Monitor for Hydrogen Dissolved in Transformer Oil

A new monitor of hydrogen gas dissolved in transformer oil is described and tested under different conditions. Hydrogen diffuses from the oil through a permeable membrane into the monitor and reacts electrochemically with oxygen from the ambiant air in a fuel cell type arrangement. The monitor can be installed on a transformer for in-service continuous analysis of evolved hydrogen. It can also be used as a portable analyzer for the rapid on-site estimation of hydrogen in oil samples. The monitor is not influenced by the presence of other commonly found gases in oil, and readings can easily be corrected for temperature. Preliminary results from a test on a 20 MVA transformer are presented.