Owner’s Engineer for secure, climate-resilient transmission line
Client: Power and Water Corporation
Location: Northern Territory, Australia
Date: September 2014 –September 2017
Determining the optimum design and overseeing construction of a cyclone-resistant 132 kV transmission line across a river
Background
The 132 kV transmission line from Channel Island Power Station (the largest power station in the Northern Territory and the main source of electricity for the city of Darwin) to the Hudson Creek 132 kV Terminal Station required augmenting to ensure that the new section of the transmission line crossing the 700 m span of the Elizabeth River would be able to withstand a Category 4 cyclone.
Solution
Entura acted as the Owner’s Engineer for the Northern Territory Government’s Power and Water Corporation, supporting it throughout the procurement, design and construction phases of this transmission line project.
The project’s challenges included provision of a 700 m span across the Elizabeth River using 70m-tall towers while ensuring that this section would survive a Category 4 cyclone (280 km/hr). Program timing was critical to be able to construct the line in the dry season, between April and September 2016.
Entura explored various solutions (including use of high-temperature low-sag conductors, HV cable, and lattice steel towers or steel poles) with the tenderers and the client to determine the optimum solution by comparing and contrasting technical advantages and disadvantages, operation and maintenance requirements and associated costs, reliability of proposed materials and arrangements, as well as reviewing tenderers’ experience and capability to execute the program of works.
Entura prepared the technical specification for the overhead line including technical specifications for various alternative options; responded to technical queries from all tenderers; prepared the tender assessment report; provided expert advice for design and procurement; reviewed the contractor’s design; and supervised the works on site on behalf of the client during construction.
Services provided
- technical specification for the overhead line
- technical specifications for various alternative options (i.e. cable options and steel pole)
- Owner’s Engineer through to procurement, design, and construction including site supervision
Outcome
Working closely with Power and Water Corporation and the construction contractor, Entura’s project team was successful in scoping and executing the project to meet all project requirements. Entura’s involvement during the tender stage assisted Power and Water Corporation to adequately assess the suitability and practicality of each of the proposed solutions.
Entura’s flexibility in conducting a progressive review of the design assisted the contractor to minimise re-work by providing opportunity to address identified concerns with the submitted designs early in the design process, saving time and costs.
The in-depth technical review of the contractor’s designs provided reasonable investigations and crosschecks to steer the design towards achieving the project goals, helping the client achieve an effective, successful and safe solution. As part of the Owner’s Engineer role and in coordination with Power and Water Corporation, Entura deployed expert staff to supervise construction.
