Transformer Oil Dissolved Gas Analysis Applications

A transformer is the core substation equipment and the transit point of power flow. The safe and reliable transformer performance is essential to ensure the security and stability of the electrical grid. It is proved that by measuring dissolved gas we can obtain the information of internal state of the transformer, monitor and diagnose latent fault, determine the type of fault and trends in a timely manner.Firstly, this paper describes the Dissolved Gas Analysis and Fault Diagnosis technology’s research status, significance, and the correspondence analysis between the dissolved gas and common faults inside transformer. Then, it discusses the principle used in Gas Chromatography as well as Online Monitoring and Analysis. By comparing the field application with the data collected in two methods(Gas Chromatography, Online Monitoring and Analysis), we figure out the factors that restrict Online monitoring:Regarding management system there are several defects, such as lack of standard of measurement and management, uneven status and limited coverage of equipment, disconnection of alarming and maintenance, problem of integrating data. In terms of technology, there are problems including low measurement sensitivity for online monitoring, the limitation of gas sample, low level of data analysis, etc.With the rapid development of electrical grid and the gradual implementation of condition-based maintenance, collection and processing of the transformer state requires more rigid standards. Proving that the issues of online monitoring in management system and techniques, it is a long-term process to change plan-based maintenance to condition-based maintenance, which requires to conduct step by step and to establish complete monitoring mechanism as well as the strict equipment examination. And further by narrowing the technical gap between field and laboratory technique, it will really play an important role in collecting and accumulating data. However, with the advancement of technology and the development of the technical level, online technology will be the future trend of dissolved gas analysis.