A large population of aged equipment is apparently contaminated with moisture. Effects on life of Power transformer due to moisture in the solid insulation are:
• Accelerated rate of aging for cellulosic materials such as paper and press board
• Reduction of the dielectric strength of paper and press board materials
• Risk of bubble evolution at high temperatures and limited Overloading capacity

Now a days two approaches are applied; the measurement of charging and discharging currents in time domain (Polarization and Depolarization Currents PDC) and the dielectric spectroscopy in frequency domain (Frequency Domain Spectroscopy FDS) & provides an indication of the insulation condition such as:

• Moisture content in the oil/paper insulation
• Faults in OIP, RBP and RIP high voltage bushings & CT
• Faults in the generator, motor and cable insulation
• Monitoring of moisture content in solid insulation during maintenance actions such as On-site drying will be very effective and should be considered as an important application

Omicron Dirana