On single pole instrument voltage transformer overheating

The paper deals with calculation of overheating of a voltage instrument transformer used in medium voltage substations. Calculation of the primary and secondary windings is compared with measured values. These values are evaluated according to IEC 618691:2007, IEC 61869-3:2011 and IEC 60085:2007. In evaluation we focused on the state 1.9 × nominal voltage and thermal limiting output state. The article also compares the results for various parameters of instrument transformers that are necessary for clarification of calculation.