA rating without hydro generation. Winter peaks surpass planning criteria, and mobile transformers installed in 2026 are not viable long-term solutions. Hydro generation was used in 2025 but is unreliable due to drought, necessitating permanent corrective action.
5.1.2 92H Feeder Overloads Feeder 92H‑331 reached a 2025 winter peak of 432 A, with an annual growth rate of 4.3% from 2022– 2025. This significantly exceeds the 325 A planning criterion and presents an immediate reliability and capacity c...
AI summary Three feeders (92H-331, 92H-332, 92H-334) are exceeding planning criteria due to increasing loads. Feeder 92H-331 requires immediate action, 92H-332 needs long-term modifications by 2029, and 92H-334 requires continued monitoring due to uncertain growth. All pose reliability and capacity concerns.
Substation Transformer kV Rating (MVA) Vintage Estimated Years Remaining 92H-TIDEWATER 92H-T61 138-13.2 7.5/10/12.5 1985 10.5 Further to the transformer age, the bus structures in the 92H Tidewater substation are wooden and deteriorated. T...
AI summary The transformer at the 92H-Tidewater substation, manufactured in 1985, has an estimated 10.5 years remaining before replacement. Additionally, the wooden bus structures in the substation are deteriorated and will require full replacement within 10 years.
5.2 Hammonds Plains Area Concerns The overloads identified in this section are based on measured winter peak conditions, with future violations forecasted using the observed annual growth rates from 2022–2025. Several major developments in...
AI summary The Hammonds Plains area faces potential grid overloads due to new developments adding 5.7 MW (Bedford West) and 15 MW (Sandy Lake) of residential/mixed-use load, plus a 6.9 MVA commercial expansion. These projects may accelerate capacity violations beyond historical growth trends, introducing uncertainty in loading patterns.
5.2.1 137H Transformer Overload The transformer 137H-T61 reached a winter peak load of 50.6 MVA in 2025, equal to 121% of its 42 MVA top rating. Historical loading on this transformer has increased by 4.1% annually and it is forecasted to...
AI summary Transformer 137H-T61 exceeded its winter load rating in 2025, with annual loading increases projected to surpass design limits by 2026. The 137H substation's contingency capacity is insufficient, risking system reliability. Immediate corrective actions are required to address overload and capacity issues.
5.2.2 137H Feeder Overloads Feeder 137H-411 had a peak load of 337 A in 2025 and is expected to grow at an average rate of approximately 4.4% per year. Since this exceeds the planning criteria of 325 A, measures to offload this feeder are...
AI summary Three 137H feeders (411, 412, 413) exceed 325A planning criteria with projected growth rates of 4.4%, 3.3%, and 1.9% annually. Measures to offload these feeders are required due to residential growth and the potential impact of the 15MW Sandy Lake development on feeder 413. Feeder 414 remains under capacity.
5.2.3 Voltage Issues Based on the CYME modelling for 2025 winter peak there is a low voltage issue past the Pockwock intersection on the 137H-412 feeder. Alternatives to address these overloaded feeders will also ensure the voltage is main...
AI summary The text identifies a voltage issue on the 137H-412 feeder past the Pockwock intersection during the 2025 winter peak, as modeled by CYME. Alternatives are needed to address overloaded feeders and maintain voltage at 114 V to meet NSPI's 110 V nominal requirement at customer service entrances.
6.1.2 92H Fourth Feeder Feeder 92H‑331 is severely overloaded and growing rapidly. During extreme cold weather events, the feeder required active monitoring for potential load shedding to avoid exceeding conductor and protection limits. To...
AI summary Feeder 92H-331 is overloaded and requires a new fourth feeder (92H-335) to alleviate congestion. The proposed 6 km extension along Peggy's Cove Road would reduce 92H-331's load to 179 A, with further extension contingent on load growth. Alternatives like using 92H-332 were rejected due to existing overload.
6.2 Hammonds Plains Capacity Winter peak loading at 137H-Hammonds Plains has increased to the point where both normal loading limits and contingency capacity shortfall present near-term risk. The existing station exceeds its available cont...
AI summary Winter peak loading at Hammonds Plains has exceeded contingency capacity limits, with feeders surpassing design criteria. Alternatives are needed to restore compliance with planning standards and accommodate future growth in Hammonds Plains and Bedford.
6.2.1 Alternative A: New Stillwater Lake Substation Stillwater Lake was identified as the preferred location for a potential new substation for several reasons. Appropriate land is available for sale near a 138 kV transmission line and Ham...
AI summary Alternative A proposes the construction of a new substation at Stillwater Lake to improve reliability and efficiency by leveraging existing distribution lines and reconfiguring feeders. This option also includes the installation of a second transformer at Hammonds Plains in 2037.
Stillwater - - 23.2 24.0 24.7 25.5 26.3 27.1 27.9 28.7 Under this configuration, the Pockwock wind generation site will be supplied from a Stillwater Lake feeder. This will require a study to ensure there are no negative system impacts fro...
