N-2NSPML (BW) RIRs 1-22 - Redacted
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Bipole Outages – Maritime Link In Service For loss of the bipole, NERC transmission planning standards permit planned and controlled load loss in order to maintain system stability. In the context of the Labrador – Island Link loss of the...
AI summary The document discusses the implications of a bipole outage on the Labrador-Island Link and the Maritime Link. It outlines how a special protection scheme would manage load loss and system stability, and notes that Nova Scotia must plan for the loss of 500 MW from the Maritime Link without load loss, while Newfoundland and Labrador Hydro must ensure no adverse impact on neighboring systems.
Date: 10-Apr-2012 Prepared by: Peter Anderson RELIABILITY & AVAILABILITY ASSESSMENT OF THE HVDC ISLAND LINK Revision
AI summary This document, dated 10-Apr-2012, is a reliability and availability assessment of the HVDC Island Link, prepared by Peter Anderson. It focuses on evaluating the performance and reliability of the High Voltage Direct Current transmission system.
- 1) Nalcor Energy-Lower Churchill Project, :Basis of Design, Document LCP-PT-ED-0000-EN-RP-0001-O1. - 2) A Survey of the Reliability of HVDC Systems throughout the World during 2007 2008, M.G. Bennett, N.S.Dhaliwal, A. Leirbukt CIGRE 2010...
AI summary The document lists several references related to HVDC systems and reliability studies, including a survey of HVDC system reliability, a report on the Lower Churchill Project, and studies on iceberg risks to subsea cables in the Strait of Belle Isle.
4.1.3 Other Revenue Streams Detailed transaction data for a set of U.S. PSH plants in 2014–2018 shows that energy sales were the largest revenue stream; however, in a few instances, a combination of capacity payments and ancillary service...
AI summary Pumped Storage Hydropower (PSH) plants generate revenue primarily from energy sales, but capacity payments and ancillary service revenues can account for over half of annual revenue. These facilities provide grid services like frequency regulation and voltage control, with revenue composition analyzed via FERC Electric Quarterly Reports.
od of this line was 150 year, complimented by the installation of additional generation support near the load center (Avalon) to support the future load growth increases. Figure 2.3 Typical Optimization Problem Figure 2.4 Flow Chart for Op...
AI summary The text discusses the installation of additional generation support near the Avalon load center to address future load growth increases, emphasizing infrastructure planning and grid modernization efforts to meet evolving energy demands.
When assessed at a high level, Overhead lines (OHL) can be divided into two main systems. These are (1) the Wire Support System (WS) and (2) the Structure Support System (SS). The SS can be further broken down to include (1) the tangent su...
AI summary Overhead lines (OHL) are divided into two main systems: the Wire Support System (WS) and the Structure Support System (SS). The SS is further broken into tangent and dead-end support subsystems. Loads are transferred through the WS and SS to the foundation and surrounding soil and rock. The WS includes conductors, overhead ground wires, insulators, and hardware components.
r Members that have exceeded Strength Capacity Significantly (Vulnerability Under NLH Design Criteria) 6.1.3.2 Probabilistic Analysis – LIL DESIGN and CSA 60826 and selected towers Using NLH Criteria Figures 6.7 present the comparison unde...
AI summary The analysis compares NLH, CSA 60826-10, and LIL design criteria for transmission towers under unbalanced ice loads. NLH is found to be 18% more conservative than CSA 60826-10 for Structure S1-318, while LIL underestimates POF due to ignoring load combinations. The author questions why LIL design, which traverses harsh meteorological conditions, does not account for these combinations.
10.0 References - Alteen, Peter 2018 Written Submission on Behalf of Newfoundland Power Inc. to Commission of Inquiry respecting the Muskrat Falls Project. - ASCE Manual Practice No. 74 2010 Guidelines for Electrical Transmission Line Stru...
AI summary The references list technical documents, studies, and reports on power system reliability, structural design, and transmission line assessments. Key entities include Newfoundland Power Inc., Commonwealth Associates, EFLA, and Newfoundland and Labrador Hydro. Topics focus on system reliability and grid modernization.
