Vacuum interrupter assembly for a power diverter switch, comprising: - a vacuum interrupter which is configured to open and close associated electrical contacts in a vacuum, - a driving mechanism which is coupled with the vacuum interrupter and which is configured to drive opening and closing of the electrical contacts of the vacuum interrupter, wherein the driving mechanism includes a driving rod and a guiding tube enclosing the driving rod such that the driving rod is axially movable inside the guiding tube along a longitudinal axis of the vacuum interrupter assembly, - a damping unit coupled with the driving mechanism and comprising a first chamber, a second chamber and a piston arranged there between with respect to the longitudinal axis, wherein the chambers (21, 22) are coupled with each other hydraulically and limited by the guiding tube and the piston, and wherein the piston is coupled with the driving rod axially movable along the longitudinal axis such that in interaction with a fluid the damping unit provides hydraulic damping both when opening and when closing the electrical contacts of the vacuum interrupter due to movement of the driving rod and the piston, characterized in that the damping unit further comprises a first disc and a second disc fixedly arranged to the guiding tube at opposite sides of the piston with respect to the longitudinal axis limiting the first and the second chamber (21, 22) respectively, wherein the first disc, the second disc and the piston all are arranged axially with respect to the longitudinal axis inside the guiding tube and enclosing the driving rod such that the first disc and the second disc are connected to the guiding tube and the piston is connected to the driving rod and all are arranged radially between the guiding tube and the driving rod. - a vacuum interrupter which is configured to open and close associated electrical contacts in a vacuum, - a driving mechanism which is coupled with the vacuum interrupter and which is configured to drive opening and closing of the electrical contacts of the vacuum interrupter, wherein the driving mechanism includes a driving rod and a guiding tube enclosing the driving rod such that the driving rod is axially movable inside the guiding tube along a longitudinal axis of the vacuum interrupter assembly, - a damping unit coupled with the driving mechanism and comprising a first chamber, a second chamber and a piston arranged there between with respect to the longitudinal axis, wherein the chambers (21, 22) are coupled with each other hydraulically and limited by the guiding tube and the piston, and wherein the piston is coupled with the driving rod axially movable along the longitudinal axis such that in interaction with a fluid the damping unit provides hydraulic damping both when opening and when closing the electrical contacts of the vacuum interrupter due to movement of the driving rod and the piston, characterized in that the damping unit further comprises a first disc and a second disc fixedly arranged to the guiding tube at opposite sides of the piston with respect to the longitudinal axis limiting the first and the second chamber (21, 22) respectively, wherein the first disc, the second disc and the piston all are arranged axially with respect to the longitudinal axis inside the guiding tube and enclosing the driving rod such that the first disc and the second disc are connected to the guiding tube and the piston is connected to the driving rod and all are arranged radially between the guiding tube and the driving rod.