What happens to the turbine speed when load increases?

When the load on a turbine increases, the speed of the turbine typically decreases. This is particularly relevant in systems where turbine generators are used. As the demand for power increases, the turbine must supply more energy, which often leads to a decrease in speed if the energy input does not adjust immediately to meet the higher load demand.

The reason for this behavior is tied to the basic principles of energy conversion and mechanical inertia. When the load increases, the turbine experiences a higher resistance against its rotation, which can lead to a drop in its rotational speed until the governor or control system responds appropriately by adjusting the fuel or steam input to match the load demand. This response time can result in a transient decrease in speed until balance is achieved.

While there are different types of governors and control mechanisms that can influence how speed changes with load, the general principle remains that an increase in load corresponds to a decrease in turbine speed if the system isn't immediately adjusted to match that load. Therefore, the correct understanding of the relationship between load and turbine speed is that an increase in load results in a decrease in speed as the turbine reacts to the additional demand.