Ice Monitoring - In response to icing experienced on the LIL, Hydro has undertaken capital projects for the installation of - a real-time weather station, as well as the installation of on-line ice and galloping monitoring - equipment. In-...
AI summary Hydro has implemented capital projects to install real-time weather stations and ice monitoring equipment on the Labrador-Island Link (LIL) in 2025, with plans for a second station in central Labrador by late 2026 to address icing issues.
1.0 Introduction - The Labrador-Island Link ("LIL") is an important transmission line for the provincial energy grid due to its - power carrying capacity that is used to deliver a large portion of the winter peak energy and demand to - the...
AI summary The Labrador-Island Link (LIL) is critical to Nova Scotia's energy grid, with past failures attributed to icing and unbalanced loading. Newfoundland and Labrador Hydro conducted investigations, leading to a 2026–2028 capital project to reinforce the line, including tower modifications, damping systems, and electrode conductor relocations to enhance reliability.
Table 1: Tower Types Tower Type Structure Type Insulator Assembly Type Deflection Angle Limit (degree) A1, A2, A3, A4 Guyed Suspension 0–1 B1 Guyed Suspension 0–3 B2 Self-Support Suspension 0–3 C1, C2 Self-Support Dead-End 0–30 D1, D2 Self...
AI summary Table 1 outlines different tower types used in power infrastructure, including their structure type, insulator assembly type, and deflection angle limits. This information is relevant to infrastructure planning and grid modernization.
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.
6.0 OPTION 2 DESIGN The second design option is to further increase the insulator length and address structural shortcomings in the insulator attachment to the cross-arm as described in the Failure Investigation Report. The hardware change...
AI summary Option 2 Design addresses structural and insulator attachment issues by increasing insulator length, replacing hardware with U-bolts and socket ball extensions, and modifying cross-arm configurations. Changes aim to reduce load moments, improve electrical clearance, and comply with 350 kV HVdc technical specifications.
Appendix D LIL Engineering Study – Calculations for OPGW Peak Reinforcement
AI summary Appendix D references an engineering study focused on calculations for OPGW (Optical Ground Wire) peak reinforcement as part of the Labrador-Island Link (LIL) project. The content includes visual aids but lacks detailed textual analysis or discussion of specific methodologies or findings.
1.1 900 MW Test and Software All software functionality required for operation up to 900 MW was proven and accepted as satisfactory during pole overload tests in winter 2023 prior to April 2023 commissioning; however, as committed, 1 "Newf...
AI summary The document outlines the status of 900 MW pole overload tests for the Labrador-Island Link (LIL), including completed winter 2023 testing, planned fall 2024 tests, and prerequisites like system conditions and risk mitigation. It also addresses software upgrades, grounding studies, and equipment replacement timelines.
N-4NSPML (IG) RIRs 1-26 - Redacted
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1 c) Due to site conditions, limited access, and the extent of damage, repairs could not be undertaken immediately; the two impacted customers restored their service through their own backup power source. Repairs were completed and power w...
AI summary An unplanned outage occurred on the Lower Island Link (LIL) on February 9, 2024, due to a DC Line Protection Fault caused by ice buildup. Both poles of the LIL were operated in Reduced Voltage Mode until February 12, 2024, to prevent further protection activations. Repairs were completed, and service was restored to both poles.
5 Ice Monitoring - 6 A total of three sensors were installed on structures 514 (central Labrador), 1224 (southern Labrador) - 7 and 2597 (central Newfoundland) in 2025 to monitor ice load and galloping.
AI summary Three sensors were installed in 2025 on structures located in central Labrador, southern Labrador, and central Newfoundland to monitor ice load and galloping. This initiative aims to enhance infrastructure monitoring and safety in these regions.
Optimizing Clamp Designs - Three alternative suspension clamps were installed on the electrode conductor at 10 structures in 2024, - and will be inspected annually for performance. These alternative clamp designs are intended to reduce - s...
AI summary The document discusses the installation and evaluation of alternative suspension clamps on electrode conductors to reduce stresses from oscillations and unbalanced icing. Redesigned clamps and tower reinforcements based on ice load studies are proposed to enhance system reliability and address overloading risks.
