Electric transformer assembly, method for determining a thermal state of an electric transformer, and determination device

A transformer assembly, comprising:

• an electric transformer, particularly a rail vehicle traction transformer;
• a temperature sensor system;
• and
• a computation unit for determining a thermal state of the electric transformer,
• the electric transformer including a cooling device having:
• at least one liquid coolant channel arranged such as to absorb exhaust heat from the electric transformer by means of a liquid coolant that is passed through the liquid coolant channel;
• a heat spreader in thermal communication with the liquid coolant channel for transferring heat from the liquid coolant to a heat dissipation surface of the heat spreader;
• an air blower arranged and configured to effect an airstream along the heat dissipation surface of the heat spreader,
• the temperature sensor system including:
• an entering coolant sensor arranged for measuring an entering coolant temperature of the liquid coolant upstream of the cooling device and for providing an entering coolant temperature signal;
• a leaving coolant sensor arranged for measuring a leaving coolant temperature of the liquid coolant downstream of the cooling device and for providing a leaving coolant temperature signal;
• an entering airstream sensor arranged for measuring an entering airstream temperature of the airstream upstream of the heat spreader and providing an entering airstream temperature signal;
• and
• a leaving airstream sensor arranged for measuring a leaving airstream temperature of the airstream downstream of the heat spreader and providing a leaving airstream temperature signal, and
• the computation unit being configured to receive the sensor signals from the temperature sensor system, and configured to determine a thermal state of the transformer, in particular of the cooling device or parts thereof, by relating the sensor signals to each other.