The invention relates to a device (1) and a method for controlling the stability of a local network (3). The local network (3) comprises a plurality of outgoing circuits (41, 42, . . . , 4M,), each having at least one load (5) and/or at least one decentralized energy generation system (6). Said device is provided with an on-load tap-changer (14) for adjusting an output voltage of the local network transformer (10). The device is characterized in that a unit (16) for measuring current, connected to at least one of the plurality of outgoing circuits (41, 42, . . . , 4M,), and a unit (18) for measuring voltage, connected to a busbar (8) of the local network (3), are arranged in a transformer housing (20).