PJM approved the removal of a special protection scheme (SPS) on Conemaugh Unit 2 on Sept. 1.

The SPS was designed to mitigate transient instability conditions arising from an outage of the Conemaugh–Juniata 500-kV line, #5005. When enabled during an outage of the line, the SPS trips Conemaugh unit 2 if the Keystone-Conemaugh 500-kV line, #5003, is lost. Without the SPS, both the Conemaugh and Hunterstown generators would have had to reduce output in such a scenario.

The SPS hasn’t been used since 2011. The new Conemaugh 500/230-kV transformer and Conemaugh–Seward 230-kV line, which were placed in service in March, provide an additional outlet for Conemaugh and Hunterstown generation, rendering the SPS unnecessary.

The removal of the SPS is currently under review by Reliability First Corp.

New Mosby–BrambletonLine to Fix Overloads

Dominion Resources is adding a 500-kV line parallel to an existing 500-kV line between Mosby and Brambleton.

The new 500-kV Mosby–Brambleton line will be designated #546. The 2013 RTEP study identified overload violations on the Loudoun 500/230-kV transformers #1 or #2 for loss of the #590 Mosby–Brambleton 500-kV line. The new 500-kV line would be placed in an existing right-of-way and resolve this issue. The line (RTEP project #B2373) is expected to be in service by May 2018.