CN105116283A - Downhole power cable insulation monitoring device - Google Patents
Downhole power cable insulation monitoring device Download PDFInfo
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- CN105116283A CN105116283A CN201510507644.4A CN201510507644A CN105116283A CN 105116283 A CN105116283 A CN 105116283A CN 201510507644 A CN201510507644 A CN 201510507644A CN 105116283 A CN105116283 A CN 105116283A
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- 238000009413 insulation Methods 0.000 title claims abstract description 44
- 238000012806 monitoring device Methods 0.000 title claims abstract description 17
- 238000012545 processing Methods 0.000 claims abstract description 27
- 239000003990 capacitor Substances 0.000 claims abstract description 20
- 238000004891 communication Methods 0.000 claims abstract description 9
- 230000003750 conditioning effect Effects 0.000 claims abstract description 9
- 239000003245 coal Substances 0.000 abstract description 5
- 230000035945 sensitivity Effects 0.000 abstract description 5
- 238000001914 filtration Methods 0.000 abstract description 2
- 230000003321 amplification Effects 0.000 abstract 1
- 238000003199 nucleic acid amplification method Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 description 22
- 238000012544 monitoring process Methods 0.000 description 7
- 238000001514 detection method Methods 0.000 description 5
- 230000007547 defect Effects 0.000 description 4
- 238000005457 optimization Methods 0.000 description 4
- 238000005065 mining Methods 0.000 description 3
- 239000002817 coal dust Substances 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
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- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
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Abstract
The invention discloses a downhole power cable insulation monitoring device comprising a low-frequency voltage source, first to fourth inductors, a Hall current sensor, a signal conditioning circuit, an A/D converter, a processing module, a display module, an alarm, and a communication module. The processing module comprises a processing unit and a determining unit. The signal conditioning circuit comprises a wave trap circuit, a filtering circuit, an amplification circuit, and a rectification circuit. The wave trap circuit comprises first to fourth resistors, a first capacitor, a second capacitor, and an operational amplifier. The downhole power cable insulation monitoring device may online monitor the insulation state of a cable in real time, improves coal mine power supply continuity, reliability and security, achieves high sensitivity and low errors, and timely notifies downhole and ground workers for carrying out handling so as to guarantee operation safety and prevent economic losses.
Description
Technical Field
The invention relates to the technical field of insulation monitoring of power equipment, in particular to an underground power cable insulation monitoring device.
Background
With the rapid development of new energy industries such as wind power generation, photovoltaic power generation and the like, the number and the length of power cables are also rapidly increased. The power cable is widely applied to departments such as industrial and mining enterprises, railways, urban power supply and the like, wherein in a coal mine, the cable enables a large user to operate overvoltage and gradual permeation of moisture due to mechanical damage in the running process of the cable due to the special environment under the coal mine, and under the long-term action of an electric field, the phenomenon of partial discharge can occur inside the cable, so that aging and insulation resistance reduction are caused, if a fault line is determined and cut off in time, a power supply system has a great potential safety hazard, and gas and coal dust explosion caused by electric arc can be caused in serious conditions, so that the safety of people and equipment is endangered; because the mining cable has a severe operating environment, the probability of electrical faults caused by the cable is large, which accounts for about 2/3 of the total number of power supply accidents, and the cable is one of the main reasons for causing serious accidents such as gas and coal dust explosion.
In the prior art, a regular inspection mode is adopted for insulation detection of a power cable, namely, a test system is regularly set up, and the insulation state of the power cable is detected off line. However, this method has the following disadvantages: the power cable is required to exit from operation, so that the continuity of power supply is influenced, and the insulation hidden danger of the power cable cannot be detected truly due to the difference between the test condition and the actual operation condition; the inspection cycle is long, and the insulation hidden trouble of the power cable cannot be found in time. The traditional monitoring methods for cable insulation are mostly offline detection, and the methods are all carried out in a power failure state, so that the insulation level of the cable in operation is difficult to judge in time, and the operation state of the cable cannot be continuously reflected. In addition, offline detection is very blind, wasting manpower and material resources, and even some offline detection methods can damage cable insulation.
Various existing online monitoring methods, such as a direct current component method, a power frequency method and the like. These methods still suffer from the following drawbacks: the direct current component method is easily influenced by field stray current, so that weak current signals are difficult to extract and difficult to implement in engineering practice; the industrial frequency method adds low-voltage AC voltage with frequency consistent with the voltage frequency of the power grid into the power grid, and the method can detect the insulation parameters (insulation resistance and distributed capacitance) of the cable without additional power supply, and the method is simple, but has low sensitivity and larger error.
