Expriments on Copper Corrosion in Insulating Oil

• Published in: Journal of The Japan Petroleum Institute Vol. 17; no. 7; pp. 560 - 563
• Main Authors: Miyazaki, Teruhisa, Matsumura, Susumu
• Format: Journal Article
• Language: English
• Published: The Japan Petroleum Institute 1974
• ISSN: 0582-4664
• DOI: 10.1627/jpi1958.17.560

Copper corrosion by sulfur compounds in transformer insulating oil is a very important problem in view of the interruption of electric power supply. The factors considered to affect this phenomenon are oil temperature, surrounding gas, water content of oil, surface condition of copper, voltage stress imposed on copper surface and oil additive which will suppress copper corrosion. To acquire some knowledge on the effect of these factors, the authors carried out many short time tests with the test conditions similar to ASTM corrosive sulfur test. The results are as follows: 1. Corrosivity at low temperatures remains at a lower level in the air atmosphere than in the nitrogen atmosphere. 2. Water in oil promotes corrosion. 3. Oxide film on copper surface suppresses corrosion. 4. Voltage stress on copper surface heavily accelerates corrosion. 5. The addition of benzotriazole or 2-mercaptobenzothiazole suppresses corrosion over the temperature and voltage stress ranges which are ordinarily encountered in transformers.