Active equalization circuit and active equalization method and device of transformer substation direct current system

The invention discloses an active equalization circuit and an active equalization method and device of a transformer substation direct current system. The active equalization circuit comprises a plurality of battery packs, a plurality of mutual inductors and a plurality of switches, each battery pack comprises two battery units; the battery units are connected in series; the mutual inductor comprises a first mutual inductor, a second mutual inductor and a third mutual inductor; the switches comprise a first switch, a second switch and a third switch; the first end of each first mutual inductor is connected with each third node, and the second end of each first mutual inductor is connected with each second node; the first end of each second mutual inductor is connected with each first node, and the second end of each second mutual inductor is connected with the second stage of each second switch and the first stage of each third switch; the first end of each third mutual inductor is connected with each second