Topic:"Power Infrastructure" in M12696

LO WER CHURCHILL PROJECT ctor/Su EPC(M) Document Number: 505573-480A-47ER-0017 Issue Number: 00

AI summary The document appears to be a technical or engineering document related to the Churchill Project, possibly involving electrical infrastructure or power generation. It includes an EPC(M) document number and an issue number, indicating it may be part of a larger project documentation set.

hem operational is deemed too expensive. Nonfederal public owners (publicly owned utilities, state agencies, municipalities, and cooperatives) added the remaining 28% of new capacity to their plants. The Northwest and Southwest display the...

AI summary The text details new project developments and capacity changes from 2010–2019, emphasizing regional project distribution (Northwest, Southwest), types of installations (conduits, NPDs, NSDs), and specific examples like Smithland NPD and Pueblo Dam NPD. It highlights 583.1 MW in capacity additions, 215.8 MW in downrates, and retirements impacting installed capacity.

CALLIGAN CREEK The Calligan Creek hydropower plant started operation in 2018 in King County (Washington). The developer of this NSD, PUD No.1 of Snohomish County, submitted a license application in August 2013, and the Federal Energy Regul...

AI summary The Calligan Creek hydropower plant, a 6-MW run-of-river facility in Washington, began operation in 2018. Developed by PUD No.1 of Snohomish County, it received its FERC license in 2015 after construction started in 2014. The project includes a Pelton turbine, weir, fish ladder, and grid interconnection.

JAMES W. BRODERICK PLANT AT PUEBLO DAM In 2011, the Southeastern Colorado Water Conservancy District submitted a proposal to develop hydropower at Pueblo Dam in response to a call for applications by the U.S. Bureau of Reclamation (Reclama...

AI summary The Southeastern Colorado Water Conservancy District developed a 7.01 MW hydropower facility at Pueblo Dam after securing a lease of power privilege (LOPP) from the U.S. Bureau of Reclamation in 2017. The $20.2 million project, 85% funded by a low-interest loan, began operations in 2019 and includes 30-year power purchase agreements (PPAs) with local utilities.

FULTON HYDROPOWER PROJECT The Fulton hydropower project is in Custer County (Idaho). It has a Pelton-Twin Jet turbine with a nameplate capacity of 0.406 MW. The developer applied to FERC for qualifying conduit determination in December 201...

AI summary The Fulton Hydropower Project in Idaho, with 0.406 MW capacity, faced permitting delays until 2018 due to BLM authorization. FERC approved the project in 2015, and construction resumed in 2018, completing in 2019. Reclamation's simplified LOPP process accelerated permitting for similar projects.

RED ROCK HYDROELECTRIC PROJECT The Red Rock project in Marion County (Iowa) adds 36 MW of hydropower generation capability to the U.S. Army Corps of Engineers-owned Red Rock dam. FERC issued the license for this project to the Western Minn...

AI summary The Red Rock Hydroelectric Project in Iowa adds 36 MW of hydropower capacity to the U.S. Army Corps of Engineers' Red Rock dam. Licensed by FERC in 2011 to the Western Minnesota Municipal Power Agency, construction faced delays due to 2019 flooding but was completed in 2020, with commercial operation expected in 2021.

13 Lower Klamath in Oregon and California (169.6 MW), Eagle and Phenix in Georgia (27.7 MW), Morris Shepard in Texas (22.5 MW), Borel in California (12 MW), and Jackson Bluff in Florida (12 MW). 14 On September 23, 2016, PacifiCorp and the...

AI summary The text lists several hydroelectric projects with their capacities and locations, including Lower Klamath (Oregon/California), Eagle and Phenix (Georgia), Morris Shepard (Texas), Borel (California), and Jackson Bluff (Florida). It also details PacifiCorp and Klamath River Renewal Corporation's joint application to transfer ownership and surrender the license for the Lower Klamath project in 2016.

ess, projects that have obtained a FERC preliminary permit, and projects with an expired preliminary permit but that have submitted a Notice of Intent to file a license or a draft license application. \ \ Pending License includes projects...

AI summary The text categorizes U.S. hydropower projects by license status (pending, issued) and discusses regional distribution, noting that 87% of conduit projects are in the Northwest/Southwest, while 92% of NPD projects are in other regions. Pennsylvania, Kentucky, and Louisiana lead in proposed capacity, with Alaska hosting most NSD projects.

oth PSH units and a desalination facility. Others proposed PSH in states that have rarely been considered for this type of storage facility in the past decade such as the Freestone project in Georgia. No new license applications were submi...

AI summary The U.S. PSH development pipeline includes ongoing projects like Mineville (240 MW), Lake Elsinore (500 MW), and Pearl Hill (5 MW), with FERC managing environmental reviews. Two projects were dropped due to licensing issues: Parker Knoll (Utah) and Hurricane Cliffs (Arizona). Washington State provided water quality certification for Pearl Hill, while FERC delayed Lake Elsinore's acceptance until 2019.

nia), or sale revenue (e.g., Brazil) (Pineau et al. 2017). In India, the royalty is typically the free delivery of a percentage of the power generated by the plant to the state in which it is located. The duration of the license or concess...

AI summary The text compares global hydropower licensing practices, noting differences in duration between government-owned and private projects. Government projects often have indefinite licenses, while private ones in the U.S. typically have 40-year FERC licenses. Recent trends show some countries shortening license terms (e.g., UK, France) to enhance regulatory flexibility.

008 is one of the key drivers for the generally low wholesale electricity price levels in Figure 23. In the Pacific Northwest and the SPP territory, large growth in installed wind capacity has also contributed to the low prices. The cost-b...

AI summary Federal hydropower prices show less year-to-year variation than wholesale market prices. Eastern PMAs (SWPA, SEPA) have higher average rates than wholesale prices since 2011, while BPA and WAPA align with regional prices. Revenue variability for SWPA and SEPA is greater due to factors like rainfall dependence and drought resilience. PMAs are considering ISO/RTO market participation to adapt to changing market structures.

on submission. From July 2019 to the end of March 2020, only one license application eligible for the new process was submitted to FERC, and the developer did not request to use the expedited process. In 2019 as part of AWIA's mandate, FER...

AI summary The text discusses FERC's expedited licensing process, AWIA's 2019 reports on federal non-powered dams (NPDs) and closed-loop pumped storage hydropower (PSH), and EPA's 2019-2020 NOPR updating Section 401 water quality certification (WQC) rules to improve transparency and efficiency in FERC licensing. The NOPR addressed ambiguities in WQC scope, conditions, and timelines after stakeholder feedback.

The importance of the line is determined based on its electrical capacity (MW transfer), the consequences of the loss of the line, and the impact of the loss of the line on the overall BEPS reliability. Therefore, the line design engineer...

AI summary The document discusses balancing power line capital costs with reliability and outage risks using probabilistic models. Higher return periods (e.g., 500 years) reduce failure probabilities but increase costs, necessitating trade-offs against expected energy not supplied (EENS) and outage costs. Studies by Haldar and CEATI International emphasize optimizing design parameters and generation support for reliability.

5.1 LIL Modelled as a Series System The LIL is modelled as a series system and the system acts as a "weak link" because the system fails and may lose its functionality if one of the line element fails. The series system model is described...

AI summary The Labrador Island Transmission Link (LIL) is modeled as a series system where failure of any component leads to system failure. Reliability is analyzed using N-1/N-2 criteria, with equations for upper and lower bounds of failure probability based on Cornell (1967). Mechanical failures can cause prolonged outages despite electrical redundancy.

7.2 Uncertainty on the topographical effect on LIL design Lines are normally designed for two primary classes of loads (1) reliability class and (2) security class. Under reliability class of loads, structures and major line components are...

AI summary The text discusses the impact of topographical effects on the design of Long International Line (LIL) transmission systems, highlighting how wind speed-up effects in hills, valleys, and mountains can significantly increase wind and combined wind-ice loads on support structures. Current design standards like CSA 60826-10 do not account for these topographic effects, which can lead to increased risk of failure. The study by Bitsuamlak et al. (2015) recommends assessing these effects for specific terrain configurations.

- A comparative evaluation of Combined loads using Environment Canada model data and EFLA data versus combined wind and ice load data based on CSA 60826-10 should be done and if it is shown there is a significant gap, this needs to be clos...

