Cable defect judgment method based on dielectric loss measurement under cosine square wave and damped oscillation wave

A technology of damping oscillating waves and dielectric loss, which is applied in the measurement of electrical variables, dielectric properties, resistance/reactance/impedance, etc., can solve the problems of lack of judgment standards and methods, and achieve the effect of simple methods

Active Publication Date: 2021-09-14
STATE GRID CORP OF CHINA +1
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Problems solved by technology

Dielectric loss is an important characteristic quantity reflecting cable defects. It can be measured under cosine square wave voltage and damped oscillation voltage, but only the measured value can be given, and there is a lack of judgment standards and methods.

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  • Cable defect judgment method based on dielectric loss measurement under cosine square wave and damped oscillation wave

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Embodiment Construction

[0015] see figure 1 , a cable defect judgment method based on the measurement of dielectric loss under cosine square wave and damped oscillatory wave, the steps are as follows:

[0016] (1) Measure the dielectric loss value of the cable under cosine square wave voltage, denoted as DL1.

[0017] (2) Measure the dielectric loss value of the cable under the damped oscillatory wave voltage, denoted as DL2.

[0018] (3) Calculate the ratio of DL1 / DL2.

[0019] (4) When the ratio of DL1 / DL2 is less than or equal to 1.2, the cable has no defects.

[0020] (5) When the ratio of DL1 / DL2 is greater than 1.2 but less than or equal to 2, the cable is an aging defect.

[0021] (6) When the ratio of DL1 / DL2 is greater than 2, the cable is moisture intrusion type without defects.

[0022] The defect state of the cable can be divided into three types: no defect, aging defect and moisture intrusion defect. The dielectric loss values ​​of these defects have different performances under dam...

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Abstract

The invention belongs to the field of power equipment, and particularly relates to a cable defect judgment method based on dielectric loss measurement under cosine square waves and damped oscillation waves. The method comprises the following steps: (1) measuring a dielectric loss value of a cable under a cosine square wave voltage, and recording the dielectric loss value as DL1; (2) measuring the dielectric loss value of the cable under a damped oscillation wave voltage, and recording the dielectric loss value as DL2; (3) calculating the ratio of DL1 / DL2; (4) when the ratio of DL1 / DL2 is less than or equal to 1.2, determining that the cable has no defect; (5) when the ratio of DL1 / DL2 is greater than 1.2 but less than or equal to 2, determining that the cable has an aging type defect; and (6) when the ratio of DL1 / DL2 is greater than 2, determining that the cable is in a moisture invasion type and has no defect. According to the invention, after dielectric loss values are respectively measured under a cosine square wave voltage and a damped oscillation voltage, the cable defect is judged according to the ratio of the dielectric loss values, so that the cable defect is accurately judged, the defects of a numerical method are effectively avoided, and the method is simple and practical.

Description

technical field [0001] The invention belongs to the field of power system application technology and the field of measurement and testing, in particular to a cable defect judgment method based on dielectric loss measurement under cosine square wave and damped oscillation wave. Background technique [0002] In the prior art, many major accidents in power grids at home and abroad are caused by cable defects, causing huge economic losses and adverse social impacts. Effective detection of cables is of great significance to prevent cable accidents and improve the reliability of power grids. Dielectric loss is an important characteristic quantity reflecting cable defects. It can be measured under cosine square wave voltage and damped oscillation voltage, but only the measured value can be given, and there is a lack of judgment standards and methods. The invention provides a cable defect judgment method based on dielectric loss measurement under cosine square wave and damped oscil...

Claims

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Application Information

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IPC IPC(8): G01R27/26
CPCG01R27/2694Y04S10/52
Inventor 刘帅刘楠吕越朴永鑫张浩叶岚峰宋光达尹宝鑫
Owner STATE GRID CORP OF CHINA
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