CN110736785A - cable accessory lead sealing electrical connection defect live-line detection method and device - Google Patents
cable accessory lead sealing electrical connection defect live-line detection method and device Download PDFInfo
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- CN110736785A CN110736785A CN201911146444.5A CN201911146444A CN110736785A CN 110736785 A CN110736785 A CN 110736785A CN 201911146444 A CN201911146444 A CN 201911146444A CN 110736785 A CN110736785 A CN 110736785A
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- 238000007789 sealing Methods 0.000 title claims abstract description 95
- 230000007547 defect Effects 0.000 title claims abstract description 38
- 238000001514 detection method Methods 0.000 title claims description 17
- 230000008878 coupling Effects 0.000 claims abstract description 26
- 238000010168 coupling process Methods 0.000 claims abstract description 26
- 238000005859 coupling reaction Methods 0.000 claims abstract description 26
- 238000000034 method Methods 0.000 claims abstract description 17
- 229910052782 aluminium Inorganic materials 0.000 claims description 19
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 19
- 229910052751 metal Inorganic materials 0.000 claims description 15
- 239000002184 metal Substances 0.000 claims description 15
- 238000002347 injection Methods 0.000 claims description 13
- 239000007924 injection Substances 0.000 claims description 13
- 230000008569 process Effects 0.000 claims description 3
- 230000001939 inductive effect Effects 0.000 claims description 2
- 230000005291 magnetic effect Effects 0.000 abstract description 17
- 230000008859 change Effects 0.000 description 6
- 230000006698 induction Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000005674 electromagnetic induction Effects 0.000 description 2
- 230000000149 penetrating effect Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
- G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
Abstract
The invention discloses a method and a device for detecting the electrical connection defect of cable accessory lead sealing, wherein current signals with known changes of lead sealing and different power frequencies are injected in a coupling way, a changing magnetic field is generated on the surface of the lead sealing, a signal sensor with a coupling coil is placed on the outer surface of the lead sealing, induced electromotive force is generated in the coupling coil, the difference of the surface magnetic field is detected by the sensor, so that the electrical connection defect of a lead sealing point part is detected in an electrified way, the sensor axially moves 1 time along the lead sealing part of the cable accessory, and the test work of the electrical connection of the lead sealing can be completed.
Description
Technical Field
The invention relates to an electrified detection method and device for cable accessory lead sealing electrical connection defects, and belongs to the technical field of power transmission and transformation equipment.
Background
At present, poor lead sealing connection of cable accessories is easy to cause metal suspension discharge inside cable aluminum sheaths or cable accessories to cause cable faults. Because the cable accessory lead sealing outer part wraps up the pyrocondensation pipe, and its inboard contacts with tail pipe, aluminium sheath, can't see the inside lead sealing electrical connection condition with the naked eye, increased the degree of difficulty that lead sealing electrical connection detected. The traditional method mainly adopts an eddy current inspection method to detect the lead sealing defect of a cable accessory in the heat-shrinkable tube, the main principle of the method utilizes the difference of air and metal magnetic conductivity, when the surface of the lead sealing defect is cracked or seriously uneven, the change of induced voltage or induced current of a test coil is caused, and then the lead sealing defect is judged, but when the surface of the lead sealing part is smooth and the internal electrical connection has poor contact, the method has difficulty in detection, and the method needs a probe to slide along the surface of the lead sealing part, so that the operation is complex and the detection period is long.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides the live-line detection method and the live-line detection device for the lead-sealed electrical connection defect of cable accessories, which can be used for live-line detection of the lead-sealed electrical connection defect in a cable, and are simple and convenient to operate and high in efficiency.
In order to solve the technical problems, the invention adopts the technical scheme that the cable accessory lead sealing electrical connection defect live-line detection method comprises the steps of injecting current signals into the cable accessory lead sealing;
obtaining a plurality of induced electromotive forces on the surface of a lead sealing part by moving a plurality of sensors arranged on the outer surface of the lead sealing of the cable accessory;
and finding out the maximum induced potential and the minimum induced potential in the sensor, wherein when the absolute value of the difference between the maximum induced potential and the minimum induced potential is larger than a set threshold, the lead sealing part of the cable accessory has an electrical connection defect.
