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  Pacific Gas & Electric – Poe U2 Restart
Pacific Gas & Electric – Poe U2 Restart

Ivyland, PA – Pacific Gas & Electric (PG&E) has selected American Governor Company (AGC) to provide digital governor equipment, engineering, project management, and start-up services to convert the second Pelton mechanical governor at Poe to digital control. AGC converted the Unit 1 governor in 2014, but in 2016 PG&E put the conversion of the second unit on hold due to scheduling conflicts with their construction department and a reshuffling of project priorities.

Construction of the Poe penstock and powerplant began in 1953 and was completed in 1958. Located on the North Fork of the Feather River 28 miles northeast of Oroville, the Poe powerplant has been owned and operated by PG&E ever since. During a typical year the plant reliably generates over 500 gigawatt-hours of clean, renewable electricity.

The Poe powerplant is comprised of two Francis turbines (Pelton Water Wheel Company) driving two 71.4MW generators (General Electric). Although the generators were rewound in 1985 by GE, the original Pelton turbines and mechanical governors have remained in service, largely unchanged, since commissioning in 1958. AGC has provided PG&E with spare parts, field service, and training support since its start in 2000.

While spare parts and support for Pelton mechanical cabinet actuators remain available from AGC, PG&E elected to convert these governors to digital control to better integrate the units with their Supervisory Control and Data Acquisition (SCADA) system in order to better participate in the new electricity market structures created by the California Independent System Operator (CAISO).

AGC will utilize PG&E’s preferred Allen-BradleyControl Logix™ family of controllers and input/output modules, and the new equipment will be mounted in an enclosure that replaces the original Pelton governor front panel.

Existing field wiring terminal blocks will be utilized as much as possible to minimize installation time and simplify troubleshooting. A secure DNP3 communication module will be used to integrate the governor system with PG&E’s plant control and SCADA systems.

Comprehensive start/stop, mode-select and load-following capabilities will be provided both locally and remotely, as the plant is typically not staffed.

Maintenance will be minimized by replacing the existing Pelton mechanical flyball assembly, dashpot, feedback links and levers with the simple and elegant AGC ElectroHydraulic Interface (EHI). Redundant speed sensing will be provided through modification of the existing Pelton PMG and addition of high-precision Potential Transformer (PT) speed sensing. In the turbine pit, the existing cable restoring mechanism will be replaced with modern, high-precision electronic position sensing.


About American Governor Company
American Governor Company provides fully engineered digital governor conversion systems for hydro plants, including PLC-based digital controls, electro-hydraulic valve manifolds, hydraulic power units, electronic feedback devices and unit/plant control and monitoring systems. Installation, start-up, commissioning and field training services are provided by our staff of experienced governor specialists and field service engineers. American Governor also provides full support for legacy governor systems, including a complete line of replacement parts for all types of Woodward governors and a growing inventory of new and reconditioned parts and assemblies for other OEM governors. American Governor offers Field Service, Training, Retrofit kits and Technical Support for legacy governors. The Training and Repair Facility near Stevens Point WI offers factory repair services for governor pumps and permanent magnet generators as well as our annual Governor School and twice yearly Focus Classes. American Governor has provided more than 600 digital governor upgrades and has supported over 1,500 hydropower plants in North America.

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