CN110888086A - Circuit electric leakage detection positioning system based on signal injection - Google Patents
Circuit electric leakage detection positioning system based on signal injection Download PDFInfo
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- CN110888086A CN110888086A CN201911242351.2A CN201911242351A CN110888086A CN 110888086 A CN110888086 A CN 110888086A CN 201911242351 A CN201911242351 A CN 201911242351A CN 110888086 A CN110888086 A CN 110888086A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
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Abstract
The invention provides a line leakage detection positioning system based on signal injection, which comprises an injection signal generator, an isolation transformer, a coupling reactor, a signal acquisition unit, a signal conditioning unit, a control processing unit, a display unit, an alarm unit and a communication unit, wherein the injection signal generator is connected with the isolation transformer; the line leakage detection system injects signals into each phase line, then collects the low-frequency zero-sequence current signals of the lines, analyzes and judges whether the cable has a leakage fault, positions a specific fault line and gives an alarm in time. The invention provides a line electric leakage detection positioning system based on signal injection, which can accurately judge whether an electric leakage phenomenon and a specific fault line occur on the line, thereby ensuring the safety of equipment and personnel.
Description
Technical Field
The invention belongs to the technical field of electric power detection, and particularly relates to a line electric leakage detection positioning system based on signal injection.
Background
Along with the increase of the demand of people on electric energy in production and life, a power distribution system is more and more complex and diversified, and the working environments of lines are different. With the insulation aging of the cable or the electrical equipment, improper management or maintenance and accidents, the insulation level of the power distribution system can be damaged or the insulation level of the electrical equipment is reduced, which is not beneficial to normal production, and finally leads to the leakage fault of the cable.
The leakage fault is one of the main faults of the low-voltage power grid, and when the leakage fault occurs to the line, certain threats can be caused to equipment and personal safety, so that a reliable leakage detection system is an important guarantee for the safety and reliability of the line.
The invention provides a line leakage detection positioning system based on signal injection, which is characterized in that a low-frequency signal is injected into a line, a low-frequency zero-sequence current signal is collected according to the state of the low-frequency signal in the line, the low-frequency zero-sequence current signal is analyzed and judged, and whether a fault occurs or not and a specific fault line is finally determined.
Disclosure of Invention
The invention provides a line electric leakage detection positioning system based on signal injection, which can accurately judge whether an electric leakage phenomenon and a specific fault line occur on the line, thereby ensuring the safety of equipment and personnel.
The invention particularly relates to a line leakage detection positioning system based on signal injection, which comprises an injection signal generator, an isolation transformer, a coupling reactor, a signal acquisition unit, a signal conditioning unit, a control processing unit, a display unit, an alarm unit and a communication unit, wherein the injection signal generator is sequentially connected with the isolation transformer and the coupling reactor; the line leakage detection system injects signals into each phase line, then collects the low-frequency zero-sequence current signals of the lines, analyzes and judges whether the cable has a leakage fault, positions a specific fault line and gives an alarm in time.
The injection signal generator receives a control instruction of the control processing unit to obtain signal waveform information from a read-only memory, generates PWM signals with duty ratio change according to different values in a sine wave value taking table, removes higher harmonics through a low-pass filter circuit, finally obtains a sine alternating current power supply with an effective value of 20V and a frequency of 10Hz, and is coupled to a power frequency power grid through the isolation transformer and the coupling reactor.
The transformation ratio of the isolation transformer to the coupling reactor is 1: 1.
The signal acquisition unit adopts a zero sequence current sensor to acquire zero sequence current signals of each phase circuit.
The signal conditioning unit comprises an amplifying module, a filtering module and an A/D conversion module, and the amplifying module is used for amplifying the input zero sequence current signal; the filtering module comprises a trap circuit and a band-stop filtering circuit, the trap circuit filters 50HZ power frequency interference signals, and the band-stop filtering circuit selects 10Hz frequency and better collects 10Hz signals; the A/D conversion module AD conversion chip carries out AD conversion on the input signal.
The control processing unit adopts a singlechip to perform information processing and integral control on the line leakage detection system, compares an input low-frequency zero-sequence current signal with a low-frequency zero-sequence current reference value, controls the alarm unit to give an alarm if the input low-frequency zero-sequence current signal is greater than the low-frequency zero-sequence current reference value, controls the display unit to perform fault display, and uploads fault information to a monitoring center through the communication unit.
