First of all, the power generated by generators in power plants depends on the power consumption on the power grid, that is to say, the power consumption will decrease with the decrease of power equipment in the power grid. Because the generated electricity cannot be temporarily stored, the power generation load of the power plant will change according to the change of electricity consumption. When the power consumption of the power grid is too low, that is, the useful power is too small, the power factor of the generator will be too low (the power factor of the power plant is usually required to be 0.85), which will bring harm to the generator.

Danger:

Safety: When the load power factor of the generator is too low, the operating power factor of the generator will be greatly reduced, which will overload the excitation winding and even cause insulation breakdown and burning of the excitation winding.

Economically speaking, improving the power factor of electrical appliances can reduce the transmission current, and then reduce the power loss on transmission lines. If the power factor is too low, the power loss on the line will increase.

Therefore, the power load of power grid should not be too low, otherwise some generators should be stopped properly to ensure the safety of generators and power grid.