KEPCO Journal on Electric Power and Energy

Korea Electric Power Corporation (한국전력공사)
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Study on Decomposition Gas Characteristics and Condition Diagnosis for Gas-Insulated Transformer by Chemical Analysis

  • Kim, Ah-Reum (KEPCO Research Institute, Korea Electric Power Corporation) ;
  • Kwak, Byeong Sub (KEPCO Research Institute, Korea Electric Power Corporation) ;
  • Jun, Tae-Hyun (KEPCO Research Institute, Korea Electric Power Corporation) ;
  • Park, Hyun-Joo (KEPCO Research Institute, Korea Electric Power Corporation)
  • Received : 2020.05.06
  • Accepted : 2020.08.28
  • Published : 2020.12.30
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Abstract

Since SF6 gas was discovered in the early 1900s, it has been widely used as an insulation material for electrical equipment. While various indicators have been developed to diagnose oil-immersed transformers, there are still insufficient indicators for the diagnosis of gas-insulated transformers. When necessary, chemical diagnostic methods can be used for gas-insulated transformers. However, the field suitability and accuracy of those methods for transformer diagnosis have not been verified. In addition, since various types of decomposition gases are generated therein, it is also necessary to establish appropriate analysis methods to cover the variety of gases. In this study, a gas-insulated transformer was diagnosed through the analysis of decomposition gases. Reliability assessments of both simple analysis methods suitable for on-site tests and precise analysis methods for laboratory level tests were performed. Using these methods, a gas analysis was performed for the internal decomposition gases of a 154 kV transformer in operation. In addition, simulated discharge and thermal fault experiments were demonstrated. Each major decomposition gas generation characteristics was identified. The results showed that an approximate diagnosis of the inside of a gas-insulated transformer is possible by analyzing SO2, SOF2, and CO using simple analysis methods on-site. In addition, since there are differences in the types of decomposition gas generation patterns with various solid materials of the internal transformer, a detailed examination should be performed by using precise analysis methods in the laboratory.

Keywords

Acknowledgement

This work was supported by R17TA16 of Korea Electric Power Corporatio, granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea.

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