The on-line monitoring system for the insulation state of the mining high-voltage cable with the application number of 201410225812.6 overcomes the defect that the traditional monitoring method cannot be applied to a power supply system with a neutral point grounded through an arc suppression coil, can monitor the insulation state of the cable on line in real time, but has low sensitivity and larger error.
How to solve the defects of the prior art is an important problem to be solved urgently in the technical field of insulation monitoring of power equipment.
Disclosure of Invention
The invention aims to solve the technical problem of overcoming the defects of the prior art and provides an underground power cable insulation monitoring device which can monitor the insulation state of a cable on line in real time and improve the continuity, reliability and safety of coal mine power supply.
The invention adopts the following technical scheme for solving the technical problems:
the invention provides an underground power cable insulation monitoring device which comprises a low-frequency voltage source, first to fourth inductors, a Hall current sensor, a signal conditioning circuit, an A/D converter, a processing module, a display module, an alarm and a communication module, wherein the processing module comprises a processing unit and a judging unit; wherein,
the low-frequency voltage source is connected with one end of the first inductor, the other end of the first inductor is connected with one end of each of the second to fourth inductors, the other ends of the second to fourth inductors are connected with three-phase wires in the cable, the Hall current sensor is sleeved on the cable, the Hall current sensor is sequentially connected with the trap circuit, the filter circuit, the amplifying circuit, the rectifying circuit, the A/D converter, the processing unit and the display module, the communication module is connected with the processing unit, and the processing unit is sequentially connected with the judging unit and the alarm;
the signal conditioning circuit comprises a trap circuit, a filter circuit, an amplifying circuit and a rectifying circuit which are connected in sequence; the trap circuit comprises first to fourth resistors, a first capacitor, a second capacitor and an operational amplifier, wherein one end of the first resistor is connected with one end of the first capacitor and one end of the second capacitor respectively, one end of the second resistor is connected with one end of the fourth resistor and the anode of the operational amplifier respectively, the other end of the fourth resistor is grounded, the other end of the second capacitor is connected with one end of the third resistor and the cathode of the operational amplifier respectively, and the other end of the third resistor is connected with the other end of the first capacitor and the output end of the operational amplifier respectively.
As a further optimization scheme of the underground power cable insulation monitoring device, the operational amplifier is an LM741 operational amplifier.
As a further optimization scheme of the underground power cable insulation monitoring device, the central processing unit is an FPGA.
As a further optimization scheme of the underground power cable insulation monitoring device, the Hall current sensor is a CE-IJ03-52BS2 Hall current sensor.
As a further optimization scheme of the underground power cable insulation monitoring device, the frequency of the low-frequency alternating voltage signal is 10 Hz.
Compared with the prior art, the invention adopting the technical scheme has the following technical effects:
(1) the device can monitor the insulation state of the cable on line in real time, and improves the continuity, reliability and safety of coal mine power supply;
(2) workers in the well and on the ground can be informed to process the information in time, so that the operation safety is ensured, and the economic loss is avoided;
(3) the device has high sensitivity and small error.
Drawings
Fig. 1 is a schematic structural view of the present apparatus.
FIG. 2 is a notch circuit diagram.
The reference numerals in the figures are to be interpreted: 1-low frequency voltage source, 2-Hall current sensor, 3-cable.
Detailed Description
The technical scheme of the invention is further explained in detail by combining the attached drawings:
as shown in fig. 1, an insulation monitoring device for an underground power cable comprises a low-frequency voltage source 1, first to fourth inductors, a hall current sensor 2, a signal conditioning circuit, an a/D converter, a processing module, a display module, an alarm and a communication module, wherein the processing module comprises a processing unit and a judging unit; the signal conditioning circuit comprises a trap circuit, a filter circuit, an amplifying circuit and a rectifying circuit which are connected in sequence; wherein,
the low-frequency voltage source is connected with one end of the first inductor, the other end of the first inductor is connected with one end of each of the second to fourth inductors, the other ends of the second to fourth inductors are connected with three-phase wires in the cable 3, the Hall current sensor is sleeved on the cable, the Hall current sensor is sequentially connected with the trap circuit, the filter circuit, the amplifying circuit, the rectifying circuit, the A/D converter, the processing unit and the display module, the communication module is connected with the processing unit, and the processing unit is sequentially connected with the judging unit and the alarm;
the low-frequency voltage source is used for outputting a low-frequency alternating-current voltage signal, the low-frequency alternating-current voltage signal is injected into the cable after passing through the first inductor and the second to fourth inductors, and then forms a low-frequency current loop with the cable ground insulation resistor and the ground;
the Hall current sensor is used for outputting the acquired current signal to the signal conditioning circuit;
the trap circuit, the filter circuit, the amplifying circuit and the rectifying circuit are used for respectively trapping, filtering, amplifying and rectifying the current signals and then outputting low-frequency current signals to the A/D converter;
the A/D converter is used for converting the low-frequency current signal into a digital signal and outputting the digital signal to the processing unit;
the processing unit is used for analyzing and processing the received digital signals to obtain the ground insulation resistance of the cable and outputting the ground insulation resistance to the judging unit, the display module and the communication module;
the judging unit is used for judging that when the ground insulation resistance of the cable is smaller than the preset alarm insulation resistance, an alarm signal is output to the alarm to give an alarm;
the display module is used for displaying the ground insulation resistance of the cable;
and the communication module is used for outputting the ground insulation resistance of the cable to an external ground monitoring center.
