Automation, arborists & new investment to bust blackouts
Local electricity generation & distribution company, Top Energy has embarked on a multi-million dollar network investment plan aimed at improving reliability, performance and security of electricity supply.
The plan includes a $4.4 million, automation programme which is nearing completion, a $2m programme to reduce the effects of lightning strikes, a 3-year, $9 million vegetation control programme and substantial new network investments in the region’s eastern districts, over the next 5 to 7 years.
According to Top Energy, the actual number of outages over the last few years has remained fairly static. But the company has noticed trees are having an increasing impact as the major cause of these outages. Currently around 50% of all outages across the network are tree related, while about 21% is caused by lightning strikes.
To reduce the effects of lightning strikes on the network the company is installing additional arresters and has a long term detailed inspection strategy aimed at identifying potentially aging equipment on the network before failure.
Under the automation programme, new reclosers, line sectionalisers and remote control switches have been installed on areas of the network, allowing the company to split feeders into smaller power consumer clusters, so that fewer consumers are affected when an outage does occur.
According to Top Energy CEO, Russell Shaw, the automated switching and isolation devices will enhance Top Energy’s ability to quickly isolate faults and restore power, thereby minimising outage impact for greater numbers of consumers. “Once this upgrade is completed, we anticipate that during an outage, affected
consumers on each feeder will be cut by up to two thirds”, he said.
The step-up in vegetation control is seen as a major strategy in the company’s outage reduction plans.
“Power consumers on our network have experienced some of the highest levels of power disruption, when compared with similar networks in other regions. This is mostly caused by trees being brought down onto lines in severe weather events, which in recent history have increased in frequency and intensity. For example, in one 3-day period last year, successive storms wreaked havoc all over the network. That event alone resulted in an average 430 minutes of outage per consumer, against our full year’s target of 460 minutes. Most scientists and observers say this is as a result of global warming and is here to stay. So whilst
we can’t do a lot about changing the weather patterns, we can be vigilant about making sure vegetation is better controlled around lines”, Shaw says.
The company has teams of arborists and specialist tree trimmer crews, based at its Kaitaia and Puketona depots. Additional staff are being trained and investment in specialist vehicles and equipment is underway.
Says Shaw, “When it comes to minimising tree related outages the community also has a direct role to play. You’d think it would be common sense to not plant trees under or near power
lines. But time and again, we see property owners doing just this. Of course small trees from the garden centre don’t look like they’d cause too much trouble, but given two or three years of rapid growth in this climate, they can quickly become a threat to the power supply.”
Where trees or shelter belts have grown too close to power lines, Top Energy will consult with property owners about the best action to take. This can include a first cut or trim (at Top Energy’s cost) where property owners declare their responsibility for ongoing tree maintenance. Where property owners are not prepared to take responsibility, the company will likely remove the vegetation altogether. For more information about tree and vegetation control around power lines, please visit www.topenergy.co.nz/safety.
Within the company’s broader network development plan, there is to be significant new investment in the region’s eastern area as well. Planning has already begun for a new 110,000 Volt bulk feeder line to Waipapa, together with major new substations in Waipapa, Kerikeri, Purerua and Kaeo. To support this, the company is also planning new dedicated 33,000 Volt feeders into Kerikeri and Russell.
These strategies are explained in further detail in Top Energy’s current Asset Management Plan, available on the company’s website, at www.topenergy.co.nz
