A study on the characteristics of degradation sensor for insulation oil

It is well known that degraded transformer oil consequently leads to the failure of power transformers. This paper discusses the characteristics of porous ceramic sensors used for checking transformer oil condition under live line working. The degradation sensor is composed of a base ring, electrodes and a porous ceramic passed through the transformer oil´s conductive particles, thereby checking the transformer oil condition from the sensor´s leakage current. It is important, therefore, to minimize the leakage current of the base ring and connection parts. To investigate their leakage currents, their V-T-I characteristics DC 2 kV were examined. It was verified that the expansion of oil temperature resulted in an increase in the leakage current of porous ceramic sensors