CN108169644A - A kind of high-tension cable PD On-Line Measurement System - Google Patents
A kind of high-tension cable PD On-Line Measurement System Download PDFInfo
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- CN108169644A CN108169644A CN201810091790.7A CN201810091790A CN108169644A CN 108169644 A CN108169644 A CN 108169644A CN 201810091790 A CN201810091790 A CN 201810091790A CN 108169644 A CN108169644 A CN 108169644A
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- cable
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- detection structure
- door
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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
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
Abstract
The invention discloses a kind of high-tension cable PD On-Line Measurement System, including high-tension cable Partial Discharge Detection structure；Transition joint is in series between the connector of two detection structures；The metal screen layer of transition joint both sides cable is connected as one；First group of detection structure is connect with the first signal receiving device；The near joints of first group of detection structure are provided with first antenna；The first antenna is connect with first signal receiving device；First signal receiving device is connect with the first frequency-selecting amplifying device；The first frequency-selecting amplifying device is connect by four road signal outputs with the first modulator；The present invention provides a kind of high-tension cable PD On-Line Measurement Systems, pass through this on-line detecting system, it can maximumlly realize that removing for Partial discharge signal is made an uproar, and then realize the remote transmission of partial discharge detection signal, and pass through the detection that computer is capable of accurate judgement partial discharge position, realize the accurate positionin of cable local discharge position.
Description
Technical field
The present invention relates to a kind of high-tension cable PD On-Line Measurement Systems.
Background technology
With the rapid development of economy, the electricity consumption of urban distribution network increases year by year, with reference to the design for aesthetic in city, electric power electricity
The a large amount of use of cable, it has also become the major product of electric power is transmitted in city.Since the insulating structure design of cable and scene are applied
The service life aging of the reasons such as work technique and cable, the Insulation Problems of cable are more and more, shelf depreciation (hereinafter referred to as partial discharge)
It is especially prominent.If cannot timely detect and handle cable partial discharge Insulation Problems, once cable insulation breakdown may result in weight
Large-scale blackout influences the normal operation in city.Therefore, to the research of the partial discharge detection of twisted polyethylene cable and localization method
It is particularly important.
At present, high-tension cable partial discharge location method mainly uses the time domain reflectometry of HF current transformer.This method
When an existing serious problems are exactly wireline test, due to environment complexity, live serious interference, cable partial discharge signal belongs to high
Frequency signal, detection signal sensitivity is small, and interference is larger and transmits on long cables there are severe transmission attenuation characteristic, so with
Time domain reflectometry can not carry out partial discharge location in the positioning of long cable partial discharge.Current cable partial discharge detecting instrument both domestic and external is all
It can not realize the cable partial discharge positioning of long range.
Therefore those skilled in the art are dedicated to developing a kind of detecting system that cable local discharge position is accurately positioned.
Invention content
In view of the drawbacks described above of the prior art, the technical problems to be solved by the invention, which are to provide one kind, to be accurately positioned
The detecting system of cable local discharge position.
To achieve the above object, the present invention provides a kind of high-tension cable PD On-Line Measurement System, including high pressure
Cable local discharge detection structure；Transition joint is in series between the connector of two detection structures；The transition joint both sides
The metal screen layer of cable is connected as one；First group of detection structure is connect with the first signal receiving device；First group of inspection
The near joints of geodesic structure are provided with first antenna；The first antenna is connect with first signal receiving device；Described
One signal receiving device is connect with the first frequency-selecting amplifying device；The first frequency-selecting amplifying device passes through four road signals outputs and the
One modulator connects；First modulator is connected with the first demodulator by optical fiber；First demodulator is provided with four tunnels
Signal exports, and wherein two paths of signals output is connect with the first Noise gate, and another two paths of signals output is connect with the second Noise gate；It is described
First Noise gate continues door with first and connect；Second Noise gate is connect with NJ；Described NJ continues door with second and connect；
Second group of detection structure is connect with second signal reception device；The near joints of second group of detection structure are provided with the second antenna；
Second antenna is connect with the second signal reception device；The second signal reception device and the second frequency-selecting amplifying device
Connection；The second frequency-selecting amplifying device is connect by four road signal outputs with the second modulator；Second modulator passes through
Optical fiber is connected with the second demodulator；Second demodulator is provided with four road signal outputs, wherein two paths of signals output and third
Noise gate connects, and another two paths of signals output is connect with the 4th Noise gate；The third Noise gate is connect with described NJ；Described
Four Noise gates continue door with third and connect；Described first, which continues door, the second lasting door and third, continues the signal transmission of door to meter
Calculation machine.
