Power has become the major part of our daily life. Furthermore, transformers are important to transmit and distribute power. Without them, Power would not be efficient. Outages cause significant economic losses and inconvenience. Power transformers are used in electricity transmission and primary-distribution systems. They are used to increase the voltage supplied by generators at power stations to the extremely-high voltages necessary for electricity transmission and, at bulk power centers, to incrementally reduce those voltages to lower levels. Their reliable operation is a key factor in the overall reliability of the power grid.
To keep the power transformers operational, we have to track the ageing of their insulation system. Ageing in the insulation system of power transformers is caused by impact of air, moisture, temperature, mechanical and electrical overstressing and insulation contamination. To gain information about the condition of a power transformer, we have to apply a set of the numerous of diagnostic methods available.