The key issue for the oil filter product sand operating status of the transformer oil filter, and in-depth research, based on the research and development of the transformer oil filtering device charged. Charged transformer oil filtering device structure includes an external oil circulation system, internal purification systems and automatic control and protection system of three parts. The device has also explained the conventional oil filter and oil filter charged two modes, when conventional oil filter modes election, workflow is identical with ordinary oil filter; If you choose to live oil filtering mode, you need to set the control variable range and start monitoring and adjustment, transformer oil filtering method has been put live field application, its efficiency and reliability of the actual verification.