CN209946244U - Cable buffer layer current detection device - Google Patents
Cable buffer layer current detection device Download PDFInfo
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- CN209946244U CN209946244U CN201822212182.5U CN201822212182U CN209946244U CN 209946244 U CN209946244 U CN 209946244U CN 201822212182 U CN201822212182 U CN 201822212182U CN 209946244 U CN209946244 U CN 209946244U
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Abstract
The utility model discloses a cable buffer layer current detection device, the device includes: the giant magnetoresistance sensor comprises a giant magnetoresistance sensor, a display terminal and a power supply, wherein the display terminal and the power supply are connected with the giant magnetoresistance sensor; the giant magnetoresistance sensor comprises a magnetism gathering ring, and the magnetism gathering ring is used for acquiring a current signal of the cable; and the display terminal is used for adjusting the operation of the giant magnetoresistance sensor and outputting and displaying the current signal. The utility model discloses a set up huge magnetic resistance sensor and gather the magnetic ring, can effectively improve the precision that cable buffer layer defect current detected, guarantee power cable's normal operating has promoted the fail safe nature of electric wire netting operation greatly.
Description
Technical Field
The utility model relates to an electrician detects technical field, concretely relates to cable buffer layer current detection device.
Background
The operational reliability of the power cable is directly related to the intrinsic safety of the power grid. In recent years, dozens of high-voltage crosslinked polyethylene insulated cable faults caused by buffer layer ablation occur in areas such as Beijing, Shanghai, Xinjiang and the like in China, similar reports are also made abroad, and even when the faults are serious, the insulation shielding layer completely penetrates, the cable insulation breakdown is caused, and the power failure accident is caused.
At present, an effective technical means and a method for detecting the burn or discharge defect of an insulation shielding layer by a cable operation and maintenance unit are not available, measures cannot be taken to prevent the defect from spreading and diffusing, if the phenomenon is not found and treated in time and causes the cable body insulation breakdown to cause the cable operation fault, the whole fault cable can be scrapped and a new cable can be laid again, and the safety and reliability of the power grid operation can be greatly reduced. In addition, the cost of replacing the cable and the socio-economic loss caused by power failure are very large in economic aspects.
The probability of finding such defects by adopting a partial discharge detection method is low, mainly because the sensitivity, the field interference and the running voltage of a partial discharge detection device are low and partial discharge signals are caused intermittently, a novel detection method needs to be developed urgently, and then cable faults caused by ablation defects of the buffer layer are effectively found.
SUMMERY OF THE UTILITY MODEL
For the problem that provides among the above-mentioned background art of solution, the utility model provides a cable buffer layer current detection device through the magnetic ring that gathers who sets up huge magnetic resistance sensor, can effectively improve cable buffer layer defect current detection's precision.
The utility model provides a cable buffer layer current detection device, the device includes: the giant magnetoresistance sensor comprises a giant magnetoresistance sensor, a display terminal and a power supply, wherein the display terminal and the power supply are connected with the giant magnetoresistance sensor; the giant magnetoresistance sensor comprises a magnetism gathering ring, and the magnetism gathering ring is used for acquiring a current signal of the cable; and the display terminal is used for adjusting the operation of the giant magnetoresistance sensor and outputting and displaying the current signal.
As an alternative, the giant magnetoresistance sensor further comprises: the device comprises a magnetic resistance chip, a differential amplifier, a low-pass filter, an analog-to-digital converter and a communication module; the magnetic resistance chip is electrically connected with the magnetic gathering ring and used for detecting a current signal; the differential amplifier is electrically connected with the magnetic resistance chip and receives a current signal output by the magnetic resistance chip; the low-pass filter is electrically connected with the differential amplifier and is used for filtering interference signals; the analog-to-digital converter is electrically connected with the low-pass filter and is used for converting an analog current signal into a digital signal; the communication module is electrically connected with the analog-to-digital converter and is used for communicating with other devices
As an alternative, the magnetism gathering ring is a non-continuous annular cylinder with an air gap and comprises a magnetic core and the air gap, and the magnetic core is made of a magnetic material with high magnetism gathering capacity.
As an alternative, the magnetism gathering ring further comprises a demagnetization coil, and the demagnetization coil is wound and connected on the magnetic core.
