Oil immersion transformer oil paper electrical resistivity inversion method based on Newton-Ralph Johnson method

Abstract

The invention discloses an oil immersion transformer oil paper electrical resistivity inversion method based on the Newton-Ralph Johnson method. The inversion method comprises the steps that step 1, N groups of actual values of the stabilized insulation electrical resistance Rjr of a whole transformer are respectively measured under N types of pressurization methods, the oil immersed papers are divided into N inversion zones considering the basic structures of the oil immersed papers; step 2, a finite element model of the insulation structure inside a transformer is built by adopting the finite element method, based on the finite element model the finite elements are computed using the oil immersed paper electrical resistivity of each inversion zone as the input variable, a computational model of the stabilized insulation electrical resistance corresponding to each pressurized method is built; step 3, based on the stabilized insulation electrical resistance computation model, inversions are performed on the oil immersed paper electrical resistivity by adopting the Newton-Ralph Johnson method, according to the actual values of the oil and electricity resistivity of the transformer and the N groups of stabilized insulation electrical resistance. The inconveniences in sampling measurements and the damages to the insulation structure of the transformer are avoided, and meanwhile the distribution of the aging zones of the oil immersed papers is obtained.

Description

technical field [0001] The invention relates to an oil-immersed power transformer oil-paper insulation state evaluation technology, in particular to an oil-immersed transformer oil-immersed paper resistivity inversion method based on the Newton-Raphson method. Background technique [0002] There are two main types of insulating materials inside transformers: liquid insulating materials (transformer oil) and solid insulating materials (oil-impregnated paper). With the long-term high temperature and high pressure environment, the insulating material will gradually age, and various material parameters, such as resistivity, will also change accordingly. Therefore, parameters such as resistivity can be used to reflect its aging state. Due to its fluid characteristics, the distribution of material parameters of transformer oil is relatively uniform, and its insulation characteristics can be measured by direct sampling. As the weak link of the transformer's internal insulation, s...

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Problems solved by technology

As the weak link of the transformer's internal insulation, solid insulating materials usually deteriorate in local areas. The direct sampling and measurement process is not only cumbersome, but also damages the insulation structure. The cost of sampling is high, and there is a certain degree of dispersion. aging characteristics

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