阅读说明：本技术 多层油纸绝缘空间电荷预测方法及设备 (Multilayer oiled paper insulation space charge prediction method and equipment ) 是由 田杰 梁兆杰 李艳 张大宁 于 2021-07-09 设计创作，主要内容包括：本申请涉及一种多层油纸绝缘空间电荷预测方法及设备。用于解决现有技术对获取多层油纸绝缘对应的空间电荷分布规律效率较低的问题。在加压与撤压两种情况下,分别对两层油纸绝缘试品与三层油纸绝缘试品对应的电压信号进行采集,以分别生成第一空间电荷分布图与第二空间电荷分布图；根据第一空间电荷分布图以及第二空间电荷分布图,获取空间电荷在不同时刻以及不同空间区域的分布密度；对分布密度进行分析计算,得到不同层数的油纸绝缘试品空间电荷的密度差值；根据空间电荷的密度差值,对多层油纸绝缘试品对应的空间电荷分布规律进行预测。通过上述方法,提高对空间电荷分布规律测量的效率。(The application relates to a method and equipment for predicting space charge of multi-layer oilpaper insulation. The method is used for solving the problem that the efficiency of obtaining the space charge distribution rule corresponding to the multilayer oilpaper insulation is low in the prior art. Under two conditions of pressurization and pressure removal, respectively collecting voltage signals corresponding to the two layers of oil paper insulation test articles and the three layers of oil paper insulation test articles to respectively generate a first space charge distribution map and a second space charge distribution map; acquiring the distribution density of space charges at different moments and different space regions according to the first space charge distribution map and the second space charge distribution map; analyzing and calculating the distribution density to obtain the density difference of the space charges of the oiled paper insulation test articles with different layers; and predicting the space charge distribution rule corresponding to the multilayer oiled paper insulation test sample according to the density difference of the space charge. By the method, the efficiency of measuring the space charge distribution rule is improved.)

1. A multilayer oiled paper insulation space charge prediction method is characterized by comprising the following steps:

under two conditions of pressurization and pressure removal, respectively acquiring voltage signals corresponding to two layers of oil paper insulation samples and three layers of oil paper insulation samples through a space charge measuring device;

generating a first space charge distribution diagram corresponding to the two layers of oil paper insulation test articles and a second space charge distribution diagram corresponding to the three layers of oil paper insulation test articles according to the collected voltage signals;

acquiring the distribution density of space charges at different moments and different space regions of the space charges in an electric field according to the first space charge distribution map and the second space charge distribution map;

analyzing and calculating the distribution density to obtain the density difference of the space charges of the oiled paper insulation samples with different layers in the same space region corresponding to the same time;

acquiring the density difference of space charges in the same space region corresponding to the oiled paper insulation samples with different layers at different moments;

and predicting the space charge distribution rule corresponding to the multilayer oiled paper insulation test article according to the density difference of the space charge.

2. The method according to claim 1, wherein before predicting the space charge distribution rule corresponding to the multi-layer oiled paper insulation sample according to the space charge density difference, the method further comprises:

predicting a distribution rule of space charges corresponding to the four layers of oil paper insulation test articles according to the density difference, and generating a predicted third space charge distribution diagram corresponding to the four layers of oil paper insulation test articles; wherein, the electric field spatial distribution of four layers of oil paper insulation test articles is: a cathode, an interlayer interface, an anode;

collecting the distribution data of the space charges corresponding to the four layers of the oil paper insulation test articles through the space charge measuring device;

generating a third space charge distribution map corresponding to the four-layer oil paper insulation test sample according to the collected distribution data;

and comparing the predicted third space charge distribution diagram with the generated third space charge distribution diagram, and determining that the distribution rule meets the prediction requirement under the condition that the error rate of the predicted third space charge distribution diagram and the generated third space charge distribution diagram is less than a first preset value.

3. The method of claim 2, wherein the comparing the predicted third space charge distribution map with the generated third space charge distribution map, and after determining that the distribution rule meets the prediction requirement if an error rate of the third space charge distribution map and the generated third space charge distribution map is less than a first preset value, the method further comprises:

constructing a multilayer insulation oilpaper space charge distribution prediction model according to the distribution rule, a first space charge distribution diagram corresponding to the two layers of oilpaper insulation test articles, a second space charge distribution diagram corresponding to the three layers of oilpaper insulation test articles and a third space charge distribution diagram corresponding to the four layers of oilpaper insulation test articles;

predicting the space charge distribution rule corresponding to the multilayer oiled paper insulation test article according to the density difference of the space charge, comprising the following steps of:

and predicting the space charge distribution rule corresponding to the multilayer oilpaper insulation test sample through the multilayer oilpaper space charge prediction model and the number of layers corresponding to the multilayer oilpaper insulation test sample.

4. The method according to claim 1, wherein the collecting the voltage signals corresponding to the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample respectively comprises:

applying electrical stress to the two layers of oil paper insulation test articles and the three layers of oil paper insulation test articles to enable space charges to be generated inside the two layers of oil paper insulation test articles and inside the three layers of oil paper insulation test articles respectively;

respectively applying electric pulse signals generated by a preset electric pulse source to the two layers of oiled paper insulation test articles and the three layers of oiled paper insulation test articles to enable the space charges to generate first disturbance;

converting a signal generated by the first disturbance into a first voltage signal through a piezoelectric sensor;

amplifying the first voltage signal, and collecting the amplified first voltage signal;

withdrawing the electrical stress applied to the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample so as to generate a second disturbance on the space charge;

converting, by the piezoelectric sensor, a signal generated by the second disturbance into a second voltage signal;

and amplifying the second voltage signal, and collecting the amplified second voltage signal.