As an alternative, the magnetic core material is a magnetic material having a high magnetic gathering capacity.
As an alternative, the display terminal includes a control component, the control component includes a gear unit, a demagnetization unit, and a communication unit, the gear unit is used for controlling and adjusting the filtering parameter of the low-pass filter corresponding to the amplification factor of the differential amplifier, so as to realize the measurement function of different measured current ranges; the demagnetization unit is used for controlling the demagnetization coil so as to correct the zero point of the detection device for multiple times; the communication unit is used for controlling the communication mode between the giant magnetoresistance sensor and the display terminal.
As an alternative, the display terminal further comprises a working state indicating component, an output display component, a communication interface and a power interface; the working state indicating component is used for indicating the working state of the cable buffer layer current detecting device; the output display part is electrically connected with the giant magnetoresistance sensor through a communication interface and used for outputting a digital signal for displaying the detection current, the communication interface is used for being connected with other devices, and the power supply interface is used for being connected with a power supply.
As an alternative, the magnetic resistance chip is installed in the air gap of the magnetic gathering ring and is electrically connected with the demagnetization coil.
As an alternative, the connection mode of the communication module or the communication interface with the external communication includes a wired connection or a wireless connection.
The utility model has the advantages that: the utility model provides a cable buffer layer current detection device through setting up huge magnetic resistance sensor and gathering the magnetic ring, can effectively improve cable buffer layer defect current detection's precision, ensures power cable's normal operating, has promoted the fail safe nature of electric wire netting operation greatly.
Drawings
FIG. 1 is a schematic block diagram of the current detection device for the cable buffer layer of the present invention
1-giant magnetoresistance sensor; 2-a display terminal; 3-power supply
FIG. 2 is a schematic view of the magnetic flux collecting ring structure of the giant magnetoresistance sensor of the embodiment of the present invention
FIG. 3 is a schematic diagram of the structure of the magnetoresistive chip of the giant magnetoresistance sensor according to an embodiment of the present invention
FIG. 4 is a schematic diagram of the differential amplifier circuit of the giant magnetoresistance sensor according to an embodiment of the present invention
FIG. 5 is a schematic structural diagram of the display terminal of the present invention
FIG. 6 is an installation schematic diagram of detecting a buffer layer defect current in a cable system according to an embodiment of the present invention
4-cable termination; 5-a power cable; 6-cable ground wire; 7-protective grounding box
Fig. 7 is a schematic diagram of a power cable according to an embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings in combination with specific embodiments.
Example one
Referring to fig. 1, an embodiment of the present invention provides a schematic block diagram of a current detection device for a cable buffer layer, the current detection device for the cable buffer layer includes: giant magnetoresistance sensor 1, display terminal 2, and power supply 3.
Specifically, the giant magnetoresistance sensor 1 includes a magnetism collecting ring 11, a magnetoresistance chip 12, a differential amplifier 13, a low pass filter 14, an analog-to-digital converter 15, and a communication module 16.
The magnetism gathering ring 11 is a non-continuous annular cylinder with air gaps, and includes a magnetic core 111, air gaps 112 and a demagnetization coil 113, wherein the magnetic core 111 can be made of a magnetic material with high magnetism gathering capability, such as permalloy, ferrite, silicon steel sheets, amorphous alloys, and the like. The demagnetization coil 113 is wound on the magnetism gathering ring 11 and used for correcting the zero point of the detection device after multiple measurements, and measuring errors are reduced.
The giant magnetoresistance sensor provided by the embodiment adopts an annular cylinder structure, is matched with a concentric cylinder structure of a cable grounding wire, ensures that magnetic force lines are uniformly accumulated in a magnetic flux collecting ring when the defect current of a cable buffer layer flows through the grounding wire, penetrates through a sensitive shaft of a magnetic resistance chip, and improves the detection precision of the defect current of the cable buffer layer.
The demagnetizing coil 113 is wound on the magnetic gathering ring 11 of the giant magnetoresistance sensor 1, and the giant magnetoresistance sensor 1 can be controlled to demagnetize through the display terminal 2, so that the zero point of the detection device can be corrected after multiple measurements, and the measurement error of the defect current of the cable buffer layer is reduced from the aspect of hardware.
