On the 20 December 2007 at 04:12:57 hrs (AEST), the Sheffield Burnie No.1 220 kV transmission circuit and the Sheffield Burnie No.2 110 kV transmission circuit tripped. Severe lightning activity was present in northern Tasmania at the time of the line trips. The fault condition resulted in a significant transient depression in system voltage in Tasmania. This led to a commutation failure at the George Town converter station for the Basslink HVDC Interconnector. Coincident with the initial voltage depression was some loss of load and the subsequent voltage recovery on clearance of the fault resulted in the switching out of Basslink filters, which resulted in a loss of link signal being issued and FCSPS initiated load shedding. Consequently, the power flow on the Basslink interconnector reduced to 50 MW from 350 MW into Tasmania.
This report has been prepared under clause 4.8.15 of the Rules to assess the adequacy of the provision and response of facilities and services and the appropriateness of actions taken to restore or maintain power system security.
This report is largely based upon information provided by Transend, Basslink Pty Ltd and Roaring 40s.
For further information on this document, please contact: Michael Lyons, Head of System Operations Planning and Performance.
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Power System Incident Report: Multiple Contingency Event -Trip of Sheffield-Burnie 220 kV & 110 kV Transmission Circuits - 16 Jun 2008 filename: 232-0093.pdf |