5. The method of claim 4, wherein prior to applying the electrical stress to the two-layer oiled paper insulation test article and the three-layer oiled paper insulation test article, the method further comprises:

respectively horizontally placing the two layers of oiled paper insulation test articles and the three layers of oiled paper insulation test articles in a test article cavity of the space charge measuring device;

extracting air in the test sample cavity through a vacuum pump and an air extraction valve on the test sample cavity so as to reduce the vacuum degree in the test sample cavity to a preset vacuum degree;

standing the sample cavity for a preset time, and measuring the vacuum degree in the sample cavity through a vacuum pressure gauge;

applying electrical stress to the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample comprises the following steps:

and under the condition that the vacuum degree reduction range is smaller than a second preset value, carrying out voltage signal acquisition on the two-layer oil paper insulation test sample and the three-layer oil paper insulation test sample.

6. The method of claim 4, wherein prior to converting the signal generated by the first perturbation to a first voltage signal by a piezoelectric sensor, the method further comprises:

applying the electric pulse signal passing through the coupling capacitor to the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample;

applying a correction voltage to an electrode of the preset space charge measuring device; wherein the correction voltage is opposite in polarity to the electrical pulse signal;

by means of the correction voltage, the influence of the electric pulse signal on the voltage signal is cancelled.

7. The method according to claim 4, wherein the generating a first space charge distribution map corresponding to a two-layer oiled paper insulation test sample and generating a second space charge distribution map corresponding to a three-layer oiled paper insulation test sample according to the collected voltage signals comprises:

generating a first space charge distribution map corresponding to the two layers of the oil paper insulation test articles according to the collected first voltage signal and the second voltage signal corresponding to the two layers of the oil paper insulation test articles; wherein, the electric field spatial distribution of the two layers of oiled paper insulation test articles is as follows: the first space charge distribution diagram comprises a first pressurization space charge density diagram, a first pressurization different-time charge distribution diagram, a first pressurization preset time electric field distribution diagram, a first pressure-removing space charge density diagram and a first pressure-removing different-time charge distribution diagram;

generating a second space charge distribution diagram corresponding to the three-layer oiled paper insulation test sample according to the collected first voltage signal and the second voltage signal corresponding to the three-layer oiled paper insulation test sample; wherein, the electric field spatial distribution of the three-layer oiled paper insulation test sample is as follows: the second space charge distribution diagram comprises a second pressurization space charge density diagram, a second pressurization different-time charge distribution diagram, a second pressurization preset time electric field distribution diagram, a second pressure-removing space charge density diagram and a second pressure-removing different-time charge distribution diagram.

8. The method of claim 7, wherein after generating the second space charge distribution map corresponding to the three-layer oiled paper insulation test sample according to the collected second voltage signal corresponding to the three-layer oiled paper insulation test sample, the method further comprises:

the acquiring the distribution densities of the space charges at different time and different space regions of the space charges in the electric field according to the first space charge distribution map and the second space charge distribution map includes:

determining the charge density in the same spatial region corresponding to any one time in the first and second pressurized space charge density maps;

the analyzing and calculating the distribution density to obtain the density difference of the space charges of the oiled paper insulation samples with different layers in the same space region corresponding to the same time comprises the following steps:

calculating the difference in charge density of the two interfacial regions between layers in the second pressurized space charge density map;

the method for acquiring the density difference of the space charges in the same space area corresponding to the oiled paper insulation test articles with different layers at different moments comprises the following steps:

determining a plurality of non-adjacent time points within a preset time length;

respectively determining the variation trends of the space charges of different space regions at the plurality of time points in the first pressurization different-time charge distribution graph and the second pressurization different-time charge distribution graph, and calculating the density difference values of the space charges of the same space region at the plurality of time points;

predicting the space charge distribution rule corresponding to the multilayer oiled paper insulation test article according to the density difference of the space charge, comprising the following steps of:

respectively determining the spatial regions where the maximum electric field intensity values are located in the first pressurization preset time electric field distribution diagram and the second pressurization preset time electric field distribution diagram;

and determining the distribution rule of the space charges generated by the oil paper insulation samples with different layers under the pressurizing condition according to the charge density in the same space region corresponding to the same moment under the pressurizing condition, the charge density difference of the two interlayer interface regions, the density difference of the space charges corresponding to the time points and the space region where the maximum value of the electric field intensity is located.

9. The method according to claim 7, wherein after generating the second space charge distribution map corresponding to the three-layer oiled paper insulation test sample according to the collected second voltage signal corresponding to the three-layer oiled paper insulation test sample, the method comprises:

the acquiring the distribution densities of the space charges at different time and different space regions of the space charges in the electric field according to the first space charge distribution map and the second space charge distribution map includes:

determining the charge density in the same space region corresponding to any time in the first voltage-removing space charge density map and the second voltage-removing space charge density map;

the analyzing and calculating the distribution density to obtain the density difference of the space charges of the oiled paper insulation samples with different layers in the same space region corresponding to the same time comprises the following steps:

calculating the charge density difference of two interlayer interface regions in the second voltage-removing space charge density map;

the method for acquiring the density difference of the space charges in the same space region corresponding to the oiled paper insulation test articles with different layers at different moments comprises the following steps:

determining a plurality of non-adjacent time points within a preset time length;

respectively determining the variation trends of the space charges of different space regions at the plurality of time points in the first voltage-removing different-time charge distribution diagram and the second voltage-removing different-time charge distribution diagram, and calculating the density difference values of the space charges of the same space region corresponding to the plurality of time points;

predicting the space charge distribution rule corresponding to the multilayer oiled paper insulation test article according to the density difference of the space charge, comprising the following steps of:

respectively determining the spatial regions where the maximum electric field intensity values are located in the first voltage-removing preset time electric field distribution map and the second voltage-removing preset time electric field distribution map;

and determining the distribution rule of the space charges generated by the oil paper insulation samples with different layers under the pressure removing condition according to the charge density in the same space region corresponding to the same time under the pressure removing condition, the charge density difference of the two interlayer interface regions and the density difference of the space charges corresponding to the time points.

