CN217404404U - Volume resistivity measuring device for cable buffer layer - Google Patents
Volume resistivity measuring device for cable buffer layer Download PDFInfo
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- CN217404404U CN217404404U CN202123301012.2U CN202123301012U CN217404404U CN 217404404 U CN217404404 U CN 217404404U CN 202123301012 U CN202123301012 U CN 202123301012U CN 217404404 U CN217404404 U CN 217404404U
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Abstract
The utility model provides a cable buffer layer volume resistivity measuring device, aassessment method and system. The device includes: a first electrode; a second electrode disposed over the first electrode; a tray disposed above the second electrode; a weight member disposed on the tray; the two ends of the power supply module are respectively connected with the first electrode and the second electrode; and the test module is connected with the test loop. The utility model fully considers the actual situation of the buffer layer in the corrugated aluminum sheath high-voltage cable, and selects the second electrode matched with the actual contact point area between the buffer layer and the corrugated aluminum sheath aiming at the measurement problem of the buffer layer, so that the improvement of the shape of the second electrode is closer to the real contact surface of the buffer layer and the metal sheath; the tray and the counterweight are arranged on the second electrode, and the running condition of the cable is simulated, so that the accuracy of volume resistivity measurement is improved, and the measured volume resistivity is more accurate.
Description
Technical Field
The utility model relates to the technical field of cables, particularly, relate to a cable buffer layer volume resistivity measuring device.
Background
The corrugated aluminum sheath crosslinked polyethylene insulated high-voltage power cable is widely applied in China due to excellent bending mechanical properties, and almost all high-voltage cable lines in China are corrugated aluminum sheathed cables. Because the expansion coefficient of the crosslinked polyethylene material is far greater than that of the metal sheath, enough gaps need to be reserved between the outer side of the cable insulation shield and the metal sheath, and the phenomenon that the corrugated metal sheath leaves impressions on the insulation shield and even extrudes the insulation layer is prevented; meanwhile, the existence of gaps and the structural design of wrinkles also cause that the cable does not have longitudinal water-blocking performance.
Referring to fig. 1 and 2, there is shown a structure of a high voltage cable proposed in the prior art. As shown in fig. 1 and fig. 2, the voltage cable is provided with a conductor 1', a conductor shielding layer 2', an insulating layer 3', an insulating shielding layer 4', a buffering water-blocking tape 5', a corrugated aluminum sheath 6' and an outer sheath 7' in sequence from the center to the outside; the problem is solved by the aid of the buffer water-blocking tape 5 'wrapped between the insulating shielding layer 4' and the corrugated aluminum sheath 6', and the buffer water-blocking tape 5' can be a semi-conductive water-blocking buffer layer.
The common semiconductive water-blocking buffer layer is generally formed by coating a layer of conductive carbon powder and polyacrylate expansion powder between polyester fiber non-woven fabric and semiconductive fluffy cotton in a sticking mode, and the water-blocking buffer tape can expand when meeting water so as to prevent water entering the cable from longitudinally spreading, and meanwhile, good electrical contact between the insulation shield and the metal sheath is guaranteed.
However, with the increasingly widespread use of high-voltage cables of this type, new problems have developed in recent years: the buffer layer ablation phenomenon frequently occurs in high-voltage cable lines in China, so that the wide attention is drawn, and the safety of a power grid is seriously threatened. At present, the mechanism of buffer layer ablation is not determined in academic circles, but the material performance of the buffer layer material undoubtedly has important influence on the buffer layer material, and the current national standards of cables GB/T11017.2 and GB/T18890.2 only require that the buffer layer of the high-voltage cable meets the requirements of JB/T10259-2014 and the buffer layer is in good electrical contact with the shielding layer. The volume resistivity measurement method of the cable water-blocking tape specified in the standard JB/T10259-2014 comprises the following steps:
as shown in FIG. 3, a sample 9' of a water-blocking tape having a diameter of 100mm was pressed against a copper plate electrode 10' having a diameter of 100 mm. times.100 mm. times.10 mm by using a copper rod electrode 8' having a weight of 2kg and a diameter of 50mm, a DC voltage of 4.5V was applied between the two electrodes, and after charging was continued for 1min, the volume resistance R was measured by using the ohmic contact of a multimeter.
