DryKeep® transformer dehydration system vanquishes #1 enemy: Moisture

Moisture – No. 1 enemy to a transformer As load demands on aging substation power transformers increase, damage control has become the key strategy for...

byVAISALA



Moisture – No. 1 enemy to a transformer

As load demands on aging substation power transformers increase, damage control has become the key strategy for avoiding catastrophe. The loss of energy not only shuts down communities, but the costly replacement of equipment can become an economic burden. While engineers face multiple challenges, moisture is a persistent enemy to the life of a power transformer.

Moisture can take a power transformer offline because it deteriorates the mechanical properties of the paper insulation and the dielectric properties of the insulation system. Even worse, the problem grows exponentially because moisture build-up inside a transformer is an auto-acceleratory process: Moisture is a byproduct of the natural ageing of the insulation; the presence of moisture speeds up insulation degradation; creating even more moisture.

Keeping the transformer dry

Until fairly recently, utility companies took a reactive approach to this problem. To assess moisture, engineers would take an oil sample and send it to a lab for analysis. If higher than permissible moisture levels were detected, a portable dehydration system would be brought in to dry out the transformer.

Ed Vance, sales manager for DryKeep®, a brand of the Ardry Group, remembers those days.

“The old way of doing things was good for the time because that’s all that was available,” he says. “But by using reactive strategies they were not necessarily dealing with the actual problem. They were fixing it temporarily with portable units, and then allowing the moisture to build-up again. All the while the mechanical properties of the paper continued to deteriorate on an accelerated pace in-between those intermittent, reactionary dry-outs. That deterioration is irreversible.”

The DryKeep® System changed all that about 15 years ago. The benefits were so immediate the innovation won praise as the original on-line molecular sieve dry-out system for power transformers.

Vance says the system is effective because it is permanently attached to the transformer and therefore continuously removes moisture while monitoring moisture-in-oil and oil temperature with SCADA Ready SMART* Dehydration Control.

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