The magnetic resistance chip 12 is a rectangular parallelepiped structure, is installed in the air gap 112 of the magnetic focusing ring 11, and is electrically connected to the demagnetization coil 113 on the magnetic focusing ring, and the size of the magnetic resistance chip 12 needs to match the size of the air gap 112, and the magnetic resistance chip may be composed of a hall element, a giant magnetoresistance element, and the like.
Further, combine that fig. 3 shows the embodiment of the utility model provides a giant magnetoresistance sensor's magnetic resistance chip structure sketch map has operating voltage (Vbias, GND) and output voltage (V +, V-) pin, and the operating voltage pin is used for inserting external dc power supply, and the output voltage pin is used for exporting the detection output voltage signal, and this voltage linearity is directly proportional to the measured current signal. As shown in fig. 3, the 4 magnetoresistive resistors R11, R12, R21 and R22 are connected in a full-bridge manner, a constant operating voltage is applied to the Vbias and GND pins, and when an external field H is applied thereto, the resistance values of the 4 magnetoresistive resistors are increased or decreased accordingly.
The output voltage proportional to the current of the cable buffer defect is thus detected as:
V(H)＝V+(H)-V-(H)
the differential amplifier 13 is electrically connected to the magnetic resistance chip 12, receives a current signal directly detected by the magnetic resistance chip, and includes an operational amplifier and a plurality of resistors, wherein a portion of the resistors are variable resistors to achieve different times of amplification.
Further, with reference to the schematic diagram of the differential amplifier circuit of the giant magnetoresistance sensor shown in fig. 4 in the embodiment of the present invention, since no potential at two ends of the output voltage is grounded, a differential amplifier circuit is selected, in order to obtain different amplification factors by adjusting the resistance value, the resistance values of R1 and R3 in the circuit are fixed and equal, R2 and R4 are formed by a resistor array, wherein R2 is formed by n equal-ratio resistors and control switches, which are respectively R21 and K21, R22 and K22 … R2n and K2n, and R4 is formed by n equal-ratio resistors and control switches, which are respectively R41 and K41, R42 and K42 … R4n and K4 n. In practical application, for convenience of gear adjustment, when each amplification factor is adjusted, K2n and K4n act simultaneously, and the following relationship corresponding to the resistance values holds:
R2n＝R4n
the output voltage amplified by the differential amplifier 13 at this time is:
the differential amplifier 13 adopts a part of resistors with variable resistance values, and is matched with the control part 21 of the display terminal 2 to realize the amplification function of different multiples, so that the test range of the cable buffer layer current detection device is widened, and the test range of (10 < -6 > -102) < A > can be realized.
The low pass filter 14 is electrically connected to the differential amplifier 13 for providing the amplified detection current signal and filtering out the high frequency interference signal.
The analog-to-digital converter 15 is electrically connected to the low-pass filter 14, and converts an analog signal of the detection current into a digital signal.
The communication module 16 integrates wireless and wired communication modes. The wired communication mode provides two kinds of communication interfaces, is the communication cable interface and the communication fiber interface of area shielding respectively, and the wireless communication mode provides the communication module of wifi and bluetooth.
The display terminal 2 is composed of a control unit 21, an operation state indicating unit 22, an output display unit 23, a communication interface 24, and a power supply interface 25.
The control unit 21 includes a shift position unit 211, a demagnetization unit 212, and a communication unit 213. The gear unit 211 controls and adjusts the filtering parameters of the low-pass filter 14 corresponding to the amplification factor of the differential amplifier 13, so as to realize the measuring function of different measured current ranges. The demagnetization unit 212 directly controls the demagnetization coil 113 on the poly-magnetic ring 11, so as to correct the zero point of the detection device after multiple measurements and reduce the measurement error. The communication unit 213 directly controls the communication mode between the giant magnetoresistance sensor 1 and the display terminal 2, and different communication types can be selected according to the environmental conditions of the test site.
The working state indicating component 22 is used to indicate the working state of the cable buffer layer current detecting device, and includes at least three states: normal, overload, off state.
