Comparison of accuracy of online monitoring equipment for dissolved gas in transformer oil

Abstract

The accurate measurement of dissolved gas concentration in transformer oil is directly related to the safe operation state of transformer. In order to realize real-time and automatic monitoring of dissolved gas in transformer oil, online monitoring method has been developed and applied, but the accuracy of online monitoring method remains to be investigated. Therefore, this paper evaluates the accuracy of two online monitoring methods, i.e., gas chromatography and photoacoustic spectroscopy, that have been used in the market. The results show that the test results of both two online monitoring methods can meet the requirements of Class A standard. Among them, the online monitoring method using gas chromatography has less error and higher accuracy, but its operation is relatively complicated and requires carrier gas. The online monitoring method using photoacoustic spectroscopy does not need carrier gas and the test speed is fast, but its test error is relatively large and the accuracy is relatively low, indicating further research is still needed to improve the test accuracy.