It's very simple, because of the number of induction coils. The coils required to reach full power at 1800 rpm are less than those selected at 1500 rpm. In today's wind power situation, cost reduction means survival.
In addition, because of the specific wind speed of the wind field, the wind speed is fast and the blade cutting surface is large, so it must be designed to rotate at 1800 rpm.
The rated power of wind turbines is generally divided into three types
The first is small 100KW for home use
The second is 500KW for mountainous use
The third is the grid-connected operation of large-scale units and power systems above 1,000Kw
The power is 1,000KW.H, although it is much different from the 300,000KW per hour of thermal power generation
But it is still no problem to supply a city or industrial area
You said that the blades of the wind turbine rotate very slowly. Let me explain.
The rotation speed of the generator should be 3000 rpm. Only a generator can generate electricity
But it is impossible to have such a fast wind speed
So there is a large variable speed gearbox inside the wind turbine to make the low-speed blades move in the gearbox. Under the condition of variable speed, the speed is increased to 3000 rpm, and then the reactive power is released through the capacitor to excite the generator stator to generate electrical energy. Generally, the generated electricity is 690V, which is raised to 200KV through the substation and sent to regional substations to supply electricity to households and businesses.