, injecting a current signal to the lead sealing of the cable accessory, which comprises:
a current signal sent by the coupling injection signal source is transmitted to the cable body aluminum sheath or the cable accessory grounding lead, and the current signal is transmitted to the cable accessory lead sealing part through the cable body aluminum sheath or the accessory grounding lead;
, moving several sensors on the outer surface of the lead sealing part to obtain several induced electromotive forces on the surface of the lead sealing part, which is:
a plurality of sensors are made into a cylindrical shape to surround the surface of a lead sealing part of a cable accessory through steering of a steering knuckle buckle, the sensors axially move along the lead sealing part of the cable accessory through a test support rod, and the inductive potential on the surface of the lead sealing part is obtained through each sensor in the moving process.
live detection device for lead-sealed electrical connection defect of cable accessory, which is characterized by comprising a coupling injection signal source, a signal sensor and a signal display device which are connected in sequence;
the coupling injection signal source is used for injecting a current signal to the lead sealing of the cable accessory; the signal sensor is used for acquiring a plurality of induced electromotive forces on the surface of the lead sealing part of the cable accessory after current signals are injected; the signal display device is used for displaying the obtained plurality of induced electromotive forces.
, the coupling injection signal source comprises a detachable feedthrough transformer and a signal generator which are connected with each other, the signal generator is used for sending a current signal to the detachable feedthrough transformer, the detachable feedthrough transformer is detachably mounted on the cable body aluminum sheath or the cable accessory grounding lead, and the signal sent by the signal generator is coupled and injected into the cable body aluminum sheath or the cable accessory grounding lead and is transmitted to the cable accessory lead sealing part.
And , the signal generator sends out pulse signal, rectangular wave signal and triangular wave signal.
, the signal sensor comprises a plurality of sensors which are buckled and sleeved on the surface of the lead sealing part of the cable accessory through a steering knuckle.
the sensor comprises a metal wire core and a coupling coil wound on the metal wire core, and the steering knuckles are buckled at two ends of the metal wire core.
And , a roller is also arranged on the side of the sensor close to the lead sealing part of the cable accessory.
, the signal sensor also includes a test support rod, the end of the test support rod is mechanically connected with the sensor, the end is a handle, the test position of the sensor is controlled by the handle, the invention has the advantages that:
according to the invention, a current signal is injected by sealing lead of a cable accessory; moving a plurality of sensors arranged on the outer surface of the lead sealing part of the cable accessory to obtain a plurality of induced electromotive forces on the surface of the lead sealing part; finding out the maximum induced potential and the minimum induced potential in the sensor, wherein when the absolute value of the difference between the maximum induced potential and the minimum induced potential is larger than a set threshold, the lead sealing part of the cable accessory has an electrical connection defect;
the sensor is manufactured into a cylindrical shape to be coated on the lead sealing part of the cable accessory through steering of the steering knuckle buckle, and the cylindrical shape axially moves for 1 time along the lead sealing part of the cable accessory, so that the test work can be completed, and the device is flexible, simple and convenient to operate and has a good application prospect.
Drawings
FIG. 1 is an equivalent schematic diagram of a lead sealing crack of a cable accessory;
FIG. 2 is a schematic view of a magnetic line of force penetrating a sensor when the cable accessory is normal;
FIG. 3 is a schematic view of a magnetic line of force penetrating a sensor when a cable is attached with a crack defect;
FIG. 4 is a schematic structural diagram of detection devices according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of sensor configurations according to an embodiment of the present invention;
the meanings of the symbols in the figures: 1-coupled injection signal source, 101-detachable feedthrough transformer, 102-signal generator, 2-signal sensor, 201-sensor, 202-test support rod, 3-signal display device.
Detailed Description
The invention is further described with reference to the following figures.
The cable accessory lead sealing is used for connecting accessory metal tubular components, such as an aluminum sheath and a terminal tail pipe, an aluminum sheath and a joint copper shell, and the lead sealing is also tubular.
The current signal that injects the known change of cable seal lead position and be different from power frequency current signal through cable accessories ground lead coupling, according to the biot-savart law, current signal can produce the change magnetic field at the seal lead surface, place the seal lead surface with coupling coil's signal sensor, according to Faraday's electromagnetic induction law, can produce induced electromotive force in the coupling coil, if seal lead position electrical connection is bad, then can change the homogeneity of coupling coil internal current distribution, change the homogeneity of seal lead position surface magnetic field simultaneously, detect the difference in seal lead position surface magnetic field through the sensor, thereby realize the electrified detection of seal lead position electrical connection defect.