AI summary The text recommends evaluating load data methods for combined wind and ice loads, suggesting direct use of Environment Canada and EFLA data over CSA 60826-10 probability-based methods due to potential overestimation. It also emphasizes conducting progressive collapse analyses on suspension towers using FEM programs, considering factors like terrain roughness and test data to improve reliability assessments and failure rate calculations under ULS.

NSPML Responses to Bates White Information Requests 1 Request IR-16: 3 Please refer to Exhibit N-1, Attachment 1, page 30 lines 17-18 4 a) Is it the Witness's position that the software issues experienced by the LIL to date are 5 "minor"?...

AI summary The document discusses NSPML's response to information requests regarding software issues experienced by the Labrador Island Transmission Link (LIL). The response clarifies that Ms. Powers' testimony refers to general high-voltage transmission projects, not LIL specifically, and notes that such operational and commissioning issues are typically not made public. It also mentions that large infrastructure projects often face challenges such as delays and cost overruns.

Table 4: EqFOR Overview (%) 1-Jan-2024 to 1-Jan-2025 to Base Planning Analysis Range of Planning Analysis Asset Type Measure 31-Dec-2024 31-Dec-2025 Value Values LIL EqFOR 3.37 0.9616 5 1–10 15 The resource planning model does not differen...

AI summary Table 4 presents an overview of the Equivalent Forced Outage Rate (EqFOR) for the Labrador Island Transmission Link (LIL) from 2024 to 2025, showing a decrease in the EqFOR value from 3.37 to 0.9616, with a base planning analysis value of 5 and a range of 1–10. It notes that the resource planning model does not differentiate between DAFOR and DAUFOP.

Appendix A: Summary of all Failure Investigation Recommendations Appendix B: LIL Engineering Study – Mid-Span Structure Addition Report Appendix C: LIL Engineering Study – A1 Electrode Suspension Assembly Appendix D: LIL Engineering Study...

AI summary The document includes appendices summarizing failure investigation recommendations and engineering studies related to the Labrador-Island Link (LIL), including mid-span structure additions, electrode suspension assemblies, and cost estimates for wood poles and mid-span structures.

Table 3: Investigation Reports Report Title Document Number Failure Investigation Report – TL3501/2 Tower and Conductor Damage Icing Event January 2021 in Labrador7 ILK-EG-ED-6200-TL-H15-0001-01 L3501/2 Failure Investigation – OPGW Tower P...

AI summary This section lists several failure investigation reports related to icing events and structural failures on the Labrador-Island Link (LIL) transmission line, along with their document numbers. It also mentions a capital project related to LIL engineering studies scheduled for 2024–2025.

5.1.2 Remove Electrode Line Conductor from Towers and Install on Wood Poles - This alternative would remove the EL from towers and install on a wood pole line. In addition to - reducing the ice loads on the towers, there are several other...

AI summary This alternative proposes moving the electrode line from towers to wood poles, reducing ice loads and facilitating repairs. However, it requires a new right-of-way, incurs higher costs (~$101,562 per tower), and may face challenges with obstacles like waterbodies. The wood pole line has shorter spans and may not handle elevation changes effectively.

Summary of all Failure Investigation Recommendations Document Number Report Title Recommendation Status Comments Addressed Redesign completed by consultant in 2023. A contractor was engaged to reinforce the top plate connection of the 61 c...

AI summary The document outlines recommendations from a failure investigation related to OPGW (Optical Power Ground Wire) on towers, including reinforcing top plates on critical tower types. Redesign and reinforcement work has been completed or is ongoing, with some installations expected to be finished in 2026. The project is part of a broader strengthening capital initiative.

3.6 S1- 307 (308) Tower S1-307 (308) has a large span imbalance due to both AS and BS running uphill relative to increasing stationing. This tower configuration shows local peak overstresses, in addition to overstresses in the electrode cr...

AI summary Tower S1-307 (308) exhibits structural stress issues due to span imbalance caused by AS and BS running uphill relative to increasing stationing. Local peak overstresses are observed in electrode cross arms and cage diagonals, attributed to electrode wire tension.

3.1 EXISTING INSULATION LENGTH (ELECTRODE AND POLE) The electrode insulator length on the tower type A1 electrical clearance drawing ILK-JY-SD-6200-TL-D99-0012-01-A3 is listed as 1245 mm from string attachment point on tower to center of c...

AI summary The document compares electrode and pole insulator lengths from different drawings and models, noting discrepancies and selecting the more dimensionally certain values (1133 mm for electrode, 5562 mm for pole) for use in the report.

APPENDIX A: GALLOPING ELLIPSE RESULTS LIL Engineering Study – A1 Electrode Suspension Assembly Newfoundland and Labrador Hydro

AI summary Appendix A presents the Galloping Ellipse results, including an engineering study on the LIL's electrode suspension assembly by Newfoundland and Labrador Hydro, referenced in Figure 1.

3.0 RESULTS Finite element analysis was conducted for OPGW peak of each tower family (i.e., A2, A4, B1, and B2). Von mises stress distribution was checked for each of the 4 loading cases shown in Table 2. Stress values were compared to the...

AI summary Finite element analysis of OPGW on tower groups A2, A4, B1, and B2 showed maximum Von Mises stress below 350 MPa yield stress, except for stress concentrations due to geometry changes, which are considered negligible.

Line L3501/2 is the 350 kV HVdc overland transmission line portion of LIL traversing a distance of approximately 1,100 km through three major meteorological loading zones: average, alpine and eastern. The HVdc line has two poles, one OPGW,...

AI summary The document describes the 350 kV HVdc overland transmission line (L3501/2) of the Labrador-Island Link (LIL), which spans approximately 1,100 km through three major meteorological loading zones. The line includes two poles, an OPGW, and two electrode conductors for a portion of the line. The corridor is divided into 19 loading zones based on meteorological, pollution, and geographic factors, and eleven tower types were designed to meet specific loading requirements.

4. Summary, Conclusions, and Recommendations There have been a number of failures on the L3501/2 transmission line due to ice events over the past 4 years. The electrode crossarms and the electrode conductor are two components that are oft...

AI summary Over the past four years, the L3501/2 transmission line has experienced failures due to ice events, primarily caused by unbalanced ice loads. Removing the electrode conductor from towers and running it parallel on a wood pole line could reduce damage. Analysis shows significant benefits, especially for ice loads of 70 mm, with some sections showing greater improvements under higher ice loads.

2.0 Background - Line L3501/2 is the 350 kV High Voltage direct current ("HVdc") overland transmission line portion of the - LIL, traversing approximately 1,100 km through three major meteorological loading zones, referred to as - average,...

AI summary The document provides background on Line L3501/2, a 350 kV HVdc transmission line as part of the LIL project. It traverses 1,100 km through three meteorological loading zones, with specific tower designs and configurations, including electrode conductors and different tower types.

Top Plate Design - Analysis was completed in 2024 to determine the towers that were susceptible to top plate connection - issues due to design error. 61 A3 towers and 2 A4 towers were determined to be critical and should be - fixed as soon...

AI summary Analysis identified 61 A3 and 2 A4 towers with critical top plate design issues, requiring immediate reinforcement completed in 2024. Additional tower types (A2, A4, B1, B2) will undergo phased reinforcement starting in 2026, with completion by 2028. Engineering assessments indicate non-critical structures may only need repairs during annual maintenance if deformation occurs.

5.1.2 Remove Electrode Line Conductor from Towers and Install on Wood Poles - This alternative would remove the EL from towers and install on a wood pole line. In addition to - reducing the ice loads on the towers, there are several other...

AI summary The alternative proposes removing the electrode line conductor from towers to wood poles, reducing ice loads and facilitating repairs, but requires a new right-of-way and does not address OPGW issues. Estimated costs are around $101,562 per tower.

5.3 Scope of Work - The project scope includes procurement and installation work on a total of 309 Type A1 towers, as - follows: - Replacement of OPGW peaks, EL crossarms, and EL assemblies for 186 towers: - o 18 A1 towers from structure 1...

AI summary The project scope involves replacing OPGW peaks, EL crossarms, and assemblies on 309 Type A1 towers across multiple sections, prioritizing areas with past failures. Material procurement for reinforcement and installation on specific towers is included, with repairs deemed non-urgent but necessary for structural integrity under maximum ice loads.

- 2 There have been 10 failure events on L3501/2 over the past five years. These failures were localized - 3 issues, affecting a small number of transmission line components. Due to the importance of L3501/2 to - 4 the provincial energy gr...

