April 5 (Reuters) - ITC Holdings Corp will turn on power transmission equipment along the Michigan-Ontario border on Thursday which is expected to improve power flow reliability. The long awaited phase angle regulator (PAR) transformers are designed to improve the reliability of the transmission system by controlling unscheduled flows of power around Lake Erie, which could save consumers around the lake in Ontario, Michigan, Ohio, Pennsylvania and New York millions in electric costs. The following is a timeline for the PARs: 1975 - Ontario Hydro's Keith PAR in Ontario enters service. This is the first of the five PARs on the Michigan-Ontario interface and was originally installed to control local flows between Michigan and Ontario Early 1990s - Unscheduled power flows on the transmission lines in Ontario, known as the Lake Erie loop flow, increase significantly, using up transmission capacity and leading to curtailments of power transfers between Ontario, New York and Michigan 1998 - Detroit Edison, the former parent of ITC, and the former Ontario Hydro develop plans for Detroit Edison to install a PAR at Bunce Creek in Michigan and Ontario Hydro to install two PARs at Lambton in Ontario. The Lambton PARs are for two separate lines that connect the Ontario and Michigan grids. Ontario Hydro is later broken into several companies, including transmission firm Hydro One 1998 - Detroit Edison applies with U.S. Department of Energy to modify a presidential permit to allow for installation of the Bunce Creek PAR 2000 - Swiss-Swedish multinational ABB delivers first PAR to Lambton 2000 - Department of Energy grants presidential permit to ITC for Bunce Creek PAR 2001 - First PAR at Lambton fails, has to be returned to ABB for rebuild 2002 - ABB delivers second PAR to Lambton 2003 - The original Bunce Creek PAR, also made by ABB, fails while in service in March. Shortly afterward, the tower supporting the Canadian side of the Bunce Creek-Scott transmission line collapses in bad weather 2005 - ABB delivers first PAR back to Lambton, Hydro One says it is ready to operate the Lambton PARs 2006 - The tower and line for the Bunce Creek-Scott line are replaced. ITC orders two new PARs from Smit Transformer of the Netherlands to replace Bunce Creek PAR that failed in 2003 2008 - New York Independent System Operator says Lake Erie loop flow costs state's market almost $100 million in first seven months of the year. The ISO said PARs would have helped reduce transmission congestion 2008-2009 - Smit Transformer delivers the two PARS to Bunce Creek 2009 - ITC applies with Department of Energy to amend presidential permit to replace the failed Bunce Creek PAR with two PARs 2010 - ITC completes installation of new Bunce Creek PARs Aug 2011 - ITC and Midwest ISO complete operating agreements with Ontario power grid operator IESO and Hydro One 2011 - ITC and Midwest ISO working on cost-allocation agreement with New York ISO and PJM power grid operators before FERC, and settlement for presidential permit before the Department of Energy Q1 2012 - Department of Energy approves of presidential permit. Q2 2012 - ITC turns on the Bunce Creek PARs. Cost allocation dispute between ITC, MISO, PJM and New York ISO at FERC ongoing.