Modern Transformer Technologies - Forum 2022

45 minutes presentation includes 10 minutes of Q&A.

9:00am - 9:45am

Intellirent

Life Extension of Power Transformers Through Proper Moisture Management
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Excessive moisture within the oil and insulating materials of a transformer has a significant effect on the life cycle of these critical and expensive assets. Moisture is one of the most influential elements that can accelerate ageing in oil, paper, and pressboard insulation, possibly resulting in severe damage and premature failure. In this session we will discuss how moisture accumulates, how it effects the aging process, and how significant damage or failure from excessive moisture can occur. We will look at ways to determine the amount of moisture that is present, including the challenges associated with using traditional dissolved gas analysis, (DGA), or oils screens for moisture determination. We will explore more modern techniques such a dielectric frequency response, (DFR). Included are specific case studies that will support the findings and recommendations.
 

9:45am - 10:30am

Transmission & Distribution Services, LLC (TDS)

Transformer & CB Leak Repair
Leakers... What a Mess!!!
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Scheduled transmission outages make it difficult to take extended outages for transformer or circuit breaker repairs. Emergent oil leaks cannot always wait to the next outage window. The common leak repair on transformers removes every radiator and bushing and regaskets everything to address these leaks. Work that can take weeks to perform. This presentation describes an alternative leak repair technique utilizing either drilling and injecting sealant into the gasket groove on a leaking flange, or applying an external clamp, filled with the same sealant. This technique is applied to essentially all flanges on the transformer: radiators; pumps; piping; bushings; as well as any valves. Many repairs on the lower end of transformer radiators, pumps, and piping can be performed with the transformer energized. Leaks on the upper end of radiators and bushings require an outage for safe work clearances. Similar repairs can also be performed on oil filled or SF6 gas filled circuit breakers. In these repairs, the external clamp technique is the most common solution.
 

10:30am - 11:15am

Dynamic Ratings Inc.

Failure Characteristics of OIP versus RIP Bushings
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Resin Impregnated Paper (RIP) bushings are becoming increasingly popular with utilities today. The seismic withstand capabilities, improved mechanical strength, and improved safety performance with composite outer envelopes are often cited as reasons utilities are moving towards RIP bushings.
While in general, RIP bushings offer improved reliability, failures may still occur. Understanding the design and failure characteristics of RIP bushings vs. Oil Impregnated Paper (OIP) bushings can help the user make better decisions when interpreting their online and offline test data. Since the failure modes of these two bushing types are completely different, understanding how they fail, is necessary when investigating alarms from online monitoring systems.
This presentation will review the basic design principals of OIP and RIP bushings, typical failure modes, and correlate these failure modes with data collected from online monitoring systems.
 

11:15am  – 12:00pm

Delta-X Research

Online Monitoring for Transformer Insulating Liquids

Periodic sampling of transformer insulating liquids for analysis, including dissolved gas analysis (DGA), is an essential inspection routine for sound transformer maintenance. As technology is improving and becoming more affordable, the use of online monitors for continuous observation of insulating liquids in transformer fleets is growing. It is important to balance the investment in technology with the expected benefits. In this presentation, we explore the variety of online monitors for insulating liquids, including those for dissolved gases, moisture and temperature, and consider the practical application of varying capabilities offset by their respective costs.