Capacitance oilpaper transformer sleeve insulation state assessment method

Abstract

The invention discloses a capacitance type oilpaper transformer sleeve insulation state assessment method, which belongs to the electrical equipment insulation diagnosis technology field, relates to the capacitance type oilpaper sheathed tube insulation diagnosis and particularly relates to a capacitance type oilpaper sleeve insulation state assessment method. The capacitance type oilpaper transformer sleeve insulation state assessment method comprises steps of performing the mathematics exponential function fitting on the cannula capacitance frequency domain spectrum curve through the combination of the mathematics modeling simulation and laboratory test and utilizing the integration of the fitting function to perform description on the frequency domain spectrum curve variation under various insulation states. As a result, the accurate and lossless assessment on the cannula insulation state through the application of the frequency domain dielectric spectrum method can be achieved. The capacitance oilpaper transformer sleeve insulation state assessment method can perform accurate assessment on the insulation state without assembling and disassembling the cannula, and is easy. Furthermore, the capacitance oilpaper transformer sleeve pipe insulation state assessment method can make accurate and effective assessment on the insulation state of the capacitanc type oilpaper cannula and can provide accurate basis to the maintenance and replacement of the cannula.

Description

technical field [0001] The invention belongs to the technical field of electrical equipment insulation diagnosis, and relates to the insulation diagnosis of a capacitive oil-paper bushing, in particular to a method for evaluating the insulation state of a capacitive oil-paper bushing. technical background [0002] As the core of energy conversion in the process of power transmission and distribution, the power transformer is one of the most critical equipment for the safe and stable operation of the power grid. The bushing of a high voltage transformer is a key component of the transformer. During the operation of the bushing, it will be affected by the operating environment such as high-voltage electric field, magnetic field and temperature. The insulation will deteriorate, the insulation performance will drop, and even the insulation effect will be completely lost, resulting in the failure of the bushing and the power transformer. The capacitor core of the bushing is the ...

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Problems solved by technology

[0004] (1) The content of dissolved gas and furfural in the oil in the chemical method will change due to transformer oil change and maintenance, and cannot accurately characterize the insulation state of the casing oil-paper insulation structure

The degree of polymerization of insulating paper is widely considered to be the most basic characteristic quantity for evaluating the state of oil-paper insulation at home and abroad. However, to test the degree of polymerization of equipment, the bushing must be disassembled and sampled, which brings certain difficulties to the application of the degree of polymerization to evaluate the insulation state.

[0005] (2) The dielectric loss factor and capacitance evaluation method evaluated by electrical methods, the sensitivity of the two to find the insulation fault of the bushing is reduced by the defect-to-insulation volume ratio of the bushing, and even the change and defect of the insulation state cannot be detected in time ;

[0006] (3) The method of three-phase bushing vector sum is greatly affected by signal acquisition and transformer operating environment, and has not been widely used in practical applications

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