RA
Calculated by the formula rho ═ t, the calculation result rho is less than or equal to 1 multiplied by 10 5 And omega.m is qualified.
In the formula, R is the measured volume resistance of the sample, and A is the sectional area of the copper rod electrode; t is the average thickness of the sample; ρ is the volume resistivity of the sample.
This approach has significant limitations:
(1) it can be observed from fig. 1 and fig. 2 that the actual contact point between the buffer water-blocking tape 5 'and the corrugated aluminum sheath 6' is an annular area with a width of less than 10mm, while the standard specified test electrode is a circular area with a diameter of 50mm, the measurement area is far larger than the actual situation, the water-blocking tape is formed by coating a layer of polyacrylate expansion powder between non-woven fabric and fluffy cotton, the distribution of the expansion powder and carbon black adhered inside the water-blocking tape is not uniform, the volume resistivity measured by the test is higher in the area where the powder is concentrated under the test electrode inevitably, and the quality of the water-blocking tape cannot be accurately reflected by the measurement result.
(2) The mass of the test electrode in the standard is 2kg, the pressure of the test electrode to the water blocking tape is about 9.99kPa through calculation, and the pressure born by the buffer tape is different in cables of different cable grades.
(3) And a protection electrode is not arranged, so that measurement errors caused by stray current can be detected during measurement.
(4) Because the buffer zone is formed by coating a layer of conductive carbon powder and polyacrylate expansion powder between the polyester fiber non-woven fabric and the semi-conductive fluffy cotton in a sticking way, the expansion powder and the carbon black are not uniformly distributed, the quality of the buffer zone cannot be reflected only by measuring the volume resistivity of part of samples, and the performance of the water-blocking zone is not checked in place due to the fact that the volume resistivity evaluation method of the water-blocking zone is too single-sided at present, so that ablation faults of the buffer layer occur.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model provides a cable buffer layer volume resistivity measuring device aims at solving when current buffer layer is measured test electrode and causes it to measure the area and lead to the unsafe problem of volume resistivity for standard electrode size far away more than actual conditions.
The utility model provides a cable buffer layer volume resistivity measuring device, the device includes: a first electrode; the second electrode is arranged above the first electrode and used for clamping a point to be tested of the cable buffer layer sample to be tested between the first electrode and the second electrode; the tray is arranged above the second electrode and plays a role in supporting; the counterweight is arranged on the tray and used for adjusting the total mass of the tray, the counterweight and the second electrode to be matched with the embossing pitch mass of the cable to which the cable buffer layer sample to be detected belongs; the two ends of the power supply module are respectively connected with the first electrode and the second electrode and used for applying direct current voltage to the first electrode and the second electrode so as to enable the power supply module, the first electrode, the second electrode and the point to be tested to form a test loop; and the test module is connected with the test loop and used for measuring the volume resistance of the point to be tested so as to determine the volume resistivity of the point to be tested.
Further, according to the volume resistivity measuring device for the cable buffer layer, the protective electrode is sleeved on the periphery of the second electrode.
Further, in the above device for measuring volume resistivity of a cable buffer layer, the guard electrode is grounded.
Further, in the above apparatus for measuring volume resistivity of a cable buffer layer, the protection electrode has an annular structure.
Further, the above-mentioned cable buffer layer volume resistivity measuring apparatus, the test module includes: the voltmeter is used for acquiring a voltage value between the first electrode and the second electrode; the ammeter is used for acquiring the current value of the test loop; and the processing unit is used for determining the volume resistance of the point to be tested according to the voltage values at the two ends of the point to be tested and the current value of the test loop.
Further, in the device for measuring the volume resistivity of the cable buffer layer, the weight member is a weight.
Further, according to the volume resistivity measuring device for the cable buffer layer, the negative electrode of the power supply module is grounded.
Further, in the above device for measuring volume resistivity of a cable buffer layer, the first electrode is a copper plate electrode.
Further, in the volume resistivity measuring device for the cable buffer layer, the second electrode is a copper rod electrode.
