New working group takes pole position

A recent international visit to Australia from UK and Norwegian overhead line study group members has reinforced the need for a new working group that will look at the issues and maintenance of wooden power poles.

Historically these assets have been of little concern as they have proven long lasting with reports that up until the 1990’s the wood poles for Europe and the UK could last up to 90 years when appropriately maintained. There are also many long lasting examples in Australia as well.

However with the present limitations in initial treatments available and the reduced available wood types, recent pole supplies now may only last 10-15 years – a significant reduction in the likely service life.

This is coupled with a range of other issues including:

• Wood poles are conductive and can cause electric shocks, and a recent fatality in Sweden demonstrated this;
• Pole strength degradation means that some poles can’t be guaranteed to provide their expected capacity;
• In some overseas cases, the creosote treatment used has not penetrated past the outer layer of the pole, reducing its service life, with some poles even exhibiting rot at the time of delivery;
• Poles with defects/rot that are not visible from the ground may result in premature failure, and this has caused injury to linesman and resulted in alternative sometimes difficult access methods to be required;
• Environmental considerations around the preservatives applied means that other treatments need to be found that provide a reasonable service life.
• Whilst this subject was raised by our international visitors, which is the benefit of CIGRE’s international forum, the issues identified are relevant to Australian and NZ utilities, and their wood pole populations.

It is therefore CIGRE Australia’s intention to leverage this international know-how to help develop solutions and guidance for the local industry. To facilitate this CIGRE are considering a new working group entitled “Assessment and testing of wood and alternative material type poles”.

The proposed scope for the new working group covers the following:

• Define “unassisted” pole failure so that extreme climatic events don’t skew the available failure numbers;
• Determine the present status of wood pole experience and extent of failures;
• Identify and qualify the range of methods available for testing and inspecting wood poles at the time of delivery and subsequently during their service life, considering the practicality and effectiveness of the methods, and the required inspection/testing frequency;
• Identify and discuss the various methods used to strengthen or reinforce degraded poles;
• Provide guidance on alternative preservatives/treatments and compare their potential environmental impacts; and,
• Provide guidance on alternative pole materials that are available, including existing experience with the alternatives.

Keep an eye on the CIGRE Australia website for updates on the findings of the group or talk to your local CIGRE representative to find out more.  Attached are some photos of the visit