CN-121978487-A - Acoustic-electric-fused high-voltage transformer oil paper insulation defect development evaluation method and system

CN121978487ACN 121978487 ACN121978487 ACN 121978487ACN-121978487-A

Abstract

The invention belongs to the technical field of high voltage and insulation, and provides a method and a system for evaluating the development of the paper insulation defect of high-voltage transformer oil fused with sound and electricity, which are used for solving the problem that the prior art cannot evaluate the development process of the paper defect discharge accurately in advance. The development evaluation method of the paper insulation defect of the high-voltage transformer fused with the sound and electricity comprises the steps of obtaining ultrahigh frequency signal characteristics corresponding to I type partial discharge and II type partial discharge and ultrasonic signal characteristics which synchronously appear with the characteristics, identifying the type of partial discharge, calculating the t second percentage of the I type partial discharge pulse, the time change rate of the t second of the I type partial discharge pulse and the time change rate and the pulse change rate of the t second of the II type partial discharge pulse, and further evaluating the development stage of the paper defect in the ultrahigh voltage transformer. The method can accurately evaluate the defect development state by utilizing the change rule of the ultrahigh frequency and ultrasonic signals excited by the internal defects of the high-voltage transformer and early warn the insulation faults in advance.

Inventors

MAO GUANGHUI
YU WEINAN
LIU TIANQI
WANG KUNHAN
AN YIYAN
LIU WEIDONG
DIAO FENGXIN
SHI HAIPENG
ZHOU YAN
WANG YANWEI
ZHANG PING

Assignees

国网内蒙古东部电力有限公司电力科学研究院
清华大学

Dates

Publication Date: 20260505
Application Date: 20260407

Claims (10)

1. The method for evaluating the development of the paper insulation defect of the high-voltage transformer fused with the sound and electricity is characterized by comprising the following steps of: Extracting the ultrahigh frequency signal characteristics and ultrasonic signal characteristics which appear synchronously with the ultrahigh frequency signal characteristics in the development process of the oilpaper insulation defect in the ultrahigh voltage transformer, and identifying the partial discharge type which comprises the type I partial discharge and the type II partial discharge; Obtaining a t second percentage P I (t) of the type I partial discharge pulse, a t second time change rate R I (t) of the type I partial discharge pulse and a t second time change rate R II (t) of the type II partial discharge pulse according to the total times N I (t) of the type I partial discharge pulse and the total times N II (t) of the type II partial discharge pulse in the t second obtained by statistics, and further obtaining a pulse change rate R (t) according to the weighted sum of the R I (t) and the R II (t); And (3) evaluating the development stage of the oilpaper defect in the extra-high voltage transformer by integrating the accumulated sum of N I (t) and N II (t) with a comparison result of a set first threshold value, whether N II (t) is 0, a comparison result of P I (t) and a set second threshold value and a comparison result of R (t) and a set third threshold value.
2. The method for evaluating development of paper insulation defects of high-voltage transformer fused with sound and electricity according to claim 1, wherein when N I (t)+N II (t) < first threshold value or N II (t) =0, the paper insulation defects inside the high-voltage transformer are in an initial development stage.
3. The method for evaluating development of paper insulation defects of high-voltage transformer fused with sound and electricity according to claim 1, wherein when N I (t)+N II (t) is equal to or greater than a first threshold value, N II (t) is greater than 0, and P I (t) is equal to or less than a second threshold value or R (t) is equal to or less than a third threshold value, the paper insulation defects in the high-voltage transformer are in a stable development stage.
4. The method for evaluating the development of the paper insulation defect of the high-voltage transformer fused with the sound and electricity according to claim 1, wherein when N I (t)+N II (t) is equal to or greater than a first threshold value, N II (t) is greater than 0, and P I (t) is greater than a second threshold value or R (t) is greater than a third threshold value, the paper insulation defect in the high-voltage transformer is in a rapid development stage.
5. The method for evaluating the development of the paper insulation defect of the high-voltage transformer fused with the sound and electricity according to claim 1, wherein when N I (t)+N II (t) is equal to or larger than a first threshold value, N II (t) is greater than 0, P I (t) is greater than a second threshold value, and R (t) is greater than a third threshold value, the paper insulation defect in the high-voltage transformer is in an impending breakdown state.
6. The evaluation method for development of insulation defect of oil paper of high-voltage transformer fused with sound and electricity according to claim 1, wherein the characteristics of the ultrahigh frequency signal corresponding to the type I partial discharge excited in the development process of the insulation defect of the oil paper in the ultrahigh voltage transformer and the characteristics of the ultrasonic signal synchronously appearing with the ultrahigh frequency signal are as follows: The duration of the ultrahigh frequency original signal is lower than 350ns, and the peak value is lower than 200mV; the frequency of the ultra-high frequency original signal is distributed between 250MHz and 350MHz, and the frequency points are distributed between 260MHz and 320MHz; The ultrasonic signal duration is less than 6ms and the peak value is less than 150mV.
7. The evaluation method for development of insulation defect of oil paper of high-voltage transformer fused with sound and electricity according to claim 1, wherein the characteristics of the ultrahigh frequency signal corresponding to the II-type partial discharge excited in the development process of the insulation defect of the oil paper in the ultrahigh voltage transformer and the characteristics of the ultrasonic signal synchronously appearing with the ultrahigh frequency signal are as follows: the duration of the ultra-high frequency original signal is more than 500ns, the peak value exceeds 200mV, and the peak value is lower than 300mV; The frequency of the ultra-high frequency original signal is distributed between 100MHz and 300MHz, and the frequency points are distributed among 120MHz, 190MHz and 260MHz; The ultrasonic signal duration exceeds 8ms and the peak value is greater than 9V.
8. An acoustic-electric fusion high-voltage transformer oil paper insulation defect development evaluation system, characterized in that the acoustic-electric fusion high-voltage transformer oil paper insulation defect development evaluation method based on any one of claims 1-7 comprises the following steps: The partial discharge type identification module is used for extracting the ultrahigh frequency signal characteristics and the ultrasonic signal characteristics which synchronously appear with the ultrahigh frequency signal characteristics in the development process of the oilpaper insulation defect in the ultrahigh voltage transformer and identifying the partial discharge type, and comprises type I partial discharge and type II partial discharge; The partial discharge pulse parameter calculation module is used for obtaining a t second percentage P I (t) of the type I partial discharge pulse, a t second time change rate R I (t) of the type I partial discharge pulse and a t second time change rate R II (t) of the type II partial discharge pulse by using the total times N I (t) of the type I partial discharge pulse and the total times N II (t) of the type II partial discharge pulse in the t second obtained according to statistics, and further obtaining a pulse change rate R (t) according to weighted sum calculation of the R I (t) and the R II (t); The oilpaper defect development stage evaluation module is used for evaluating the development stage of the oilpaper defect in the ultra-high voltage transformer by integrating the accumulated sum of N I (t) and N II (t) with a set first threshold value, whether N II (t) is 0, the comparison result of P I (t) with a set second threshold value and the comparison result of R (t) with a set third threshold value.
9. A computer-readable storage medium, on which a computer program is stored, characterized in that the program, when being executed by a processor, implements the steps in the method for evaluating development of insulation defects of a high voltage transformer paper fused with sonoelectricity according to any one of claims 1 to 7.
10. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor performs the steps in the method for evaluating the development of an insulation defect in a paper of a high voltage transformer fused with sonotrode of any one of claims 1-7 when the program is executed.