As shown in fig. 2, the trap circuit includes first to fourth resistors R1-R4, a first capacitor C1, a second capacitor C2, and an operational amplifier, wherein one end of the first resistor is connected to one end of the first capacitor and one end of the second capacitor, one end of the second resistor is connected to one end of the fourth resistor and an anode of the operational amplifier, respectively, the other end of the fourth resistor is grounded, the other end of the second capacitor is connected to one end of the third resistor and a cathode of the operational amplifier, respectively, and the other end of the third resistor is connected to the other end of the first capacitor and an output terminal of the operational amplifier, respectively.
The operational amplifier is an LM741 operational amplifier.
The central processing unit is an FPGA.
The Hall current sensor is a CE-IJ03-52BS2 Hall current sensor.
The frequency of the low-frequency alternating voltage signal is 10 Hz.
The invention adopts a low-frequency signal injection method, injects a low-frequency alternating-current signal voltage to a tested cable through a neutral point of a three-phase inductor, and realizes the online monitoring of the cable insulation by detecting the alternating-current signal current; the method can detect the alternating current impedance of a cable power grid, and the alternating current impedance is closer to the actual cable insulation condition than the direct current insulation resistance detected by an additional direct current power supply method; in addition, compared with a power frequency method, the method has the advantages of high sensitivity and small error. The low-frequency signal injection method adopted by the system overcomes the defect that the cable-to-ground distributed capacitance cannot be detected by an additional direct-current power supply method; the method has the characteristics of small detection error and high accuracy.
The above embodiments are only for illustrating the technical idea of the present invention, and the technical idea of the present invention is not limited to the above embodiments, and any modifications made on the basis of the technical scheme according to the technical idea of the present invention fall within the scope of the present invention.
Claims (5)
1. An underground power cable insulation monitoring device is characterized by comprising a low-frequency voltage source, first to fourth inductors, a Hall current sensor, a signal conditioning circuit, an A/D converter, a processing module, a display module, an alarm and a communication module, wherein the processing module comprises a processing unit and a judging unit; wherein,
the low-frequency voltage source is connected with one end of the first inductor, the other end of the first inductor is connected with one end of each of the second to fourth inductors, the other ends of the second to fourth inductors are connected with three-phase wires in the cable, the Hall current sensor is sleeved on the cable, the Hall current sensor is sequentially connected with the trap circuit, the filter circuit, the amplifying circuit, the rectifying circuit, the A/D converter, the processing unit and the display module, the communication module is connected with the processing unit, and the processing unit is sequentially connected with the judging unit and the alarm;
the signal conditioning circuit comprises a trap circuit, a filter circuit, an amplifying circuit and a rectifying circuit which are connected in sequence; the trap circuit comprises first to fourth resistors, a first capacitor, a second capacitor and an operational amplifier, wherein one end of the first resistor is connected with one end of the first capacitor and one end of the second capacitor respectively, one end of the second resistor is connected with one end of the fourth resistor and the anode of the operational amplifier respectively, the other end of the fourth resistor is grounded, the other end of the second capacitor is connected with one end of the third resistor and the cathode of the operational amplifier respectively, and the other end of the third resistor is connected with the other end of the first capacitor and the output end of the operational amplifier respectively.
2. A downhole power cable insulation monitoring device according to claim 1, wherein the operational amplifier is an LM741 operational amplifier.
3. A downhole power cable insulation monitoring device according to claim 1, wherein the central processing unit is an FPGA.
4. A downhole power cable insulation monitoring device according to claim 1, wherein the hall current sensor is a CE-IJ03-52BS2 hall current sensor.
5. A downhole power cable insulation monitoring device according to claim 1, wherein the frequency of the low frequency ac voltage signal is 10 Hz.