Further, in the device for measuring the volume resistivity of the cable buffer layer, the tray is an insulating rubber tray.
The utility model provides a cable buffer layer volume resistivity measuring device, the actual conditions of buffer layer in wrinkle aluminium sheath high tension cable is fully considered, to the measurement problem of buffer layer, measured electrode and measuring device have been improved, through choosing for use the buffer layer and wrinkle the second electrode of the regional phase-match of actual contact point between the aluminium sheath, make the improvement of the shape of second electrode more close to buffer layer and metal sheath's true contact surface, the measuring result can reflect the actual conditions of cable operation more; the tray is arranged on the second electrode to support the counterweight through the tray, so that the stable placement of the second motor is ensured, the total mass of the tray, the counterweight and the second electrode is adjusted by adjusting the weight of the counterweight until the total mass of the tray, the counterweight and the second electrode is matched with the embossing pitch mass of the cable to which the buffer layer sample of the cable to be measured belongs, so that the running condition of the cable, namely the mass applied to the closest contact position of the buffer layer and the metal sheath is fully simulated, the accuracy of volume resistivity measurement is improved, and the measured volume resistivity is more accurate; through the guard electrode, prevent stray current to the influence of measuring result, further improve the accuracy of measuring.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
fig. 1 is a cross-sectional view of a prior art high voltage cable;
FIG. 2 is a longitudinal cross-sectional view of a prior art high voltage cable;
FIG. 3 is a view showing a structure for measuring the volume resistivity of the water-blocking tape;
fig. 4 is a schematic structural diagram of a cable buffer layer volume resistivity measuring apparatus provided by an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a second electrode, a tray and a guard electrode according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that, in the present invention, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
Referring to fig. 4, it is a schematic structural diagram of a cable buffer layer volume resistivity measuring apparatus provided by an embodiment of the present invention. As shown, the apparatus comprises: the device comprises a first electrode 1, a second electrode 2, a tray 3, a counterweight 4, a power supply module and a test module; wherein the content of the first and second substances,
the second electrode 2 is arranged above the first electrode 1, and is used for clamping a point to be tested of the cable buffer layer sample 5 between the first electrode 1 and the second electrode 2. Specifically, the first electrode 1 may be a copper plate electrode, which may be disposed on the insulating pad 6 to perform an insulating function. In this embodiment, the first electrode 1 may be a copper plate electrode, or may be an electrode made of other materials, which is not limited in this embodiment; the second electrode 2 may be a copper electrode, or may be an electrode made of other material, which is not limited in this embodiment. As shown in fig. 5, the second electrode 2 is a columnar electrode structure, and the specific size thereof can be determined and matched according to the actual contact point between the buffer layer, i.e. the buffer water-blocking tape, and the corrugated aluminum sheath, for example, when the actual contact point between the buffer layer and the corrugated aluminum sheath is an annular region with a width of less than 10mm, the second electrode 2 can be a columnar electrode with an outer diameter of 10mm and a height of 10mm, so that the contact area between the second electrode 2 and the point to be measured is matched with the actual contact point region between the buffer layer and the corrugated aluminum sheath. The first electrode may be a copper plate electrode, and the second electrode may be a copper rod electrode.
The tray 3 is disposed above the second electrode 2 and serves as a support for supporting the weight member 4 so as to be pressed against the second electrode 2. Preferably, the tray 3 may be an insulating tray to perform an insulating function; further preferably, the tray 3 may be an insulating rubber tray. As shown in fig. 5, the tray 3 may be a disc-shaped structure; in this embodiment, the tray 5 may be a disk-shaped insulating rubber tray 10mm thick and 50mm in radius.
