windings, and iron can come from the core and the shell of the unit. These three metals are considered to be
those that comprise the major construction of a unit. Other metals such as tin, lead, zinc, and silver are minor
components and their presence can indicate the involvement of such things as connectors and solder joints.
Conclusion
The technology presently exists and is being used to detect and determine fault gases below the part per million
level. However there is still much room for improvement in the technique, especially in developing the methods
of interpreting the results and correlating them with incipient faults. It is also important to realize that even
though there is further need for improvement in the technique, the analysis of dissolved fault gases represents a
practical and effective method for the detection of incipient faults and the determination of their severity. In
addition to utility companies, many industries and installations that have on-site transformers are recognizing
that the technique of dissolved fault gas analysis is an extremely useful, if not essential, part of a well developed
preventative maintenance program.