AI summary Over the past five years, there have been 10 failure events on L3501/2, primarily due to overloading from ice accumulation and unbalanced ice loads. A 2024–2025 capital project addressed some recommendations, while others will be implemented in a 2026–2028 project, including tower reinforcement and conductor modifications to improve reliability and reduce ice-related failure risks.

1.0 INTRODUCTION NL Hydro has experienced several performance issues for the Labrador-Island Transmission Link, +/- 350 kV HVDC. Performance issues include the following: - · Electrode conductor failure - Electrode cross-arm structural fai...

AI summary NL Hydro's Labrador-Island Transmission Link (LIL) faces multiple technical issues, including electrode conductor failures and structural weaknesses. The memo proposes mid-span structures to reduce tower loading and improve weight span balance.

3.6 S1-307 (308) Tower S1-307 (308) has a large span imbalance due to both AS and BS running uphill relative to increasing stationing. This tower configuration shows local peak overstresses, in addition to overstresses in the electrode cro...

AI summary Tower S1-307 (308) exhibits structural stress issues due to span imbalance, electrode wire tension, and cage diagonal overstresses, raising concerns about infrastructure integrity and potential safety risks.

3.6.3 Discussion As shown in Table 13, adding a mid-span structure will slightly improve weight imbalance, but it won't be enough to avoid overstresses. This is due to the land topography at this section (towers running uphill), which intr...

AI summary Reinforcing existing towers is proposed as a practical solution to address weight imbalance caused by uphill terrain, as adding a mid-span structure only slightly improves the imbalance without resolving overstress issues.

3.7 OPTION 2 PERMISSIBLE INCREASE The tower type A1 reinforcement scope showed significant overusages in most of the electrode cross-arm members that are not easily addressed with reinforcement. For this reason, it is more economical to de...

AI summary Option 2 involves replacing cross-arms instead of reinforcing due to overusage, allowing a 325 mm permissible increase governed by wind swing cases. Additional length may be added if the climbing bolt is removed, confirmed by NL Hydro. Structural improvements and insulation adjustments are discussed.

APPENDIX C: NEW HARDWARE DRAWINGS

AI summary Appendix C presents new hardware drawings, likely related to power infrastructure projects. The content includes visual references (e.g., Figure 1 on page 102) but lacks textual details on specific components, compliance standards, or regulatory implications.

LIL Engineering Study – Calculations for OPGW Peak Reinforcement Newfoundland and Labrador Hydro Report No. ILK-TT-CD-6200-TL-H15-0002-01 TT Document Number: 705-2579500100-REP-G0003-00 July 21, 2025

AI summary Newfoundland and Labrador Hydro submitted a report (ILK-TT-CD-6200-TL-H15-0002-01) dated July 21, 2025, detailing engineering calculations for OPGW (Optical Ground Wire) peak reinforcement under the Labrador-Island Link (LIL) project. The document focuses on technical assessments for power line infrastructure reinforcement.

2.1 GEOMETERY As seen in Figure 1 below, the grey members are the existing members, while the green members represent additional steel sections to be added for reinforcement. As shown in the figure, the suggested reinforcement includes add...

AI summary The text describes structural reinforcement measures for transmission towers, including adding bent plates, back-to-back angles, and stiffeners for towers A4 and B1. Visual aids (Figures 1 and 2) illustrate the existing and proposed steel configurations for reinforcement.

LIL Engineering Study Calculations for OPGW Reinforcement Newfoundland and Labrador Hydro

AI summary The document presents engineering study calculations for OPGW reinforcement as part of the Labrador-Island Link (LIL) project by Newfoundland and Labrador Hydro (NLH). It focuses on infrastructure planning and transmission planning for power line reinforcement.

3.0 RESULTS Finite element analysis was conducted for OPGW peak of each tower family (i.e., A2, A4, B1, and B2). Von mises stress distribution was checked for each of the 4 loading cases shown in Table 2. Stress values were compared to the...

AI summary Finite element analysis of OPGW on tower families A2, A4, B1, and B2 showed maximum Von Mises stress below 350 MPa, with exceptions due to stress concentration from sharp edges or geometry changes, which are deemed negligible.

Wood Pole and Mid-Span Cost Estimates Summary

AI summary This document summarizes cost estimates for wood poles and mid-span components in a Nova Scotia regulatory proceeding. However, the provided text lacks specific details, so the summary reflects the general context of the proceeding.

Appendix F Analysis Removing the Electrode Conductor from L3501/2 Analysis of Removing the Electrode Conductor from L3501/2 May-2025

AI summary This document outlines the analysis of removing the electrode conductor from L3501/2 (Pole 1 and Pole 2 of the line) as part of a regulatory proceeding in May 2025, focusing on technical and infrastructural considerations.

Line L3501/2 is the 350 kV HVdc overland transmission line portion of LIL traversing a distance of approximately 1,100 km through three major meteorological loading zones: average, alpine and eastern. The HVdc line has two poles, one OPGW,...

AI summary The 350 kV HVdc transmission line (L3501/2) of the Labrador Island Link (LIL) spans approximately 1,100 km through three major meteorological loading zones. It includes two poles, an OPGW, and two electrode conductors. The line uses 11 tower types designed for specific wind and ice loads, with sections using wood poles and a separate right of way for electrode conductors.

structure 1209 to 1229 (Figure 8) have less failures than all other section. Under balanced ice loading, between 0% and 43% of the structures with the electrode in the section will fail with 60 mm and 70 mm of ice load, respectively. Witho...

AI summary Analysis of structural failures in power line sections 1209-1229 under balanced and unbalanced ice loads (UBL) shows that removing electrodes significantly reduces failure rates, particularly under UBL with 80mm ice. Structures without electrodes exhibit minimal failures on EL1, EL2, P1, P2, while failures on OPGW (G) remain high but lower than with electrodes.

Appendix A NL Hydro Transmission Line Failure (Conductor EL-1 and EL-2 at Suspension Tower 1225) report by Wayland Engineering Ltd.

AI summary Report on NL Hydro's transmission line failure involving conductors EL-1 and EL-2 at Suspension Tower 1225, prepared by Wayland Engineering Ltd.

Table of contents Executive summary ii Figure D-1: SEM backscatter image of a representative example of a zinc coated steel reinforcing strand for the intact conductor. The image shows the significant variation in the thickness of the zinc...

AI summary The document contains a table of contents and several figures and tables related to the inspection and analysis of a failed conductor following an incident on March 30, 2024. The content includes SEM images of zinc-coated steel reinforcing strands and tables summarizing damage and wire strand diameter measurements.

a second representative example of the aluminum strand fusing observed (subsequent to conductor disassembly). Figure 2-21: Top-down view of the lower circumferential surface of the wire clamp associated with conductor EL-2. The image shows...

AI summary The text describes the examination of failed conductor EL-2, highlighting localized brinelling observed on a wire clamp. Figures 2-21 and 2-22 illustrate the damage morphology, focusing on the lower circumferential surface of the clamp and a close-up sectional view of the brinelling. The analysis is part of a technical investigation into conductor failure.

3 EVALUATION OF THE CONDUCTOR DIMENSIONAL AND MECHANICAL PROPERTIES The intervals of conductor fixed within the insulator clamps of the failed EL-1 and EL-2 sections were dissembled in order to conduct a dimensional characterization of the...

AI summary The evaluation involves measuring wire strand diameters and zinc coating thickness using SEM on failed and intact conductors from NL Hydro, along with a uniaxial tension test to assess tensile strength of the Grackle ACSR 54/19 conductor.

nerated by the test procedure. Section 4.1 and Section 4.2 include the fractographic images for the fractured aluminum wire strands from conductor EL-1 and conductor EL-2 for comparison, respectively. It should be noted that the coil diame...

AI summary The uniaxial tension test on a used conductor from NL Hydro revealed potential issues with coiling diameter and clamping methods, which may have introduced plastic strain and reduced breaking strength. The conductor's coil diameter was below recommended standards, and ends were fixed with electrical tape instead of mechanical clamps.

4.2 Metallurgical Characterization of Failed Conductor EL-2 Samples from several of the outer aluminum wire strands, which included the fracture surface associated with the strand failure were removed from conductor EL-2. The samples were...

AI summary This section discusses the metallurgical analysis of failed conductor EL-2, focusing on the fracture surfaces and fusing between strands. SEM and EDS analyses revealed ductile fracture mechanisms and the presence of zinc from steel reinforcing strands, which contributed to the failure.

