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Oil-paper insulation surface charge measuring device and method based on DC superimposed harmonics

A DC superposition, oil-paper insulation technology, applied in the direction of measuring devices, measuring electricity, measuring electrical variables, etc., can solve the problem of not fully considering the influence of the obvious different insulation failure characteristics of converter transformers, complex electric field distribution inside the converter transformer, and insulation problems. Research and other issues to achieve the effect of fast switching, convenient and safe experiment, and stable output voltage

Inactive Publication Date: 2018-10-19
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with the wide application of traditional AC power transformers, the application of converter transformers is less, and the research on its insulation problems is not sufficient, and the obvious difference between the electrical stress of converter transformers and ordinary power transformers is not fully considered in the insulation design. and the effect on insulation failure characteristics
In the HVDC transmission system (High Voltage Direct Current, HVDC), the valve side winding of the converter transformer bears the composite voltage composed of AC, DC, repetitive transient pulses and a large number of harmonics, and at the same time performs the power flow reversal operation in the HVDC transmission system , the valve side winding will also bear the polarity reversal voltage, resulting in a more complicated electric field distribution inside the converter transformer than that of the AC power transformer

Method used

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  • Oil-paper insulation surface charge measuring device and method based on DC superimposed harmonics
  • Oil-paper insulation surface charge measuring device and method based on DC superimposed harmonics
  • Oil-paper insulation surface charge measuring device and method based on DC superimposed harmonics

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0063] The production steps of the cellulose insulating paper sample:

[0064] ①In this example, the cellulose insulating paper produced by Nantang Zhongli Co., Ltd. is used, with a thickness of 0.13mm. The cellulose insulating paper is cut into a square sample of 40mm*40mm, and the sample is placed in a model 401B thermal aging test box For drying, the temperature is set to 90° C., and the drying time is set to 12 hours.

[0065] ②Use Great Wall 25# transformer oil for vacuum oil filtering treatment.

[0066] ③Put the treated cellulose insulating paper into the transformer oil, and put it in a vacuum drying oven model DZF-6020 / 6050 for 48 hours to reduce the influence of moisture in the sample on the charge measurement; control the insulation paper and The mass ratio of insulating oil is less than 1:20, the ambient temperature is set to 40°C, and the vacuum degree is set to 50Pa.

[0067] ④ Take out the oil-impregnated insulating paper after oil-immersion treatment for subs...

Embodiment 2

[0077] 1) Sample drying: Cut the cellulose insulating paper into a square sample, put the insulating paper sample in a drying box, and dry it at 80°C for 24 hours;

[0078] 2) Oil immersion treatment: After taking out the sample, immerse the insulating paper sample in the transformer oil, and place it in an environment with a vacuum degree of 70Pa for more than 24 hours, and control the mass ratio of insulating paper to insulating oil to be less than 1:20;

[0079] 3) Set the amplitude of the DC power supply to 4kV, and make the sum of the DC voltage amplitude and the effective value of the harmonic voltage 8kV;

[0080] 4) Set the output voltage amplitude of the harmonic power supply so that the ratio of the harmonic voltage to the amplitude of the DC voltage in step 3) satisfies 1:1, and set the frequency to 350Hz;

[0081] 5) Set the corona charging time to 4 minutes;

[0082] 6) recording: the camera is aimed at the electrostatic potentiometer screen, and the indication o...

Embodiment 3

[0087] 1) Sample drying: Cut the cellulose insulating paper into a square sample, put the insulating paper sample in a drying box, and dry it at 85°C for more than 24 hours;

[0088] 2) Oil immersion treatment: After taking out the sample, immerse the insulating paper sample in the transformer oil, and place it in an environment with a vacuum degree of 60Pa for more than 24 hours, and control the mass ratio of insulating paper to insulating oil to be less than 1:20;

[0089] 3) Set the amplitude of the DC power supply to 7kV, and make the sum of the DC voltage amplitude and the effective value of the harmonic voltage 8kV;

[0090] 4) Set the output voltage amplitude of the harmonic power supply so that the ratio of the harmonic voltage to the amplitude of the DC voltage in step 3) satisfies 1:7, and set the frequency to 150Hz;

[0091] 5) Set the corona charging time to 3 minutes;

[0092] 6) recording: the camera is aimed at the electrostatic potentiometer screen, and the in...

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Abstract

The invention discloses an oil-paper insulation surface charge measuring device based on DC superimposed harmonics. The device is mainly composed of a charge injection device, a surface potential measuring device and a temperature control device. The charge injection device comprises a DC power source, a harmonic power source and a voltage recombination unit. The output end of the DC power sourceand the output end of the harmonic power source are connected to the input end of the voltage recombination unit. The temperature control device is mainly composed of a microprocessor constant-temperature preheating platform. An oil-paper insulation surface charge measuring method based on DC superimposed harmonics is also disclosed. The device and method are safe and reliable in experiments, stable in output voltage and flexible in regulation, can accurately simulate the actual working condition of the valve-side sleeve of a converter transformer, and provide an efficient experimental platform and method for the study of the oil charge insulation characteristics, the breakdown mechanism and the degradation mechanism.

Description

technical field [0001] The invention belongs to the field of electric charge measurement of oil-paper insulation of converter transformers, and relates to a device and method for measuring surface charge of oil-paper insulation based on DC superimposed harmonics. Background technique [0002] The converter transformer is the core equipment of the UHV DC transmission system, which directly affects the operation reliability of the DC transmission project. With the increase of the operating life of the DC transmission project, the insulation problems of the converter transformers that have been put into operation have become increasingly prominent. The first ±800kV converter transformers designed and manufactured by Siemens and ABB in the "Yunguang" project of China Southern Power Grid Corporation and the "Upward" project of State Grid Corporation, which were put into operation in 2008, had insulation failures during the test process. The statistics of the insulation fault cas...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/12
CPCG01R31/1263
Inventor 朱闻博杜伯学苏金刚孔晓晓姜金鹏
Owner TIANJIN UNIV
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