Method for estimating low-frequency dielectric loss of paper oil insulation system based on parameter identification

Abstract

The invention discloses a method for estimating the low-frequency dielectric loss of a paper oil insulation system based on parameter identification. Firstly, an XY model is used for simulating the polar characteristics of the transformer paper oil insulation system, a paper oil insulation system XY model equivalent circuit is established, and a relation expression among the circuit parameter, the characteristic quantity complex capacitance and the dielectric loss factor of the XY model equivalent circuit is established; a frequency domain dielectric spectrum method is used for measuring the complex capacitance and the dielectric loss factor of the paper oil insulation system of a field transformer; parameterization is conducted on the equivalent circuit model through the measured complex capacitance of the high-frequency section and the dielectric loss characteristic quantity, and a mathematical optimization model of parameter estimation is established; an improved particle swarm optimization algorithm is used for distinguishing the parameter value of the XY model equivalent circuit with four polar branch circuits; finally, the distinguished parameter value of the XY model equivalent circuit is used for calculating the complex capacitance and the dielectric value of the low-frequency section of the paper oil insulation system, and a frequency domain dielectric spectrum in a wide range is obtained. According to the method for estimating the low-frequency dielectric loss of the paper oil insulation system based on parameter identification, the paper oil insulation state of the large power transformer can be rapidly estimated based on the frequency domain dielectric spectrum method.

Description

technical field [0001] The invention relates to the technical field of electrical equipment insulation aging and life prediction, in particular to a method for estimating low-frequency dielectric loss of an oil-paper insulation system based on parameter identification. Background technique [0002] The safe operation of power equipment is the first line of defense to ensure the safety of the power grid. The oil-immersed power transformer is the core and hub of power transmission and distribution, and is one of the most important and expensive equipment in the power grid. A serious accident of a transformer will not only cause its own damage, but also interrupt the power supply, causing huge economic losses. Faults caused by internal insulation problems account for an important part of transformer accidents, and have attracted the attention of power operation departments and researchers over the years. The main component of transformer internal insulation is oil-paper insula...

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Problems solved by technology

[0004] However, the frequency domain dielectric spectrum method measures a wide range of frequency domains, and the measurement time in this frequency domain segment is very long, and it is very difficult to measure data in frequency domain segments below 1 Hz, and is easily affected by field factors.

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