5.2 General Discussion The physical, chemical and metallurgical evidence indicates that the mechanism responsible for the failure of conductors EL-1 and EL-2 at Tower #1225 is consistent with ductile limit load fracture of the aluminum con...

AI summary The failure of conductors EL-1 and EL-2 at Tower #1225 is attributed to ductile limit load fracture caused by excessive ice accumulation (100–125 mm) and wind speeds (70–60 km/h), exceeding design criteria. Cyclic loading from wind-induced galloping likely contributed, with steel core migration reducing conductor strength. Radiographic imaging is suggested for detecting core migration.

NSPML Responses to Industrial Group Information Requests 1 Request IR-10: 11 (e) Please confirm that the LIL was always intended, from the time of its 12 commissioning, to have a rated capacity of 900 MW. 13 (f) Please confirm the capacity...

AI summary NSPML responds to Industrial Group's information requests regarding the Labrador-Island Link (LIL) capacity and operational issues, including the rated capacity, ramp-up schedule, and resolution of a ground potential rise (GPR) issue that caused equipment failures during testing.

c with accounts of detailed technical issues, problems, and fixes. However, the entire community of investors, grid operators, manufacturers, installers etc. would profit from an openhearted dialogue. This book aims at conveying a basic kn...

AI summary The preface of a technical book on submarine power cables emphasizes the complexity of the subject, the collaborative effort in its creation, and the author's acknowledgment of colleagues and family. It highlights the vast knowledge required and the limitations of individual comprehension.

Chapter 1 Applications of Submarine Power Cables

AI summary Chapter 1 provides an overview of submarine power cable applications, likely focusing on their role in energy transmission, infrastructure planning, and regulatory considerations within Nova Scotia's electricity sector.

1.1 Power Supply to Islands Islands located closely to the mainland can be connected to the mainland grid by submarine power cables. This is normally done with medium-voltage a.c. cables (≤52 kV) and a transmission power of 10–30 MW per ca...

AI summary The text discusses connecting islands to mainland grids via submarine cables, highlighting AC and HVDC technologies, examples like Vancouver Island and Gotland, and challenges of long-distance connections. It emphasizes cable redundancy, historical case studies, and the role of submarine cables as backup power.

2.1 The Conductor The current-carrying conductors of submarine power cables are made of copper or aluminium. Even though copper is more expensive than aluminium in relation to the current-carrying capability, the majority of submarine powe...

AI summary The text discusses conductor materials for submarine power cables, comparing copper and aluminium. Copper is preferred for smaller cross-sections and corrosion resistance, but aluminium is used in cost-sensitive scenarios. Hybrid approaches (e.g., Estlink project) combine materials based on route conditions. Market volatility and corrosion risks influence material selection.

2.1.1 Solid Conductor The conductor consists of a single massive wire. This design is used for cross sections up to about 400 mm2. The manufacturing is easy and the conductor has 2.1 The Conductor 11 Fig. 2.1 Conductor design naturally goo...

AI summary Solid conductors, used for cross-sections up to 400 mm², offer ease of manufacturing and natural water tightness, crucial for submarine cables. However, insulation shrink-back issues may occur, mitigated by surface treatments like knurling. They are unsuitable for high-voltage cables (>150 kV) but used in low-voltage multi-core cables.

2.1.4 Hollow Conductors for Oil-Filled Cables Oil-filled or fluid-filled cables (also called LPOF, low-pressure oil-filled, or SCFF, self-contained fluid-filled) are filled with low-viscosity oil. They contain a central duct in the conduct...

AI summary Hollow conductors in oil-filled cables use low-viscosity oil and central ducts for thermal expansion. Designs include metallic helices to prevent conductor collapse and profiled wires forming self-stabilizing vaults. Grooved surfaces facilitate oil flow between insulation and ducts.

2.2 The Insulation System The cable insulation provides an effective barrier between potential surfaces with an extreme potential difference. It is of utmost importance that the insulation system is absolutely clean and even. Furthermore,...

AI summary The insulation system for submarine cables must be clean, mechanically robust, and resistant to temperature and aging. Over 150 years of development have led to the use of a few modern insulation materials for medium and high voltage cables, with detailed properties outlined in Chapter 3.

rtical line prevents also the forming of excentrical insulation under the influence of gravity. In less common processes the cross-linking can be achieved by silane agents or electron ray irradiation. XLPE is a first-choice insulation mate...

AI summary Cross-Linked Polyethylene (XLPE) was historically problematic due to water-treeing but has improved through advanced manufacturing techniques like triple-extrusion and dry curing. Modern XLPE cables now exhibit high quality and breakdown voltage, making them the preferred insulation material for both land and submarine power cables.

2.2.3 Conductor and Insulation Screen If we would extrude the XLPE insulation layer right away onto the conductor, the grooves, ridges and irregularities of the conductor would generate local stress enhancement and would reduce the dielect...

AI summary The text discusses the importance of semi-conductive XLPE layers in cable insulation to prevent stress enhancements and ensure dielectric strength. It explains manufacturing methods, material properties (e.g., carbon-black content), adherence to international standards (CENELEC, AEIC, IEC), and cost considerations for thick semi-conductive layers in long cables.

have different values in other applications of insulation materials. For cable systems with varying load, a cumulative ageing calculation can take temporary thermal or electric stresses into account. Many more ageing models have been propo...

AI summary The text discusses how aging and humidity affect XLPE insulation, noting that thermal/electric stress, copper ions, and humidity reduce dielectric strength and accelerate aging. It highlights design strategies for submarine cables, such as polymeric layers and swelling tapes to manage humidity, and excludes UV/sunlight effects for submerged cables.

2.2.5 Applications of XLPE Insulation XLPE submarine cables are available for very long lengths (>50 km) in 3C fashion up to 170 kV from selected cable manufacturers. As voltage grows, the number of cable manufacturers is getting smaller....

AI summary XLPE submarine cables are available in long lengths up to 170 kV but face manufacturing limitations at higher voltages. Flexible joints for 400–500 kV XLPE cables are unavailable, complicating their use in extended sea routes due to technical constraints.

2.2.7 Other Extruded Insulation Systems Ethylene propylene rubber (EPR) is an extruded dielectric used by some manufacturers mainly for underground cables. Compared to XLPE, EPR has a rather high tanδ and ε r making it less suitable for th...

AI summary Ethylene propylene rubber (EPR) is used in underground cables but has higher tanδ and ε r than XLPE, limiting its use in high-voltage applications. The Venezia-Murano-Mestre 150 kV EPR cable (2001) and a 1963 Cross Channel HVDC PE cable are historical examples. EPR is less suitable for highest voltages compared to XLPE.

vier than oil so that the pressure balance changes in favour to the water pressure as the laying depth increases. This must be compensated for by a larger oil pressure in the land-based feeding units. The oil channel can be provided by dif...

AI summary The text discusses design considerations for paper-insulated oil-filled cables, emphasizing pressure balance, oil channel configurations in single-core vs. three-core designs, and length limitations (30–60 km) due to thermal expansion. The Möllerhöj cable is highlighted as an exception with unlimited length potential through its unique lead sheath design, though it will be replaced by mass-impregnated HVDC cables.

2.2.9 Paper-Mass Insulation for HVDC This insulation type has been used for HVDC cables since more than 100 years [23]. Mass-impregnated cables have been used for medium-voltage a.c. transmission, but today, they are only being used for su...

AI summary The text discusses the historical use and technical aspects of paper-mass insulation in HVDC cables, emphasizing their application in submarine transmission, material properties (e.g., high-density Kraft paper), and manufacturing requirements like humidity control. It highlights their reliability for high-voltage applications and long-distance transmission.

2.3 The Water-Blocking Sheath The dielectric insulation must be protected against undue water ingression to maintain the dielectric strength. Most high-voltage submarine cables have a metallic sheath to provide protection against water ing...

AI summary The water-blocking sheath protects dielectric insulation in high-voltage submarine cables from water ingress, using metallic sheaths (aluminum, lead, copper) or polymeric sheaths with water-absorbing agents. Metallic sheaths also guard against Teredo shipworms, with copper/brass tapes offering additional protection.

2.3.3 Copper Sheath Copper sheaths from welded and corrugated copper strips are sometimes used in submarine power cable applications. The corrugation machine can provide a wave structure with annular or helical gaps. For submarine cables,...

