Using bird-resistant insulators on high-voltage transmission lines

April 24th, 2017, Published in Articles: Energize, Featured: Energize

Ararat Wind Farm, Australia’s third largest wind farm, uses enhanced silicone polymer (ESP) insulators on the 132 kV powerline to reduce weight, improve speed of installation and increase span lengths. These insulators are also bird resistant which is critical because the powerline is located in a high bird strike zone.

The Ararat wind farm, which is located 180 km northwest of Melbourne and between 9 and 17 km northeast of Ararat in Victoria, is a 75 turbine, 240 MW facility. It spans more than 5000 ha of land owned by 17 separate landholders.

The construction of the wind farm was a joint venture between Downer and GE and the project also benefits from a power purchase agreement with the Australian Capital Territory Government (ACT), guaranteeing the purchase of approximately 40% of the energy produced at the site, which was awarded under the ACT’s Wind Auction announcement in February 2015.

Fig. 1: Ararat Wind Farm’s substation.


Beon Energy Solutions recently delivered Ararat Terminal Station (ARTS) and an associated 22 km transmission line which will link Ararat Wind Farm to the national power grid. The project was completed 22 days ahead of schedule and will help to power more than 123 000 homes by connecting Australia’s third largest wind farm to the National Electricity Market.

Fig. 2: Powerlines evacuating power from the Ararat Wind Farm.

The transmission line component of the project involved the installation of 106 steel mono poles, each between 22 and 28 m in height, 132 km of overhead conductor and 22 km of optical fibre cabling for data transmission.

Fig. 3: Steel mono poles with polymer insulators.

One of the many highlights of the project is the use of enhanced silicone polymer (ESP) insulators on the 132 kV powerline. This was the first time this type of insulator was used, as it is usual for porcelain insulators to be used in such installations.

The ESP insulator provides a braced arrangement which is stronger and can withstand higher loads than the porcelain equivalent. This allows for longer spans which lead to a reduced number of structures, with the associated financial benefits, for the project.

Enchanced silicone polymer

The need for polymer insulators results from transmission voltages which range from 500 to 750 kV and beyond, where the loading from porcelain and glass insulators becomes extreme. In recent years, the polymer has been improved to become ESP and since 1986 has remained essentially the same with a unique blend of durability, mechanical strength, tracking resistance, hydrophobicity and longevity in the environment. Since the ESP insulator is substantially lighter than porcelain, it saved significant time in construction in this project. Furthermore, the ESP insulator is also bird resistant which is critical as the powerline is located in a high bird strike zone.

With over 1,6-million ESP insulators and arresters in service in Australia alone and over 40 years of field installation experience there has been only one insulator reported with serious bird damage and even that instance did not result in a field failure. Polymer insulators provide exceptional capacity to resist conductor failure and share load between insulators.

In areas where large birds pose a risk to electrical infrastructure, ESP insulators prove their worth by not attracting birds and resisting damage done by them. This gives transmission and distribution engineers an additional resource to help ensure optimum value and long term service when building lines. In today’s environment, a utility cannot afford to build a line and then return within a year to replace damaged insulators or even worse deal with an outage condition or dropped line generated by a failed insulator.


This article was published in the February/March 2017 edition of APT’s Transmission and Distribution and is republished here with permission.

Contact Bruce Neaves, Bri-Tech,


Related Articles

  • Wild Fire Fiasco: California utility’s decision to shut off power to avoid wild fires backfires
  • Eskom rejects Nersa’s decisions regarding MYPD4 – heads to court; Nersa responds
  • US energy giant says renewables and batteries beat coal, gas and nuclear power
  • Industry collaboration determines renewal and modernisation at NETFA
  • Partnership allows for global solar PV distribution