10. A multilayer oiled paper insulation space charge prediction apparatus comprising:

at least one processor; and the number of the first and second groups,

a memory communicatively coupled to the at least one processor; wherein the content of the first and second substances,

the memory stores instructions executable by the at least one processor to enable the at least one processor to implement the steps of the method of any one of claims 1 to 9.

Technical Field

The application relates to the field of power systems, in particular to a multilayer oiled paper insulation space charge prediction method and device.

Background

The oil paper composite insulation often has a multilayer superposed structure in power equipment such as power transformers, converter transformers and high-voltage cables, and an interlayer interface exists. Moreover, many researches on polymer insulating materials show that the interlayer interface of the materials has a remarkable effect on the space charge accumulation and dissipation characteristics, so that the influence of the interlayer interface on the space charge characteristics of the oil paper insulation needs to be studied deeply.

However, in the prior art, only the space charge corresponding to the oiled paper insulation with a small number of layers can be measured to obtain the distribution rule of the space charge. However, the distribution rule of space charges corresponding to the multi-layer oilpaper insulation is usually measured one by one through experiments, the process is complicated, and the efficiency is low.

Disclosure of Invention

Therefore, in order to solve the above technical problems, it is necessary to provide a method and an apparatus for predicting space charge of multi-layer oiled paper insulation, which can solve the problem of low efficiency of obtaining a space charge distribution rule corresponding to multi-layer oiled paper insulation in the prior art.

A multilayer oiled paper insulation space charge prediction method comprises the following steps:

under two conditions of pressurization and pressure removal, respectively acquiring voltage signals corresponding to two layers of oil paper insulation samples and three layers of oil paper insulation samples through a space charge measuring device;

generating a first space charge distribution diagram corresponding to the two layers of oil paper insulation test articles and a second space charge distribution diagram corresponding to the three layers of oil paper insulation test articles according to the collected voltage signals;

acquiring the distribution density of space charges at different moments and different space regions of the space charges in an electric field according to the first space charge distribution map and the second space charge distribution map;

analyzing and calculating the distribution density to obtain the density difference of the space charges of the oiled paper insulation samples with different layers in the same space region corresponding to the same time;

acquiring the density difference of space charges in the same space region corresponding to the oiled paper insulation samples with different layers at different moments;

and predicting the space charge distribution rule corresponding to the multilayer oiled paper insulation test sample according to the density difference of the space charge.

In one embodiment, before predicting the space charge distribution rule corresponding to the multilayer oiled paper insulation sample according to the density difference of the space charges, the method further comprises:

according to the density difference, predicting a distribution rule of space charges corresponding to the four layers of oil paper insulation test articles, and generating a predicted third space charge distribution map corresponding to the four layers of oil paper insulation test articles; wherein, the electric field spatial distribution of four layers of oil paper insulation test articles is: a cathode, an interlayer interface, an anode;

collecting the distribution data of space charges corresponding to the four layers of oil paper insulation samples through a space charge measuring device;

generating a third space charge distribution map corresponding to the four-layer oil paper insulation test sample according to the collected distribution data;

and comparing the predicted third space charge distribution diagram with the generated third space charge distribution diagram, and determining that the distribution rule meets the prediction requirement under the condition that the error rate of the predicted third space charge distribution diagram and the generated third space charge distribution diagram is less than a first preset value.

In one embodiment, the predicted third space charge distribution map is compared with the generated third space charge distribution map, and when the error rate of the predicted third space charge distribution map and the error rate of the generated third space charge distribution map are smaller than the first preset value, after determining that the distribution rule meets the prediction requirement, the method further includes:

constructing a multilayer insulation oilpaper space charge distribution prediction model according to the distribution rule, a first space charge distribution diagram corresponding to the two layers of oilpaper insulation test articles, a second space charge distribution diagram corresponding to the three layers of oilpaper insulation test articles and a third space charge distribution diagram corresponding to the four layers of oilpaper insulation test articles;

according to the density difference of space charges, predicting the space charge distribution rule corresponding to the multilayer oiled paper insulation test sample, comprising the following steps:

and predicting the space charge distribution rule corresponding to the multilayer oilpaper insulation test sample through the multilayer oilpaper space charge prediction model and the number of layers corresponding to the multilayer oilpaper insulation test sample.

In one embodiment, the collecting the voltage signals corresponding to the two layers of oiled paper insulation test articles and the three layers of oiled paper insulation test articles respectively comprises:

applying electrical stress to the two layers of oiled paper insulation test samples and the three layers of oiled paper insulation test samples to enable space charges to be generated inside the two layers of oiled paper insulation test samples and inside the three layers of oiled paper insulation test samples respectively;

respectively applying electric pulse signals generated by a preset electric pulse source to the two layers of oiled paper insulation test articles and the three layers of oiled paper insulation test articles to enable space charges to generate first disturbance;

converting a signal generated by the first disturbance into a first voltage signal through a piezoelectric sensor;

amplifying the first voltage signal, and collecting the amplified first voltage signal;

withdrawing the electrical stress applied to the two layers of the oiled paper insulation test articles and the three layers of the oiled paper insulation test articles so as to generate second disturbance on space charge;

converting a signal generated by the second disturbance into a second voltage signal through the piezoelectric sensor;

and amplifying the second voltage signal, and collecting the amplified second voltage signal.

In one embodiment, before applying the electrical stress to the two-layer oiled paper insulation test piece and the three-layer oiled paper insulation test piece, the method further comprises:

respectively horizontally placing two layers of oiled paper insulation test articles and three layers of oiled paper insulation test articles in a test article cavity of a space charge measuring device;

extracting air in the test sample cavity through a vacuum pump and an air extraction valve on the test sample cavity so as to reduce the vacuum degree in the test sample cavity to a preset vacuum degree;

standing the sample cavity for a preset time, and measuring the vacuum degree in the sample cavity through a vacuum pressure gauge;

applying electrical stress to the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample, comprising:

and under the condition that the vacuum degree reduction range is smaller than a second preset value, carrying out voltage signal acquisition on the two-layer oil paper insulation test sample and the three-layer oil paper insulation test sample.