AI summary Copper sheaths in submarine power cables offer superior corrosion resistance, fatigue resistance, and pressure/bending properties compared to lead. Corrugation profiles (sinusoidal, trapezoidal) affect performance, with annular gaps preferred for water barrier effectiveness. Copper sheaths eliminate the need for separate wire screens and are suitable for dynamic cables on floating platforms due to fatigue resistance.

2.3.4 Polymeric Sheaths Polymeric cable sheaths have different functions depending on where they are located in the cable construction. A polymeric sheath usually protects the underlying lead sheath from corrosion and abrasion. For this pu...

AI summary Polymeric sheaths in cables serve protective and insulative functions, with HDPE and LDPE being common materials due to their chemical stability and cost-effectiveness. They prevent corrosion, provide water barriers, and manage voltage distribution. Materials like PVC and polyamide offer alternative properties, while PVDC shows potential for lower water vapour permeability though it's not yet used in power cables.

2.5 Outer Serving Scratches can deteriorate the anti-corrosion effect of bitumen and zinc layers. To avoid this, an outer serving protects the corrosion protection of the cable armoring during loading, laying, and burying of the submarine...

AI summary The document discusses the role of outer servings in submarine power cables, detailing their corrosion protection, material types (extruded polymeric vs. wound yarn), installation considerations (friction, markings), and challenges with bitumen-soaked inner layers. It emphasizes design choices for durability and visibility during laying and maintenance.

2.6 Three-Core Cables Modern medium-voltage submarine cables (≤52 kV) are usually designed as threecore (3C) cables with XLPE insulation. 2 The cable cores are similar to those of land cables. Many different design alternatives are used fo...

AI summary The text discusses the design and construction of three-core (3C) submarine cables for medium-voltage (≤52 kV) and high-voltage (up to 170 kV) applications. It highlights materials like XLPE insulation, water protection methods (e.g., extruded plastic sheaths, aluminium laminate), and the use of copper wire screens for fault currents. Modern 3C cables balance capacitive currents and are tailored for diverse submarine power link conditions.

t been tried yet. The reach of unrepeatered data transmission in increasing steadily. At standard data transmission rates of 5 or 10 GB/s for each fibre, repeater-less links can cover 200 km and more. In-field cables in OWP's are made as t...

AI summary The text discusses the integration of optical fibers in submarine power cables, including three-core medium-voltage cables for offshore wind parks (OWP) and single-core cables. It highlights placement methods, material considerations (e.g., stainless steel tubes, plastic sheaths), and trade-offs between fiber counts, data transmission needs, and maintenance practices.

2.10 Five Generic Cable Types The large number of different submarine power cable species and their varieties may be confusing to those not deeply involved in the subject. It is one of the main tasks of this book to create a better underst...

AI summary The text outlines five generic submarine power cable types, detailing their rated voltages, insulation materials, typical applications, and maximum lengths. It emphasizes that these cables are not standardized and often require customization based on specific project conditions, while suggesting that defining cable standards could reduce costs for redesign and testing.

References - 1. Ronström L et al. (2007). The Estlink HVDC Light- R Transmission System. CIGRÉ Regional Meeting on Security and Reliability of Electric Power Systems, June 18–20, 2007, Tallinn, Estonia. - 2. Hauge O et al. (1988). Performa...

AI summary The references section cites technical papers and patents on HVDC transmission systems, submarine cables, and power cable technologies, including works by Ronström, Hauge, and others, focusing on performance, materials, and testing methods.

3.1.1.1 Single Buried Cable For a single cable buried in homogeneous sea bottom soil at depth L the thermal resistance T 4 between the cable surface and the seafloor is: $$T_4 = \rho_T/(2\pi) \cdot \ln(2u) \tag{3.9}$$ where u = 2 L/De , re...

AI summary The section provides a formula for calculating thermal resistance in a single buried cable in homogeneous sea bottom soil, referencing IEC 60827 for more complex cases at shallower depths and citing Table 3.6 for thermal resistivity values.

3.1.2.3 Screen Losses The alternating magnetic field around the conductor generates circulating and eddy currents in the metallic screen and armoring. These currents contribute to heat generation and reduce the cable ampacity. Four differe...

AI summary Alternating magnetic fields in conductors generate circulating and eddy currents in metallic screens, causing heat and reducing cable ampacity. IEC 60287 categorizes four loss types, with λ¹ (circulating currents) and λ¹ (eddy currents) being significant, particularly in submarine cables. Cross-bonding measures are less effective for underwater installations.

3.1.3.1 Transient Conditions The calculation models shown so far are used to calculate ampacities for steady-state conditions reflecting the case of continuous constant load over long time. In real life, cables are rarely operated at const...

AI summary The text discusses the importance of transient thermal analysis for submarine cables, contrasting steady-state models with real-world load variations. It highlights the use of Cauer-type RC ladder networks to model heat flow and references Neher/McGrath's 1964 work influencing IEC 60287 standards.

ue is only valid for this example. Cable surface temperatures are depending strongly on the specific case. 68 3 Design The steady-state conductor temperature c is according to Eq. 3.21: $$\Theta_c = \Theta_{\text{amb}} + I_{\text{cont}}^2...

AI summary The text presents equations for calculating steady-state conductor temperatures in cables under varying loads, including overload scenarios. It uses a 1200 mm² copper conductor example to demonstrate that a 10-minute overload at 3513 A is feasible after sustained 75% load operation, based on quasi-adiabatic heat assumptions and material properties.

78 3 Design Table 3.8 Estimated utilization of submarine power cable links Type of submarine link Link utilization Supply of islands with residential demand According to island demand, 4380/8760 h Supply of G&O platforms 90% 7884/8760 h OW...

AI summary The document discusses the estimated utilization of submarine power cable links for various purposes, such as supplying islands and offshore platforms, and explores how using larger conductors can reduce cable heat losses and burial costs to meet the 2 K criteria.

3.2 Design of Mechanical Properties Submarine power cables must be designed to withstand all mechanical stresses during manufacturing, handling, transport, installation, and operation. The stresses imposed to submarine power cables are muc...

AI summary Submarine power cables require robust mechanical design to withstand stresses during manufacturing, installation, and operation. Inadequate design can lead to system failures, increased repair costs, and premature replacement. Key challenges include ensuring tensional strength for water depth and dynamic forces during installation and operation.

he augmentation of the tensional forces due to both effects. It is much more complex to calculate the combined effects on the tensional forces of a catenary line and the vertical acceleration dynamic. The entire length of the suspended cat...

AI summary The text discusses the complexity of calculating tensional forces in submarine power cables during installation, emphasizing the impact of vertical acceleration and sea states. It highlights the use of specialized software for analysis and the trade-off between designing for moderate vs. higher sea states to balance installation feasibility and cost risks.

Link Armoring Insulation Test tension kN SWP kN/m References Morocco – Spain Italy – Greece Gulf of Aqaba Troll A DWA copper DWA steel DWA DWA LPOF MI LPOF Dc XLPE 353 471 500 375 70.6 94.2 100 75 [16] [16] [17] Table 3.13 SWP in some cabl...

AI summary The table lists various cable projects with their respective armoring, insulation types, test tension, SWP, and references. It includes projects such as Morocco – Spain, Italy – Greece, Gulf of Aqaba, and Troll A, with details on materials and specifications.

3.3.1 The Concept of Electric Strength The electric strength of an insulation material is the ability to withstand an applied voltage without a breakdown. If the voltage is higher than the electric strength, an electric breakdown occurs. N...

AI summary Electric strength refers to an insulation material's ability to withstand applied voltage without breakdown. Factors like material purity, thickness, impurities, temperature, and aging influence this property. Industrial insulation systems typically exhibit lower electric strength than laboratory samples due to real-world imperfections, emphasizing the need for careful cable design to prevent outages.

3.3.5 Dielectric Design of Mass-Impregnated Cables For practical considerations, the steady-state stress distribution in a massimpregnated d.c. cable can be calculated analytically according to [36]: $$\beta = \frac{\alpha \cdot W_C}{2\pi...

AI summary The text discusses the dielectric design of mass-impregnated DC cables, including analytical stress distribution calculations, the impact of load conditions on dielectric strength, type testing requirements, and voltage regulation strategies to enhance transmission efficiency. It highlights the relationship between temperature, pressure, and insulation performance, as well as historical and modern design stress ranges.

