CN214427563U

CN214427563U - XLPE insulating material water tree growth experimental apparatus

Info

Publication number: CN214427563U
Application number: CN202120530897.4U
Authority: CN
Inventors: 刘骥; 闫爽; 王守明
Original assignee: Harbin University of Science and Technology
Current assignee: Harbin University of Science and Technology
Priority date: 2021-03-15
Filing date: 2021-03-15
Publication date: 2021-10-19
Anticipated expiration: 2031-03-15

Abstract

The utility model discloses a XLPE insulating material water tree growth experimental apparatus, which belongs to the technical field of insulating material aging experiments and comprises an alternating current voltage regulating source, a switch, a rectifier circuit, an inverter circuit, a protection device, a high-frequency transformer, a copper electrode, an experimental tank, a NaCl solution, a sample base and an XLPE sample; the alternating current voltage regulating source, the switch, the rectifying circuit, the inverter circuit, the protection device, the high-frequency transformer and the copper electrode are electrically connected in sequence; the test tank is a metal test tank and is arranged in a grounding way; the Nacl solution is contained in a test groove; the sample base comprises a table top and a support; the support column penetrates through the upper part of the table top, and bulges are formed at four corners of the upper surface of the table top; the water tree aging research under different frequencies and different voltage levels can be realized. And the test device has simple structure and easy operation, and can ensure that the NaCl solution can immerse the lower surface of the XLPE sample but can not immerse the upper surface of the XLPE sample to contact with the high-voltage copper electrode to generate short circuit.

Description

XLPE insulating material water tree growth experimental apparatus

Technical Field

The utility model belongs to the technical field of the ageing experiment of insulating material, especially relate to a XLPE insulating material water tree growth experimental apparatus.

Background

The water tree aging is an important form of cable insulation aging, the water tree can reduce the insulation margin of the cable, the service life of the cable is further shortened, and the water tree can be possibly developed into an electric tree under certain conditions, so that the cable is subjected to insulation breakdown. This will seriously affect the operation of the power grid and cause power failure accidents. Therefore, the method has extremely important significance for researching the aging of the cable insulation water tree.

When moisture and some inducing factors such as impurities or protrusions exist in the cable insulation, under the action of an alternating electric field, the moisture generates stress along the direction of electric field lines and develops into micro-channels and continuously expands into dendritic shapes, so that the insulation is aged, and the insulation performance is damaged. The existing method for researching the growth of the water tree generally adopts a water needle electrode method to simulate the water tree generating condition. The experimental device adopted by the method is referred to the experimental device given by the national standard GB/T21224-2007. However, the method has strict requirements on experimental devices, and cannot conveniently and rapidly research the water tree aging.

Therefore, there is a need in the art for a new solution to solve this problem.

SUMMERY OF THE UTILITY MODEL

In order to overcome the defects in the prior art: the utility model provides a XLPE insulating material water tree growth experimental apparatus for solve the problem that how to make things convenient for quick research water tree to age.

In order to realize the purpose, the utility model discloses a technical scheme is: an experimental device for water tree growth of XLPE insulating materials comprises an alternating current voltage regulating source, a switch, a rectifying circuit, an inverter circuit, a protection device, a high-frequency transformer, a copper electrode, a test groove, a Nacl solution, a sample base and an XLPE sample; the alternating current voltage regulating source, the switch, the rectifying circuit, the inverter circuit, the protection device, the high-frequency transformer and the copper electrode are electrically connected in sequence; the test tank is a metal test tank and is arranged in a grounding way; the Nacl solution is contained in a test groove;

the sample base comprises a table top and a support; four corners of the table-board are respectively provided with a supporting column; the support column penetrates through the upper part of the table top, and a bulge is formed on the upper surface of the table top;

the XLPE sample is of a sheet structure, and a plurality of needle-type blind holes are formed in the central area of the lower surface of the XLPE sample; placing an XLPE sample on the table top of the sample base; the copper electrode was placed on the top surface of the XLPE sample.

Through the above design scheme, the utility model discloses following beneficial effect can be brought:

1. the water tree aging research under different frequencies and different voltage levels can be realized. And the testing device has simple structure and is easy to operate.

2. The time required for the growth of the water trees can be shortened by the frequency, the voltage level and the concentration of the NaCl solution.

And 3, jacking four corners of the XLPE sample for a certain angle, so that the condition that the NaCl solution can immerse the lower surface of the XLPE sample but cannot submerge the upper surface of the XLPE sample to be in contact with the high-voltage copper electrode to cause short circuit can be ensured.

