Topic:"Infrastructure Planning" in M12843

REDACTED (CONFIDENTIAL INFORMATION REMOVED) CI C0044172 Canso Crossing Vibration Mitigation REDACTED May 4, 2026 REDACTED (CONFIDENTIAL INFORMATION REMOVED) NSEB APPROVAL SHEET Project Title: L7005 Canso Crossing Vibration Mitigation CI Nu...

AI summary This document is an NSEB Approval Sheet for the Canso Crossing Vibration Mitigation project, submitted by Nova Scotia Power Incorporated and approved by the Nova Scotia Energy Board on May 4, 2026. It outlines the expenditure profile and type of filing for the project.

The sequence of events is as follows: - Q4 2021: Unexpected conductor damage was observed during an inspection at the L-7005 Canso crossing. The damage prompted an engineering assessment completed by a third-party conductor expert. Please...

AI summary In Q4 2021, conductor damage at L-7005 Canso crossing prompted an engineering assessment recommending revised dampers and monitoring devices. Interim repairs were made in Q3 2022, but delays in vendor manufacturing and testing prevented immediate installation. Procurement and testing concluded in Q4 2024, with custom PLP dampers and spoilers installed in Q3 2025.

Why do this project? Damage to the original set of dampers as a result of the higher than anticipated aeolian vibrations means the equipment can no longer provide sufficient protection against ongoing conductor vibrations. A third-party en...

AI summary Damage to dampers from aeolian vibrations threatens conductor integrity at the Strait of Canso, risking safety, transmission reliability, and costly repairs. A third-party assessment confirms ongoing degradation without corrective action, necessitating intervention to prevent structural damage and emergency repairs in a hard-to-access location.

Why do this project now? The original damper system that was repaired where there were damages on an interim basis in Q3 2022 has reached its end-of-life, and without mitigation the conductor is at risk of damage from ongoing aeolian vibra...

AI summary The damper system repaired in Q3 2022 has reached end-of-life, risking conductor damage from aeolian vibration. Immediate replacement is needed to avoid public safety risks over highways 104/19 and system failure in the Cape Breton Export Corridor. Additional damage discovered in Q1 2025 accelerated the project from 2026 to 2025.

Why do this project this way? Installation of the new dampening system provides a long-term solution to conductor vibration compared with further interventions using the originally installed dampening system which is now at end-of-life. In...

AI summary Installing a new dampening system is more cost-effective than replacing the entire conductor section, which would cost around $2.5 million, and offers a long-term solution to vibration issues.

Inclusions For the purposes of this document, the term power transmission line infrastructure industries is assumed to include greenfield or brownfield sites for overhead, buried and submarine transmission of electrical power in the infras...

AI summary The document defines 'power transmission line infrastructure industries' to include overhead, buried, and submarine transmission projects, excluding process plants, mining facilities, and generation substations. It references other RPs (e.g., 18R-97) and cites the Construction Industry Institute's definition of infrastructure projects as systems integral to commerce and interaction.

DESCRIPTION: This project is for the investigation, custom hardware development, testing, and installation of a new vibration dampening solution for the L-7005 transmission line across the Canso Strait. The new vibration mitigation system...

AI summary This project involves the installation of a new vibration dampening solution on the L-7005 transmission line across the Canso Strait. Fatigue-related failures were identified in the existing dampers during a 2021 inspection, caused by Aeolian vibration and galloping due to low-to-moderate wind speeds and ice accumulation, exceeding original design assumptions.

The sequence of events is as follows: - Q4 2021: Unexpected conductor damage was observed during an inspection at the L-7005 Canso crossing. The damage prompted an engineering assessment completed by a third-party conductor expert. Please...

AI summary Conductor damage was discovered in Q4 2021 at the L-7005 Canso crossing, leading to an engineering assessment and recommendations for a more robust damping system. Repairs were made in Q3 2022, but the new system was delayed due to manufacturing and testing lead times. Installation of the new system began in Q4 2024 and was completed in Q3 2025.

Summary of Related CIs +/- 2 years: Pursuant to Section 11.2 of the CEJC, related CIs for Transmission projects include "work completed on the same asset class (Padmount transformers, Breakers, etc.) or in the same location (feeder, Transm...

