AUTOMATIC FILTER RE-DRYING
Filter Life – Cost of water removal
The Filters will last a minimum of 18 months if care is taken to flush the valves on the transformer at connected to remove accumulated sludge and free water. A large number of transformers can be dried with one set of filters.
Using a Trojan 1000 on a group of identical 10 mva transmission transformers with 12000 litres of oil, 4% water in cellulose and operating at medium load, the Trojan consistently removed over 3.5 litres of water per month or 42 litres per year. Based on a Filter life of 18 months, this gives a Filter cost of less than $15 per litre of water removed. If the transformers are larger, the filter cost per litre of water is reduced further as more water will be removed in the 18 months.