In one embodiment, before converting the signal generated by the first disturbance into the first voltage signal by the piezoelectric sensor, the method further comprises:

applying an electric pulse signal passing through the coupling capacitor to the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample;

applying a correction voltage to an electrode of a preset space charge measuring device; wherein, the correction voltage is opposite to the polarity of the electric pulse signal;

by correcting the voltage, the influence of the electric pulse signal on the voltage signal is cancelled.

In one embodiment, generating a first space charge distribution map corresponding to a two-layer oiled paper insulation test sample and generating a second space charge distribution map corresponding to a three-layer oiled paper insulation test sample according to the collected voltage signal includes:

generating a first space charge distribution diagram corresponding to the two layers of oil paper insulation samples according to the collected first voltage signal and second voltage signal corresponding to the two layers of oil paper insulation samples; wherein, the electric field spatial distribution of two-layer oilpaper insulation test article does: the first space charge distribution diagram comprises a first pressurization space charge density diagram, a first pressurization different-time charge distribution diagram, a first pressurization preset time electric field distribution diagram, a first pressure-removing space charge density diagram and a first pressure-removing different-time charge distribution diagram;

generating a second space charge distribution diagram corresponding to the three-layer oiled paper insulation test sample according to the collected first voltage signal and second voltage signal corresponding to the three-layer oiled paper insulation test sample; wherein, the electric field spatial distribution of three-layer oiled paper insulation test article does: the second space charge distribution diagram comprises a second pressurization space charge density diagram, a second pressurization different-time charge distribution diagram, a second pressurization preset time electric field distribution diagram, a second pressure-removing space charge density diagram and a second pressure-removing different-time charge distribution diagram.

In one embodiment, after generating a second space charge distribution map corresponding to the three-layer oiled paper insulation test sample according to the collected second voltage signal corresponding to the three-layer oiled paper insulation test sample, the method further includes:

acquiring the distribution density of space charges at different time and different space regions of the space charges in the electric field according to the first space charge distribution map and the second space charge distribution map, including:

determining the charge density in the same spatial region corresponding to any one time in the first pressurized space charge density map and the second pressurized space charge density map;

analyzing and calculating the distribution density to obtain the density difference of the space charges of the oiled paper insulation samples with different layers in the same space region corresponding to the same time, wherein the density difference comprises the following steps:

calculating the charge density difference of the two interlayer interface regions in the second pressurized space charge density map;

the method for acquiring the density difference of the space charges in the same space area corresponding to the oiled paper insulation test articles with different layers at different moments comprises the following steps:

determining a plurality of non-adjacent time points within a preset time length;

respectively determining the variation trends of space charges of different space regions at a plurality of time points in the first pressurization different-time charge distribution diagram and the second pressurization different-time charge distribution diagram, and calculating the density difference of the space charges of the same space region at a plurality of time points;

according to the density difference of space charges, predicting the space charge distribution rule corresponding to the multilayer oiled paper insulation test sample, comprising the following steps:

respectively determining the spatial regions where the maximum electric field intensity values are located in the first pressurization preset time electric field distribution diagram and the second pressurization preset time electric field distribution diagram;

and determining the distribution rule of the space charges generated by the oil paper insulation samples with different layers under the pressurizing condition according to the charge density in the same space region corresponding to the same moment under the pressurizing condition, the charge density difference of the two interlayer interface regions, the density difference of the space charges corresponding to the multiple time points and the space region where the maximum value of the electric field intensity is located.

In one embodiment, after generating a second space charge distribution map corresponding to the three-layer oiled paper insulation test sample according to the collected second voltage signal corresponding to the three-layer oiled paper insulation test sample, the method includes:

acquiring the distribution density of space charges at different time and different space regions of the space charges in the electric field according to the first space charge distribution map and the second space charge distribution map, including:

determining the charge density in the same space region corresponding to any moment in the first voltage-removing space charge density graph and the second voltage-removing space charge density graph;

analyzing and calculating the distribution density to obtain the density difference of the space charges of the oiled paper insulation samples with different layers in the same space region corresponding to the same time, wherein the density difference comprises the following steps:

calculating the charge density difference of two interlayer interface regions in a second voltage-removing space charge density map;

the method for acquiring the density difference of the space charges in the same space region corresponding to the oiled paper insulation test articles with different layers at different moments comprises the following steps:

determining a plurality of non-adjacent time points within a preset time length;

respectively determining the variation trends of space charges of different space regions at a plurality of time points in the first voltage-removing different-time charge distribution diagram and the second voltage-removing different-time charge distribution diagram, and calculating the density difference values of the space charges of the same space region at the plurality of time points;

according to the density difference of space charges, predicting the space charge distribution rule corresponding to the multilayer oiled paper insulation test sample, comprising the following steps:

respectively determining the spatial regions where the maximum electric field intensity values are located in the first voltage-removing preset time electric field distribution map and the second voltage-removing preset time electric field distribution map;

and determining the distribution rule of the space charges generated by the oil paper insulation samples with different layers under the pressure removing condition according to the charge density in the same space region corresponding to the same time under the pressure removing condition, the charge density difference of the two interlayer interface regions and the density difference of the space charges corresponding to a plurality of time points.

A multilayer oiled paper insulation space charge prediction apparatus comprising:

at least one processor; and the number of the first and second groups,

a memory communicatively coupled to the at least one processor; wherein the content of the first and second substances,

the memory stores instructions executable by the at least one processor to cause the at least one processor to perform the steps of the method described above.

