Reactive compensation controller and control method for small hydropower line

The invention discloses a small hydropower line reactive compensation controller and a control method. Comprising an automatic control module, the automatic control module is connected with a vacuum contactor, and the vacuum contactor is connected with a capacitor; the self-control module judges whether the reactive power value is within a preset range, and if yes, a closing signal is sent to the vacuum contactor; the self-control module obtains real-time reactive data at the grid-connected point to determine a reactive quantity; reactive compensation data near a grid-connected point can be collected in real time, a vacuum compensation controller is automatically adjusted, and the voltage near the grid-connected point is maintained in a reasonable interval; when the line is under-compensated for reactive power, the voltage of the line is low and the input voltage of the capacitor is increased, and when the line is over-compensated for reactive power, the voltage of the line is high and the quit voltage of the