Example 1:
as shown in fig. 4, the cable accessory lead sealing electrical connection defect live-line detection device comprises a coupling injection signal source 1, a signal sensor 2 and a signal display device 3 which are connected in sequence.
The coupling injection signal source 1 comprises a detachable feedthrough transformer 101 and a signal generator 102 which are connected with each other. The detachable core-penetrating transformer is provided with a clamping component for realizing the opening and closing of the core-penetrating transformer, and the detachable core-penetrating transformer is directly penetrated without changing an aluminum sheath of a cable body or a grounding lead structure of a cable accessory.
The detachable feedthrough transformer 101 is used for injecting a current signal which is changed and is different from a power frequency current signal into an aluminum sheath of a cable body or an accessory grounding lead, and the detachable feedthrough transformer 101 is connected with the signal generator 102 through a metal shielding connecting lead;
the signal emitted by the signal generator 102 is coupled to the cable body aluminum sheath or the cable accessory grounding lead by the detachable feedthrough transformer 101 according to the electromagnetic induction principle, and is transmitted to the cable accessory lead sealing part through the cable body aluminum sheath or the cable accessory grounding lead. The signal generator 102 may emit a pulse signal, a square wave type signal, a triangular wave signal.
The signal sensor 2 comprises a plurality of sensors 201 and a test support rod 202.
The sensor 201 is made into a cylindrical shape through steering of a steering knuckle buckle 20103, the cylindrical sensor is sleeved on the surface of a lead sealing part of the cable accessory, the cylindrical sensor axially moves 1 time along the surface of the lead sealing part of the cable accessory to test the magnetic induction electromotive force on the outer surface of the lead sealing part, the assembling quantity of the sensors can be determined according to the outer diameter of the lead sealing part of the cable accessory and flexibly assembled to complete the lead sealing part of the cable accessory, a signal sensor 2 is connected with a signal display device 3 through a radio frequency cable and transmits a test signal to the signal display device, the quantity of the radio frequency cables is not less than 1 and at least equal to the quantity of the sensors, and radio frequency cables are connected with 35.
The end of the test support rod is mechanically connected with the sensor, and the end of the test support rod is a handle, so that the test position of the sensor can be controlled through the handle.
As shown in fig. 5, the sensor 201 includes a metal wire core 20101, a coupling coil 20102 wound on the metal wire core;
the metal wire core 20101 and the coupling coil 20102 are used for inductively acquiring alternating coupling signals passing through the surface of the lead sealing part of the cable accessory. Preferably, the metal wire core 20101 is made of high-permeability material.
The steering knuckle buckles 20103 are mounted at two ends of the metal wire core 20101 of the sensor, are made of non-magnetic-conductive materials and can be connected in a tail-collecting mode and can steer.
The side of the sensor 201 close to the lead sealing part of the cable accessory is also provided with a roller 20104, and the roller is in contact sliding with the outer surface of the lead sealing part of the cable accessory in the test process, so that the friction force can be reduced.
The signal display device 3 is connected with the signal sensor 2 through a data lead, receives the electric signal tested by the signal sensor 2 and displays data.
Example 2:
as shown in FIG. 1, the lead-sealed non-electrical connection of the cable affects the transmission path of the coupling current, and the lead-sealed part of the cable accessory is equivalent to a cylindrical tubular structure, and the electrical connection defect exists in FIG. 1.
Due to the magnetic effect of the current, a magnetic field is generated around the current channel in the tubular structure, and the magnitude of the magnetic field is related to the magnitude of the coupling injection current and the distance between the test point and the central axis of the current channel.
As shown in fig. 2 and 3, when the lead sealing component is cracked, the current channel is changed, the magnetic field intensity around the tubular structure is changed, and the lead sealing non-electrical connection defect can be detected and judged by detecting the change of the magnetic field or the magnetic induction intensity.
