Speciality and Applicability of Advanced Response Methods in Contrast to the Traditional Dielectric Measurements for Condition Assessment of Power Transformers

摘要

For oil-paper insulated transformers, an accurate assessment of condition (moistening and ageing), evaluation of the service life and determination of the highest permissible operation temperature are complex tasks. The inhomogeneous distribution of moisture, ageing by-products and temperature make the assessment even more difficult. The existing evaluation standards are based on traditional long-time established tests which characterize this complicated and inhomogeneous insulation with a single parameter. In order to carry out efficient condition assessment, extend transformer lifetime and increase load capacity, it is necessary to apply powerful and reliable diagnostic tools. The advanced dielectric methods (RVM, FDS, and PDC) characterize the insulation with a spectrum, consequently they are able to provide more precise condition assessment. Despite the fact that these methods are particularly useful for transformers, an overall guide or standard that describe their application is not available yet. This paper presents the applicability and advantages of the advanced techniques compared to the traditional dielectric measurements.