Abstract: A detection device to detect an operating condition of air-drying salts contained in a breather for power transformers operatively coupleable to the breather is described. The detection device comprises illumination means comprising at least a light source adapted to illuminate airdrying salts contained in the breather with a first light radiation. The detection device also comprises acquisition means comprising at least a light sensor adapted to receive a second light radiation coming from air-drying salts contained in the breather. The acquisition means is configured to provide first detection signals indicative of the color of the second light radiation. The detection device further comprises a control unit for controlling operation of the detection device. The control unit is configured to receive and process the first detection signals.

Abstract: A pressure relief device for a power transformer provided with a tank filled with an insulating liquid, the pressure relief device including: a support flange operatively coupleable with the tank and including a through port coupleable with an opening of the tank; a valve element displaceable between a closed position, at which it obstructs the through port, and an open position, at which it is spaced away from the support flange; a protection cover fixed with the support flange and spaced apart from the support flange and the valve element; first elastic means adapted to urge the valve element in the closed position and contrast a movement of the valve element from the closed position to the open position; and at least a switch device adapted to signal a movement of the valve element from the closed position to the open position. The switch device includes a switch pin reversibly movable between a compressed position and a released position.

Abstract: A safety device is disclosed for a power transformer containing a cooling liquid, and can include a shaped body having an inner chamber which is suitable to be at least partially immersed in cooling liquid and inside which gas can accumulate; a first floating element and a second floating element suitable to be at least partially immersed in and moved by cooling liquid; and a switch suitable to be actuated by the first floating element when the gas accumulated is such that the level of the cooling liquid in the inner chamber reaches a predetermined first threshold level and by the second floating element when the gas accumulated is such that the level of the cooling liquid in the inner chamber reaches a lower predetermined second threshold level, respectively. The first and second floating elements can be mounted on and move linearly relative to one or more corresponding guiding supports.

Abstract: A safety device is disclosed for a power transformer containing a cooling liquid, and can include a shaped body having an inner chamber which is suitable to be at least partially immersed in cooling liquid and inside which gas can accumulate; a first floating element and a second floating element suitable to be at least partially immersed in and moved by cooling liquid; and a switch suitable to be actuated by the first floating element when the gas accumulated is such that the level of the cooling liquid in the inner chamber reaches a predetermined first threshold level and by the second floating element when the gas accumulated is such that the level of the cooling liquid in the inner chamber reaches a lower predetermined second threshold level, respectively. The first and second floating elements can be mounted on and move linearly relative to one or more corresponding guiding supports.