A method for detecting the defect of lead sealing electrical connection of cable accessories by electrification comprises the following steps:
step 1, turning a plurality of sensors 201 through a knuckle buckle 20103 to form a cylindrical shape to surround the surface of a lead sealing part of a cable accessory, transmitting a signal sent by a signal generator 102 in a coupling injection signal source 1 to an aluminum sheath of a cable body or a grounding lead of the cable accessory in the signal generator through a detachable feedthrough transformer 101, and transmitting a current signal to the lead sealing part of the cable accessory through the aluminum sheath of the cable body or the grounding lead of the accessory;
step 2, the signal sensor axially moves times along the lead sealing part of the cable accessory through the test support rod 202, and the induction of the surface of the lead sealing part is obtained through each sensor in the moving processPotential Ui，
UiThe induced potential of the sensor of the ith;
step 3, calculating the maximum induced potential U of the sensormax＝Max(Ui) (ii) a Minimum induced potential U of the sensormin＝Min(Ui) (ii) a Considering errors caused by sensor angles, positions and the like, setting detection criteria as follows:
when | Umax-UminThe | is less than or equal to delta U, which indicates that the current channel in the cable lead sealing is axisymmetric and the lead sealing of the cable accessory is normal;
when | Umax-Umin|>Delta U, which indicates that the current channel in the cable lead sealing is not axisymmetric, and the lead sealing part of the cable accessory has electrical connection defect; Δ B is the error value in T due to the angle and position of the sensor; Δ U is the error value, in V, due to the sensor angle and position.
Example 3:
in the embodiment, 6 groups of sensors are adopted, namely N1, N2, N3, N4, N5 and N6, and the distances r of the sensors relative to the center position of a current channel in the cable accessory lead sealing are respectively set as r1、r2、r3、r4、r5、 r6. The magnetic induction intensity passing through the center of the sensor was defined as the average magnetic induction intensity of the sensor as B1、B2、B3、B4、B5、B6Induced potentials are respectively set to U1、U2、U3、U4、U5、 U6. The signal display device displays the induced potential read by the sensor.
In the embodiment, as shown in fig. 2, when the sensor detects the intervals of L1 and L3 as in fig. 2, the lead sealing of the cable accessories in the intervals of L1 and L3 is normal, because the sensor is symmetrical to the current channel axis and has the same model, namely r1＝r2＝r3＝r4＝r5＝r6And other parameters n, I and S are equal and are substituted into the formulas (1) and (2) to obtain B1＝B2＝B3＝B4＝B5＝B6；U1＝U2＝U3＝U4＝U5＝U6。
When | Bmax-Bmin0 or | Umax-UminAnd if | ═ 0, (in this case, Δ B ═ 0, and Δ U ═ 0) indicates that the cable accessory is sealed with lead and is free of defects.
When the sensor detects the interval as shown in L2, as shown in FIG. 3, the cable is broken in the interval L2, and the sensor is not axisymmetric with the current channel, i.e. r1≠r2＝r6≠r3＝r5≠r4Other parameters are equal and are substituted into the formulas (1) and (2) to obtain B1≠B2＝B6≠B3＝B5≠B4；U1≠U2＝U6≠U3＝U5≠U4，
When | Bmax-Bmin| not equal to 0 or | Umax-UminAnd | ≠ 0, which indicates that the lead sealing of the cable accessory is defective.
The cable accessory lead sealing electrical connection defect live-line detection device and method can perform live-line operation, inject signals into the cable body aluminum sheath or the cable accessory grounding lead by coupling, transmit the signals into the cable accessory lead sealing part, and axially move 1 time along the cable accessory lead sealing part by using the signal sensor, so that the test work can be completed, and the live-line operation device and method are flexible, simple and convenient to operate and have good application prospects.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.
Claims (10)
- The method for detecting the electrified connection defect of the lead sealing electric connection of the cable accessories is characterized by comprising the following steps:injecting a current signal into the cable accessory lead sealing;obtaining a plurality of induced electromotive forces on the surface of a lead sealing part by moving a plurality of sensors arranged on the outer surface of the lead sealing of the cable accessory;and finding out the maximum induced potential and the minimum induced potential in the sensor, wherein when the absolute value of the difference between the maximum induced potential and the minimum induced potential is larger than a set threshold, the lead sealing part of the cable accessory has an electrical connection defect.
- 2. The method for detecting the electrified connection defect of the cable accessory lead sealing electrical connection defects according to claim 1, wherein the method for detecting the cable accessory lead sealing electrical connection defects is characterized in that a current signal is injected into the cable accessory lead sealing electrical connection defects, and specifically comprises the following steps:and a current signal sent by the coupling injection signal source is transmitted to the cable body aluminum sheath or the cable accessory grounding lead, and the current signal is transmitted to the cable accessory lead sealing part through the cable body aluminum sheath or the accessory grounding lead.
