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The importance of dissolved gas analysis in transformer maintenance and how to use it
By Ir Dr K F WONG

If you choose to listen to this article, you are welcome to download the PDF version of the Journal (June 2024 issue) and activate the “Read Out Loud” function in Adobe Reader. For more details, please read the user's note.

 

Transformers play a crucial role in power systems, and the reliability of the power transformer will determine the stability and performance of a transmission network. It is critically important, therefore, to continually monitor the health of transformers and determine the right time for maintenance to avoid outages. Dissolved gas analysis (DGA) is one of the more well-known methods to monitor the condition of transformers.

 

The EL Division organised the captioned seminar on 11 March 2024. More than 300 participants joined to hear the speaker, Mr Serge Gutieres (Business Development Manager of Doble Engineering), who introduced the basics and latest applications of DGA.

 

Mr Gutieres first outlined how gases are generated in a transformer. The thermal and electrical stresses of transformers break mineral oil and paper molecules into combustible gas molecules such as hydrogen, methane and ethylene.

 

The composition of the dissolved gases in oil varies as faults and temperature develop. By measuring the concentration of different types of gases in the transformer oil, any incipient problems inside the transformer can be determined at an early stage.

 

Mr Gutieres introduced a few diagnostic tools, such as the Duval triangle, to interpret the dissolved gas data. However, the accuracy of the diagnostics depends on the sampling and the accuracy of the analytical method.

 

Mr Gutieres elucidated the importance of a portable gas chromatograph and online monitoring in improving the accuracy of DGA as the devices help to eliminate any inaccuracies due to transportation of the samples. The online equipment can also provide the trends of different types of gases inside the oil.

 

Mr Gutieres also outlined other laboratory tests for detecting incipient faults and insulation degradation in the transformer. In particular, he mentioned the moisture measurement as moisture in oil accelerates the deterioration of the insulating oil and paper. It is also a by-product of chemical reactions inside the transformer.

 

The seminar wrapped up with a question-and-answer session. Participants actively raised questions about DGA in condition monitoring and maintenance. The EL Division would like to express our gratitude to Mr Gutieres for his fruitful sharing.

 


Professional Short Course 2024 – Classes 3 and 4
By Miss Gloria WONG

If you choose to listen to this article, you are welcome to download the PDF version of the Journal (June 2024 issue) and activate the “Read Out Loud” function in Adobe Reader. For more details, please read the user's note.

 

The Professional Short Course 2024 consisting of four classes on “Empower a Smarter Living” was successfully held in March 2024.

 

The first two classes related to “Smart Grids and Artificial Intelligence” and “Distribution Protection Systems in Hong Kong”. The third and fourth classes were on “How a New Integrated Digital Twin Platform Accelerates Digitisation Across the Entire Lifecycle of Power Systems” and “Direct Wireless Power Conversion – A New Generation of Power Conversion Technology” and were organised on 12 and 15 March respectively.

 

For Class 3, Mr Junshen Chen (Head of the Southern District, ETAP China) introduced the concept of digital twin technology for addressing electrical challenges. Mr Chen showcased a variety of technologies that facilitate the interface with Building Information Modelling (BIM) and the integration of Supervisory Control And Data Acquisition (SCADA) with BIM for real-time monitoring.

 

He also provided practical demonstrations of these technologies, highlighting their effectiveness in enhancing the monitoring and management of electrical systems.

 

For Class 4, Ir Prof K T Chau (Chair Professor of Electrical Energy Engineering, Department of Electrical and Electronic Engineering, The Hong Kong Polytechnic University) discussed the development and technical details of wireless power transfer (WPT) and provided insights into their operating principles and emerging applications. Participants gained a comprehensive understanding of WPT and its potential uses.

 

All four classes in the Course received a positive reception from members, with a total of around 200 participants. On behalf of the Division, we would like to express our gratitude to all the speakers for enriching and updating our members’ understanding and practical knowledge of electrical systems. The next series of professional short course is currently being prepared. More interesting and informative classes are coming next year. Stay tuned with us for the latest news on these events.

 

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