PHT Project

340 kW, VT

Year: 2015
Running Gear: Two vertical shaft Kaplan turbines with belt driven induction generators
Scope: Control system for two new generating units at a historic mill site

Purchased in 2009, the owners of this historic mill property committed to extensive restoration and environmental cleanup of this brownfield site.  In 2015, the new hydro generating facility designed for the existing dam and mill building became the second hydroelectric project commissioned in Vermont in the last 35 years (PHT also supplied controls for the first).

The two new turbines, generators, and hydraulic power units (HPUs) were supplied by Ossberger, while PHT was selected to provide a new control system to operate the new hydroelectric power plant.  Switchgear was provided by the customer’s electrical engineer.

In addition to the standard features of a hydro control system, most projects have at least a few unique or additional requirements particular to that site. While not unheard of, one example at this site is that the interconnecting utility, Green Mountain Power, required transfer trips for this plant.  This allows GMP to manually or automatically shut down the hydro generation as needed.  GMP installed a pole-mounted recloser and SEL-351R controller, and also provided an interface cabinet inside the control room. PHT worked with GMP to interface the transfer trip equipment with the hydro control system.  Once the equipment was all installed, GMP engineers came to the site to review the controls. After a single afternoon of testing, GMP approved the plant for commercial generation to their system.

As is typical for PHT projects, Piedmont Hydro Tech designed and built the control system at our facility in NC, and installed and commissioned the new equipment on site in Vermont to bring the new power plant online.

An article from a local news service on the project can be found here:


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