4.1.1 Factory Joints A factory joint connects semi-finished pieces of cable before the armoring is applied. Factory joints are also used when production mishaps require that the production cable length must be cut to remove damaged parts....

AI summary Factory joints connect semi-finished cable pieces before armoring. Welding methods like TIG and MIG are used, with emphasis on avoiding defects and ensuring conductivity. Screw connectors are avoided due to size constraints. Weld quality checks and tensile strength are critical for submarine cable installations.

4.1.2 Offshore Installation Joints The notion "installation joint" or "field joint" describes a joint of the complete submarine power cable including conductor, insulation system, armoring and all intermediate layers. Installation joints a...

AI summary The text describes offshore installation joints for submarine power cables, detailing their manufacturing on vessels or beaches, the time required (1-10 days), and challenges like weather risks during jointing. The process involves laying cable ends in a jointing shack, with interruptions only possible by cutting the cable.

4.1.2.1 Flexible Installation Joints Flexible joints can be used with advantage when a long cable route requires the offshore jointing of subsequent delivery lengths. After the first laying campaign, the vessel would fetch the next cable l...

AI summary Flexible installation joints are critical for offshore cable projects, enabling seamless connection of cable segments during deployment. The process involves jointing conductors, insulation, and armor using techniques like welding or turnbuckles, with specific attention to tensional strength. These joints are used in both single-core and three-phase cables up to 245 kV and 150 kV, respectively, though manufacturing in short lengths remains a challenge.

4.1.2.2 Rigid Joints Rigid joints (or "stiff joints") are very different to flexible joints. The name denotes that the joint has a rigid outer casing, most often in the shape of a steel tube (Fig. 4.3). The steel tube serves as a connectin...

AI summary Rigid joints use steel tubes as outer casings for cable connections, providing mechanical strength and enabling pre-moulded joint sleeves for electrical parts. Pre-fabricated joints offer advantages like quick assembly, compatibility with various conductor connections, and factory pre-testing. These joints are used in both land and submarine cable applications.

4.2 Cable Terminations The submarine cable, when landed onshore, is normally connected (jointed) to an underground cable close to the beach. The underground cable continues to a substation, where it is terminated with a standard onshore ca...

AI summary The submarine cable is connected to an underground cable near the shore, which extends to a substation for termination. Onshore cable terminations are designed for underground cables, not submarine cables, regardless of the substation's distance from shore.

4.3.1 J-Tubes It is industrial practice to guide power cables up to stationary platforms through J-tubes, named for their J-like shape. The bow of the J is down on the seafloor and the upper end of the J is beneath or above the lowest plat...

AI summary J-Tubes are used to guide power cables to offshore platforms, with specific design considerations for installation and thermal management. The structure, including bellmouth and bow radius, must accommodate cable bending and thermal conditions to prevent issues like overheating and corrosion.

4.3.2 Hang-Off The gravity weight of vertically suspended cables on stationary or floating platforms is carried by hang-offs. A hang-off is a sophisticated connection flange between the cable armoring and the platform structure (cf. Fig. 4...

AI summary A hang-off is a connection flange between vertically suspended power cable armor and platform structures, designed to carry mechanical loads. It includes a clamping device for armor wires, with the cable core passing through to the termination. The figure illustrates a hang-off for a three-phase offshore wind turbine cable.

4.3.4 Holding Devices Various clamping devices can be used to secure submarine power cables in beach areas, along steep underwater slopes, in areas of strong currents, and elsewhere.

AI summary The text discusses the use of various clamping devices to secure submarine power cables in challenging environments such as beach areas, steep underwater slopes, and regions with strong currents.

5.1.1 The Conductor All cable manufacturing starts with the conductor. Conductor making methods are identical to those for underground cables. However, the conductor made from preshaped profiled Cu or Al wires is used almost exclusively fo...

AI summary The text details conductor manufacturing for submarine HVDC cables, emphasizing compact conductor design, jointing techniques (welding, soldering), water-blocking agents for longitudinal water tightness, and insulation materials (XLPE or lapped paper). It highlights process requirements to avoid gaps, misalignment, and mechanical weaknesses.

5.1 Manufacturing 127 Fig. 5.3 Lapping of carbon-black paper and insulation paper onto a copper conductor (Courtesy of ABB, Sweden) subsequent turns). There must be a small gap (1–4 mm) between consecutive turns. This gap is called butt ga...

AI summary This section details the manufacturing process of high-performance power cables, emphasizing the lapping of carbon-black and insulation paper onto copper conductors. Key aspects include maintaining 1–4 mm butt gaps between paper layers, tension control via brake devices, use of pre-dried paper in controlled dry environments, and logistical challenges in reloading paper reels during production.

5.1.4 Sheathing Most submarine power cables have a radial water barrier in form of a metallic sheath. 2 Shorter medium-voltage cables often have an aluminium laminate sheath consisting of aluminium foil coated with a thermoplastic layer. T...

AI summary The text details sheathing methods for submarine power cables, including lead and aluminium sheaths, their manufacturing processes (ram press vs. extrusion), material properties, and protective measures. It highlights lead alloy improvements, EN 50307 standards, and challenges like mechanical vulnerability and corrosion resistance.

5.1.5 Lay-up For the production of three-phase cables, the three cable cores must be laid up to form a coherent cable. Just taking three cores in parallel into a common armoring would render a very stiff design without flexibility. Horizon...

AI summary The text describes the lay-up process for manufacturing three-phase cables using horizontal and vertical machines, emphasizing flexibility, jointing techniques for long submarine cables, and the SZ-lay-up method to address topological challenges. It details machinery, cable core arrangement, and the envelope circle diameter calculation.

5.1.6 Armoring The most prominent attribute of submarine power cables is the armoring. Basically, submarine cable armoring is the winding of metal wires around the single core or a multicore cable. The most common wire is galvanized steel...

AI summary Submarine power cable armoring involves winding metal wires (e.g., galvanized steel) around single or multicore cables. Modern armoring machines use rotating cages and synchronized speeds to lay wires evenly. Historical illustrations and current machinery designs are described, with some factories using dual machines for double armoring.

5.2 Testing Submarine power cables are subjected to comprehensive tests during development, qualification, manufacturing and installation. The various tests serve different purposes with the single overall goal – to ascertain a trouble-fre...

AI summary Submarine power cables undergo tests during development, qualification, manufacturing, and installation to ensure trouble-free operation under specified conditions. Tests are categorized by purpose and stage, reflecting diverse requirements across cable lifecycle phases.

5.2.1 Development Tests The development of new cable types, or the extension of existing cable types to new sizes or ratings, may require comprehensive testing of materials, components, and production processes. Many of the new materials a...

AI summary The development of new or extended cable types requires comprehensive testing of materials, components, and production processes, particularly for submarine cables due to higher repair costs and outages. Tests include dielectric properties, ageing performance, mechanical stress, corrosion, and fatigue, ensuring reliability and performance under various conditions.

tion. During type test, only three of the four following parameters can be set independently: - Conductor temperature - Temperature drop over the insulation - Conductor current - Ambient temperature. The 8/16 h rhythm of the cycles is wide...

AI summary The load cycle test for mass-impregnated HVDC cables involves setting three of four parameters (conductor temperature, insulation temperature drop, current, ambient temperature). The 8/16h cycle rhythm is standard, but shorter 4/8h cycles are acceptable for development tests. Test voltage factors (1.55–1.7×U₀) are often negotiated lower than Electra 189b’s 1.8×U₀ due to higher operational dielectric strength during load phases.

5.2.6 Non-electrical Tests The various test standards stipulate, beside the electric tests, also a number of nonelectric tests. The tests are performed as sample tests on a defined share of the entire production, as routine tests on the en...

AI summary Non-electrical tests for cables are conducted alongside electrical tests to verify physical properties, including dimensional checks, material resistivity, and cross-linking quality. These tests vary in frequency and are often overshadowed by electrical tests, necessitating clear definition in project contracts.

to IHO specifications, three pings per object are required in order to detect the object. Side-scan systems can also provide some information on the seafloor texture and boulder fields (cf. Fig. 6.2). An insufficiently detailed survey may...

AI summary The text emphasizes the critical role of detailed bathymetric surveys in submarine cable projects, highlighting risks from inadequate surveys, such as equipment loss due to unexpected seafloor topography and discovering obstacles during the Wolfe Island cable route survey. Examples include a trenching plough lost on steep slopes and a misaligned power cable.