The weight 4 is arranged on the tray 3 and used for adjusting the total mass of the tray 3, the weight 4 and the second electrode 2 to be matched with the embossing pitch quality of the cable to which the cable buffer layer sample to be tested belongs. Specifically, in order to simulate the actual operation condition of the cable, the pressure of the second electrode 2 pressed on the sample of the buffer layer of the cable to be tested needs to be adjusted, therefore, the tray 3 is arranged above the second electrode 2 to support the weight 4 through the tray 3, so as to ensure the stable placement of the second motor 2, and the total mass of the tray 3, the weight 4 and the second electrode 2 is adjusted by adjusting the weight of the weight 4 until the total mass of the tray 3, the weight 4 and the second electrode 2 is matched with the embossing pitch mass of the cable to which the sample of the buffer layer of the cable to be tested belongs, so as to accurately simulate the operation condition of the cable. In this embodiment, the quality of the embossing pitch of the cable to which the cable buffer layer sample to be tested belongs can be determined based on the embossing pitch of the corrugated aluminum sheath of the cable to which the cable buffer layer sample to be tested belongs, that is, when the length of the cable to which the cable buffer layer sample to be tested belongs is the embossing pitch of the corrugated aluminum sheath, the quality of the cable section is the quality of the embossing pitch of the cable to which the cable buffer layer sample to be tested belongs. The corrugation pitch of the corrugated aluminum sheath of the cable to which the to-be-detected cable buffer layer sample belongs is the distance between two adjacent wave crests in the corrugated aluminum sheath. In this embodiment, in order to adjust the total mass of the tray 3, the weight 4 and the second electrode 2, the weight 4 may be a weight, or may be other structures with known mass, which is not limited in this embodiment.
Two ends of the power supply module are respectively connected with the first electrode 1 and the second electrode 2, and are used for applying direct current voltage to the first electrode 1 and the second electrode 2, so that the power supply module, the first electrode 1, the second electrode 2 and the point to be tested form a test loop. Specifically, the anode of the power module is connected with the first electrode 1, the cathode of the power module is connected with the second electrode 2, and the point to be tested is pressed on the first electrode 1 and the second electrode 2, so that the power module, the first electrode 1, the second electrode 2 and the point to be tested form a test loop. As shown in fig. 4, the power module may be a dc power source to provide a dc voltage, and in this embodiment, the dc power source may apply a dc voltage of 4.5V between the first electrode 1 and the second electrode 2. To ensure the safety of the measuring device, the negative pole of the power supply module is preferably arranged at ground.
The test module is connected with the test loop and used for measuring the volume resistance of the point to be tested so as to determine the volume resistivity of the point to be tested. Specifically, the test module may determine the volume resistance at the point to be measured based on the voltage value between the first electrode and the second electrode and the current value of the test loopAnd determining the volume resistivity of the point to be measured according to the volume resistance of the point to be measured. In this embodiment, the volume resistivity of the point to be measured can be determined according to
Calculating; wherein rho is the volume resistivity of the point to be measured; r is the volume resistance of the point to be measured; t is the thickness of the point to be measured; and a is the cross-sectional area of the second electrode.
With continued reference to fig. 4, in order to ensure the accuracy of the measurement, it is preferable that the outer periphery of the second electrode 2 is sleeved with a protective electrode 7 in an annular structure to prevent the influence of the stray current on the measurement result; of course, the guard electrode 7 may have other structures, and is not limited in this embodiment. To ensure the safety of the measuring device, the guard electrode may be arranged at ground. In this embodiment, the guard electrode 7 may be an annular electrode having an inner diameter of 30mm and an outer diameter of 50 mm.
With continued reference to fig. 4, the test module may include: a voltmeter, a ammeter and a processing unit; the voltmeter is used for acquiring a voltage value between the first electrode and the second electrode; the ammeter is used for acquiring the current value of the test loop; the processing unit is used for determining the volume resistivity of the point to be tested according to the voltage values at the two ends of the point to be tested and the current value of the test loop. Specifically, the voltmeter and the ammeter can obtain corresponding voltage values and current values after the power module applies voltage for a certain time; the processing unit can determine the volume resistance of the point to be tested according to the voltage values at two ends of the point to be tested and the current value of the test loop so as to utilize
And calculating the volume resistivity of the point to be measured.
