Condition Analysis of Structural Parts of the Distribution Dry Transformers

The article describes non-contact and contact analysis of 800 kVA dry power transformers with epoxy-resin insulation using an acoustic camera and a frequency analyzer with automatic sweeping for low-middle frequency area. For analysis of construction components (core, windings or taps) of power transformers are most often used. Electric non-rotate machine create electromagnetic and acoustic emissions, which may be used for analyze the dry transformers during its operation. Non-contact on-line diagnostic methods have many advantages over off-line methods in that it is not necessary to shut down the transformer from operation, and in addition, the condition and behavior of the machine during its normal operation are analyzed. In the article is presented the analysis and comparison of structural parts of the distribution dry transformers at the same type and power. The problem of insufficient or incorrect clamp-screw connection was identified by method SFRA in the source range of frequency from 200 to 2 000 kHz.