6.6 Soil and Water Temperatures The variation of subsea soil and water temperatures over the year is one of the first data the cable design engineer asks for. For many waters, comprehensive data sets are available, taking annual variations...

AI summary The section discusses the importance of subsea soil and water temperature data for submarine cable design, highlighting variations between sea bottom and surface temperatures, and challenges at landfalls such as high summer temperatures and burial depths impacting cable design.

p to 250 m water depth.). In the latter case, the pair of cables can be buried later in a single operation. 1 The laying wheel represents all type of laying gear such as wheels, chutes etc. Turntables can be divided into an inner and an ou...

AI summary The text describes methods for laying and burying submarine cables using cable laying vessels. Techniques include using turntables with inner/outer partitions, uniform-lay-direction armoring, and temporary setups for smaller projects. Cables can be bundled for single-burial operations, avoiding divergence during seabed placement.

7.1.2 Other Vessels Apart from the CLV, other vessels are often needed for a submarine cable installation. In strong winds or currents, the CLV may need the assistance of one or more tugs to keep position. During landing operations, a flee...

AI summary The text discusses the various vessels required for submarine cable installation, including tugboats, anchor handling vessels, survey ships, and specialized equipment like ROVs. It highlights the 2006 123 kV cable project between Koh Samui and Kha Nom, involving multiple vessels for laying, protection, and crew accommodation.

7.1.3 Loading and Logistics Submarine cables with short length can be handled and transported on standard or oversize drums. Most standard and all oversized drums require flatbed trailers making the onshore transport expensive. When the su...

AI summary The text discusses challenges in transporting and installing submarine cables for offshore wind parks, comparing methods like pre-cut drums versus coils. It highlights risks of damage during loading, the need for synchronized equipment, and the importance of proper cable sealing to prevent water intrusion. Logistics costs and efficiency are emphasized, particularly for long cable lengths.

7.1.4 Laying of Submarine Power Cables Submarine cables on drums, e.g. for in-field cables, can be installed from barges with simpler navigation equipment. A drum pay-off and a linear machine with brake are necessary. The cable runs over a...

AI summary The text describes the process of laying submarine power cables using barges, emphasizing the need for anchors, tugboats, and specialized vessels. It highlights risks of damaging existing infrastructure, slow progress (1–2 km/day), and challenges with visibility for ROV cameras in certain waters.

7.1.4.1 Laying of Cable Around a Curve When laying the cable around a bend with too small a bending radius, the residual bottom tension tends to drag the cable laterally over the seafloor. The minimum required bending radius can be calcula...

AI summary The text explains the calculation of the minimum bending radius (Rs) for cable laying around curves, using the formula Rs = FT_H/(Ws μ), where factors include horizontal tension, cable weight, and soil friction coefficients. It emphasizes avoiding lateral drag by maintaining a straight segment after obstacles and provides friction values for different seabed materials.

e cable in Fig. 7.15 was caused by tidal longshore currents. Fig. 7.15 Floating of a submarine power cable during landing (NorNed). Crew members wear safety harness Auxiliary boats may be necessary to keep the cable in position, while the...

AI summary The text describes methods for landing submarine power cables, including the use of auxiliary boats, shore winches, and cable-laying vessels (CLVs). It references the Baltic Cable example, highlighting challenges like managing floating cables with air cushions and ensuring sufficient cable length for installation.

7.1.6.1 In-Line Joints In the simplest laying scheme, the CLV is laying cable A first. The end of Cable A is provided with a cable seal with pulling eye, a ground wire, and a hooking arrangement before it is lowered to the seafloor. The ho...

AI summary The document details the process of laying submarine cables with in-line joints, emphasizing the use of ROVs for recovery, handling flexible vs. rigid joints, and challenges like weather constraints and trenching equipment limitations. It also mentions an alternative 'hairpin joint' method.

7.1.6.2 After-Installation Joints Sometimes it is necessary to lay down both Cables A and B onto the seafloor without jointing. A possible reason might be a short weather window not allowing for both jointing and subsequent laying in one g...

AI summary The text discusses post-lay jointing of submarine cables, noting that laying cables without initial jointing may be necessary due to weather constraints or cost efficiency. It outlines configurations for post-lay jointing, emphasizing overlap lengths based on water depth and cable guide lengths, and mentions equipment like ROVs and jointing shacks.

7.2.2 Design of a Suitable Cable Armoring The armoring of submarine cables (power or telecom) must be designed to meet the tensional forces during laying and the protection requirements during the lifetime of the cable. The telecom submari...

AI summary The design of submarine cable armoring must address tensional forces during installation and long-term protection. Telecom industry standards for armoring are referenced, though the text is truncated mid-sentence.

7.2.3.3 Simultaneous or Post-Lay Burial? Ploughs and water-jetting equipment can be used for simultaneous laying and burial of the cable, or for post-lay burial (PLB). A PLB operation can be performed at convenient occasion after the cable...

AI summary The text compares simultaneous and post-lay burial methods for submarine cable installation. Simultaneous burial reduces cable damage risks but slows operations and increases costs, especially with high-day-rate vessels. Post-lay burial is more economical but risks damage during the unprotected period. Economic trade-offs depend on vessel type, with laying barges being slower but allowing better trenching synchronization. The 'bathtub' method is proposed for tidal flats.

7.2.3.4 Trenching Depth There is always a discussion about the ideal trenching depth providing sufficient protection at reasonable cost. While it is obvious that a deeper trenching provides a better cable protection, the relationship betwe...

AI summary The text discusses the trade-offs between trenching depth and cable protection, noting that deeper trenches offer better protection but increase costs and risks. Optimal depth varies with soil conditions and future developments, with 1–1.5 m burial depth recommended to mitigate fishing gear threats. Sub-bottom burial is ideal, though practical challenges may limit achievable depths.

7.2.3.5 Other Protection Methods There are also pre-laying trenching methods using dredging or excavating. The cable trench is prepared before the laying vessel brings the cable. The necessary furrow in the seafloor can be prepared by diff...

AI summary The section outlines trenching methods for submarine cables, including dredging, mechanical disintegration, and artificial covers (cast iron, concrete, rock dumping). Challenges like rocky terrain and burial depth requirements are discussed, along with specific cases such as the 1967 SACOI HVDC cable and unconfirmed methods in Istanbul.

8.1.3 Damage by Fishing Equipment To understand the risks of damages to submarine cables some words should be mentioned about the most common fishing techniques, which may affect submarine cables. The speed of Otter trawling (Fig. 8.2) is...

AI summary The text details how fishing methods like otter trawling, beam trawling, and dredging pose risks to submarine cables through physical contact and force. It highlights specific hazards from trawl doors, anchors, and gear recovery operations, while noting that deeply buried cables are less vulnerable. A case study from Japan's Seto Inland Sea illustrates cable damage and mitigation efforts.

8.3 Fault Location A number of methods for fault location are available, each having its own possibilities and limitations. Depending on the characteristics of the fault and the design and configuration of the cable, the methods will have...

AI summary The text outlines methods for fault location in cables, emphasizing the need for experienced engineers and training. It describes identifying faults through insulation tests and highlights the importance of cable operator investment in engineer training for effective fault localization.

ing distances. Solid cursor is at joint at 199 m (93.5 m back). Features on the right side of the open cable end are the same reflections just bouncing back and forth (distances are all multiples) TDR performs best on clear cable breaks an...

AI summary The text discusses Time Domain Reflectometry (TDR) in cable testing, highlighting its effectiveness on clear breaks and low-ohmic faults, challenges with high-ohmic faults, and differences in performance between land and submarine cables. It references a figure (Fig. 8.7) illustrating TDR features and notes limitations in submarine cable measurements.

8.4 Repair Example The following example illustrates step by step how a submarine cable repair operation can be done. It should be kept in mind that the described case is just one possibility, taken from a real situation. For each task, th...

AI summary This section details a submarine cable repair process, including fault location, retrieval of damaged cable ends using an ROV, deployment of spare cable, and precise vessel positioning for jointing. The example emphasizes tailored repair strategies based on site-specific conditions.

References - 1. Lawrence M (2002). Submarine Cable Industry, -Alcatel Survey Standards and Future Trends. MUC Kiel, 2002. - 2. Hoshina R (2001). Improvements in Submarine Cable System Protection, SubOptic 2001. - 3. Shapiro S, Murray J, et...

