Manby H1L15 Breaker Incident - July 5, 2010 - IESO

Manby H1L15 Breaker Incident - July 5, 20105. System Impact5.2 Impact on Tie LinesThe Michigan and New York tie-lines saw an increase of 725 MW and 690 MW out ofOntario respectively. Flows were restored to pre-contingency levels within 12 minutesfollowing IESO operator efforts made to reduce ACE to 0 MW. No adverse impact wasreported by the IESO’s neighboring reliability coordinators.Eastern Standard Time (seconds)Figure 5 Ontario to Michigan and New York Tie-Line Flows – July 5 th , 20105.3 Impact on Load & VoltagesApproximately 1550 MW of load was interrupted as a result of the multiple fault occurrencesat the Manby West and East yards. Ontario demand dropped from 24,509 MW to 22,915MW causing voltages to rise at multiple 230 and 500 kV stations in Southern Ontario as theneed for reactive support was diminished by the loss of load. Voltages were quickly reducedto pre-contingency levels through the re-dispatch of both static and dynamic reactiveresources. The voltage profile at the Richview 230 kV switching station, locatedapproximately seven kilometers from Manby, shows this response in the following figure.October 20, 2010 Public 13