The existing single-circuit Colfax-Highland 69kV line, identified as #2 line, needs to be upgraded between Highland and Logan’s Ferry substations. This upgrade is one of the projects outlined in Duquesne Light’s Eastern Area Development Plan. It is the most economic way to implement Duquesne Light’s plan to improve reliability for its customers in this area.

The double-circuit 138kV line is required for the following reasons:

• Implement Duquesne’s overall strategy to eliminate 69kV as a transmission supply voltage.
• Convert the Highland substation from 69kV to 138kV, and replace existing transformers which are approaching end-of-life.
• Eliminate single-contingency overloads of the Colfax-Highland 69kV lines.
• Provide two of the three 138kV lines which are required to serve the 100MVA of load at Highland substation.
• Eliminate the contingency overloads of the Colfax 138-69kV autotransformers by transferring the 69kV load to the 138kV system at Logan’s Ferry substation.
• Increase reliability to the Highland area, including Penn Hills and Plum boroughs.