Is your Network SAIDI performance keeping you awake at night?

Sponsored

Innovative Aerial Cable System used to solve multiple Problems. Aerial Cable Systems (aka Hendrix Spacer) have been built since 1951 and since 1960s have reached mature material specification. Spacer cable solves many issues associated in building an operating an overhead power system.

The spacer system addresses issues of line disturbance by

• Lightning
• Vegetation Contact
• Animal and insect contact
• Vibration
• Sag control

In addition to solving these issues it also achieves much higher rating, 10-20% lower impedance, removal of Ferroresonance, compact design and multiple circuits of different voltages on same pole line. Spacer also enables safer use of live line techniques and virtually interruption free system performance.

Spacer cable is a messenger supported primary distribution system using covered conductors in a close triangular configuration. The system has the mechanical strength to weather severe storms and the electrical strength to prevent faults due to phase to ground or phase to phase contact, vegetation contact or animals. Covered conductors consist of stranded hard drawn aluminium conductors with either one, two or three extruded layers depending on the voltage rating.

Since spacer cable systems have a compact design that tolerates momentary contact, trees can be allowed to grow much closer to spacer cable than with bare wires. This greatly reduces tree trimming time & costs while improving customer relations without sacrificing reliability. In areas where there are protected trees or habitats the lower cost of maintaining and reduced need to access the lines brings long term benefits.

Around coastal areas spacer cable systems perform well because the cable and spacer design limits the leakage current where the covered conductor and polyethylene insulators prevent flashovers that can occur with bare wire on contaminated insulators. The covering also protects the conductor from corrosion.

The closer spacing of the phase conductors in the Hendrix system versus open wire circuits means less voltage drop. The comparison below shows a 21% reduction in voltage drop which could mean Networks can realise additional savings from reduced requirement for regulators or capacitors.

Spacer cable systems provides the highest form of reliability on Distribution networks. The compact configuration and the placement on one side of the pole reduces the exposure to trees. When trees or branches do come down (as shown below) the messenger wire will support the cables – ensuring uninterrupted service; until crews can get to them.

Already in use on 3 networks in New Zealand the Hendrix spacer system is drawing a lot of interest from network planners who are considering costs effective options to reduce SAIDI faults from vegetation and animal contact.

Want to discuss now? Please contact:

Bruce Blundell

P: +64 9 274 4280
M: +64 21 427 774
E: bruce.blundell@acculec.co.nz