5.0 LIL Strengthening Capital Project (2026–2028) - 5.1 Evaluation of Alternatives - For the LIL Strengthening Capital Project proposal, four alternatives were evaluated to address issues - with the OPGW peak, the electrode crossarm and th...
AI summary The LIL Strengthening Capital Project (2026–2028) evaluates four alternatives to address OPGW peak, electrode crossarm, and conductor issues: mid-span structures, wood pole relocation, electrode assembly redesign, and reinforcement. Appendices B–F provide technical reports and cost estimates for implementation.
5.1.3 Re-design EL Assembly - This alternative would include the installation of a newly designed electrode assembly on the electrode - crossarm. Two options were designed under the 2024-2025 project: one that can be installed on the - exi...
AI summary The proposed redesign of the EL assembly includes two options: one for existing electrode crossarms and another for reinforced crossarms. Both increase electrode assembly length to reduce longitudinal loads and conductor deformation under ice, but neither fully addresses OPGW peak loads. Costs are $10,000 and $29,000 per structure, respectively.
Summary of all Failure Investigation Recommendations Document Number Report Title Recommendation Status Comments Monitor ice by line patrol Addressed • Lines are monitored regularly during the winter by helicopter line patrol. Additional h...
AI summary The summary outlines recommendations from a failure investigation report related to line damage caused by icing events. Measures include monitoring ice through helicopter patrols, installing real-time ice sensors, and implementing mechanical ice removal procedures. Tower modifications and vibration equipment installation are ongoing to improve line resilience.
3.3.3 Discussion As shown in Table 7, adding one mid-span structure decreases the peak braces and legs overstresses, however, members reinforcement would still be required. The addition of the mid-span structure in this scenario of the lin...
AI summary Adding a mid-span structure to a downhill power line reduces some overstresses but creates new imbalances on adjacent structures, making it impractical. Reinforcing existing towers avoids overstresses, suggesting alternative solutions may be more viable in this scenario.
3.4 S1-318 (319) Tower position S1-318 (319) was chosen due to the long wind spans as well as weight spans on both sides of the tower with electrode wires strung. This tower configuration induces high transverse loads during wind events an...
AI summary The tower configuration at S1-318 (319) was selected due to long wind spans and weight spans on both sides with electrode wires. This setup causes high transverse loads during wind events and vertical loads during ice events. Adding one mid-span structure would create imbalance, so two (AS and BS) were added to address overstressing in the current tower A1 configuration.
3.2 ELECTRODE CONDUCTOR DROP The electrode conductor drop on the tower type A1 electrical clearance drawing ILK-JY-SD-6200-TL-D99-0012-01-A3 is listed as 270 mm. This value is dependent on the vertical departure angle and describes decreas...
AI summary The electrode conductor drop on tower type A1 is 270 mm, determined by vertical departure angles affecting electrical clearance. However, as-built data in Figure 2 adjusts this to 200 mm, considering maximum vertical departure angles of 14°, with 15° cases neglected due to limited transverse swing angles from heavy weight spans.
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.
tructure will fail with the electrode attached to the structures and between 90% to 95% will fail without the electrode attached to the structures. Under unbalanced ice load (UBL), with 60 mm of ice: - structures with the electrode: - o on...
AI summary Analysis shows that structures with electrodes attached experience higher failure rates on OPGW under unbalanced ice loads (UBL) compared to structures without electrodes, where failures are limited to OPGW. Failure percentages increase with ice thickness (60mm, 70mm, 80mm), with electrode-attached structures failing entirely at 80mm UBL.
Material Testing - Material testing of the electrode conductor was completed by Wayland Engineering Ltd. ("Wayland") to - determine the cause of failure and if there were any issues with the conductor. The summary of - conclusions and reco...
AI summary Material testing by Wayland Engineering Ltd. identified ductile limit load fracture in conductors due to ice accumulation and sustained wind velocities. The report notes steel core migration causing reduced conductor strength and recommends radiographic imaging for non-destructive testing of other line sections.
Table 4: Comparison of Field Damage and Modeling Results for Ice Loading Field Damage Modeling 9 90 mm Modeling 100 mm Crossarm EL Crossarm EL Crossarm Dan nage OPGW Tower Damage OPGW Damage OPGW Tower EL1 EL2 Peak (% Utilization) Tower Pe...