AI summary The summary outlines related Capital Improvement (CI) projects for Transmission under the CEJC, focusing on work on similar asset classes or locations. No projects are listed for years 2023 to 2027, and the depreciation class for Transmission Plant – Overhead Conductor and Devices is noted.

Why do this project now? The original damper system that was repaired where there were damages on an interim basis in Q3 2022 has reached its end-of-life, and without mitigation the conductor is at risk of damage from ongoing aeolian vibra...

AI summary The original damper system repaired in Q3 2022 has reached its end-of-life, increasing the risk of conductor damage from aeolian vibration. Immediate remediation is required to prevent conductor failure, which could pose a public safety risk and impact system operations as part of the Cape Breton Export Corridor.

Document No: XXX-XX-XXXX-XXXX Project Cost Estimate Input Checklist and Maturity Matrix Transmission Line Infrastructure Required fields: Estimate Classification Started or Preliminary Class 5 Class 4 Class 3 Class 2 Class 1 Defined or Com...

AI summary The document presents a checklist and maturity matrix for estimating the cost of transmission line infrastructure projects. It outlines different classification levels and percentages of completion for various project phases, indicating the maturity of cost estimates.

Inclusions For the purposes of this document, the term power transmission line infrastructure industries is assumed to include greenfield or brownfield sites for overhead, buried and submarine transmission of electrical power in the infras...

AI summary The document defines power transmission line infrastructure industries, including greenfield and brownfield sites for overhead, buried, and submarine transmission. It excludes power supply, distribution, generation facilities, and substations, noting that these are covered in other regulatory proceedings.

2.0 REFERENCES - [0] Interim report Oct 2021, Assessment of the 230 kV Canso strait crossing, David G. Havard Ph.D., P.Eng. - [1] Interim report on June 13, 2023, drone-based survey of nova scotia power's L7005 345 kV Canso strait crossing...

AI summary This section lists references to various technical reports and studies related to the 345 kV Canso Strait crossing project, including interim drone-based surveys and engineering assessments conducted by multiple experts and organizations.

2024 Inspection & Repair In May 2024, a drone inspection was completed. This identified no broken strands and no new significant damage to the conductor. However, there is some residual conductor damage remaining from 2023, the remaining S...

AI summary In May 2024, a drone inspection found no new significant damage but identified residual conductor damage from 2023. In July 2024, a tower climbing inspection found minor issues, including a damaged tower member. Plans are in place to address remaining conductor damage and install new dampers and Air Flow Spoilers before winter 2024/25.

10.0 TOWER ASSESSMENT Due to the additional weight of the proposed dampers and AFS, the impact on the towers, foundations and insulator assemblies needs to be studied. NSPI has engaged CIMA+ to complete this study as part of their tower as...

AI summary The document discusses a tower assessment conducted by NSPI with CIMA+ to evaluate the impact of additional weight from dampers and AFS on suspension towers 730 and 731. The study concluded that the towers can accommodate the additional load without compromising structural integrity, with minor increases within acceptable limits.

12.0 NEXT STEPS - Share damage repair procedure (as detailed in Section 5.0). - Share updated damper and AFS placement charts. - Procure cold galvanizing spray. - Procure gritted inhibitor grease. - Coordinate vibration and galloping monit...

AI summary The document outlines next steps for repair and installation procedures, including damage repair, procurement of materials, monitoring device installation, and post-repair assessments. It also mentions coordination with various entities and the use of specific technologies for inspection.

- Similar mitigation measures were applied to an equivalent L8004 span located adjacent to the L7005 span and were found adequate to protect the long crossing span against vibration and galloping. REDACTED (CONFIDENTIAL INFORMATION REMOVED...

AI summary Similar mitigation measures were applied to an equivalent L8004 span adjacent to the L7005 span and were found adequate to protect the long crossing span against vibration and galloping.

REDACTED CI C0044172 Attachment 1 Page 18 of 247 REDACTED (CONFIDENTIAL INFORMATION REMOVED) Canso Strait 230 kV Crossing Assessment Photos of the damper status in 2019 Photos of the damper status in 2021 A complete listing of these docume...