The voltage signals corresponding to the two layers of the oil paper insulation test articles and the three layers of the oil paper insulation test articles are collected to obtain the distribution density of space charges at different moments and different space regions, and accordingly the charge distribution rules corresponding to the oil paper insulation test articles with different layers are summarized according to the distribution density. Secondly, the charge distribution density is calculated from multiple aspects by inducing the distribution rule of the space charges in the same space region corresponding to the same moment and the distribution rule of the space charges in the same space region corresponding to different moments, so that the reliability and the accuracy of the distribution rule are improved. In addition, this application embodiment can predict the space charge distribution rule of multilayer oil paper insulation sample through this rule, need not to carry out the measurement one by one, has improved the efficiency of obtaining the space charge distribution rule of multilayer oil paper insulation sample.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a flow chart of a method for predicting space charge of multi-layer oiled paper insulation according to an embodiment;

FIG. 2 is a second flowchart of the method for predicting space charge of multi-layer oiled paper insulation according to an embodiment;

FIG. 3 is a graph of first applied pressure space charge density for a two layer oiled paper insulation test sample in one example;

FIG. 4 is a graph of the electric field profile for a first pressing 3600s for a two-layer oiled paper insulation test piece in one embodiment;

FIG. 5 is a graph of charge density in a first evacuation space of a two-layer oiled paper insulation test piece in one embodiment;

FIG. 6 is a second plot of space charge density under pressure for a three layer oiled paper insulation test sample according to one embodiment;

FIG. 7 is a second pressurized 3600s electric field distribution diagram of a three-layer oiled paper insulation test sample according to an embodiment;

FIG. 8 is a graph of charge density of a second evacuated space of a three layer oiled paper insulation test sample in accordance with an embodiment;

FIG. 9 is a third flowchart of a method for predicting space charge of multi-layer oiled paper insulation according to an embodiment;

FIG. 10 is a fourth flowchart illustrating a method for predicting space charge of multi-layer oiled paper insulation according to an embodiment;

FIG. 11 is a fifth flowchart illustrating a method for predicting space charge of multi-layer oiled paper insulation according to an embodiment;

FIG. 12 is a sixth flowchart illustrating a method for predicting space charge of multi-layer oiled paper insulation according to an embodiment;

fig. 13 is a schematic structural diagram of a multilayer oiled paper insulation space charge prediction apparatus according to an embodiment.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are set forth in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that the terms "first," "second," and the like as used herein may be used herein to describe various spaces, but these elements are not limited by these terms. These terms are only used to distinguish a first space from another space.

It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected to the other element through intervening elements. Further, "connection" in the following embodiments is understood to mean "electrical connection", "communication connection", or the like, if there is a transfer of electrical signals or data between the connected objects.

As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

In the description herein, references to the description of "some embodiments," "other embodiments," "desired embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, a schematic description of the above terminology may not necessarily refer to the same embodiment or example.

In one embodiment, as shown in fig. 1, a flow chart of a method for predicting space charge of a multilayer oiled paper insulation is provided. Includes steps S100 to S600.

And S100, respectively acquiring voltage signals corresponding to the two layers of oil paper insulation test articles and the three layers of oil paper insulation test articles by a preset space charge measuring device.

And S200, generating a first space charge distribution map corresponding to the double-layer oil paper insulation test sample and a second space charge distribution map corresponding to the three-layer oil paper insulation test sample according to the acquired voltage signal.

Step S300, obtaining distribution densities of the space charges at different time and in different space regions according to the first space charge distribution map and the second space charge distribution map.

And step S400, analyzing and calculating the distribution density to obtain the density difference of the space charges of the oil paper insulation samples with different layers in the same space region corresponding to the same time.

According to the charge density in the same space region corresponding to the same time under the condition of pressurization and depressurization, the density change difference of the corresponding space charge can be seen when the number of interface space layers is increased, and the cathode, the anode and the first space interface are in the same time in the same region. And determining the space charge density difference in each space interface when each space interface is added according to the charge density difference of the two interlayer interface areas.

And step S500, obtaining the density difference of the space charges in the same space region corresponding to the oiled paper insulation samples with different layers at different moments.

Specifically, the electric charge density in the same space region corresponding to different time points under the condition of pressurization and depressurization, the electric charge density difference of two interlayer interface regions, the density difference of space charges corresponding to a plurality of time points and the space region where the maximum value of the electric field intensity is located are determined. And determining the density change difference of space charges generated by the oiled paper insulation samples with different layers under the conditions of pressurization and pressure withdrawal. According to the density difference of the space charges corresponding to the multiple time points, the density change difference value of the space charges in each space region along with the change of time can be determined.

And S600, predicting a space charge distribution rule corresponding to the multilayer oilpaper insulation test article according to the density difference of the space charge.

In one embodiment, step S100, collecting voltage signals corresponding to two layers of oiled paper insulation test articles and three layers of oiled paper insulation test articles respectively by using a preset space charge measuring device, includes substeps S101 to S112.

And S101, respectively horizontally placing the two layers of oiled paper insulation test articles and the three layers of oiled paper insulation test articles in a test article cavity of a preset space charge measuring device.

And S102, extracting air in the test sample cavity through a vacuum pump and an air extraction valve on the test sample cavity so as to reduce the vacuum degree in the test sample cavity to a preset vacuum degree.

And S103, standing the sample cavity for a preset time, and measuring the vacuum degree in the sample cavity through a vacuum pressure gauge.

And step S104, under the condition that the vacuum degree reduction range is small, voltage signal acquisition is carried out on the two-layer oil paper insulation test sample and the three-layer oil paper insulation test sample.

And step S105, applying electrical stress to the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample to enable space charges to be generated inside the two-layer oiled paper insulation test sample and inside the three-layer oiled paper insulation test sample respectively.

Specifically, a direct-current high-voltage source of the preset space charge measuring device outputs a direct-current voltage of +/-30 kV, the direct-current high-voltage source is connected to an upper electrode through a high-voltage terminal and a 12M omega high-voltage-resistant protection resistor, and electric stress is applied to a two-layer oil paper insulation test piece and a three-layer oil paper insulation test piece to enable space charges to be generated inside the two-layer oil paper insulation test piece and the three-layer oil paper insulation test piece.

And step S106, respectively applying electric pulse signals generated by a preset electric pulse source to the two-layer oil paper insulation test sample and the three-layer oil paper insulation test sample so as to generate first disturbance to space charges.