Further, the control processing unit analyzes the low-frequency zero-sequence currents of all the lines, calculates and finds a line with a low-frequency zero-sequence current value equal to the sum of low-frequency zero-sequence current values of other lines, namely a fault line, controls the display unit to display a specific fault line, and transmits the fault line to the monitoring center through the communication unit.
The display unit adopts an LCD.
The alarm unit adopts an audible and visual alarm, and when the circuit has an electric leakage fault, an audible and visual alarm signal is sent out so that a worker can find and confirm the circuit in time.
The communication unit uploads the detection information of the line leakage detection positioning system to the monitoring center by adopting a wireless communication technology, and receives a control instruction of the monitoring center.
Compared with the prior art, the beneficial effects are: the line leakage detection positioning system injects a low-frequency signal into a line, then collects a low-frequency zero-sequence current signal, analyzes whether the line has a leakage fault or not according to the state of the low-frequency signal in the line, and determines a specific fault line, so that the reliability and the safety of the line are ensured.
Drawings
Fig. 1 is a schematic structural diagram of a circuit leakage detection positioning system based on signal injection according to the present invention.
Detailed Description
The following describes in detail a specific embodiment of a line leakage detection positioning system based on signal injection according to the present invention with reference to the accompanying drawings.
As shown in fig. 1, the line leakage detecting and positioning system of the present invention includes an injection signal generator, an isolation transformer, a coupling reactor, a signal acquisition unit, a signal conditioning unit, a control processing unit, a display unit, an alarm unit, and a communication unit, where the injection signal generator is sequentially connected to the isolation transformer and the coupling reactor, the coupling reactor is coupled to each phase of line, the signal acquisition unit is sequentially connected to the signal conditioning unit and the control processing unit, and the control processing unit is further connected to the display unit, the alarm unit, and the communication unit; the line leakage detection system injects signals into each phase line, then collects the low-frequency zero-sequence current signals of the lines, analyzes and judges whether the cable has a leakage fault, positions a specific fault line and gives an alarm in time.
The injection signal generator receives a control instruction of the control processing unit to acquire signal waveform information from a read-only memory, generates PWM signals with variable duty ratios according to different values in a sine wave value taking table, removes higher harmonics through a low-pass filter circuit, finally obtains a sine alternating current power supply with an effective value of 20V and a frequency of 10Hz, and is coupled to a power frequency power grid through the isolation transformer and the coupling reactor; the transformation ratio of the isolation transformer to the coupling reactor is 1: 1.
The sinusoidal alternating current power supply is strong in anti-jamming capability, and safe when the voltage amplitude is below 36V, under the high-risk condition.
The signal acquisition unit acquires zero sequence current signals of each phase circuit by adopting a zero sequence current sensor and inputs the zero sequence current signals into the signal conditioning unit.
The signal conditioning unit comprises an amplifying module, a filtering module and an A/D conversion module, and the amplifying module is used for amplifying the input zero sequence current signal; the filtering module comprises a trap circuit and a band-stop filtering circuit, the trap circuit filters 50HZ power frequency interference signals, and the band-stop filtering circuit selects 10Hz frequency and better collects 10Hz signals; the A/D conversion module AD conversion chip carries out AD conversion on the input signal.
The signal conditioning unit comprises an amplifying module, a filtering module and an A/D conversion module, and the amplifying module is used for amplifying the input zero sequence current signal;
the filtering module comprises a trap circuit and a band elimination filtering circuit which are used in a matched mode, so that the interference of signals in a power grid on the acquisition of the zero sequence current signals is reduced: the notch circuit filters 50HZ power frequency interference signals, and the band elimination filter circuit better collects 10Hz signals by selecting 10Hz frequencies;
the A/D conversion module AD conversion chip carries out AD conversion on the input signal.
The control processing unit adopts a singlechip to perform information processing and integral control on the line leakage detection system, compares an input low-frequency zero-sequence current signal with a low-frequency zero-sequence current reference value, controls the alarm unit to give an alarm if the input low-frequency zero-sequence current signal is greater than the low-frequency zero-sequence current reference value, controls the display unit to perform fault display, and uploads fault information to a monitoring center through the communication unit.
The control processing unit further analyzes the low-frequency zero-sequence currents of all the lines, calculates and finds a line with a low-frequency zero-sequence current value equal to the sum of low-frequency zero-sequence current values of other lines, namely a fault line, controls the display unit to display a specific fault line, and transmits the fault line to the monitoring center through the communication unit.
The display unit adopts an LCD.
The alarm unit adopts an audible and visual alarm, and when the circuit has an electric leakage fault, an audible and visual alarm signal is sent out so that a worker can find and confirm the circuit in time.
