PHT Project

550kW, NC

Year: 2011
Running Gear: A single 550kW Francis turbine and synchronous generator.
Scope: Replacement of the control system and switchgear.

This hydroelectric plant is located at a historic cotton mill site that has used hydropower in various forms since 1835. The current owner/operator selected PHT to upgrade the controls and switchgear in 2011.

The PHT designed system replaces an assortment of older, less reliable equipment that was difficult and expensive to maintain, and provides numerous added features for easier and more efficient operation. This project controls numerous water-control gates using distributed controllers and fiber-optic network communications.  

One unique feature developed by PHT is feed forward water level control, implemented by reading the USGS gages upstream from the plant, and automatically adjusting the headpond level setpoint.  Due to other hydroelectric plants upstream engaging in peaking operations, river flow can vary from 50 CFS to 1000 CFS and back again, over just a few hours.  By reading gages located far enough upstream to provide several hours advance notice of changing flow rate, the control system anticipates these large changes in headpond inflow, reducing spillage over the dam and increasing production.

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