The output display unit 23 is an industrial-grade liquid crystal display, and may be formed by an industrial personal computer, and is configured to output a digital signal for displaying the detection current.
The communication interface 24 is used for communicating with the current signal detected by the giant magnetoresistance sensor 1, and is connected with the giant magnetoresistance sensor 1 in a wireless or wired manner, the wired connection can be a coaxial communication cable or an optical fiber with a shielding layer, and the wireless connection is in a wifi or bluetooth manner.
In this embodiment, giant magnetoresistance sensor 1 and display terminal 2 provide 4 kinds of communication modes of coaxial cable, optic fibre, wifi and bluetooth, can select according to the cable under test and display terminal 2's distance and site conditions, can effectively shorten test time, improve on-the-spot test efficiency, reserve multiple communication interface simultaneously and be favorable to the switching of two kinds of detection modes of on-line monitoring and electrified detection, expanded detection device's application scene.
The power interface 25 is used for providing an operating voltage of the display terminal.
The power supply 3 is composed of a power supply 31 and a power supply 32, the power supply 31 supplies a necessary operating voltage to the giant magnetoresistance sensor 1, and the power supply 32 supplies a necessary operating voltage to the display terminal 2. The voltage required by the magnetic resistance chip 12 is direct current voltage, and the voltage amplitude is less than or equal to 15V. The voltage of the display terminal 2 may be a mains voltage of 50Hz ac or a dc voltage of a certain magnitude, depending on the design.
The live detection working steps of the cable buffer layer current detection device are as follows:
1. mounting a giant magnetoresistance sensor 1 on a test article;
2. the communication module 16 and the communication interface 24 are connected to communicate the giant magnetoresistance sensor 1 with the display terminal 2.
3. Turning on the power supply 31 to enable the giant magnetoresistance sensor 1 to be in a working state, and adjusting the gear to the maximum value of the test range before switching on in order to avoid burning the giant magnetoresistance sensor 1;
4. turning on the power supply 32 to operate the display terminal 2, and starting the test when the operation state indicating member 22 is in a normal state;
5. the gear unit 211 of the adjusting control part 21 selects a proper measuring range and reads a test value through the output display part 23;
6. when continuous multiple measurements are needed, the demagnetization coil 113 on the magnetism gathering ring 11 needs to be directly controlled by the demagnetization unit 212 of the control component 21, so that zero point correction of the detection device is realized, and measurement errors are reduced.
7. After the measurement is finished, the power supply 32 and the power supply 31 are turned off, the communication module 16 and the communication interface 24 are disconnected, and the giant magnetoresistance sensor 1 is detached from the test object.
8. And (4) repeating the steps 4-6 every certain time when the cable buffer layer current detection device is in an online monitoring and testing working mode.
Example two
In order to better illustrate the utility model discloses at cable buffer layer defect current detection method, give the following embodiment:
fig. 6 is the installation schematic diagram of the embodiment of the present invention at the detection buffer layer defect current of the cable system, as shown in fig. 6, the cable system is composed of a cable terminal 4, a power cable 5, a cable grounding wire 6 and a protection grounding box 7. A typical structure of the power cable 5 is shown in fig. 7, and includes a conductor 51, a conductor shield 52, an insulating layer 53, an insulating shield 54, a buffer layer 55, a metal sheath 56, and an outer sheath 57. In the operation of the power system, the cable system is typically grounded in a manner that one end is directly grounded and the other end is grounded through the protective grounding box 7.
The giant magnetoresistance sensor 1 is mounted on a cable ground wire 6 directly grounded, and communicates with the display terminal 2 through the communication module 16. The specific testing process is as described in the first embodiment, and is not described herein again.
The above technical solution and the accompanying drawings provided in the embodiments of the present invention are used for further explanation but not limitation of the present invention, and it should be noted that, as one skilled in the art should know, the technical solution described in the foregoing embodiments can still be modified, or some or all of the technical features therein can be equivalently replaced, and these modifications or replacements do not make the essence of the corresponding technical solution depart from the scope of the technical solution of the present invention.
