The disorderly charging of a large number of electric vehicles (EVs) can cause load fluctuations, peak-valley differences, active power losses, and even voltage limit violations at distribution network nodes. However, four-quadrant smart charging facilities with bidirectional vehicle-to-grid (V2G) capabilities can be regulated to serve as reactive power support devices, optimizing the operation of the distribution network. This paper is based on the active power demand of mobile charging facilities under orderly EV charging and discharging, taking into account the reactive power support capabilities of distributed gas turbines, on-load tap changers, shunt capacitor banks, and other reactive power compensation devices. It studies the optimization strategy for the coordinated participation of mobile and fixed charging facilities in reactive power compensation in the distribution network, aiming to improve the stability and economic efficiency of the distribution network operation.