Two-stage valve arrangement for activating a piston of a hydraulic piston/cylinder arrangement of an actuator for activating a high- or medium-voltage circuit breaker, with a pilot stage comprising at least one pilot valve (3, 4, 13), and with a main stage comprising at least one main valve (1, 2, 11), wherein • in a first position of the at least one pilot valve, a hydraulic connection is established from a high-pressure tank to the piston/cylinder arrangement via the main stage so that a fluid at high pressure is supplied to a space situated on one side of the piston, and • in a second position of the at least one pilot valve, the space situated on one side of the piston is connected to a low-pressure tank via the main stage, characterized in that a hydraulic valve serves for connection between a first fluid-conducting pressure line of an outlet side, connected to at least one control inlet of the main stage, of the pilot stage and a second fluid-conducting pressure line of an outlet side, connected to the piston/cylinder arrangement, of the main stage, wherein the hydraulic valve has only two connections and comprises: • a housing with a first channel inlet (21, 23) for attachment to the first pressure line, and a second channel inlet (24, 26) for attachment to the second pressure line, and a cavity situated between the first and the second channel inlet, • a sealing body which can move in the cavity and has a circumference which is greater, at least at one point, than the respective circumference of the opening (31, 32), adjoining the cavity, of the first and the second channel inlet, wherein the sealing body is geometrically matched to the cross-section of these openings (31, 32) such that it completely seals it when it sits on it, • a first spring element, fastened in the first channel opening (21, 23), which is connected to the sealing body on a first side and projects into the cavity in the relaxed state, • a second spring element, fastened in the second channel opening (22, 24), which is connected to the sealing body on a second side and projects into the cavity in the relaxed state, wherein the hydraulic valve is used in the valve arrangement between the first pressure line and the second pressure line such that passage is permitted up to a predefined volume flow or up to a predefined difference in pressure, and the two pressure lines are separated from one another above this predefined volume flow or this predefined difference in pressure, wherein, in this way, the hydraulic valve is made effective in both directions of the volume flow, wherein the valve arrangement is designed such that, in the static situation, when no switching takes place, the hydraulic valve keeps the connection between the pressure lines open, and wherein, in the dynamic situation, during switching, a change in the difference in pressure occurring between the pressure lines acts on the sealing body and effects a closure of the hydraulic valve. • in a first position of the at least one pilot valve, a hydraulic connection is established from a high-pressure tank to the piston/cylinder arrangement via the main stage so that a fluid at high pressure is supplied to a space situated on one side of the piston, and • in a second position of the at least one pilot valve, the space situated on one side of the piston is connected to a low-pressure tank via the main stage, • a housing with a first channel inlet (21, 23) for attachment to the first pressure line, and a second channel inlet (24, 26) for attachment to the second pressure line, and a cavity situated between the first and the second channel inlet, • a sealing body which can move in the cavity and has a circumference which is greater, at least at one point, than the respective circumference of the opening (31, 32), adjoining the cavity, of the first and the second channel inlet, wherein the sealing body is geometrically matched to the cross-section of these openings (31, 32) such that it completely seals it when it sits on it, • a first spring element, fastened in the first channel opening (21, 23), which is connected to the sealing body on a first side and projects into the cavity in the relaxed state, • a second spring element, fastened in the second channel opening (22, 24), which is connected to the sealing body on a second side and projects into the cavity in the relaxed state,