Description

Acoustic-electric-fused high-voltage transformer oil paper insulation defect development evaluation method and system Technical Field The invention belongs to the technical field of high voltage and insulation, and particularly relates to a method and a system for evaluating development of paper insulation defects of high-voltage transformer oil fused with sound and electricity. Background The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. The extra/extra-high voltage transformer is a key node device for electric energy transmission and is a heart of an electric power system. The ultra/extra-high voltage transformer has the advantages of large power failure range, large economic loss and serious social influence due to large conveying capacity and wide power supply coverage range. In the prior art, the type I partial discharge and the type II partial discharge fault types can be identified by utilizing technologies such as ultrasonic waves, but the oil paper insulation is a main electric insulation system of the transformer, the fault caused by the oil paper related defect is the most serious fault type of the oil immersed transformer, the defect development speed is very high, and the discharge development process of the oil paper defect cannot be accurately estimated in advance, so that the damage to the transformer insulation is large, and the safety of a power grid is seriously endangered. Disclosure of Invention In order to solve the technical problems, the invention provides a method and a system for evaluating the development of the paper insulation defect of a high-voltage transformer fused with sound and electricity, which can accurately evaluate the development state of the defect by utilizing the change rule of an ultrahigh frequency and ultrasonic signal excited by the internal defect of a high-voltage transformer and early warn the insulation fault. In order to achieve the above purpose, the present invention adopts the following technical scheme: The invention provides a sound-electricity fused high-voltage transformer oil paper insulation defect development evaluation method. In one or more embodiments, a method for evaluating development of paper insulation defect of high-voltage transformer fused with sound and electricity is provided, which comprises the following steps: Extracting the ultrahigh frequency signal characteristics and ultrasonic signal characteristics which appear synchronously with the ultrahigh frequency signal characteristics in the development process of the oilpaper insulation defect in the ultrahigh voltage transformer, and identifying the partial discharge type which comprises the type I partial discharge and the type II partial discharge; Obtaining a t second percentage P I (t) of the type I partial discharge pulse, a t second time change rate R I (t) of the type I partial discharge pulse and a t second time change rate R II (t) of the type II partial discharge pulse according to the total times N I (t) of the type I partial discharge pulse and the total times N II (t) of the type II partial discharge pulse in the t second obtained by statistics, and further obtaining a pulse change rate R (t) according to the weighted sum of the R I (t) and the R II (t); And (3) evaluating the development stage of the oilpaper defect in the extra-high voltage transformer by integrating the accumulated sum of N I (t) and N II (t) with a comparison result of a set first threshold value, whether N II (t) is 0, a comparison result of P I (t) and a set second threshold value and a comparison result of R (t) and a set third threshold value. As an embodiment, when N I(t)+NII (t) < first threshold or N II (t) =0, the paper defect inside the high voltage transformer is in the initial development stage. As an implementation mode, when N I(t)+NII (t) is more than or equal to a first threshold value, N II (t) is more than 0, and P I (t) is less than or equal to a second threshold value or R (t) is less than or equal to a third threshold value, the defect of the oilpaper inside the high-voltage transformer is in a stable development stage. As an implementation mode, when N I(t)+NII (t) > the first threshold, N II (t) >0, and P I (t) > the second threshold or R (t) > the third threshold, the high-voltage transformer internal oilpaper defect is in a rapid development stage. As an implementation mode, when N I(t)+NII (t) > is equal to the first threshold, N II (t) >0, and P I (t) > is the second threshold and R (t) > is the third threshold, the oil paper defect inside the high-voltage transformer is in an impending breakdown state. As an implementation mode, the characteristics of the ultrahigh frequency signal corresponding to the type I partial discharge excited in the development process of the oilpaper insulation defect in the ultrahigh voltage transformer and the characteristics of the ultrasonic s