AI summary The document discusses the assessment of the Canso Strait 230 kV Crossing, highlighting missing information such as installation reports, maintenance records, service outage data, and weather records. Additional verbal information from Nova Scotia Power staff was used in the report.

BACK SPAN CONCERNS This discussion has focused only on the main span. Vibration of conductors such as experienced on this crossing is not limited to a single span. The motions are fed through the suspension clamps to the adjacent span that...

AI summary The discussion highlights concerns regarding the vibration of conductors on the new Canso Strait 230 kV crossing, emphasizing the need to inspect back spans and adjacent structures for damage. It also critiques Salvi's new damping scheme for being insufficient in frequency range and suggests using airflow spoilers from the old crossing for better protection.

7. SHORT TERM RECOMMENDATIONS - ❖ Review status of back spans Add damping if damage is found - ❖ Repair known damage to conductor with reinforcing layer - ❖ Locate and install dampers for use over arm rods - ❖ Inspect tower arm members for...

AI summary The short-term recommendations focus on inspecting and repairing infrastructure, including checking for damage, reinforcing conductors, installing dampers, and setting up monitoring systems to ensure the safety and reliability of the power grid.

8. INTERMEDIATE TERM RECOMMENDATIONS ❖ Get help from ZTTcable or Statnett to design alternative long term damping schemes for main span REDACTED CI C0044172 Attachment 1 Page 44 of 247 Canso Strait 230 kV Crossing Assessment - Consider dam...

AI summary The text outlines intermediate-term recommendations for addressing damping and structural integrity issues in the Canso Strait 230 kV Crossing, including testing alternative damping schemes, procuring better suspension clamps, and using air flow spoilers.

10. REALLY LONG TERM CONSIDERATIONS (IF ALL ELSE FAILS) - \ Replace conductor with twin or triple bundle with smaller subconductors - \ Replace conductor with self-damping conductor - ❖ Install connections for a snow and ice melting loop u...

AI summary The section outlines long-term considerations for infrastructure replacement, including conductor upgrades, snow and ice melting systems, and under-sea cable installation, as contingency measures if other options fail.

REDACTED CI C0044172 Attachment 1 Page 50 of 247 APPENDIX 1 DOCUMENT LIST DOCUMENT FILE NAME AND DATE DOCUMENT TITLE AND AUTHOR SUMMARY OF CONTENTS AUTHOR'S COMMENTS OVERALL DESIGN H349324-001-95-122-0001 — Design Bases.PDF 2016-02-12 Desi...

AI summary The document lists several technical documents related to transmission line design and climate risk analysis for Nova Scotia Power Inc. (NSPI). The design basis document outlines criteria for materials and electrical capabilities, while the climate risk analysis report examines long-term climate risks for NSPI assets, though its utility for current issues is questioned.

EXECUTIVE SUMMARY L7005 345 kV line crossing the Canso Strait is a key link in a system of delivery of power from Labrador to load centers in Canada and USA. Due to its history of weather induced damage, the line was surveyed in June 2023...

AI summary An inspection of the L7005 345 kV line crossing the Canso Strait was conducted in June 2023 using drone technology. The line is generally in good condition, though some dampers show signs of vibration or galloping damage, particularly near Tower 731. The report recommends focused monitoring on the Cape Breton Island end and suggests a thorough inspection of Tower 731 bolts.

6. RECOMMENDATIONS - ❖ Vibration recording, video cameras and weather monitoring should be at the Cape Breton end of the span. - ❖ The cause of the weight falling off the PLP-Helix damper should be investigated. - ❖ All new Helix dampers s...

AI summary The recommendations focus on safety and monitoring measures for the Canso Strait 345 kV Crossing. These include vibration recording, video monitoring, inspection of dampers and towers, and ongoing data review to ensure structural integrity and performance.

REDACTED CI C0044172 Attachment 1 Page 90 of 247 REDACTED (CONFIDENTIAL INFORMATION REMOVED) REDACTED CI C0044172 Attachment 1 Page 91 of 247 200, 1290 - 91 Street SW Edmonton, AB, Canada T6X OP2 F: 780.481.1373 T: 780.960.1950 Based on th...