Specifically, a pulse source of the preset space charge measuring device can generate a stable electric pulse signal with the pulse width of 5ns and the amplitude of 200V-1000V, the stable electric pulse signal is coupled to a two-layer oiled paper insulation test sample and a three-layer oiled paper insulation test sample through a high-voltage ceramic capacitor with the frequency of 1000pF, and the space charge in the test sample is disturbed by the electric field force.

And S107, applying the electric pulse signal passing through the coupling capacitor to the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample.

Step S108, a correction voltage is applied to the electrodes of the preset space charge measuring device. Wherein the correction voltage is opposite to the polarity of the electric pulse signal.

In step S109, the influence of the electric pulse signal on the voltage signal is canceled by the correction voltage.

Specifically, when measuring space charge, it is necessary to apply a narrow electric pulse in the voltage application or voltage removal stage of the sample to generate a micro-disturbance in the charge to generate a sound pressure wave, which is converted into a voltage signal that can be easily measured by the piezoelectric sensor. Therefore, the measured signal necessarily includes the influence of the pulse signal. In order to more accurately obtain the distribution rule of space charge in the sample, a correction voltage needs to be applied for correction.

Further, in the embodiment of the present application, the selected pulse amplitude is 200V, and the pulse width is 5 ns. Therefore, the value of the applied dc voltage opposite to the polarity of the pulse may be 14V. At this point, the effect of the pulse on the charge measurement signal has been substantially eliminated.

In step S110, the signal generated by the first disturbance is converted into a first voltage signal by the piezoelectric sensor.

And step S111, amplifying the first voltage signal, and collecting the amplified first voltage signal.

Specifically, an acoustic signal generated by the first disturbance passes through the lower electrode, is detected by the piezoelectric sensor and is converted into a first voltage signal, and then the first voltage signal is output to a data acquisition module of the preset space charge measurement device through the broadband amplifier, so that data acquisition processing is completed. And obtaining the charge density and electric field intensity distribution in the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample under the condition of pressurization.

Step S112, withdrawing the electrical stress applied to the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample, so that the space charge generates a second disturbance.

In step S113, the signal generated by the second disturbance is converted into a second voltage signal by the piezoelectric sensor.

And step S114, amplifying the second voltage signal, and collecting the amplified second voltage signal.

Specifically, stable electric pulse signals with the pulse width of 5ns and the amplitude of 200V-1000V are withdrawn from the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample, and the space charges in the test samples are subjected to second disturbance by electric field force. And the acoustic signal generated by the second disturbance passes through the lower electrode, is detected by the piezoelectric sensor and is converted into a second voltage signal, and then the second voltage signal is output to a data acquisition module of the preset space charge measuring device through the broadband amplifier, so that data acquisition processing is completed. And obtaining the charge density and electric field intensity distribution in the two-layer oiled paper insulation test sample and the three-layer oiled paper insulation test sample under the condition of pressure removal.

In one embodiment, as shown in fig. 2, a second flow chart of a method for predicting space charge of multi-layer oilpaper insulation is provided, and step S200 is to generate a first space charge distribution map corresponding to a two-layer oilpaper insulation test sample and a second space charge distribution map corresponding to a three-layer oilpaper insulation test sample according to the collected voltage signal, and includes substeps 201 and step S202.

Step S201, generating a first space charge distribution diagram corresponding to the two layers of oil paper insulation samples according to the collected first voltage signal and the second voltage signal corresponding to the two layers of oil paper insulation samples. Wherein, the electric field spatial distribution of two-layer oilpaper insulation test article does: cathode, interlayer interface, anode. The first space charge distribution diagram comprises a first pressurization space charge density diagram, a first pressurization different-time charge distribution diagram, a first pressurization preset-time electric field distribution diagram, a first pressure-removing space charge density diagram and a first pressure-removing different-time charge distribution diagram.

Specifically, the first pressurized space charge density map is used for recording the space charge distribution result in 3600s after the two layers of oiled paper insulation samples are applied with the voltage of 6 kV. The first pressurizing different-time charge distribution diagram is used for recording the distribution density of space charges in the two layers of test articles at different times. The first pressurization preset time electric field distribution diagram is used for recording the electric field distribution density of the two layers of test articles along the thickness direction after 3600s of external application of 6kV direct current voltage. The first voltage-removing space charge density graph is used for recording the space charge distribution density within 3600s after 6kV voltage is removed from the two layers of oiled paper insulation samples. The first voltage-removing different-time charge distribution diagram is used for recording space charge distribution density in the two layers of samples at different times after voltage removal.

In one embodiment, two layers and three layers of oil paper insulation samples are respectively used as research objects in the embodiment of the application, the single-layer thickness of the insulation paper is 80 micrometers, and the insulation paper is subjected to vacuum drying and is used as a test object after being soaked in transformer oil. In order to be consistent with the external field intensity born by the single-layer test sample, the applied voltage of the 2-layer test sample is 6kV, and the applied voltage of the 3-layer test sample is 9 kV. Respectively counting the corresponding space charge distribution rules in the charge injection process in the applied voltage 3600s and the charge dissipation process in the removed voltage 3600 s.

In one embodiment, as shown in FIG. 3, a first pressurized space charge density plot of a two-layer oiled paper insulation sample is provided. The abscissa of the coordinate system is the electric field spatial distribution of the two layers of the oiled paper insulation test articles, and the ordinate is the pressurizing time. And reflecting different charge densities according to different colors and shade changes of the colors in a coordinate system, and recording the distribution change condition of space charges in 3600s after the voltage of the two layers of oil paper insulation samples is applied to 6 kV.

In one embodiment, as shown in fig. 4, a first pressurized 3600s electric field distribution diagram of a two-layer oiled paper insulation test sample is provided, and the abscissa of a coordinate system is the electric field spatial distribution of the two-layer oiled paper insulation test sample, and the ordinate is the electric field intensity. As can be seen from fig. 4, the maximum value of the electric field intensity occurs at the boundary between the positive and negative space charge regions, i.e., the boundary of the space charge accumulation region.

