Diagnostic techniques and apparatus for detecting faults in perfluorocarbon liquid immersed transformers

This paper deals with techniques and an apparatus designed to dkdgnosis transfornler faults by detecting CzF1, C2F6 and C3F6 gases contained in perfluorocarbon (PFC) liquid. The authors first established fault diagnostic techniques that employ gas pattems, gas composition ratios and fault diagnostic diagram and flow chart , based on the C2F4, C2F6 and C3F6 gases generated by overheating, partial discharges and arc discharges. Then, the authors verified the possibility of diagnosing internal faults in PFC liquidimmersed transformers when internal fault simulation tests on transformer model are conducted. The C2F4 and C3F6 gases generated there are detected with the gas diagnostic apparatus equipped with a gas sensor.