Unscheduled loop flow, a fairly significant technical problem that complicated power transmission in the Great Lakes area, is being solved after many years of effort. The IESO noted that “the ability to manage system reliability will be enhanced when the International Transmission Company puts the Bunce Creek phase angle regulators (PARs) into service.” Initial operation was scheduled to take place on April 5, 2012. The Bunce Creek PARs join PARs already in service at Ontario’s interconnections with Michigan at Lambton TS and Keith TS. Without these devices, power traded from one part of the US, say upstate New York, to another part of the US, say Michigan, might sometimes take a short cut through Ontario. Although the transfer was physically safe, it interfered with the ability to make dependable sales and purchases of power on both sides of the border.
Once this equipment becomes operational, IESO and the Midwest Independent System Operator (MISO) will begin using all available PARs on the Michigan interface to maintain power flow equal to the net import and export schedule, to the extent possible. Although operating in this mode will cause a slight reduction in transmission capability, the reduction in inadvertent power flows is expected to allow much greater utilization of the interface for energy trade. Also, the ability to directly manage flows on the Michigan-Ontario interface provides the IESO and MISO with an effective and timely means to help mitigate the impacts of outages and other contingencies.
Using the Michigan-Ontario PARs to help manage circulation (or loop) power flows through the electrical systems around Lake Erie is the culmination of 12 years of work. All affected systems will benefit from the reduced variability and quantity of circulation experienced.
See also “NYISO seeks coordination with other ISOs,” IPPSO FACTO, February 2010, and “Loop Flow traders not gaming,” August 2009.