Top Energy electrical engineers think they have found the fault that caused the power outage that impacted homes and businesses across Northland on Friday. They suspect that there may be a broken insulator in the electricity substation in Kaikohe and are co-ordinating with Transpower to de-energise the assets and start repairs as early as this afternoon.
The company will attempt to fix the equipment without disrupting power supplies but warns that should the insulator fail again an outage will occur and will impact the entire Mid and Far North.
Engineers were conducting extensive testing over the weekend and all day today. Together with engineers from Transpower they analysed the sequence of protection mechanisms which operated on Friday. A corona camera was used in the early hours of Saturday and Sunday mornings to measure the level of electrical discharge from the insulators within the substation and lines. Early morning is when arcing is most likely to occur due to the presence of dew. Nothing out of the ordinary was detected.
Today they dug deeper into the protection operation and settings and commissioned acoustic testing on the Kaikohe substation, which Top Energy acquired from Transpower in 2012.
“We acquired these assets from Transpower at the end of their life-span and in very poor condition, precisely because we felt they were a priority for the security of the electricity supply in our region,” said Russell Shaw, CEO of Top Energy.
“Since acquiring the Kaitaia and Kaikohe substations we have been flat-out conducting asset replacement and renovation works. Over the past 12 months alone we have spent $5m on upgrading this particular asset. It’s frustrating that we hadn’t yet replaced the piece of kit which likely caused Friday’s outage.”
Mr Shaw said that two years ago one of the transformers at Kaitaia substation also failed, although Top Energy was able to manage that incident without cutting power to the town. This was also one of the assets the company bought from Transpower in 2012. The transformer was replaced with a new unit in March of this year.
“We’ve been refurbishing and replacing these assets as quickly as we possibly can,” Mr Shaw said.
“We apologise sincerely for Friday’s disruption and I can assure our business and domestic customers that we will keep up the pressure to bring these assets back up to the standard that we require and that they, quite rightly, demand of us.”