In one embodiment, as shown in fig. 5, a first voltage-removing space charge density map of a two-layer oiled paper insulation sample is provided, and the abscissa of a coordinate system is the electric field spatial distribution of the two-layer oiled paper insulation sample, and the ordinate is the voltage-removing time. And (3) reflecting different charge densities according to different colors and shade changes of the colors in a coordinate system, and recording the distribution change condition of space charges in 3600s after 6kV voltage is removed from the two layers of oiled paper insulation samples.

Step S202, generating a second space charge distribution map corresponding to the three-layer oil paper insulation test sample according to the collected first voltage signal and the second voltage signal corresponding to the three-layer oil paper insulation test sample. Wherein, the electric field spatial distribution of three-layer oiled paper insulation test article does: cathode, interlayer interface, anode. The second space charge distribution map includes a second pressed space charge density map, a second charge distribution map at different pressing moments, a second pressed preset time electric field distribution map, a second pressed space charge density map, and a second pressed moment electric field distribution map.

Specifically, the second pressurized space charge density map is used for recording the space charge distribution rule in 3600s after the voltage of the three-layer oiled paper insulation sample is applied to 9 kV. And the second pressurizing different-time charge distribution diagram is used for recording the distribution rule of space charges in the three layers of test articles at different times. And the second pressurized preset time electric field distribution diagram is used for recording the electric field distribution rule of the three-layer test article along the thickness direction after the action of the external 9kV direct current voltage for 3600 s. And the second voltage-removing space charge density map is used for recording the space charge distribution rule of the three-layer oiled paper insulation sample within 3600s after the voltage of 9kV is removed. And the second voltage-removing different-time charge distribution diagram is used for recording the space charge distribution rule in the three layers of samples at different times after the voltage is removed.

In one embodiment, as shown in fig. 6, a second compression space charge density map of a three-layer oiled paper insulation test sample is provided, and the abscissa of the coordinate system is the spatial distribution of the electric field of the two-layer oiled paper insulation test sample, and the ordinate is the compression time. And (3) reflecting different charge densities according to different colors and shade changes of the colors in a coordinate system, and recording the distribution change condition of space charges in 3600s after the voltage of the three-layer oiled paper insulation sample is applied by 9 kV.

In one embodiment, as shown in fig. 7, a second pressurized 3600s electric field distribution diagram of the three-layer oiled paper insulation test sample is provided, and the abscissa of the coordinate system is the electric field spatial distribution of the three-layer oiled paper insulation test sample, and the ordinate is the electric field intensity. As can be seen from fig. 7, the electric field distribution is not uniform due to the accumulation of space charges inside the sample, the interlayer interface hinders the charge migration, so that the polarities of the space charges accumulated on the two sides of the interlayer interface adjacent to the cathode are opposite, and the positive and negative space charge accumulation regions meet at the interface, which results in the maximum electric field intensity at the interface.

In one embodiment, as shown in fig. 8, a second voltage-removing space charge density map of the three-layer oiled paper insulation test sample is provided, and the abscissa of the coordinate system is the electric field spatial distribution of the three-layer oiled paper insulation test sample, and the ordinate is the voltage-removing time. And (3) reflecting different charge densities according to different colors and shade changes of the colors in a coordinate system, and recording the distribution change condition of space charges in 3600s after the three-layer oiled paper insulation sample is removed of the applied voltage of 9 kV.

In one embodiment, as shown in fig. 9, a third flow chart of a method for predicting space charge of multi-layer oil paper insulation is provided, and step S202 includes steps S301, S401, S501, S502, S601 and S602 after generating a second space charge distribution map corresponding to a three-layer oil paper insulation sample according to a first voltage signal and a second voltage signal corresponding to the collected three-layer oil paper insulation sample. Step S300, obtaining the distribution density of the space charges at different time and in different space regions according to the first space charge distribution map and the second space charge distribution map, includes substep S301. In step S301, the charge density in the same spatial region corresponding to any one time is determined in the first and second pressurized space charge density maps. Step S400, analyzing and calculating the distribution density to obtain the density difference of the space charges in the same space region corresponding to the oil paper insulation samples with different layers at the same time, and the substep S401 is included. In step S401, a charge density difference in the two interlayer interface regions is calculated in the second pressurized space charge density map.

For example, when the pressing is performed for 60s, the space charge densities of the anode regions corresponding to the first pressing space charge density map and the second pressing space charge density map are recorded respectively, and the difference between the space charge densities is calculated, so that the charge distribution difference caused by the difference of the number of the layers of the oiled paper insulation test articles in the same time and the same region is obtained.

For another example, the second pressurized space charge density map has two interlayer interface spaces, so that the difference of the charge density of the two interlayer interface spaces is recorded when the pressure is applied for 60s, thereby obtaining the influence of the interlayer interface increase on the space charge distribution density.

Step S500, obtaining the density difference of the space charges in the same space region corresponding to the oil paper insulation samples with different layers at different times, and comprises substeps S501-S502. Step S501, a plurality of non-adjacent time points are determined in a preset time length. Step S502 is to determine the variation trend of the space charges in different spatial regions at a plurality of time points in the first pressurization different-time charge distribution map and the second pressurization different-time charge distribution map, and calculate the density difference of the space charges in the same spatial region at a plurality of time points. And S600, predicting a space charge distribution rule corresponding to the multilayer oilpaper insulation test sample according to the density difference of the space charges, and comprising substeps S601-S602. In step S601, spatial regions where the maximum electric field intensity is located are respectively determined in the first pressurization preset time electric field distribution map and the second pressurization preset time electric field distribution map. Step S602, determining a distribution rule of space charges generated by different layers of the oiled paper insulation test articles under pressurization according to the charge density in the same space region corresponding to the same time under pressurization, the charge density difference between two interlayer interface regions, the density difference of space charges corresponding to multiple time points, and the space region where the maximum value of the electric field intensity is located.

