Generally from the distribution panel of the A-phase ammeter transformer (series common) to obtain the sampling current, but also can be set up separately transformer to obtain the sampling current. The transformer from which the reactive power compensation controller is to sample current is installed in the main distribution panel.

Reactive power compensator is a compensation device, in the electronic power supply system to assume the role of improving the power factor of the grid, reduce the power supply transformer and transmission line losses, improve power supply efficiency, improve the power supply environment. So the reactive power compensation device in the electric power supply system in an indispensable and very important position. Reasonable choice of compensation devices can be done to reduce network losses, so that the quality of the power grid to improve. On the contrary, if the choice or use of improper, may cause the power supply system, voltage fluctuations, harmonic increase and many other factors.