Claims (9)
1. A cable buffer current sensing apparatus, the apparatus comprising:
the giant magnetoresistance sensor comprises a giant magnetoresistance sensor, a display terminal and a power supply, wherein the display terminal and the power supply are connected with the giant magnetoresistance sensor;
the giant magnetoresistance sensor comprises a magnetism gathering ring, and the magnetism gathering ring is used for acquiring a current signal of the cable;
and the display terminal is used for adjusting the operation of the giant magnetoresistance sensor and outputting and displaying the current signal.
2. The cable buffer current sensing device of claim 1, wherein said giant magnetoresistance sensor further comprises:
the device comprises a magnetic resistance chip, a differential amplifier, a low-pass filter, an analog-to-digital converter and a communication module;
the magnetic resistance chip is electrically connected with the magnetic gathering ring and is matched with the magnetic gathering ring to detect and obtain the current signal;
the differential amplifier is electrically connected with the magnetic resistance chip and receives a current signal output by the magnetic resistance chip;
the low-pass filter is electrically connected with the differential amplifier and is used for filtering interference signals;
the analog-to-digital converter is electrically connected with the low-pass filter and is used for converting an analog current signal into a digital signal;
the communication module is electrically connected with the analog-to-digital converter and is used for communicating with other devices.
3. The cable buffer current detection device according to claim 2,
the magnetic gathering ring is a non-continuous annular cylinder with an air gap and comprises a magnetic core and the air gap, and the magnetic core is made of magnetic materials with high magnetic gathering capacity.
4. The cable buffer current detection device according to claim 3,
the magnetism gathering ring further comprises a demagnetization coil, and the demagnetization coil is wound and connected on the magnetic core.
5. The device for detecting the current of the cable buffer layer as claimed in claim 4, wherein the magnetic core material is a magnetic material with high magnetic gathering capability.
6. The device for detecting the current of the cable buffer layer according to claim 4, wherein the display terminal comprises a control component, the control component comprises a gear unit, a demagnetization unit and a communication unit,
the gear unit is used for controlling and adjusting the filtering parameters of the low-pass filter corresponding to the amplification factor of the differential amplifier so as to realize the measurement function of different measured current ranges;
the demagnetization unit is used for controlling the demagnetization coil so as to correct the zero point of the detection device for multiple times;
the communication unit is used for controlling the communication mode between the giant magnetoresistance sensor and the display terminal.
7. The cable buffer layer current detection device according to claim 6, wherein the display terminal further comprises an operation state indication unit, an output display unit, a communication interface and a power interface;
the working state indicating component is used for indicating the working state of the cable buffer layer current detecting device;
the output display part is electrically connected with the giant magnetoresistance sensor through a communication interface and is used for outputting a digital signal for displaying the detection current;
the communication interface is used for being connected with other devices, and the power interface is used for being connected with a power supply.
8. The apparatus as claimed in claim 7, wherein the magnetic resistance chip is mounted in the air gap of the magnetic focusing ring and electrically connected to the demagnetization coil.
9. The apparatus as claimed in claim 8, wherein the communication module or the communication interface is connected to the external communication module in a wired or wireless manner.
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| CN201822212182.5U CN209946244U (en) | 2018-12-26 | 2018-12-26 | Cable buffer layer current detection device |
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| CN201822212182.5U CN209946244U (en) | 2018-12-26 | 2018-12-26 | Cable buffer layer current detection device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109813949A (en) * | 2018-12-26 | 2019-05-28 | 国网电力科学研究院武汉南瑞有限责任公司 | A kind of cable slack layer current detection means |
| CN114324486A (en) * | 2022-03-16 | 2022-04-12 | 国网天津市电力公司电力科学研究院 | Defect detection method, device and equipment for cable buffer layer and storage medium |
-
2018
- 2018-12-26 CN CN201822212182.5U patent/CN209946244U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109813949A (en) * | 2018-12-26 | 2019-05-28 | 国网电力科学研究院武汉南瑞有限责任公司 | A kind of cable slack layer current detection means |
| CN114324486A (en) * | 2022-03-16 | 2022-04-12 | 国网天津市电力公司电力科学研究院 | Defect detection method, device and equipment for cable buffer layer and storage medium |
| CN114324486B (en) * | 2022-03-16 | 2022-05-27 | 国网天津市电力公司电力科学研究院 | Defect detection method, device and equipment for cable buffer layer and storage medium |
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