Topic:"Distribution" in M12696

Figure 1 Figure 2 Figure 3 In an area of southern Labrador, both electrode line conductors were severed and the tower wings supporting them, as well as the Optical Ground Wire (OPGW), were damaged. NLH acted quickly and restored the LIL to...

AI summary A power line failure occurred in southern Labrador due to heavy ice accumulation and strong winds. NLH restored the line quickly using a monopole metallic return configuration. The incident involved ice thickness and wind speeds exceeding design limits, leading to conductor and tower damage.

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.

Table 3-1: Reliability Performance of One Pole of the HVdc Line Element Failure Rate (f/yr) Repair Time (hrs) Downtime (hrs/yr) L1-388 km 0.741 1.78 1.32 C-Submarine cable 0.0022 4,163 9.24 L2-680 km 1.3 1.78 2.31 Total 2.042 6.3 12.87 REL...

AI summary Table 3-1 presents the reliability performance of one pole of the HVdc line, including failure rates, repair times, and downtime for various elements such as L1-388 km, C-Submarine cable, and L2-680 km. The data highlights the reliability and availability assessment of the HVDC Island Link.

Table 2.1 Degree of Severity for BES Disturbances and Local Disturbances (Billinton and Wangdoe, 2006)............................................................................................................................................

AI summary The text provides a list of tables from a technical document discussing reliability, design requirements, and loading scenarios for power systems, referencing standards and studies from various organizations such as CSA, EFLA, and others.

6.3.2 ULS Criterion The elements within the OPGW and the electrode line systems were identified under DLS, as the most critical elements; POF for this OPGW element was relatively high. In general, the study has also identified that the cab...

AI summary The analysis identifies OPGW and electrode line systems as critical elements under DLS, with a high POF. The ULS analysis shows that POF under ULS is 43% of that under DLS, translating to a return period of 106 to 211 years, estimated as 160 years using strength factors of 0.9 and 1.0. Table 6.4 provides POF exceedance values for ULS criteria.

- 9 a) Please explain why the section of line at issue is designed for a maximum of 50 mm of radial 10 glaze ice and a combined wind and ice load of only 25 mm of radial glaze ice with 60 km/h 11 wind, given the climatic conditions prevale...

AI summary The document requests explanations regarding the design criteria for a power line section, specifically its ice and wind load capacity, and whether these were consistent with standards. It also inquires about past icing incidents, the duration and causes of a recent outage, and the impact of the icing event on energy deliveries. Engineering reports and corrective actions are requested.

sup>1 While the design loads for this section of line are slightly below the combined load case specified by CSA 22.3 No. 60826, the final as-built line will meet the CSA 50 year combined loads. scope items2 1 , while others required addit...

AI summary The document discusses reinforcement measures for a section of line to meet CSA 50-year combined load requirements, including capital project recommendations for 2026–2028. It also references customer outages caused by extreme icing on Hydro's transmission and distribution lines between 2020 and 2026, with specific details on the Line L3501/2 structures affected in the April 2024 incident.

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 January 15, 2022, in the Hawke's Bay area due to galloping conductor, snow, and ice buildup, leading to line slapping and damaged conductors. Repairs were carried out, and power was partially restored by sectionalizing the line, with full restoration achieved by 1605 hours.

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.

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.

rameter. For mass-impregnated HVDC cables of the past 15 years a test voltage of $1.55 \times U_0$ , $1.6 \times U_0$ , or $1.7 \times U_0$ have been specified by purchasers for the cooling phase. The test cable is terminated with oil-fill...

AI summary The text discusses load cycle tests for mass-impregnated and extruded HVDC cables, including test voltages, oil flow prevention, polarity reversal tests, and impulse testing. It highlights specific test procedures and references industry standards like Cigré Technical Brochure 219.

9.2.1 The Cigré Studies The Cigré organisation (Cigré=Conseil International des Grands Réseaux Électriques) has established a working group that regularly collects data on submarine power cable reliability. In 1986 it published an often-ci...

AI summary The Cigré organisation has conducted studies on submarine power cable reliability, with a notable 1986 compilation of data from thousands of kilometres of submarine power cables.

1. Deschamps L et al. (1980). Development in France of High Voltage Cables with Synthetic Insulation, Paper Cigré 21–06. A Assembly time, 112 distribution, 94 Thermoplastic polyethylene, 253 d.c, 99 Three-core cables (3C), 40 mechanical, 8...

AI summary The text is a reference to a 1980 paper by Deschamps L et al. discussing the development of high voltage cables with synthetic insulation in France. It includes a table with various technical terms and measurements related to cable manufacturing, installation, and marine environments.

An electrode line will be provided at each converter station to connect to a remote ground electrode. These lines, under bi-pole mode, will carry only the unbalance current between the two poles of the dc line but will also be used at 150%...

AI summary The document discusses the design and reliability of electrode lines for a high-voltage direct current (HVDC) system, including their construction, failure rates, and operational considerations during normal and monopolar modes. It also addresses reliability improvements when electrode lines are mounted on the main HVDC line.

3.3 Electrode Lines As mentioned above, the link can still be operated at full power or reduced power even for the complete loss of the electrode line at either end of the link. As such, the reliability of the electrode line is considered...

AI summary The electrode line's reliability does not significantly affect the composite reliability of the link, as the link can operate at full or reduced power even with the complete loss of an electrode line at either end.

15,236 46,766 -31,530 Aug-23 83,742 83,265 477 62,197 -61,720 Sep-23 81,041 53,804 27,237 20,904 6,333 Oct-23 83,742 83,742 0 71,399 -71,399 Nov-23 81,041 81,041 0 43,905 -43,905 Dec-23 83,742 80,959 2,784 51,369 -48,586 Jan-24 83,514 83,5...

AI summary The table presents undelivered and makeup volumes of Base Block from 2021 to 2025, showing monthly figures in MWh. The data reflects variations in delivered and makeup volumes over time, with some months showing negative values indicating undelivered volumes.

dates designed to remedy non-critical software punch list items," verification of "several Supervisory Control and Data - Acquisition (SCADA) points to enable greater LIL visibility and control at the NSPML Application, page 17 line 25 to...

AI summary The text discusses software punch list items and SCADA points related to the Labrador Island Link (LIL), including the impact of bipole and monopole outages on transfer capability and NSPML's explanation of delivery performance relative to contract values.

that the September 2023 planned maintenance outages between the LIL and the Maritime Link were indeed coordinated and that the timing of the bipole outage on the LIL minimized the impact on customers. On September 3, both the LIL and the M...

AI summary The document discusses the coordination of planned maintenance outages on the Labrador Island Link (LIL) and the Maritime Link in September 2023, emphasizing that the timing of the outages minimized customer impact. Maintenance on both links was carried out in a coordinated manner, with specific availability limits during the outages.

Haldar Recommended to go Slow and Collect Actual Geographic Specific Data The Haldar Report indicates that under its more extreme value assessment only 2% of towers are potentially in need of reinforcement in anticipation of potential stor...

AI summary The Haldar Report suggests only 2% of towers may need reinforcement due to potential storms, but recommends collecting more geographic data before proceeding. NLH has addressed 10 failure events on L3501/2, with seven caused by ice accumulation. Reinforcement projects are planned for 2026-2028 to improve reliability and reduce failure risks.