AI summary Table 4 compares field damage observations with modeling results for ice loading on various structures, including towers and crossarms, under different ice thickness scenarios (9 mm and 100 mm). The data includes utilization percentages and damage indicators for specific poles and electrodes.
Table 4-2: Semi-quantitative SEM EDS analysis results for the clamp material immediately adjacent to the site of localized brinelling in conductor EL-1. Figure 4-6 shows the locations of the EDS analyses.
AI summary The text references a table and figure related to a semi-quantitative SEM EDS analysis of clamp material near localized brinelling in conductor EL-1, indicating a focus on material analysis and structural integrity assessment.
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.
iii. Supervisory Control and Data Acquisition (SCADA) Capability The wind plant shall provide SCADA capability to transmit data and receive instructions from Transmission Provider to protect system reliability. Transmission Provider and th...
AI summary The wind plant must provide SCADA capability to transmit data and receive instructions from the Transmission Provider to ensure system reliability. Essential SCADA information is determined by the Transmission Provider and the wind plant's Interconnection Customer, considering factors like plant size, location, and reliability impact.
2.7 Two-Core Cables Two-core cables have been used for HVDC systems where two conductors naturally occur. A development of the Mollerhoj cable has two fully insulated cable cores in a common lead sheath and has been used for the Danish par...
AI summary Two-core cables are used in HVDC systems, such as the KontiSkan and NorNed links, offering advantages like magnetic field cancellation. They operate with opposing voltages or through sea electrodes. Future applications include 6-phase AC systems for offshore wind power, minimizing magnetic losses in steel armor.
2.9 Optical Fibres Inside Submarine Power Cables Optical fibres can be integrated into submarine power cables for several purposes: - 1. Distributed measurement of temperature (DTS) - 2. Data transmission - 3. Measurement of cable strain o...
AI summary Optical fibres in submarine power cables enable distributed temperature sensing (DTS), data transmission, strain/vibration measurement, fault detection, and route monitoring. Temperature is measured via laser impulses and back-scattered light analysis, providing spatially resolved profiles for identifying hotspots along the cable.
N-5NSPML (NSEB) RIRs 1-19 - Redacted
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Page 1 of 1 1 Q. Please provide any studies of reliability for the post Muskrat Falls project and 2 Labrador Island Link project. 3 4 5 A. Please refer to the following attached reports: 6 7 PUB‐NLH‐212 Attachment 1: "Technical Note Labrad...
AI summary The document requests studies on the reliability of the post-Muskrat Falls project and the Labrador Island Link project. The response refers to two technical reports dated 2011 and 2012 that assess the impacts of the HVdc link on the Island Interconnected System.
The addition of a 900 MW HVdc transmission line between Muskrat Falls in Labrador and Soldiers Pond on the Island portion of the province Province has raised concerns regarding the impact that such a significant change will have on the rel...
AI summary The addition of a 900 MW HVdc transmission line between Muskrat Falls and Soldiers Pond has raised concerns about its impact on the reliability of the Island Interconnected System. This technical note aims to assess system reliability, interrelationships affecting it, and the potential impact of the proposed HVdc line.
n observed icing events in one of the most heavily loaded sections of the HVdc route. For the refined icing event analysis the following periods are extracted for the annual load shape for evaluation: - Based upon the load shape presented...
AI summary The document analyzes icing events on the HVdc route, selecting specific periods in February, April, and December for evaluation. It highlights a significant reduction in exposure hours and an increase in availability when considering only icing load conditions, not winter peak loads. Tables 8 and 9 provide exposure and unsupplied energy calculations with and without the Maritime Link.
for a new 50 MW combustion turbine in the 2032 time frame in order to maintain a very high level of system availability based upon a 1:50 year return period design for the Labrador – Island HVdc Link. Given the nature of the project in the...
AI summary The document discusses the design load for the Labrador-Island HVdc Link, emphasizing the need for a 50 MW combustion turbine by 2032 to ensure system reliability with a 1:50 year return period. It highlights the complexity of balancing increased return periods for weather loads against grid upgrades and standby generation costs, stressing the need to evaluate outage impacts on customer classes.