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Doble Africa’s Kenya Seminars: A Discussion on Managing the Reliability of Aging Power Transformers

By in Training & Education | January 2, 2019

This article was co-authored by Raben Naidoo.

 

The Doble team returned to Nairobi, Kenya for two technical seminars hosted by Kenya Electricity Generating Company (KenGen) and Kenya Power and Lighting Company (Kenya Power).

Home to nearly 50 million people, Kenya’s current installed capacity is 2,150 MW – produced from 45% hydroelectric, 31% renewables and 24% geothermal energy. KenGen is Kenya’s primary generation company, producing nearly 80% of its electricity, while Kenya Power is responsible for transmission and distribution of the country’s power. Both KenGen and Kenya Power presently face challenges caused by a worldwide issue: aging electrical infrastructure.

 

The technical seminars centered around discussions of managing the reliability of aging power transformers, with a focus on making assessments based on thermal and mechanical models for transformers. Seminar sessions emphasized the use of on-line and off-line testing for field testing.  This included review of interpretation of results while presenting a range of case studies which delved further into the topic of meaningful analysis of results, demonstrating appropriate interventions based on common testing results scenarios. A live demo of the Doble M7100 asset analyzer was a highlight of the seminars, giving attendees an opportunity to catch a glimpse of the high-voltage testing device in action.

Protection Systems Testing

During a seminar session designated for addressing protection-related questions and concerns, the Doble team and attendees exchanged industry best practices and techniques for protection relay testing and current transformer testing.

Brainstorming efforts between participants at the session revealed key solutions to local protection system maintenance issues, such as using real time digital simulation alongside Doble F-Series instruments as an investigation technique to understand the root cause of maloperations.

An additional challenge addressed during the session, such as how to meet the needs of utilities unable to test relays with GOOSE messaging, was resolved with the help of the Doble F6150sv and its use of sample values testing. Attendees noted the versatility of the F6150sv, as well as its distinct high current output, use of sample values alongside its onsite repair and calibration service benefits. An interactive demonstration of the F6150sv showcased the power system simulator’s high current output, appropriate for the needs of local Kenyan utilities with electromagnetic relays.

Comparisons between the use of several industry current transformer testers and current transformer analyzers were made during the session, with the Doble Vanguard EZCT 2000C Current Transformer Tester proving as the superior option regarding insulation test performance and its test voltage of 2kV, as opposed to 120V from other current transformer analyzers.

Partial Discharge Testing

The Doble team was on hand to answer attendees’ questions about partial discharge (PD) – particularly, detection techniques and interpretation. Seminar participants provided feedback on case studies presented featuring the Doble DFA300, gaining insight into the value obtained from oil testing of assets, such as tests for furans, dissolved-gas-analysis (DGA), and oil quality.

Attendees were introduced to Doble’s DGA signature patterns, specially refined for the region’s transformers by applying the Doble method to over 30,000 DGA samples from transformers located in South Africa. In the absence of an oil lab in Kenya, the Morgan Schaffer portable gas analyzer Myrkos, along with its diagnostic software Insideview, was suggested as the ideal solution for oil management in the region due to its accuracy, speed and repeatability of results.

Looking to the Future

“The presentation was excellent. I thoroughly enjoyed the insights shared,” said attendee Beatrice Gitonga, of the seminars.

Involvement from Kenya’s Synergy Power Systems was integral to coordinating the technical seminars and connecting attendees to resources needed to find solutions for their asset health and maintenance issues. With many attendees current Doble M4100 users, they look forward to introducing the Doble M7100 into their testing routines.

 

Interested in learning more?  Contact a member of the Doble team to receive information about technical seminars near you.

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