The Key to Generation System Reliability

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Brian Sparling
Dynamic Ratings Inc.

Tara-lee MacArthur
BEng (Elec) CPEng NER

Power companies maximize revenue by operating the critical generation power equipment without any unexpected shutdowns. They invest heavily on identifying and eliminating potential reliability issues on individual components of that system, but seldom look upon it as a system. There is a need for thorough, effective, condition monitoring and condition-based maintenance of all the components that are employed to deliver the energy, from the prime mover out through the walls of the plant and onto the grid.

Power produced by the generator is normally transmitted via a bus-duct and connected to the step-up transformer. Power generation would be interrupted if any component in the chain fails. A common misconception is that bus-ducts don’t require maintenance or monitoring as the MV bus is inside a sealed enclosure. Most forced outages occur because the generation power system is not considered as a whole system. It has been and continues to be common practice in the industry to only monitor rotating machinery for mechanical type failures. This selective view of individual components can lead to potentially catastrophic failure and repairs that could last for a week to several months.

In this paper, the following topics will be covered by means of multiple case histories affecting the different components:

  • Discuss the root-causes of the more common failure modes to understand why a failure may occur and its impact.

  • How to choose which critical components to be selected for monitoring and why.

  • Innovations in sensing methods and sensors.

  • Using bushing power-factor and transformer electrical PD monitoring over traditional methods, in combination with online DGA monitoring to reduce the risk of unexpected transformer failures.

  • Detailed case examples will be provided to illustrate how monitoring of bus-duct and transformers can reduce the risk of unexpected failures and identify the source and/or the nature of the fault.

  • Combining and making available all the operation data to all involved, leads to a better understanding of where limiting factors may be hiding, with respect to the power output of the system.

Sources will include recent CIGRE Reliability Surveys for transformers and bushings.

Brian Sparling, a Senior Member of IEEE, is a Senior Technical Advisor with Dynamic Ratings Inc. Brian has over twenty years of experience in the field of power and distribution transformers. For the last 26 years, he has been involved in all aspects of on-line monitoring and diagnostics and condition assessment of power transformers.

He has authored and co-authored more than 30 technical papers on several topics dealing with the monitoring and diagnostics of transformers.

He has worked on many guides and standards with the Canadian Electricity Association, IEEE Transformers Committee and, the CIGRÉ A2 Transformer committee.

Tara-lee MacArthur is a Substation Design Standards Engineer at Ergon Energy. She is responsible for standardising design strategies, standards and equipment specifications for substation assets focusing on power transformers. She is an active member in Australian´s CIGRE panels A2 and WG A2.49 Transformer Condition Assessment. She holds a BSc EE from the Queensland University of Technology and has experience working in the energy, mining and building services industries. Tara-Lee attained Chartered Professional status (CPEng) in 2017. Her expertise and achievements earned her the title of Engineers Australia's ‘Graduate Electrical Power Engineer of the Year for 2018’ and recipient of the E.S Cornwall Scholarship.