Lithonia Lighting, located just outside of Atlanta, Georgia, is the world\'s lar

Question

Lithonia Lighting, located just outside of Atlanta, Georgia, is the world's largest manufacturer of light fixtures, with more than $1 billion in annual sales. One afternoon, the power transformer at its corporate headquarters exploded, leaving the entire office complex, including the corporate data center, without power. The data center's backup power system immediately took over and kept critical parts of the data center operational. However, it was insufficient to power all systems, so the system supporting sales for all of Lithonia Lighting's North American agents, dealers, and distributors had to be turned off. The transformer was quickly replaced and power was restored. However, the 3-hour shutdown of the sales system cost $1 million in potential sales lost. Unfortunately, it is not uncommon for the cost of a disruption to be hundreds or thousands of times the cost of the failed components. What would you recommend to avoid similar losses in the future?

Explanation / Answer

A fire in a power transformer may occur due to a varying number of reasons. One of the most common reason is the poor maintenance of oil which leads to gradual decay of insulation level due to increase in moisture content, constant overload heating and partial discharges. Buccholz relay which forms a major part of transformer protection under such cases needs to be maintained regularly because it is the first line of defence in such cases.

Transformer may explode also due to surge which strikes the transformer due to lightning which may cause a flashover across its insulator and puncture the insulation of the transformer thus leafing to phase to phase fault or even LLL fault which can be very catastrophic under loaded conditions. To prevent this more efficient and fast response protection devices which operate on intelligent relays need to be employed. With mechanical relays the response time sometines is so large that the transformer explodes before it. A more efficient and a faster protection system designed can save the transformer from exploding by tripping it.

Third possibility to avoid loss of time due to complete failure is by keeping a 100% redundant system while designing the plant. The 100% redundant plant might look like additional capital investment initially but during such emergencies the loss due to complete shutdown of plant is 1000 times than what the equipment cost would be. Therefore it is always recommended to go for a 100% redundant system sharing 50% of the load each.

Another solution to this problem of transformer which is fast emerging is the alternative of using a dry type transformer. Dry type transformer use VPI impregnation as insulation and no oil is present. Oil forms a major form of fire hazard in a plant. Use of dry type transformer can eliminate this fire hazard. However dry type transformer are still under evolution as it has not been effectively used at the EHV level. However it has given good results when it is used upto 11kV level.

DO GIVE A THUMBS UP!!

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