A novel methodology for on-site validation of RV measurement data

Large number of power transformers that are operating today have already outlived their designed life. Such equipments, which are now prone to failures, are still in operation in order to maximize asset utilization. Extending the life of such equipments by policies based on proper condition assessment can mean substantial saving for the utilities. Modern techniques based on dielectric response measurement and analysis provides valuable information regarding the condition of the HV insulation. However, commercial equipments available for recording dielectric response are extremely costly. The paper reports the design of a low-cost instrument developed at High Tension Laboratory of Jadavpur University for measurement of return voltage of high voltage oil-paper insulation. In addition a method is also discussed that facilitate user to carry out on-site validation of RV measurements recorded using the above instrument.