A new advanced Sensor for corrosive sulphur detection and monitoring

In order to answer technologically to the challenge of measuring and monitoring oil corrosivity and corrosive sulphur dissolved in oil, a new sensor has been designed to measure quantitatively the corrosivity of oil during service operation. The sensor has an intelligent measuring head which manages the whole measuring process according to ASTM D1275 A and B and IEC 62535 for spot measurements (within 24 h up to 72 h), or also through permanent monitoring of the transformer. In both cases, the measurements are done in situ (with the sensor installed on the transformer), avoiding cumbersome and expensive procedures and oil sampling, since the sensor can be easily installed at the transformer valves. The sensor has two active parts which highlight different aspects of the oil corrosion process: the first measures directly the corrosion level on the copper through a suitable sensor, while the second displays the threat level of the byproducts of the copper corrosion, by measuring the change of conductivity of the dielectric as a consequence of such byproducts accumulation. In this way a robust and accurate method for the assessment of the overall corrosion process and its effect on the transformer is obtained, lowering considerably the possibility of false alarms. In this paper a number of real case tests of the sensor are presented, and results are discussed, providing evidence of the effectiveness of this new technological device.