Hydro turbine hydraulic governor knowledge
The definition of hydro turbine governor:
Change accordingly with the change of power load, turbine guide vane changing (or needle valve stroke opening) accordingly, to keep the hydro turbine generator unit speed recovery and stay at rated speed, all this process called the hydro-turbine governing.
The task of hydraulic turbine governor:
- Along with the change of external load, rapidly change in the output of the unit.
- Keep the hydro turbine generator unit speed and frequency variation within the prescribed scope, the maximum deviation is not more than ±0.5 Hz for micro hydropower and mini hydropower system, large power system, not more than ±0.2 Hz.
- Start the unit, stop the unit, decrease and increase the load, for grid connection unit adjustment (load distribution), in order to achieve economic and reasonable running.
Turbine flow adjusting way by governor:
- For reaction turbine: single control by changing the guide vane opening angle, double control like Kaplan turbine by changing the blade Angle at the same time.
- For impulse turbine: by changing the nozzle opening (needle valve stroke)
Primary frequency modulation or Primary Frequency Regulation of your micro hydropower plant
When your micro hydropower turbine generator is on Grid connected operation, affected by the external load changes, the grid frequency changes, at this time, the regulation system of your hydro turbine generator unit will participate in the regulation to balance the unit load with the outside load. At the same time, it will also try to reduce the change of the power grid frequency; this process is the primary frequency regulation.
- Primary frequency regulation refers to when the power system frequency deviation from default, generator adjust the active efforts to reduce the frequency deviation automatically by the hydro turbine governor system.
- Grid-connected hydropower generator units must have primary frequency modulation function, otherwise don’t allow grid connected operation.
- PFR evaluation content: primary frequency regulation operation rate must be 100%, the unit primary frequency regulation artificial dead zones (within + / – 0.05 Hz) of hydropower unit control, speed control governor system change rate (hydro turbine permanent slip is not greater than 4%), the speed regulation system of delay rate (or hydro governor speed dead zone is less than 0.04%), the unit primary frequency regulation range of load adjusting (hydropower unit primary frequency regulation load limit is + / – 10% of the rated load), primary frequency modulation response behavior (including primary frequency modulation of the load response lag time (rated head in 50 meters and above should be less than 4 seconds, less than 50 meters should be less than 10 seconds), primary frequency modulation of the maximum load adjustment (all unit primary frequency regulation load adjustment should be in about 15 seconds to the theoretical calculation of the maximum load of primary frequency adjustment of 90%)).