Method for simulating a transformer

A method for determining an operating state of a transformer disposed in a high-voltage grid, the transformer containing a tank filled with an insulating liquid, an active part disposed in the tank and having windings enclosing a core and sections of the core, and a cooling unit for cooling the insulating liquid, which comprises the steps of:

• obtaining measurement values from sensors disposed in or on the transformer, wherein the measurement values are used to obtain at least one liquid temperature measurement value which corresponds to a measurement temperature of the insulating liquid or is calculated from a plurality of temperature values, wherein at least one of the temperature values corresponds to the measurement temperature of the insulating liquid;
• supplying the measurement values and/or values derived therefrom to a thermohydraulic simulation model as input values;
• ascertaining, via the thermohydraulic simulation model, the operating state of the transformer by virtue of the thermohydraulic simulation model providing, on an output side, simulated state parameters which together represent the operating state of the transformer, wherein at least one of the simulated state parameters is an insulating liquid temperature state parameter which corresponds to a temperature value which is simulated for the insulating liquid;
• and
• ascertaining, via at least one controlled system connected upstream of an input side of the thermohydraulic simulation model, a control deviation which is formed from a difference between liquid temperature measurement values and corresponding simulated insulating fluid temperature state parameter.