INSULATION QUALITY MATTERS
Many do not recognize the importance of specifying the insulation system and the vital role it plays in the attainment of the specification’s objective. This article makes a great case that investing a few more dollars of cost by specifying a more robust and reliable insulation system reduces the total cost of ownership by adding life to the asset.
Today’s electric utilities are driven by customers’ needs and have a very low tolerance for failures, making “risk-costs” a very real consideration. The quality of the insulation system used inside a transformer is critical to the requirements that matter most to the asset owner: reliability, efficiency, and longevity.
Since each transformer can feed a large number of customers, failure of a single transformer and the resultant loss of service means lost revenue, repair or replacement, and other collateral costs to the asset owner and operator. Sudden, catastrophic failures can be highly visible and negatively impact customer satisfaction and bottom-line financial performance of the utility/asset owner.
When utility engineers and managers were asked in a recent survey to rank the importance of operation factors, they listed equipment reliability as number one for the following reasons:
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Reduce unplanned outages
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Minimize the risk of major incidents, especially with an aging fleet of transformers
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Reduce maintenance cost and cost of the overall operation
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Reduce insurance costs
In normal power transformer operation, the condition of the insulation system determines the life expectancy of the transformer.
A simple risk analysis shows the different levels of risk for the transformer manufacturer and the owner/end user relating to insulation.
Simply stated, while important to both the manufacturer and the end user, the risk for the end user is much greater than that of the transformer manufacturer.
Specifying high quality insulation materials will only negligibly impact the overall price, but significantly augment the efficiency, reliability, and longevity of the asset, lowering the end user’s total cost of ownership.
Since the quality of materials used inside a transformer is critical to the requirements that matter most to the asset owner ─ reliability, efficiency and longevity, it stands to reason that the purchaser should have a greater say in the selection and design of the insulation system.
Have you ever wondered why there can be a large difference in prices offered by different manufacturers for the same quote request? How is this possible? A major reason has to do with the priorities and strategy of the transformer manufacturer.
The first priority is for the unit to pass the factory test so it can be shipped and sold.
The second priority is to get the transformer through the warranty period, so they are no longer responsible.
These priorities sometimes lead the manufacturer to use cheaper, lower quality insulation alternatives, but these types of materials will not deliver the long term reliability needs of the end users who rely on the transformer to operate efficiently and reliably for many years.
Many transformer purchasers’ specifications contain very specific requirements for items such as copper conductors, core materials, fluids, cooling equipment, bushings gauges, instruments, paint and external components/hardware. However, many do not recognize the importance of specifying the insulation system and the vital role it plays in the attainment of the specification’s objective. Given that the total insulation system cost makes up only 2-8% of the total transformer price, you would anticipate that all operators/end users would specify this in their tender documents, but this is not the case.
Specifying only the highest quality insulation materials available to be used inside the transformer will negligibly impact the price whereas significantly augment the efficiency, reliability, and longevity of the asset and lower the end users, total cost of ownership.
In the final analysis, it is the responsibility of the utility transformer specialist to specify the best transformer designs and materials for construction to maximize operational reliability, while minimizing risk, as a key part of their investment and performance improvement strategies. With the insulation system of the power transformer making up only 5% of the total cost and a fraction of the total investment of a generation facility or substation, it makes sense to specify the best insulation materials, designs, and systems to reduce overall risks and total cost of ownership.
The quality of materials used inside a transformer is critical to the requirements that matter most to the asset owner: reliability, efficiency, and longevity.
Another important reason end users should be sure to specify top-quality insulation materials are used inside their transformers has to do with transformer designs which have evolved from previous decades when transformers were over-engineered and over-built. Driven mainly by cost/economic pressures to do more with less, modern-day power transformer designs deliver the same or higher operating performance as their hefty predecessors, but today's power transformers are often smaller in size and lighter in weight with capabilities more closely aligned with operating needs.
These modern-day “efficiencies” were not achieved by accident, but rather by optimization and pushing the edges of design parameters which have significantly decreased the size of oil/flow/cooling channels, resulting in increasing demands and stresses on the critical magnet wire insulation. Significant cost savings in steel, copper and oil have been achieved at the burden of the single most important component to reliability and longevity of a transformer – the magnet wire insulation.
Yet another important reason why end users should be sure to specify that only top-quality insulation materials are used inside their transformers is that today's power transformers are expected to operate well beyond the 20-30-year life expectancy of their hefty predecessors, while utilities now expect 50-60 years of reliable service from their fleet.
The condition of the insulation system determines the life expectancy of the transformer.
This is despite leaner-designed transformers, increasingly severe weather events, increasing electrical demands, increasing grid/transmission voltages and grid-resilience requirements, all of which place operation stress on the most critical component to transformer reliability and life expectancy ─ the insulation material.
Such expansion in life expectancy of power transformers is only possible with a combination of:
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Solid/reliable design which manufacturers provide
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Top-quality insulation materials
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Operational excellence supported by state-of-the-art monitoring