AI summary The document discusses the potential system impacts of supplying the Pockwock wind generation site from a Stillwater Lake feeder and the need for a second transformer at 137H-Hammonds Plains due to continued load growth. A long-term load forecast for 137H-T61 was developed based on historical growth rates and proposed system configurations.
6.2.2 Alternative B: Additional Transformer at Hammonds Plains Another option for adding new capacity in the Hammonds Plains area is adding a transformer at the 137H-Hammonds Plains substation. This station was built for a second transform...
AI summary Alternative B involves installing an additional transformer at the 137H-Hammonds Plains substation to add new capacity. While the transformer installation is relatively simple, significant feeder development and reconfiguration are required. This alternative poses risks to budget and schedule due to challenges in obtaining easements and constructing along a congested road.
6.2.3 Alternative C: Feeders from Lucasville A third alternative is leveraging capacity from the 131H-Lucasville substation. A new feeder can be built into Stillwater Lake to offload 137H-412 and enable feeder reconfigurations. This additi...
AI summary Alternative C proposes building new feeders from the Lucasville substation to increase contingency capacity. One feeder would provide 44 MVA, but a second feeder is required to reach 48 MVA, enabling deferral of the Stillwater Lake substation upgrade.
Scope of this alternative: - Construct a new feeder at 131H Lucasville. - Extend the new feeder 13.3 km from Lucasville to Stillwater Lake. - Build a second additional feeder from Lucasville and extend 1.8 km to Bryanston Road to provide c...
AI summary The proposed alternative involves constructing and extending new power feeders, transferring lines between circuits, and building a new substation in Stillwater Lake by 2029 to improve grid reliability and capacity.
6.3 Tidewater Capacity The immediate concerns for Tidewater are addressed by the immediate actions recommended in Section 6.1. However, in 2029 the feeder 92H-332 is expected to exceed the 325 A planning criterion and the total station loa...
AI summary The Tidewater area faces capacity and voltage challenges by 2027-2033, including overloaded feeders (92H-332, 103H-432, 92H-334) and low voltage in Five Island Lake. Solutions include converting 12kV distribution in Hubley, expanding 92H Tidewater capacity, and infrastructure upgrades like line extensions. Deteriorated 92H substation structures also require attention.
6.3.1 Alternative A: Hubley Conversion and Transfer to Stillwater Lake The Hubley area has experienced significant load growth, and the feeder 92H-332 has previously been identified as overloaded. To address this, distribution supplied fro...
AI summary Alternative A involves converting Hubley's 12 kV system to 25 kV and transferring it to Stillwater Lake to address load growth and overloading. A new substation at Stillwater Lake will provide a new 25 kV source, and temporary supply from feeder 103H-432 will be used during the transition. The plan includes installing transformers, extending feeders, and rebuilding the Tidewater substation.
Rather than converting the Hubley area to 25 kV, it is possible to expand the Tidewater substation and add an additional 12 kV feeder. There is no space for expansion at the current substation site, so a new station would need to be built...
AI summary The text outlines an alternative approach to upgrading the electrical infrastructure in the Hubley area by building a new Tidewater substation, reconfiguring feeders, and relocating existing transformers, rather than converting the area to 25 kV. This involves constructing a new substation, upgrading protection systems, and modifying feeder configurations to address capacity issues.
Hammonds Plains Capacity Alternative A - Stillwater Lake Year Qty Unit Cost Total Construct Stillwater Lake Substation 2027 1 $ 10,000,000 $ 10,000,000 Reconfigure Feeders 2027 1 $ 50,000 $ 50,000 Add transformer at 137H 2037 1 $ 4,000,000...
AI summary The document outlines three alternatives for capacity improvements at Hammonds Plains and Tidewater, detailing project timelines, quantities, unit costs, and total costs for each alternative. The alternatives involve constructing substations, reconfiguring feeders, adding transformers, and extending feeders to various locations.
7.4.1 Hammonds Plains Alternative A: Stillwater Lake Substation Construction of a new substation in the Stillwater Lake area provides the most effective solution for the identified capacity concerns. This alternative introduces a new distr...
AI summary Construction of a new Stillwater Lake substation addresses capacity concerns by reducing feeder lengths, improving voltage performance, and lowering outage risks. It transfers load from existing feeders, reduces transformer loading, and accommodates future growth with low capital costs and existing land acquisition. This alternative is deemed the preferred solution due to its efficiency and long-term viability.
7.4.2 Hammonds Plains Alternative B: Second Transformer at Hammonds Plains Adding a second transformer at 137H provides additional substation capacity and improves operational redundancy at the existing station. The 137H site was originall...
AI summary Alternative B proposes adding a second transformer at Hammonds Plains to enhance substation capacity and redundancy. While it resolves feeder capacity issues, it introduces reliability risks from long feeders, construction challenges due to heavy development along Hammonds Plains Road, and defers a Stillwater Lake substation until 2032, increasing overall costs. These factors make Alternative B less favorable than Alternative A.