AI summary The document recommends a thorough climbing inspection of bolts, including checking and marking their torque, and adding washers to suspension insulator hardware bolts to reduce wear and bending.

Canso Strait 345 kV Crossing: Drone Inspection May 2024

AI summary The text references a drone inspection of the Canso Strait 345 kV Crossing conducted in May 2024, indicating an activity related to infrastructure monitoring or maintenance.

1. Introduction An earlier report gave a detailed description of the Strait of Canso crossing, the technical problems and damage due to vibration and galloping and included suggestions for remedial action [1]. In the intervening year, dama...

AI summary This report details the results of a drone inspection of the 345 kV conductor crossing in the Strait of Canso in May 2024. Minor damage was observed, and recommendations include repair of conductor damage and early installation of vibration and galloping controls on all six phases.

8. Conclusions - ❖ The line has survived the past winter with far less damage than in previous winters. - ❖ The photos show a few surface marks where dampers had been installed. - ❖ There is some minor conductor damage from previous damper...

AI summary The document discusses the condition of the Canso Strait 345 kV power line after a winter, noting minimal damage despite previous concerns. Photos show some surface marks and minor conductor damage, with greater damage observed at the Cape Breton Island end. The condition of the conductors across the main span remains unknown.

9. Recommendations - ❖ The main span needs to be surveyed or photographed to determine whether there is a need for any repairs before the new vibration and galloping hardware is installed. - ❖ Any vibration recording, video cameras and wea...

AI summary The recommendations outline procedures for inspecting and monitoring the Canso Strait 345 kV power line, including surveys, vibration monitoring, drone inspections, and regular site visits by engineers to ensure the safety and integrity of the infrastructure before the winter of 2024.

NOMENCLATURE Single Support and Double Support Length : Identified by "S" and "D" appearing in the length column on the catalog page. Should the maximum distance between tied supports exceed 12 inches on double crossarm construction, consu...

AI summary The text provides technical specifications for conductor supports, including single and double support lengths, rod diameter, number of rods per set, center mark, color coding, identification tape, and thermal ratings for suspension clamps and conductor repairs.

A second 345 kV crossing, designated L7005, was built in 2017 to connect hydroelectric power from Labrador to Nova Scotia, necessitating high reliability. Despite being equipped with vibration dampers, this new line also suffered conductor...

AI summary A second 345 kV transmission line, L7005, built in 2017 to connect Labrador to Nova Scotia, faced conductor damage due to wind-induced vibrations. Remedial actions, including the installation of PLP-Helix dampers and air flow spoilers, were delayed until late 2022. AAB Engineering is modeling the effects of these measures on the line's suspension span to ensure reliability.

ASSUMPTIONS AND EXCLUSIONS - The weight of the airflow spoilers was determined based on a 60mm Maximum Radial Ice load, consistent with the original crossing design. The weight of the dampers was sourced from the PLP specification sheet. -...

AI summary The text outlines assumptions and exclusions related to the design and installation of airflow spoilers and dampers on a 1445m suspension span. Calculations were made based on PLP specifications, with adjustments made to the number of spoilers and dampers due to technical constraints.

RESULTS A clearance comparison was conducted with and without the addition of airflow spoilers (AFS) and dampers. The resulting clearance, measured from the centerline after installing the AFS and dampers, is presented in the table below....

AI summary A clearance comparison was conducted with and without airflow spoilers (AFS) and dampers, resulting in a reduction of approximately 6.67 meters. An inconsistency was found between the 'Asbuilt' PLS-CADD model provided by NSPI and the original measurements.

RECOMMENDATIONS - ➤ It is recommended that a detailed analysis of the towers and foundations be conducted following the installation (if possible, prior to installation) of the airflow spoilers (AFS) and dampers, accounting for the additio...

AI summary The recommendations emphasize the need for a detailed analysis of towers and foundations after installing airflow spoilers and dampers, addressing a design discrepancy in the L7005 crossing span, and noting positive outcomes from similar installations on the L8004 span.

Current Projects - 1) Improved alignment editing including rubber band lines to show what alignment will look like after PI add/move/delete is done. Also added option to heave ahead/back structures should stay anchored to current position...