Drawings

Fig. 1 is a schematic structural view of the experimental apparatus for water tree growth of XLPE insulating material of the present invention.

Fig. 2 is an assembly drawing of the test tank of the experimental apparatus for water tree growth of XLPE insulating material.

Fig. 3 is a sectional view of a test tank of the experimental apparatus for water tree growth of XLPE insulating material of the present invention.

Fig. 4 is a schematic view of a sample base of the XLPE insulating material water tree growth experimental apparatus of the present invention.

Fig. 5 is a schematic structural view of an XLPE sample of an experimental apparatus for water tree growth of XLPE insulating material.

In the figure, 1-an alternating current voltage regulating source, 2-a switch, 3-a rectifying circuit, 4-an inverter circuit, 5-a protection device, 6-a high-frequency transformer, 7-a copper electrode, 8-a test groove, 9-NaCl solution, 10-a sample base, 101-a table top, 102-a support, 103-a bulge, 11-an XLPE sample and 111-a pin type blind hole.

Detailed Description

The following detailed description of the embodiments of the present invention will be made with reference to the accompanying drawings

It should be noted that, the terms "front and back, up and down, left and right" and the like in the text are only simplified terms for visually describing the positional relationship based on the drawings, and do not limit the technical solution.

Shown in attached figures 1-5: an experimental device for water tree growth of XLPE insulating materials comprises an alternating current voltage regulating source 1, a switch 2, a rectifying circuit 3, an inverter circuit 4, a protection device 5, a high-frequency transformer 6, a copper electrode 7, a test tank 8, a NaCl solution 9, a sample base 10 and an XLPE sample 11; the alternating current voltage regulating source 1, the switch 2, the rectifying circuit 3, the inverter circuit 4, the protection device 5, the high-frequency transformer 6 and the copper electrode 7 are electrically connected in sequence; the test tank 8 is a metal test tank and is arranged in a grounding way; the Nacl solution 9 is contained in a test groove 8;

the sample base 10 comprises a table top 101 and a support 102; four corners of the table-board 101 are respectively provided with a supporting column 102; the pillar 102 penetrates above the table-board 101, and a protrusion 103 is formed on the upper surface of the table-board 101;

the XLPE sample 11 is of a sheet structure, and a plurality of needle-type blind holes 111 are formed in the central area of the lower surface of the XLPE sample 11; the XLPE sample 11 is placed on the table-board 101 of the sample base 10; the copper electrode 7 is arranged on the upper surface of the XLPE sample 11; the four corners of the XLPE sample 11 are jacked up by the bulges 103 for a certain angle, so that the NaCl solution 9 can be ensured to be immersed in the lower surface of the XLPE sample 11 but not to be in contact with the high-voltage copper electrode 7 to be short-circuited with the upper surface of the XLPE sample 11.

The utility model discloses a growth of water branch under certain frequency, certain voltage level is realized to AC voltage regulation power supply unit, switch unit, rectifier unit, contravariant unit, protection unit, high frequency transformer unit, test tank unit. Meanwhile, the time required by the growth of the water trees can be shortened by improving the voltage level, the frequency and the concentration of the NaCl solution. The alternating current voltage regulating source 1 has the advantages of adjustable output voltage, stability, no distortion, reliability in operation and the like, and provides voltage for the whole set of experimental device. The switch 2 can control the on-off of the whole circuit. The rectifying circuit 3 converts alternating current voltage provided by the voltage regulating source into direct current. The inverter circuit 4 can realize frequency adjustment and convert a direct current voltage into an alternating current voltage. The protection device 5 can detect the inverted output current, and when the detected inverted output current exceeds a specified value, the switch 2 is switched off. The high-frequency transformer 6 can convert low voltage into high voltage under high frequency, and the high voltage is transmitted to the copper electrode 7 to provide high voltage for water tree growth experiments. The test chamber 8 serves as a vessel for containing the NaCl solution 9 and is grounded as a ground electrode.

In a specific implementation, the test tank 8 is made of stainless steel material. The concentration of the Nacl solution 9 is 1.8 mmol/L-1.8 mol/L. The strut 102 is a nylon column. The thickness of the XLPE sample 11 is 2mm, and a needle type blind hole 111 with the depth of 1mm is punched by a needle with the curvature radius of 15 +/-5 mu m at every 15mm interval in the central area of the lower surface of the XLPE sample 11.

The voltage required by the experiment is obtained by calculating the transformation ratio of the high-frequency transformer 6 and the input of the alternating-current voltage regulating source 1; the frequency required for the experiment is written by the program of the inverter circuit 4.

