April 10, 2015
Kingaroy residents, especially those on the northern and western sides of town, may be experiencing more blackouts than they should be.
southburnett.com.au has been told by electrical industry sources that aged infrastructure at Ergon Energy’s Doonkuna Street zone sub-station, which distributes power to Kingaroy, could be the reason for some of the recent power outages in the town.
Two 66,000 volt lines come into the Doonkuna Street sub-station from Tarong Power Station.
The electricity is then routed through two transformers to knock it down to 11,000 volts before it is distributed out on six feeders: to Wooroolin, Coolabunia, Kumbia and three into Kingaroy (North, East and West).
southburnett.com.au was told heavy duty switches at Doonkuna Street date back to the 1960s.
However, in recent years they have been mated with new high-speed electronic controls.
Insiders believe this has led to “super sensitivity” at the sub-station, causing switches designed to protect equipment to trip unnecessarily, particularly on the Kingaroy North feeder which supplies power to the northern and western parts of Kingaroy, including Kingaroy Hospital.
For example, a lighting arrestor on a distribution sub-station in Moore Street, Kingaroy, recently failed in the early hours of March 31 – days after it had been struck by lightning.
These sub-stations (large boxes on poles) reduce the voltage from 11,000 to 240 volts for distribution to local homes and are dotted throughout Kingaroy.
The Moore Street failure, we were told, should have led to a blackout in the immediate area only, however eventually about 3000 Ergon Energy customers in Kingaroy and Wooroolin lost power, along the Northern and Wooroolin feeders.
About 1700 customers were blacked out initially and then a further 1400 customers were affected for a shorter period as part of “switching operations”, according to the official Ergon Energy statement.
The failure in Moore Street somehow caused a trip down the line in the Doonkuna Street sub-station, something which should not have happened.
And, we were told, these unknown “trips” at the zone sub-station are far more frequent than they should be.
Ergon Energy is planning to start construction of a second zone sub-station to service Kingaroy in 2018. This will be located in River Road and will run in conjunction with Doonkuna Street.
However, there are apparently no upgrades scheduled at the existing zone sub-station.
“They should do some work at Doonkuna Street before the new sub-station is built,” one insider said.
“Doonkuna Street is past its use-by date and we are wearing the problem as a result.”
Footnote: Ergon Energy was approached for a comment but southburnett.com.au received no reply before our deadline.
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