NSW Bayswater current transformer explosion triggered 1000 MW under- frequency loadshedding across the NEM, 2 July 2009

First 9 of 9 paragraphs shown At 10 45 am on 1 July 2009 an explosion and fire at a current transformer at the TransGrid Bayswater switchyard created a drop of frequency to 49 Hertz.
Fourth Bayswater yard explosion since 1998: The event appeared to happen with no warning and was described as a “random” event. The charts shows Interconnector Flow 2 changes as ancilliary services were triggered after the Bayswater explosion.
Fourth explosion of CT at this yard: There were previous incidents at Bayswater in 1995 and 1998 and 2004 involving the failure of 330 kV current transformers. Following those events in the mid to late 90’s, TransGrid installed monitoring facilities onto the current transformers, including the one that failed on 13 August 2004.
Surprised: Electricity Week was told the current Transformer had "failed explosively".
NEM frequency fell to 49 Hertz: This triggered NEM-wide underfrequency load-shedding ( blackouts and the call-on of ancillary services). The event was resolved within an hour and load restored, Electricity Week was told.
“No specific trigger”: Electricity Week was told it was a "random event" - at over one of 4000 CTs across the TransGrid system. It was ten years old; was tested every four years, and was mid-way between tets. No equipment supplier was named.
Fourth in 20 years at this location: This was the fourth such event at the Bayswater yard over 20 years. The last one was 2004, and had a similar NEM-side load-shed impact.
Last blow-out had similar 4-state blackout: On the evening of Friday 13 August 2004 at 21:41 hrs, a current transformer at Bayswater power station exploded. It led to loss of 6 big generation units in NSW.Frequency fell to 48.9 Hz, which then resulted in approximately 1500 MW of under-frequency load shedding (UFLS).
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