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Transformer monitoring and conservation system (SMCT)


The SMCT manages the power transformer oil moisture (in the most important Electrical System Substation equipment, about 56% of the total cost) by removing the internal humidity trough a dry atmosphere of nitrogen. Moisture alongside oil oxidation has been the main factor of degradation of transformer´s insulation, accelerating its wear and dramatically reducing its load capacity and life, causing its total and irreversible collapse. SMCT, due to its effectiveness, results in lower maintenance costs, fewer interventions and longer life, delaying the aging process of the electrical insulation. Transformer´s reliability loss is directly linked to its aging, resulting from the oxidation of the paper and oil insulating, resulting from moisture and contact with the oxygen of atmospheric air. There is a proportionality between the % of water in the oil, the moisture in the paper and its degradation. Currently, the oil treatment is adopted every two years to remove the moisture through the use of large systems that are attached during this maintenance. Besides of being a costly procedure, also involves safety issues and complex logistics, and furthermore results only in a partial removal of the moisture present in the winding, through the migration of paper moisture to the freshly treated oil, with limited efficiency. With the vast array of possibilities offered by the SMCT, we avoid any contact of the oil with the air and permanently monitor indicators that allow control the operation, assisting in maintenance planning besides of prediction and detection of any problems. Seeking to provide more comprehensive results and to use the potentialities pointed out in the innovation through the control of atmosphere and humidity, the SMCT incorporates the following features: N2 sampling system and the analysis of combustible gases for diagnosis of the state of the transformer and possibility of failure, the autonomous system of nitrogen generation for the operation in case of small leaks and the remote data communication module for results and analysis information in real time. With the continuous quality oil control, we gain performance and increase the life of the transformer. There are also gains in the reliability and possibility of applying higher loads, improving the utilization factor. The SMCT is fitted with a N2 sample collection module that withdraw the N2 from the expansion tank when the oil volume increases, for analysis and evaluation of the amount of other gases produced inside the transformer. In its latest version the SMCT also makes it possible to evaluate the amounts of hydrocarbons and acetylene gas present in this mixture. Acetylene is an explosive gas, generated when there are high temperatures in points inside the transformer and indicates the risk of failure. The indicator will serve as an alert to prevent accidents and the total failure. SMCT is ready for commercialization, however, two points for development have been identified: the current productive process is handcrafted, with a high production lead time and high production cost, with no equivalent benchmark for comparison, this is an equipment that incorporates market solutions with other innovations that are not yet fully widespread. There is tendency to compare the SMCT to the alternatives which customers are more familiar with, like bags and membranes that passively avoid the contact of the insulating oil of the transformer with the air. The competitors market is originated from the same problem that generates demand for SMCT, oil degradation and transformer insulation failure. Due to its configuration SMCT has a higher cost, justified by its technological differential and additional functionalities. This suggests the need of a proper marketing plan for market insertion. (AU)

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