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| CN201510507644.4A CN105116283A (en) | 2015-08-19 | 2015-08-19 | Downhole power cable insulation monitoring device |
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| CN201510507644.4A CN105116283A (en) | 2015-08-19 | 2015-08-19 | Downhole power cable insulation monitoring device |
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106297166A (en) * | 2016-08-24 | 2017-01-04 | 无锡卓信信息科技股份有限公司 | A kind of liquid hazardous materials transportation vehicle monitor system |
| CN106395517A (en) * | 2016-10-28 | 2017-02-15 | 江苏金米智能科技有限责任公司 | Elevator strop control device based on signal conditioning circuit |
| CN106442270A (en) * | 2016-11-15 | 2017-02-22 | 江苏智石科技有限公司 | Signal processing circuit based automatic monitor for dust on filter screen of air purifier |
| CN106429665A (en) * | 2016-10-28 | 2017-02-22 | 江苏金米智能科技有限责任公司 | Stabilized power supply-based elevator stopping control device |
| CN106555603A (en) * | 2016-11-15 | 2017-04-05 | 江苏智石科技有限公司 | A kind of Control System of Tunnel Ventilation based on signal amplification circuit |
| CN106597919A (en) * | 2016-11-15 | 2017-04-26 | 江苏智石科技有限公司 | Signal conditioning circuit-based automatic cleaning system of air purifier |
| CN106647451A (en) * | 2016-11-15 | 2017-05-10 | 江苏智石科技有限公司 | Automatic cleaning system for air cleaner |
| CN106627626A (en) * | 2016-10-28 | 2017-05-10 | 江苏金米智能科技有限责任公司 | Intelligent and telescopic metro seat based on signal conditioning |
| CN106908689A (en) * | 2017-01-11 | 2017-06-30 | 中国船舶工业系统工程研究院 | A kind of marine geophysical prospecting towing cable based on FGPA is powered monitor equipment in real time |
| CN107100613A (en) * | 2016-02-19 | 2017-08-29 | 中石化石油工程技术服务有限公司 | High-power underground rig carrier wave remote monitoring system |
| CN109631986A (en) * | 2018-12-03 | 2019-04-16 | 国网浙江省电力有限公司电力科学研究院 | A kind of cable and its monitoring of working condition early warning system |
| CN109669104A (en) * | 2019-01-29 | 2019-04-23 | 镇江赛尔尼柯自动化有限公司 | A kind of method and its monitoring device based on Injection Signal monitoring ship network system Intelligent insulation state |
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107100613A (en) * | 2016-02-19 | 2017-08-29 | 中石化石油工程技术服务有限公司 | High-power underground rig carrier wave remote monitoring system |
| CN106297166A (en) * | 2016-08-24 | 2017-01-04 | 无锡卓信信息科技股份有限公司 | A kind of liquid hazardous materials transportation vehicle monitor system |
| CN106429665A (en) * | 2016-10-28 | 2017-02-22 | 江苏金米智能科技有限责任公司 | Stabilized power supply-based elevator stopping control device |
| CN106627626A (en) * | 2016-10-28 | 2017-05-10 | 江苏金米智能科技有限责任公司 | Intelligent and telescopic metro seat based on signal conditioning |
| CN106395517A (en) * | 2016-10-28 | 2017-02-15 | 江苏金米智能科技有限责任公司 | Elevator strop control device based on signal conditioning circuit |
| CN106442270A (en) * | 2016-11-15 | 2017-02-22 | 江苏智石科技有限公司 | Signal processing circuit based automatic monitor for dust on filter screen of air purifier |
| CN106555603A (en) * | 2016-11-15 | 2017-04-05 | 江苏智石科技有限公司 | A kind of Control System of Tunnel Ventilation based on signal amplification circuit |
| CN106597919A (en) * | 2016-11-15 | 2017-04-26 | 江苏智石科技有限公司 | Signal conditioning circuit-based automatic cleaning system of air purifier |
| CN106647451A (en) * | 2016-11-15 | 2017-05-10 | 江苏智石科技有限公司 | Automatic cleaning system for air cleaner |
| CN106908689A (en) * | 2017-01-11 | 2017-06-30 | 中国船舶工业系统工程研究院 | A kind of marine geophysical prospecting towing cable based on FGPA is powered monitor equipment in real time |
| CN106908689B (en) * | 2017-01-11 | 2019-05-24 | 中国船舶工业系统工程研究院 | A kind of marine geophysical prospecting towing cable based on FGPA is equipped for pyroelectric monitor in real time |
| CN109631986A (en) * | 2018-12-03 | 2019-04-16 | 国网浙江省电力有限公司电力科学研究院 | A kind of cable and its monitoring of working condition early warning system |
| CN109669104A (en) * | 2019-01-29 | 2019-04-23 | 镇江赛尔尼柯自动化有限公司 | A kind of method and its monitoring device based on Injection Signal monitoring ship network system Intelligent insulation state |
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