Hydro Control Systems

PHT specializes in small hydro control systems. We integrate commercially available components from trusted names, with custom software and programming specific to each plant, to provide reliable, cost-effective solutions. Standard features reduce cost and save time, while ensuring all aspects of your plant work together for optimal results, from under 100kW, to over 10 MW.

PHT’s proven PLC based control systems are optimized for the needs of smaller and run-of-river hydro operations, and are designed for grid-tied plants that operate unmanned most of the time. PHTs controls provide an integrated control and protection solution, and provide the operator with complete control and status of unit operation, either on-site, or through remote access.

Unit Controls

  • Automatic start/stop sequences, including automatic synchronization - start-up and export power at the touch of a button
  • Automatic headpond level control and recording to maximize production - Automatic headpond level control is essential for run-of-river facilities that need to respond to changing inflows, and make the most of the water available.
  • Governor, contactor, exciter, protection and more are all monitored and controlled through a single interface
  • Automatic control of contactor, exciter, and wicket gate operator/governor ensure flawless event timing
  • Failure protection (reverse power, overspeed, phase-current imbalance, bearing overtemp, low auxiliary battery, low water, high water flood conditions, and more) protect equipment from costly damage
  • Automatic re-starting - if your plant trips offline due to grid power disruption, auto-restart ensures you are back up and producing power under all safe conditions.
  • Control brakes, cooling water, lubrication, and much more - All I/O points and unit controls are designed for the specific needs and budget of each plant.

Operator Interface

PHT's touch screen user interface is state of the art and easy to use. All of the information you need to safely and reliably operate your plant is right at your fingertips. You always know the status of unit operation, and have control over the entire system, both on site, and remotely through a secure internet connection.

PHT's intuitive touchscreen graphical user interface puts the operator in charge of the entire system from one location.

  • Alarms, data logs, trends, and notifications clearly communicate system status
  • Remote control – secure web-based remote access and control from PCs or mobile devices
  • Standard screens display critical information, and allow manual control, configuration, and troubleshooting of the entire system.
  • Notification of events by email or text message - web enabled locations ensure the operator is always informed of the current status of unit operation.
  • Alarm logs and displays - fully detailed and in plain English
  • Data logging and visualization is clearly communicated through standard tables and graphs
  • Automatic email reports provide plant statistics, such as production, up time, and water level charts.  Daily, weekly, monthly and annual reports provide useful, condensed information for making decisions and improving operations
  • Custom reports and data logs can be automatically generated for regulatory compliance.

Station Control

Software Features

  • Unit Dispatch – Software will automatically determine best combination of turbines to use at a given flow.  This can either advise the operator, or automatically start and stop generators as needed.
  • Optimal flow sharing  - Coordinate any number of generators to optimally use flow between multiple units, maximizing power production.
  • Variable headpond level control – coordinate with flow fluctuations caused by upstream operations.  Increase production by reducing spilled water.
  • Load scheduling – vary power output according to an easily-adjustable schedule
  • Auxiliary Systems

Control Equipment

  • Inlet valves or headgates
  • Turbine outlet gates / dewatering
  • Spill gates
  • Bypass flow – automatically regulate and measure bypass flow for FERC compliance
  • Automatic trashrack control - based on differential across rack, operates trashrack cleaners only as needed to balance reduced power production with unnecessary wear on trashrack equipment
  • Interior and exterior lights
  • Web cams
  • Backup generator
  • Air compressor
  • Transformer protection – Differential relaying, temperature, Buchholz relay

Generator Protection

  • Integrated, digital multifunction generator protection relay
  • Multiple temperature sensors on bearings and stator ensure proper operating temperatures are not exceeded
  • Optional vibration sensors detect out of balance conditions and other mechanical problems, avoiding costly damage

The utility grade, Basler BE1-11g multifunction generator protection relay is standard, and provides many protective features, including:

  • Phase and Ground Overcurrent (50/51P, 50/51Q, 50/51N)
  • Over/Under Voltage (59P/27P)
  • Loss of Excitation (40Q)
  • Over/Under Frequency (81O/U)
  • Reverse Power (32)
  • Sync Check (25)

Additional generator protection can be provided as needed:

  • Differential relay
  • Field ground protection
  • Redundant relaying
  • Vibration sensors
  • Shaft runout sensors

Excitation Control

  • Standard Payne solid-state exciter for synchronous generators
  • PLC provides automatic power factor and voltage regulation modes
  • Keeping power factor in tolerance avoids costly utility charges, and keeps generators running cool and efficiently


  • Electro-hydraulic actuators for turbine flow control
  • Replace traditional mechanical governors, reducing complexity and maintenance cost
  • Single-axis Francis operators, up to six-nozzle Peltons with jet deflectors
  • Complete range of control functions for all types of hydro turbines

Our governors use AC hydraulic power units, with hydraulic actuators controlled by the PLC.  Several control modes are available, each with many settings to provide detailed control.

  • Synchronization – Seek and maintain proper speed and phase angle to match grid power
  • Level control - follow the water level controller’s commands for power output.
  • Load control – maintain power output specified by the operator
  • Frequency control – maintains steady speed when running off-grid
  • Manual gate position – used when offline, for turbine maintenance

Additional Governor Features

  • Gate position and rate limits
  • Optimized efficiency with 3D-cam or needle valve control
  • Rough zone avoidance
  • Black start capability
  • Redundant pumps and sensors

Hydropower Automation

  • Generator Protection
  • Excitation
  • Governor
  • Unit Controls

Control one or many generators, synchronous or induction

Grid-connected, off-grid, or dual-mode operation.

All turbine types supported – Francis, Kaplan, Pelton… even waterwheels

New projects, or upgrades to existing facilities


It is important to PHT that both you and your equipment are protected. Systems are designed with safe operation as the highest priority. All systems are supplied with industry spec lockout, tag-out features.


Bench testing of systems and components is completed before delivery. PHT control systems are designed by and for small hydro owner/operators - people who use these systems every day, and are responsible for maximizing power production by finding ways to increase up time.


We offer complete on-site training and commissioning for start-up of small hydro control systems. We also provide comprehensive documentation, including a user’s manual.  And, to ensure every detail is correct, one year of technical support is included with every system.


Our products proudly come with a one-year parts and labor warranty.

We strive for technical excellence; our control systems will increase up time, and help your plant make more power.

Call or email us to discuss a solution that's right for your hydroelectric facility.