In the preparation stage, equipment required by the experiment, such as an alternating current voltage regulating source 1, a switch 2, a rectifying circuit 3, an inverter circuit integrated module 4, a protection device 5, a high-frequency transformer 6, a test groove 8 and the like, and an XLPE sample 11 with the thickness of 2mm required by the experiment are prepared.

And in the calculation stage, the voltage required by the experiment is determined: the voltage required to be provided by the alternating current voltage regulating source 1 can be calculated according to the transformation ratio of the high-frequency transformer 6; the frequency required by the experiment is determined by the inverter circuit 4, and can be written into the inverter circuit 4 by the DSP program.

Connecting the prepared devices according to a structural schematic diagram shown in fig. 1, setting a calculated voltage by an alternating current voltage regulator 1, setting a frequency required by an experiment by an inverter circuit 4, making a groove body of a test groove 8 from a stainless steel material, connecting the groove body with the ground to form a ground pole, filling a Nacl solution 9 in the groove, simulating a moisture environment condition required by water tree aging of a cable in an actual operation process, placing a sample base 10 in the test groove 8, placing a needle-shaped blind hole 111 of an XLPE sample 11 on the sample base 10 downwards, and paying attention that the Nacl solution 9 should be soaked on an upper edge surface of the sample base 10 but cannot exceed the upper edge surface of the XLPE sample 11, so that the Nacl solution 9 can be soaked in the needle-shaped blind hole 111 to form a water needle point; pressing a copper electrode 7 on an XLPE sample 11, and connecting the copper electrode 7 with the secondary side output of a high-frequency transformer 6 through a lead to form a high-voltage electrode required by an experiment; the test chamber 8 was covered with a perforated epoxy plate to prevent contamination of the NaCl solution 9.

The XLPE sample 11 in the test cell 8 can be subjected to water tree aging at high frequency and high voltage, high frequency and low voltage, low frequency and low voltage or low frequency and high voltage. The aging period of the water tree generally varies from 1 to 3 weeks, and the higher the voltage level, the higher the frequency and the higher the concentration of the NaCl solution 9, the shorter the time required for the water tree to age to the same degree.

It is obvious that the above-described embodiments are only some of the embodiments of the present invention, and not all of them. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Claims

1. The utility model provides an experimental apparatus that XLPE insulating material water tree grows which characterized in that: the device comprises an alternating current voltage regulating source (1), a switch (2), a rectifying circuit (3), an inverter circuit (4), a protection device (5), a high-frequency transformer (6), a copper electrode (7), a test tank (8), a Nacl solution (9), a test sample base (10) and an XLPE test sample (11); the alternating current voltage regulating source (1), the switch (2), the rectifying circuit (3), the inverter circuit (4), the protection device (5), the high-frequency transformer (6) and the copper electrode (7) are electrically connected in sequence; the test tank (8) is a metal test tank and is arranged in a grounding way; the Nacl solution (9) is contained in a test groove (8);

the sample base (10) comprises a table top (101) and a pillar (102); four corners of the table top (101) are respectively provided with a support column (102); the support post (102) penetrates through the upper part of the table top (101), and a bulge (103) is formed on the upper surface of the table top (101);

the XLPE sample (11) is of a sheet structure, and a plurality of needle-type blind holes (111) are formed in the central area of the lower surface of the XLPE sample (11); an XLPE sample (11) is placed on a table top (101) of a sample base (10); the copper electrode (7) is placed on the upper surface of the XLPE sample (11).

2. An experimental facility for water tree growth of XLPE insulating material according to claim 1, characterized in that: the test tank (8) is made of stainless steel materials.

3. An experimental facility for water tree growth of XLPE insulating material according to claim 1, characterized in that: the concentration of the Nacl solution (9) is 1.8 mmol/L-1.8 mol/L.

4. An experimental facility for water tree growth of XLPE insulating material according to claim 1, characterized in that: the strut (102) is a nylon column.

5. An experimental facility for water tree growth of XLPE insulating material according to claim 1, characterized in that: the thickness of the XLPE sample (11) is 2mm, and a needle type blind hole (111) with the depth of 1mm is punched by a needle with the curvature radius of (15 +/-5) mu m at every 15mm interval in the central area of the lower surface of the XLPE sample (11).

6. An experimental facility for water tree growth of XLPE insulating material according to claim 1, characterized in that: the protection device (5) is used for detecting the inversion output current of the inversion circuit (4), and the switch (2) can be switched off when the detected current exceeds a specified value.