Method for detecting XLPE insulation degree based on partial discharge frequency properties

A technology of frequency characteristics and partial discharge, applied in the direction of testing dielectric strength, etc., can solve problems such as large errors, and achieve the effect of effective evaluation of XLPE insulation defect state

Active Publication Date: 2014-01-08
STATE GRID CORP OF CHINA +3
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Problems solved by technology

[0004] However, due to many factors that interfere with the measurement of partial discharge, there is a large error in the discharge measurement value compared with other high-voltage tests. Therefore, it is urgent and important to find a new method to judge the severity of XLPE insulation defects.

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  • Method for detecting XLPE insulation degree based on partial discharge frequency properties
  • Method for detecting XLPE insulation degree based on partial discharge frequency properties
  • Method for detecting XLPE insulation degree based on partial discharge frequency properties

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Embodiment Construction

[0030] The following describes the content of this method through specific experiments in conjunction with the drawings.

[0031] 1. Principle

[0032] According to engineering requirements, the defect can be simplified to figure 1 Show the equivalent model, and use this equivalent model to analyze the discharge situation at the defect. Where C i Is the equivalent capacitance of a single defect, C bi Is the equivalent capacitance of the insulating medium in series with the defect, C a With R a Is the equivalent capacitance and equivalent resistance of the normal part of the insulation, Z is the external impedance, AC is the AC power supply, and the partial discharge of the defect severity detection is actually the sum of the partial discharges of multiple defects. For a single equivalent capacitance C i In other words, since the conductance is very small, it can be ignored, and C i >>C bi . Since the duration of a pulse is generally ns, for each discharge pulse, the power freque...

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Abstract

The invention provides a method for detecting XLPE insulation degree based on partial discharge frequency properties. The method includes the first step of pre-processing an XLPE cable to be detected as the following ways, the second step of taking out the preprocessed XLPE cable to be detected, enabling a high-frequency CT station to detect discharge pulse signals of the XLPE cable to be detected, and enabling a synchronous coil to detect partial PD signals of the XLPE cable to be detected, the third step of building and using an expert diagnose system to separate and classify the collected signals and recognize the discharge modes, and building characteristic spectrograms representing different types of pulse properties, and the fourth step of judging the severity of XLPE insulation defects by observing the characteristic spectrograms of the pulse properties, and using obtained partial discharge measured data to come to a conclusion through comparison. The method has the advantages that discharge signal spectrograms can be obtained by carrying out partial discharge measurement on XLPE insulation of different defect severities, and the XLPE insulation defect state can be evaluated effectively.

Description

Technical field [0001] The invention relates to a method for detecting the degree of insulation of XLPE (cross-linked polyethylene), in particular to a method for detecting the severity of XLPE insulation defects based on partial discharge frequency characteristics, and belongs to the technical field of power system measurement. Background technique [0002] Compared with ordinary polyethylene, cross-linked polyethylene (XLPE) has excellent electrical insulation properties, higher impact strength and tensile strength, outstanding wear resistance, excellent stress crack resistance, creep resistance and Dimensional stability, heat resistance, low temperature resistance, aging resistance, chemical resistance, and radiation resistance are also very good. Therefore, XLPE is often used as an insulating material to be widely used in various voltage levels of the power system. It has high insulation strength, low dielectric loss coefficient, good acid and alkali resistance, salt spray re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/12
Inventor 杨帆陈俊武苏勇赵健康阮羚张耀东童歆夏荣
Owner STATE GRID CORP OF CHINA
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