In summary, the volume resistivity measuring device for the cable buffer layer provided by the embodiment sufficiently considers the actual situation of the buffer layer in the corrugated aluminum sheath high-voltage cable, improves the measured electrode and the measuring device aiming at the measurement problem of the buffer layer, and makes the improvement of the shape of the second electrode 2 closer to the actual contact surface of the buffer layer and the metal sheath by selecting the second electrode 2 matched with the actual contact point area between the buffer layer and the corrugated aluminum sheath, so that the measurement result can reflect the actual situation of the cable operation; and set up the tray 3 on the second electrode 2, in order to support the weight 4 through the tray 3, guarantee the stable placement of the second motor 2, and through adjusting the weight of the weight 4, adjust the total mass of tray 3, weight 4 and second electrode 2, until the total mass of tray 3, weight 4 and second electrode 2 and the crimp pitch quality of the cable that the cable buffer layer sample to be measured belongs to match, in order to fully simulate the cable running state to apply the mass in the most compact place of buffer layer and metal sheathing contact, thus improve the accuracy of volume resistivity measurement, make the volume resistivity measured more accurate.
Preferably, the influence of stray current on the measurement result is prevented by the protective electrode, so that the measurement accuracy is further improved.
It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
Furthermore, it should be noted that, unless otherwise explicitly stated or limited in the description of the present invention, the terms "mounted," "connected" and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A cable buffer layer volume resistivity measuring device, characterized by comprising:
a first electrode;
the second electrode is arranged above the first electrode and used for clamping a point to be tested of the cable buffer layer sample to be tested between the first electrode and the second electrode;
a tray disposed above the second electrode;
the counterweight is arranged on the tray and used for adjusting the total mass of the tray, the counterweight and the second electrode to be matched with the embossing pitch mass of the cable to which the cable buffer layer sample to be detected belongs;
the two ends of the power supply module are respectively connected with the first electrode and the second electrode and used for applying direct current voltage to the first electrode and the second electrode so as to enable the power supply module, the first electrode, the second electrode and the point to be tested to form a test loop;
and the test module is connected with the test loop and used for measuring the volume resistance of the point to be tested so as to determine the volume resistivity of the point to be tested.
2. The apparatus for measuring the volume resistivity of the cable buffer layer according to claim 1, wherein the outer circumference of the second electrode is sleeved with a guard electrode.
3. The cable buffer volume resistivity measuring device according to claim 2, wherein the guard electrode is disposed in a grounded state.
4. The apparatus of claim 2, wherein the protection electrode is a ring structure.
5. The cable buffer volume resistivity measuring device according to any one of claims 1 to 4, wherein the test module includes:
the voltmeter is used for acquiring a voltage value between the first electrode and the second electrode;
the ammeter is used for acquiring the current value of the test loop;
and the processing unit is used for determining the volume resistance of the point to be tested according to the voltage values at the two ends of the point to be tested and the current value of the test loop.
6. The apparatus according to any one of claims 1 to 3, wherein the weight member is a weight.
7. The cable buffer volume resistivity measuring device according to any one of claims 1 to 3, wherein a negative electrode of the power supply module is grounded.
8. The cable buffer layer volume resistivity measuring device according to any one of claims 1 to 3, wherein the first electrode is a copper plate electrode.
9. The cable buffer volume resistivity measuring device according to any one of claims 1 to 3, wherein the second electrode is a copper rod electrode.
10. The cable buffer layer volume resistivity measuring device according to any one of claims 1 to 3, wherein the tray is an insulating rubber tray.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202123301012.2U CN217404404U (en) | 2021-12-24 | 2021-12-24 | Volume resistivity measuring device for cable buffer layer |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202123301012.2U CN217404404U (en) | 2021-12-24 | 2021-12-24 | Volume resistivity measuring device for cable buffer layer |
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| CN217404404U true CN217404404U (en) | 2022-09-09 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115616293A (en) * | 2022-09-14 | 2023-01-17 | 广州岭南电缆股份有限公司 | Volume resistivity measuring device for semi-conductive buffer layer |
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2021
- 2021-12-24 CN CN202123301012.2U patent/CN217404404U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115616293A (en) * | 2022-09-14 | 2023-01-17 | 广州岭南电缆股份有限公司 | Volume resistivity measuring device for semi-conductive buffer layer |
| CN115616293B (en) * | 2022-09-14 | 2024-01-23 | 广州岭南电缆股份有限公司 | Volume resistivity measuring device for semiconductive buffer layer |
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