AI summary The document outlines current projects focused on improving alignment editing, structure integration, and structure spotting and wire stringing capabilities in software tools used for power line design and management.

APPENDIX G – CANSO CROSSING PERMIT DRAWING (CURRENT VS ESTIMATED)

AI summary Appendix G presents a comparison between the current and estimated CANSO Crossing Permit drawing, likely related to infrastructure planning or regulatory compliance.

L7005 Tower Inspections Summary Document Canso Crossing REDACTED CI C0044172 Attachment 1 Page 184 of 247 Nova Scotia Power Inc. L7005 Tower Inspections Canso Crossing Inspection completed July, 2024

AI summary This document provides information on the inspection of the L7005 tower at the Canso Crossing, conducted by Nova Scotia Power Inc. in July 2024. The inspection is part of a regulatory process related to infrastructure maintenance.

REDACTED CI C0044172 Attachment 1 Page 185 of 247 Nova Scotia Power Inc. L7005 Tower Inspections Canso Crossing

AI summary This document page from a Nova Scotia regulatory proceeding includes a redacted section referencing 'Nova Scotia Power Inc. L7005 Tower Inspections Canso Crossing,' suggesting it involves infrastructure inspection activities related to a power tower at Canso Crossing.

Scope Inspection of towers 729, 729A, 730, 731, 732 and 732A was completed during July 2024. The inspection followed the direction of document "Engineering Work Package – L7005 Inspection Document" which was supplied by NSPI. The inspectio...

AI summary A structural inspection of towers 729, 729A, 730, 731, 732, and 732A was conducted in July 2024 following the 'Engineering Work Package – L7005 Inspection Document' provided by NSPI. The inspection included visual and climbing assessments to identify structural defects and determine maintenance priorities.

Block pattern cracking The main issue identified during the inspections was that several foundations had cracking and concave patterns, which looked to be in the shape of the installed rebar. This pattern was more evident in certain founda...

AI summary During inspections of foundations, cracking and concave patterns resembling installed rebar were identified, particularly in some foundations. This issue should have been detected earlier and is not new.

TECHNICAL NOTICE NT-230424-1 VIBRATION DAMPER PLACEMENT Rev. Description Date (dd/mm/yy) 1 Initial version 23/04/24 2 Revised span lengths 2/08/24 VIBRATION DAMPER PLACEMENT CHART NOVA SCOTIA CANSO STRAIT CROSSING L7005

AI summary This technical notice outlines the placement of vibration dampers on the Nova Scotia Canso Strait Crossing L7005, with revisions dated 23/04/24 and 2/08/24. The notice includes a chart detailing span lengths and revisions.

CI C0044172 – L7005 Canso Crossing Vibration Mitigation (NSEB M12843) NSPI Responses to Nova Scotia Energy Board Information Requests 1 Request IR-2: 2 3 Attachment 1, p.15 to p.88, the Havard Engineering report, is marked as a draft. Plea...

AI summary The Nova Scotia Energy Board requested clarification on the status of the Havard Engineering report and details about work performed under the Canso Crossing Vibration Mitigation project. NSPI confirmed the report is final and provided a breakdown of actions taken in 2022 and 2023, including inspections, installations, and engineering reviews.

in the original engineering design. The existing vibration control dampers had experienced fatigue-related deterioration and were no longer providing adequate long-term protection for the conductors. NS Power retained external experts to a...

AI summary NS Power identified deterioration in vibration control dampers on the L7005 transmission line, leading to potential conductor damage. External experts recommended mitigation measures, which NS Power implemented between 2022 and 2024. The Board recognizes L7005 as a critical asset, with conductor failure posing public safety risks and disrupting power flow through a key transmission corridor.

asset in Nova Scotia's electricity system. A conductor failure at the Strait of Canso crossing could create public safety risks and interrupt the power flow through an important transmission corridor. The evidence established that the proj...

AI summary The Board finds that the L7005 Canso Crossing Vibration Mitigation Project was necessary due to conductor and damper deterioration, supported by external engineering reviews. The project's cost of $2,431,095, including third-party consulting and installation, is considered justified.