Transformer Oil Dry-Out System(TO-DOS) is permanently connected with the transformer, while it continuously keeps on removing the moisture from the transformer in the charged state. During the filtration process, moisture PPM level is continuously monitored. This process removes moisture from insulation as well. Filter Cartridges can easily be replaced at customer point only. This System capable of removing solid contamination and maintain NAS-4. It will keep on maintaining PPM & NAS value which is required for the long life and good health of transformers. SCADA Compatible PLC is an optional feature for this system.