Has your network considered the covered MV Conductor to improve SAIDI?

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Has your network considered the covered MV Conductor to improve SAIDI?

An open invitation to a webinar – Covered Conductor for MV Overhead Lines – postponed to 30 September 2020.

Overview

MV overhead networks are predominantly uninsulated conductors. However, using a covered conductor in specific locations can significantly improve your network SAIDI as well as offering other advantages. The covered conductor system is designed to provide protection from flashovers from conductors clashing, bird or animal incursions, or tree branches falling onto the line, especially in severe weather conditions and when there is high pollution.

Hendrix spacer cable systems are essentially three covered conductor phases in a close triangular configuration supported by a ‘messenger’ or catenary cable. Spacer cable is a pre-engineered electrical distribution system designed for high reliability and improved right-of-way flexibility. The high strength messenger (catenary) wire, which provides mechanical support, is system neutral and acts as a shield wire against lightning. The conductors are hung loosely beneath the messenger and supported by ‘spacers’, which results in virtually no tension on the conductors.

Spacer cable advantages

MV overhead spacer cable provides very good solutions in a number of different situations. A few are listed below:

1. Improved voltage regulation

• 15-20% better than bare wire or tree wire
• better end-of-line voltage on voltage-limited long feeders
• higher power facto

2. Improved system reliability

• where wildfire mitigation is a consideration
• to avoid conductors clashing
• in severe weather conditions

3. Tree relayed advantages

• tree trimming costs reduced by up to 80%
• improved aesthetics & public relations
• economics – as the spacer cable systems have a more compact design that tolerates momentary contact, trees can be allowed to grow closer to the covered conductor than to bare wires
• Around coastal areas the system design limits the leakage current compared to bare conductor.

4. Environmental management

• lines co-exist with trees
• preserve wildlife & migratory birds
• electromagnetic fields vastly reduced
• protection of National Parks & Recreation Areas

5. Access

With road widening projects, commercial alleyways or residential backlots, the insulating properties of the covering allow the messenger and the conductors to be bundled into a compact area. The messenger wire is used as the earth for the system because of its high strength and high conductivity.

Long spans, such as river crossings, can be the best economical option is shown in this example:

Example of a 500m River Crossing

• Option 1 submarine cable – estimated cost $1m
• Option 2 build around shoreline – estimated cost $800k
• Option 3 spacer cable – estimated cost $100k

If your network hasn’t seriously looked at the advantages of spacer cable over any other covered system, that means opportunities are going begging. As the distributor of the Hendrix Spacer cable system in New Zealand, Acculec offers in-house line design and costing to your network’s specifications.

To sign up (or sign someone else up) for one of the webinars – Covered Conductor for MV Overhead Lines – during September (different times available), please send an inquiry via email to sales@acculec.co.nz or call
Bruce Blundell, Acculec
Phone (NZ): 09 274 04280 or mobile: 021 427 774