AI summary The references discuss technical aspects of submarine cables, including protection, reliability, installation, and environmental factors, citing industry standards, risk assessments, and case studies from various experts and organizations.

9.1.1 Common Measures for All Kind of Submarine Power Cables The cable operator must protect the cable from a number of hardships, such as overvoltage, overheating, external violence, fatigue, etc. This requires an active involvement and t...

AI summary The cable operator must implement measures to protect submarine power cables from overvoltage, overheating, external damage, and fatigue. Strategies include surge arresters, DTS monitoring, free span stabilization, and vessel traffic monitoring. Thermal hazards require bathymetric studies and satellite tracking, while asset management and infrastructure planning are critical for long-term cable integrity.

9.1.2 Instrumentation Taking active control of the operation of a submarine power cable may increase the availability and profitability of the cable link. Suitable instrumentation is available to do this.

AI summary The text discusses the potential benefits of active control for submarine power cables, noting that suitable instrumentation can enhance availability and profitability of the cable link.

10.3.2 Choice of Other Cable Materials The choice of insulation material is determined by the intended use of the cable and the state-of-the-art. Only sometimes there is a free choice. Most modern submarine power cables have an insulation...

AI summary The selection of insulation materials for submarine power cables is influenced by intended use and technological advancements. Modern cables typically use XLPE, which produces gaseous by-products during the peroxide-based crosslinking process, such as acetophenone and alpha-methylene-styrene.

10.5.4 Chemical Impact Under normal operation conditions submarine power cables do not release chemicals, consumables, or other agents to the ambient. The materials are designed to be stable under the influence of seawater for decades. Cab...

AI summary Submarine power cables typically do not release chemicals under normal operation, but oil-filled cables may leak insulation oil upon damage. Synthetic oils like LAB are biodegradable but have toxicity concerns. Historical incidents, such as the 1979 Öresund cable damage, highlight environmental risks, though synthetic oils evaporate quickly. The text discusses the chemical impact of cable materials and their environmental implications.

10.6 Recycling of Submarine Power Cables There are few options to proceed after the useful life of a submarine power cable. It is easy to leave the defunct submarine cable in place and announce it as "abandoned" to authorities. It is diffi...

AI summary The text discusses challenges in recycling submarine power cables, including environmental and economic considerations. Options include leaving cables abandoned, recovering and recycling materials like metals and polymers, or repurposing cables as artificial reefs. Recycling methods involve mechanical separation, chemical processes, and using polymers as fuel.

11.4 S-Lay and Coiling Direction Each trade has its own unwritten laws. Young engineers entering a design department of a radio manufacturer learn very early that volume knobs on the stereo always are to be turned clockwise to increase the...

AI summary The text discusses the historical standardization of S-lay (left-handed) armor direction in cables, tracing its origin to 1898 and the practical challenges faced during coiling. It highlights the inconvenience of right-handed lay in coiling processes and the engineering solution to switch to left-handed lay, avoiding untwisting in transatlantic cables.

11.8 Unusual Cable Ships The "Great Eastern" shown in Fig. 11.2 was the largest ship in the world of those days, mobilized for this truly great cable-laying job. Not every submarine power cable project of more recent date did enjoy the par...

AI summary This section discusses historical and unconventional methods of submarine cable installation, including the 'Great Eastern' ship, floating cable drums used by NKT Cables A/S for the Oresund cables, and speculative airship-based techniques. It highlights the evolution of cable-laying vessels and their adaptability to different environments and project needs.

11.12 Loops When a large cable ship installed a large HVDC cable some years ago, the DP system was not really the latest and could hold only a limited number of preprogrammed way points. During the night, the officer on duty fell asleep fo...

AI summary During an HVDC cable installation, a vessel's outdated DP system and an officer's lapse led to a cable loop formation when pre-programmed waypoints were exhausted. The loop required costly rock protection as post-lay trenching was impossible, highlighting infrastructure planning and operational risks in power transmission projects.

1. Deschamps L et al. (1980). Development in France of High Voltage Cables with Synthetic Insulation, Paper Cigré 21–06. A Assembly time, 112 Marine survey, 70 Mass-impregnated P dielectric constant, 60, 281–282 Paper insulation, 126 loss...

AI summary The text discusses technical details related to high voltage cables with synthetic insulation, including topics such as marine surveys, materials like polyethylene and paper insulation, and offshore infrastructure like windfarms and pipelines. It also references various cables, models, and technologies used in the industry.

PARTIALLY CONFIDENTIAL Decision, 2 1 that, without such an agreement or provision, the Maritime Link Project 2 could not be approved. Applying the test under s. 5(1)(a) of the ML Regulations, 3 the Board concluded that the Maritime Link Pr...

AI summary The Board approved the Maritime Link Project contingent on NSPML securing access to Nalcor's Market-priced Energy. The Energy Access Agreement, filed as a compliance measure, allows NSPML to access at least 1.2 TWh of non-firm energy annually from Nalcor until 2041, based on economic terms rather than guaranteed delivery.

Pole Outages – Maritime Link In Service Of the 807.9 MW delivered to Soldiers Pond, 162.2 MW is assigned to supply the Emera block, leaving 645.7 MW as the peak deliveries to the Island Interconnected System. For loss of a pole the Emera b...

AI summary The document discusses the impact of pole outages on power delivery via the Maritime Link, noting a 27.5 MW shortfall during monopolar operation. However, spinning reserves and planned combustion turbine startups (up to 150 MW) are expected to prevent under-frequency load shedding, ensuring system reliability despite the shortfall.

The objectives of this Reliability and Availability (R&A) Assessment are: - To develop R&A performance indices for the converter stations - To develop R&A performance indices for the HVdc transmission line from Muskrat Falls to Soldiers Po...

AI summary This Reliability and Availability (R&A) Assessment aims to develop and evaluate performance indices for various components of the HVdc transmission system, including converter stations, transmission lines, and submarine cables, and to assess potential improvements through design considerations.

λ = Failure rate (1-phase) = 0.01 f/yr N = No. of Components = 6 R1 = Repair Time (replacement with spare) = 168 hrs R2 = Repair Time at Factory = 4380 hrs With no spare, Average outage time per pole = 0.01x3x4380 = 131 hrs/yr With one spa...

AI summary The text discusses the impact of having spare components in HVDC converter stations on outage time. It provides calculations showing that with one spare, the average outage time per pole decreases significantly from 131 hours per year to 7 hours per year. CIGRE statistics are referenced to support this design measure.

Table 2. Calculation of undelivered and makeup volumes of Base Block (2021-2025) (MWh)[37](#page-12-1) 1 Month/Year Contract Net Undelivered Net Undelivered Volume Delivered Undelivered Makeup (Month) (Cumulative) Aug-21 45,923 6,131 39,79...

AI summary Table 2 presents the calculation of undelivered and makeup volumes for the Base Block from 2021 to 2025, detailing monthly and cumulative figures. The data includes net undelivered volumes, makeup volumes, and delivered volumes for each month.

esign, it is our assessment that the LIL has some inherent design weakness and less robust in certain sections, particularly in Labrador where the suspension tower carries five cables.[94](#page-31-0) - NLH, for its part, acknowledged that...

AI summary The Labrador Island Link (LIL) faces design weaknesses, particularly in Labrador, with unbalanced ice loading causing outages. NLH acknowledges design discrepancies compared to industry standards and past practices, citing icing events in 2021, 2022, and 2024 that damaged infrastructure without disrupting operations. The March 2024 outage is linked to prior unbalanced ice events.

ate (%) of the Maritime Link, as proposed by NSPML in M05419. Please include the base case and any sensitivities for this assumption used in M05419. 13. Please refer to Exhibit N-1, page 5 lines 31-32, page 11 lines 24 to page 12 line 2, a...

AI summary The document contains a series of questions related to the availability, outage rates, and transfer capabilities of the Maritime Link and Muskrat Falls Generating Station, referencing Board Matter M05419 and other exhibits. These questions are aimed at obtaining detailed operational and performance data for regulatory review.

pers, and analyses that the Witness relied upon to independently assess the details and necessity of the July 2023 outage. 14. Please describe the Witness’s efforts to independently verify the details and necessity of the September 2023 ou...

AI summary The text consists of a series of questions directed at a witness regarding their verification of outages in 2023 and 2024, as well as their reliance on documents and analyses, and their understanding of the Labrador Island Link (LIL) and its design standards.