1. Speeder Governor: The speeder governor is the primary governing mechanism for impulse turbines. It monitors the turbine's rotational speed and adjusts the position of the deflector (or spear valve) at the turbine inlet. By varying the deflector's opening, the governor can regulate the amount of water flowing through the turbine, thereby controlling its speed.
2. Pressure Governor: The pressure governor ensures that the pressure in the penstock (the pipe supplying water to the turbine) remains within a specified range. It works in conjunction with the speeder governor and adjusts the wicket gates at the turbine inlet to maintain a constant pressure. The wicket gates regulate the flow of water into the turbine's buckets.
3. Load Limiter: The load limiter protects the turbine from overloading. It monitors the electrical load on the turbine and automatically adjusts the deflector or wicket gates to prevent excessive load on the turbine.
4. No-Load Governor: The no-load governor prevents the turbine from overspeeding when there is no electrical load. It detects when the electrical load drops below a certain level and quickly closes the deflector or wicket gates to reduce the water flow and maintain safe operating conditions.
5. Electronic Governors: Modern impulse turbine governing systems often utilize electronic governors. These systems use sensors to monitor turbine speed, pressure, and electrical load, and employ advanced control algorithms to precisely adjust the deflector or wicket gates. Electronic governors provide precise control and fast response to changing conditions.
By combining these governing mechanisms, impulse turbines can maintain a constant rotational speed regardless of load variations or changes in water flow. Proper governing ensures efficient and reliable operation of impulse turbines in hydroelectric power plants.
