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April 7, 2020
The role of water turbine governor
The equipment usually uses the control guide vane servomotor (or paddle servomotor) to operate the oil quantity, so as to promote the opening of the guide vane (propeller blade) to control the size of the water flow of the hydro turbine, and The speed of the hydro turbine can be adjusted, which is the speed regulation function of the hydro turbine governor.
The main function of the water turbine governor is to adjust the flow into the hydro turbine according to the increasing and decreasing trend of the generator load, so that the output of the hydro turbine can adapt to the external load, and can also keep the speed stable within the rated value. So as to ensure that the frequency (f = 50Hz) does not change or changes within the allowable range.
The hydro turbine governor can automatically and manually start and stop the unit and stop the accident. When the units are operated in parallel, the load between each unit will be automatically distributed. The basic functions are as follows.
1. It can automatically adjust the speed of the hydro-generator set so that it can keep normal operation within the allowable deviation of the rated speed, so as to meet the standard requirements of the power grid for frequency quality.
2. The water turbine governor can allow the hydro-generator set to obtain a quick start effect in an automatic or manual manner, adapting to the increase and decrease of the load of the power grid and the needs of normal shutdown or emergency shutdown.
3. When the hydro-generator set runs in parallel in the power system, the hydro-hydro turbine governor can automatically assume the predetermined load distribution to allow each unit to achieve economic operation.
4. The speed governor can also meet the need of double co-adjustment of rotary and impact hydro turbines.
Structure of governor of water hydro turbine
The main structure of the governor is usually composed of automatic adjustment mechanism, control mechanism, hydraulic equipment, protection device, monitoring instrument and other parts.
1. The structure of automatic adjustment mechanism is composed of flying pendulum, pilot valve, buffer, servomotor, main pressure distribution valve, permanent adjustment number difference mechanism and transmission lever device of feedback mechanism.
2. The control mechanism of the hydro turbine governor is composed of three parts: a speed change mechanism, a manual operation mechanism and an opening restriction mechanism.
3. The structure of the hydraulic equipment includes the oil return tank, screw pump, pressure oil tank, intermediate oil tank, as well as other control electric pressure gauges, safety valves, air supplement valves, check valves and other components.
4. The protection device of the water turbine governor includes the protection of the speed change mechanism and the opening limit mechanism motor, the limit switch, the low-pressure pressure signal device of the hydraulic equipment accident and the emergency stop solenoid valve.
5. The monitoring instruments and other parts in the governor structure include the indicator, tachometer, pressure gauge, oil leaker, and oil pipeline used by the speed change mechanism, the permanent adjustment number difference mechanism, and the opening limit mechanism. Parts.
Working principle of hydro turbine governor
Under normal circumstances, the two parameters of the speed signal (that is, the frequency of the unit) and the grid frequency (given frequency) are compared, and the electro-hydraulic converter is given an operation relay command to open or close the action signal according to the phase difference value, and then Control the speed adjustment action of the water flow of the hydro turbine.
The working principle of the hydro turbine governor is based on the speed deviation when the unit load changes, and the guide vane opening is quickly and automatically adjusted to achieve the purpose of adjusting the output recovery speed n. The speed governing system must have mechanisms for measuring, amplifying, executing, and feedbacking on the speed deviation. The actuators mainly use the main servomotor to change the opening of the guide vanes using pressure oil.