Specifically, the first pressure different time charge distribution diagram and the second pressure different time charge distribution diagram have the abscissa of the space charge distribution region, the ordinate of the space charge distribution region and the ordinate of the space charge density, and the curve in the diagram is the distribution density of the space charge corresponding to a certain time point in each space region. The change of the space charge density in each space region along with the change of time can be seen by putting a plurality of curves at different moments into the same pressurized charge distribution diagram at different moments.

In one embodiment, as shown in fig. 10, a fourth flowchart of the method for predicting space charge of multi-layer oil paper insulation is provided, and the step S202 includes steps S302, S402, S503, S504, S603, and S604 after generating a second space charge distribution map corresponding to a three-layer oil paper insulation test sample according to the collected first voltage signal and second voltage signal corresponding to the three-layer oil paper insulation test sample. Step S300, obtaining the distribution density of the space charges at different time and in different space regions according to the first space charge distribution map and the second space charge distribution map, includes substep S302. In step S302, the charge density in the same spatial region corresponding to any one time is determined in the first set-down space charge density map and the second set-down space charge density map. And S400, analyzing and calculating the distribution density to obtain the density difference of the space charges in the same space region corresponding to the oiled paper insulation samples with different layers at the same time, wherein the step S402 is included, and the charge density difference of the two interlayer interface regions is calculated in a second pressure-removing space charge density diagram. Step S500, obtaining the density difference of the space charges in the same space region corresponding to the oil paper insulation samples with different layers at different times, and comprising substeps S503-S504. In step S503, a plurality of non-adjacent time points are determined within a preset time period. In step S504, in the first voltage-removing different-time charge distribution map and the second voltage-removing different-time charge distribution map, the variation trends of the space charges in different spatial regions at a plurality of time points are respectively determined, and the density difference of the space charges in the same spatial region corresponding to the plurality of time points is calculated. And S600, predicting a space charge distribution rule corresponding to the multilayer oilpaper insulation test sample according to the density difference of the space charges, and comprising substeps S603-S604. Step S603, determining spatial regions where the maximum electric field intensity values are located in the first voltage-removing preset time electric field distribution map and the second voltage-removing preset time electric field distribution map, respectively. Step S604, determining the distribution rule of the space charges generated by the oil paper insulation samples with different layers under the pressure removing condition according to the charge density in the same space region corresponding to the same time under the pressure removing condition, the charge density difference of the two interlayer interface regions and the density difference of the space charges corresponding to the time points.

In one embodiment, as shown in fig. 11, a fifth flowchart of a method for predicting space charge of multi-layer oil paper insulation is provided, where step S600 includes, before predicting a space charge distribution rule corresponding to a multi-layer oil paper insulation sample according to a density difference of space charge, steps S701 to S703, and step S701 is performed to predict a space charge distribution rule corresponding to four layers of oil paper insulation samples according to the density difference, and generate a predicted third space charge distribution map corresponding to four layers of oil paper insulation samples. Wherein, the electric field spatial distribution of four layers of oil paper insulation test articles is: cathode, interlayer interface, and anode.

And step S702, collecting the distribution data of the space charges corresponding to the four-layer oil paper insulation test sample by a preset space charge measuring device.

Step S703 is to generate a third space charge distribution map corresponding to the four-layer oil paper insulation test sample according to the collected distribution data, compare the predicted third space charge distribution map with the third space charge distribution map, and determine that the distribution rule meets the prediction requirement when the error rate of the third space charge distribution map and the third space charge distribution map is smaller than the first preset value.

In the embodiments of the present application, the error rate is preferably less than 3/Cm^-3In the case of (3), the distribution rule is determined to meet the prediction requirement, and the error rate can be adjusted according to the actual situation in application.

In one embodiment, as shown in fig. 12, a sixth schematic flow chart of a multilayer oiled paper insulation space charge prediction method is provided, in step S703, a third space charge distribution diagram corresponding to a four-layer oiled paper insulation test sample is generated according to collected distribution data, the predicted third space charge distribution diagram is compared with the third space charge distribution diagram, and in case that an error rate of the third space charge distribution diagram and the error rate of the third space charge distribution diagram are smaller than a first preset value, after determining that a distribution rule meets a prediction requirement, steps S704 and S605 are further included.

Step S704, constructing a multilayer insulation oilpaper space charge distribution prediction model according to the distribution rule, a first space charge distribution diagram corresponding to a double-layer oilpaper insulation test sample, a second space charge distribution diagram corresponding to a three-layer oilpaper insulation test sample and a third space charge distribution diagram corresponding to a four-layer oilpaper insulation test sample.

Step S600, according to the density difference value of the space charges, predicting the space charge distribution rule corresponding to the multilayer oilpaper insulation test sample, and comprises substep S605. And step S605, predicting the space charge distribution rule corresponding to the multilayer oilpaper insulation test sample through the multilayer oilpaper space charge prediction model and the number of layers corresponding to the multilayer oilpaper insulation test sample.

It should be understood that, although the steps in the flowcharts of fig. 1-2, 9-12 are shown in sequence as indicated by the arrows, the steps are not necessarily performed in sequence as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least some of the steps in fig. 1-2 and 9-12 may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of performing the steps or stages is not necessarily sequential, but may be performed alternately or alternatively with other steps or at least some of the other steps or stages.

In one embodiment, as shown in fig. 13, a schematic structural diagram of a multilayer oiled paper insulation space charge prediction device is provided. Multilayer oiled paper insulation space charge prediction equipment includes: at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executable by the at least one processor to enable the at least one processor to implement the steps in the above-described method embodiments.

The embodiments in the present application are described in a progressive manner, and the same and similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the embodiments of the apparatus, the device, and the nonvolatile computer storage medium, since they are substantially similar to the embodiments of the method, the description is simple, and for the relevant points, reference may be made to the partial description of the embodiments of the method.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.