- 3. The method for detecting the electrified connection defect of the types of cable accessory lead seals according to claim 1, wherein the method comprises the following steps of obtaining a plurality of induced electromotive forces on the surface of a lead seal part by moving a plurality of sensors arranged on the outer surface of the lead seal of the cable accessory, specifically:a plurality of sensors are made into a cylindrical shape to surround the surface of a lead sealing part of a cable accessory through steering of a steering knuckle buckle, the sensors axially move along the lead sealing part of the cable accessory through a test support rod, and the inductive potential on the surface of the lead sealing part is obtained through each sensor in the moving process.
- The charged detection device for the lead-sealed electrical connection defects of the cable accessories of the varieties is characterized by comprising a coupling injection signal source, a signal sensor and a signal display device which are sequentially connected;the coupling injection signal source is used for injecting a current signal to the lead sealing of the cable accessory; the signal sensor is used for acquiring a plurality of induced electromotive forces on the surface of the lead sealing part of the cable accessory after current signals are injected; the signal display device is used for displaying the obtained plurality of induced electromotive forces.
- 5. The live detecting device for the defect of electric connection of cable accessory lead sealing according to claim 4, wherein the coupling injection signal source comprises a detachable feedthrough transformer and a signal generator connected to each other, the signal generator is used for sending a current signal to the detachable feedthrough transformer, the detachable feedthrough transformer is detachably mounted on the cable body aluminum sheath or the cable accessory grounding lead, and the signal sent by the signal generator is coupled and injected into the cable body aluminum sheath or the cable accessory grounding lead and is transmitted to the cable accessory lead sealing position.
- 6. The type cable accessory lead sealing electrical connection defect electrification detecting device according to claim 5, wherein the signal generator emits signals of types including pulse signals, rectangular wave type signals and triangular wave signals.
- 7. The charged detection device for detecting the defect of electrical connection of cable accessory lead sealing electric leads of claim 4, wherein the signal sensor comprises a plurality of sensors, and the plurality of sensors are buckled and turned to be sleeved on the surface of the lead sealing part of the cable accessory through a steering knuckle.
- 8. The kind of cable accessory lead sealing electrical connection defect electrification detecting device of claim 7, wherein the sensor includes a metal wire core, a coupling coil wound on the metal wire core, and the knuckle is snap-fitted at both ends of the metal wire core.
- 9. The kind of cable accessory lead sealing electrical connection defect electrification detecting device of claim 7, wherein a roller is further installed on the side of the sensor near the cable accessory lead sealing position.
- 10. The type cable accessory lead sealing electrical connection defect electrification detecting device of claim 7, wherein the signal sensor further comprises a test support rod, the test support rod is mechanically connected with the sensor at end , and the other end is a handle, and the position of the sensor test is controlled by the handle.
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| CN201911146444.5A CN110736785A (en) | 2019-11-21 | 2019-11-21 | cable accessory lead sealing electrical connection defect live-line detection method and device |
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| CN201911146444.5A CN110736785A (en) | 2019-11-21 | 2019-11-21 | cable accessory lead sealing electrical connection defect live-line detection method and device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112858460A (en) * | 2021-01-06 | 2021-05-28 | 西华大学 | Method for measuring concentration of solid-phase medium in solid-liquid two-phase fluid |
| CN113848246A (en) * | 2021-08-16 | 2021-12-28 | 浙江图维科技股份有限公司 | Online detection system and method for lead-lined cracking of cable accessory |
-
2019
- 2019-11-21 CN CN201911146444.5A patent/CN110736785A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112858460A (en) * | 2021-01-06 | 2021-05-28 | 西华大学 | Method for measuring concentration of solid-phase medium in solid-liquid two-phase fluid |
| CN112858460B (en) * | 2021-01-06 | 2023-07-18 | 西华大学 | Method for measuring concentration of solid medium in solid-liquid two-phase fluid |
| CN113848246A (en) * | 2021-08-16 | 2021-12-28 | 浙江图维科技股份有限公司 | Online detection system and method for lead-lined cracking of cable accessory |
| CN113848246B (en) * | 2021-08-16 | 2022-08-26 | 浙江图维科技股份有限公司 | Online detection system and method for lead-lined cracking of cable accessory |
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