PHT Project

600 kW, NY

Year: 2015
Running Gear: 3- generating units: One Francis turbine with gearbox and synchronous generator, one Francis turbine with direct-connect synchronous generator, and one propeller turbine with gearbox and induction generator.
Scope: Replacement control system.

This hydroelectric plant started generating mechanical power to run a textile mill in 1810.  Later, it powered a paper mill.  The present generation equipment was installed 1981: it is one of the small independent hydro plants built just after the federal PURPA legislation was passed in 1978.  In 2015, the existing control system included pneumatic lines controlling contactors and wicket gates, and at one point headpond level sensing was acquired using a float and over 200 feet of steel cable.  PHT was contracted to replace the plant controls with modern automation equipment.

In December 2015, after months of preparation designing and building the control system at our facility in NC, PHT began on-site work in NY.  This included replacing the old low-pressure wicket gate operators with a new hydraulic system, replacing the old mechanical switchgear with new vacuum contactors, and installing new generator protection relays.  The entire original control system was replaced, which eliminated the leak-prone pneumatic system.  Additional sensors, such as water level, temperature, vibration, oil level, and speed were added.  

Now the plant is fully automated to allow largely un-manned operation – generators will automatically synchronize when needed, and the plant can be monitored and controlled remotely.  Automatic pond level control allows optimal use of stream flow, which varies greatly due to upstream activity.  Using the new vibration sensors, it was found that one unit had higher than normal vibration near an output of 210 kW.  The controller was programmed to automatically avoid this rough zone, reducing wear on the equipment.

This is the third project completed by PHT for this customer, an investor backed company that owns several hydroelectric sites in the eastern US.

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