The communication unit uploads the detection information of the line leakage detection positioning system to the monitoring center by adopting a wireless communication technology, and receives a control instruction of the monitoring center.
The line leakage detection positioning system can also adopt a thick metal shielding box, so that the influence of electromagnetic interference on the detection positioning system is reduced.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (8)
1. The line leakage detection positioning system based on signal injection is characterized by comprising an injection signal generator, an isolation transformer, a coupling reactor, a signal acquisition unit, a signal conditioning unit, a control processing unit, a display unit, an alarm unit and a communication unit, wherein the injection signal generator is sequentially connected with the isolation transformer and the coupling reactor, the coupling reactor is coupled with each phase line, the signal acquisition unit is sequentially connected with the signal conditioning unit and the control processing unit, and the control processing unit is further respectively connected with the display unit, the alarm unit and the communication unit; the line leakage detection system injects signals into each phase line, then collects the low-frequency zero-sequence current signals of the lines, analyzes and judges whether the cable has a leakage fault, positions a specific fault line and gives an alarm in time.
2. The line leakage detecting and positioning system based on signal injection as claimed in claim 1, wherein the injection signal generator receives the control command of the control processing unit, outputs a sinusoidal ac power with an effective value of 20V and a frequency of 10Hz, and is coupled to the power frequency power grid through the isolation transformer and the coupling reactor.
3. The line leakage detection positioning system based on signal injection as claimed in claim 2, wherein the transformation ratio of the isolation transformer and the coupling reactor is 1: 1.
4. The system according to claim 3, wherein the signal acquisition unit acquires the zero-sequence current signal of each line by using a zero-sequence current sensor.
5. The line leakage detection and positioning system based on signal injection as claimed in claim 4, wherein the signal conditioning unit comprises an amplifying module, a filtering module and an A/D conversion module, and the amplifying module amplifies the input zero sequence current signal; the filtering module comprises a trap circuit and a band-stop filtering circuit, the trap circuit filters 50HZ power frequency interference signals, and the band-stop filtering circuit selects 10Hz frequency and better collects 10Hz signals; the A/D conversion module AD conversion chip carries out AD conversion on the input signal.
6. The line leakage detection and positioning system based on signal injection as claimed in claim 5, wherein the control processing unit uses a single chip to perform information processing and overall control on the line leakage detection system, compares the input low frequency zero sequence current signal with a low frequency zero sequence current reference value, and if the input low frequency zero sequence current signal is greater than the low frequency zero sequence current reference value, controls the alarm unit to give an alarm, performs fault display on the display unit, and uploads fault information to the monitoring center through the communication unit.
7. The system according to claim 6, wherein the control processing unit analyzes the low-frequency zero-sequence currents of all lines, calculates and finds a line with a low-frequency zero-sequence current value equal to the sum of the low-frequency zero-sequence current values of other lines, i.e. a fault line, controls the display unit to display a specific fault line, and transmits the fault line to the monitoring center through the communication unit.
8. The system according to any one of claims 1 to 7, wherein the communication unit uploads the detection information of the system to the monitoring center by using a wireless communication technology, and receives a control command from the monitoring center.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911242351.2A CN110888086A (en) | 2019-12-06 | 2019-12-06 | Circuit electric leakage detection positioning system based on signal injection |
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| CN201911242351.2A CN110888086A (en) | 2019-12-06 | 2019-12-06 | Circuit electric leakage detection positioning system based on signal injection |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112255572A (en) * | 2020-10-29 | 2021-01-22 | 国网江苏省电力有限公司盐城供电分公司 | Neutral point indirect grounding fault detection system based on signal injection |
| CN112858838A (en) * | 2021-01-22 | 2021-05-28 | 广东电网有限责任公司 | Cable fault positioning system and method |
| CN114217189A (en) * | 2021-12-30 | 2022-03-22 | 国网江苏省电力有限公司南通供电分公司 | GIL equipment fault positioning method adopting ultrahigh frequency transient current measurement |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112255572A (en) * | 2020-10-29 | 2021-01-22 | 国网江苏省电力有限公司盐城供电分公司 | Neutral point indirect grounding fault detection system based on signal injection |
| CN112858838A (en) * | 2021-01-22 | 2021-05-28 | 广东电网有限责任公司 | Cable fault positioning system and method |
| CN114217189A (en) * | 2021-12-30 | 2022-03-22 | 国网江苏省电力有限公司南通供电分公司 | GIL equipment fault positioning method adopting ultrahigh frequency transient current measurement |
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Application publication date: 20200317 |