1. The turbine of a hydroelectric power station usually operates at a fixed speed and the water height changes slowly, but the load on the unit changes frequently. The characteristic curve of a hydraulic turbine at fixed rotation speed and water height is the operating characteristic curve of the turbine.
2. Among the parameters that represent the operating state of a hydraulic turbine, in addition to efficiency, an operating characteristic curve of a hydraulic turbine can be obtained by taking one of them as a parameter.
3. From the operating characteristic curve, we can see the no-load opening of the turbine and the corresponding flow rate.
4. When the power is zero, the flow is not zero. The flow rate here is called no-load flow, and the opening of the corresponding guide vane is called no-load opening.