7.4.3 Hammonds Plains Alternative C: Feeders from Lucasville Alternative C involves extending feeders from the 131H–Lucasville substation to offload 137H and increase contingency capacity. While this alternative avoids major substation con...
AI summary Alternative C proposes extending feeders from Lucasville to offload 137H and increase contingency capacity. It avoids near-term substation construction but requires long feeder lines with routing challenges. Reliance on Lucasville capacity limits regional supply flexibility and defers a new substation until 2029. The approach is deemed non-preferred due to limited long-term benefits and reliance on distant infrastructure.
7.5.1 Tidewater Alternative A: Hubley Conversion and Transfer to Stillwater Lake This alternative converts portions of the Hubley distribution system from 12 kV to 25 kV and transfers this load to the proposed Stillwater Lake substation. T...
AI summary Tidewater Alternative A involves upgrading Hubley's distribution system from 12 kV to 25 kV and transferring load to the Stillwater Lake substation. This reduces Tidewater substation loading, improves reliability via new feeder ties, resolves feeder overloads, and leverages existing infrastructure, making it the lowest-cost, preferred long-term solution.
7.5.2 Tidewater Alternative B: Tidewater Substation Expansion This alternative involves constructing a new Tidewater substation with 25 MVA transformer as well as relocating the replacement 25 MVA transformer to the new facility. A new 12...
AI summary Tidewater Alternative B proposes constructing a new substation with a 25 MVA transformer and a 12 kV feeder to serve the Hubley area. While providing redundancy, it is more expensive than Alternative A and offers limited system-wide benefits. The alternative relies on an isolated 12 kV source and may require future modifications if growth continues, leading to its rejection as the preferred solution.
8.0 RECOMMENDATIONS This study identified immediate and long-term capacity constraints affecting the 92H-Tidewater and 137H-Hammonds Plains substations. These include transformer overloads, feeder loading violations, voltage concerns, and...
AI summary The study recommends immediate upgrades to 92H-Tidewater and 137H-Hammonds Plains substations to address transformer overloads, feeder loading violations, and insufficient contingency capacity. Immediate actions include replacing transformers, constructing new feeders, and building the Stillwater Lake substation. Long-term plans involve voltage upgrades and future substation expansions by 2037.
2026: - Replace transformer 92H-T61 with a 15/20/25 MVA unit. REDACTED CI C0080102 Attachment 1 Page 43 of 52 - Build new feeder 92H-335 and extend a minimum of 6 km along Peggy's Cove Road.
AI summary The 2026 plan includes replacing transformer 92H-T61 with a 15/20/25 MVA unit and constructing a new 6 km feeder line (92H-335) along Peggy's Cove Road. These infrastructure upgrades aim to enhance grid capacity and reliability in the region.
2027: - Extend feeder 92H-335 an additional 2 km to Crouchers Point Road. - Construct a new Stillwater Lake substation with one 25/33/42 MVA transformer and two feeders.
AI summary The 2027 plan includes extending feeder 92H-335 by 2 km to Crouchers Point Road and constructing a new Stillwater Lake substation with one 25/33/42 MVA transformer and two feeders, indicating infrastructure upgrades to enhance grid capacity and reliability.
2028: - Construct a third feeder from Stillwater Lake. - Convert Hubley distribution from 12 kV to 25 kV. - Transfer Hubley load to the Stillwater Lake substation by creating a feeder tie with 103H-Lakeside.
AI summary Proposed infrastructure upgrades include constructing a third feeder from Stillwater Lake, converting Hubley's distribution to 25 kV, and transferring load via a feeder tie to the Stillwater Lake substation, aiming to enhance grid reliability and capacity.
2033: - Rebuild Tidewater substation structures.
AI summary The document outlines a task for 2033: rebuilding the Tidewater substation structures. No further details or context are provided in the text.
2037: - Install a second transformer at 137H-Hammonds Plains. Implementation of these projects will restore compliance with planning criteria, provide sufficient contingency capacity, and accommodate forecast load growth in the Tidewater a...
AI summary The document outlines the installation of a second transformer at 137H-Hammonds Plains to restore compliance with planning criteria, ensure contingency capacity, and accommodate load growth in Tidewater and Hammonds Plains. Continued monitoring of development in Bedford West, Sandy Lake, and Hubley/Timberlea is recommended to adjust project timelines and identify long-term needs.
Tidewater and Hammonds Plains Area Review Proposed T Proposed Tidewater Area Area/Planning Study Metro Regio n POWER An Emera Company Prep. By: BH June 28, 2024 1 Page 1 of 2 An Emera Company Project The purpose of this purpose of this pur...
AI summary The document discusses a planning study for the Tidewater and Hammonds Plains area, highlighting the need for infrastructure upgrades due to transformer overloading and insufficient capacity. Key issues include the transformer 92H-T61 reaching 170% loading, overloaded feeders, and the need for a new 25 kV source to address long-term capacity needs.