Preferably, the described first lasting door, the second lasting door and third continue door and are connect with third signal receiving device；Institute
Third signal receiving device is stated to connect with selecting switch；The selecting switch is connected with A/D switches；The A/D switches and calculating
Machine connects.
Preferably, including the first cable and the second cable；First cable and the second cable are connected by connector；It is special
Sign is：First cable is provided with the first metal foil close to the outer surface of the joint external screen layer；Second cable leans on
The outer surface of the nearly joint external screen layer is provided with the second metal foil；It is electrically connected between first metal foil and the second metal foil
It is connected to detection impedance；
Insulating cylinder is provided in the connector；The metal screen layer of first cable and the second cable passes through the insulation
Cylinder disconnects.
The beneficial effects of the invention are as follows：The present invention provides a kind of high-tension cable PD On-Line Measurement Systems, pass through
This on-line detecting system can maximumlly realize that removing for Partial discharge signal is made an uproar, and then realizes the remote of partial discharge detection signal
Transmission, and pass through the detection that computer is capable of accurate judgement partial discharge position, realize the accurate fixed of cable local discharge position
Position.
Description of the drawings
Fig. 1 is realization partial discharge detecting system connection diagram in the specific embodiment of the invention.
Fig. 2 is Partial Discharge Detection structural profile illustration.
Fig. 3 is Partial Discharge Detection structure diagram.
Fig. 4 is the schematic diagram of Partial Discharge Detection structure in the embodiment of the invention.
Fig. 5 is the equivalent circuit diagram of Partial Discharge Detection structure in the embodiment of the invention.
Fig. 6 is the electrical schematic diagram of Partial Discharge Detection in the embodiment of the invention.
Fig. 7 is the method flow diagram in the embodiment of the invention.
Fig. 8 is cable local discharge detection method principle schematic.
Specific embodiment
The invention will be further described with reference to the accompanying drawings and examples：
As shown in Figure 1, a kind of high-tension cable PD On-Line Measurement System, including Partial Discharge Detection structure, two inspections
Transition joint NJ is in series between the connector of geodesic structure, the metal screen layer of transition joint NJ both sides cable is connected as one knot
Structure.
First group of detection structure is connect with the first signal receiving device, and the near joints of first group of detection structure are provided with
One antenna T1, first antenna T1 are connect with the first signal receiving device, the first signal receiving device and the first frequency-selecting amplifying device
Connection.First frequency-selecting amplifying device is connect by four road signal outputs with the first modulator, and the first modulator is connected by optical fiber
There is the first demodulator, the first demodulator is provided with four road signal outputs, and wherein two paths of signals output is connect with the first Noise gate, separately
Two paths of signals output is connect with the second Noise gate.First Noise gate continues door with first and connect, and the second Noise gate is connect with NJ,
NJ continue door with second and connect.
Second group of detection structure is connect with second signal reception device, and the near joints of second group of detection structure are provided with
Two antenna T2, the second antenna T2 are connect with second signal reception device, second signal reception device and the second frequency-selecting amplifying device
Connection.Second frequency-selecting amplifying device is connect by four road signal outputs with the second modulator, and the second modulator is connected by optical fiber
There is the second demodulator, the second demodulator is provided with four road signal outputs, and wherein two paths of signals output is connect with third Noise gate, separately
Two paths of signals output is connect with the 4th Noise gate, and third Noise gate is connect with NJ, and the 4th Noise gate continues door with third and connect.
By modulation-demodulation, the teletransmission of signal can be realized, anti-stop signal is decayed in transmission process.In the present embodiment,
The frequency range of the detection of Partial Discharge Detection structure is 1MHz -300MHz.
In Fig. 1, the centre frequency of signal H is set in the frequency for properly detecting the IJ transition joint Partial discharge signals, more excellent
, the central frequency range of H signal could be provided as 50MHZ---300MHz；The centre frequency of signal L is set in suitable detection
In the frequency of adjacent NJ transition joint Partial discharge signals, preferably, the central frequency range of L could be provided as 1MHZ----
50MHZ；The centre frequency of signal H and L are different, and the signal that h, l are then coupled to for antenna, after corresponding frequency-selecting amplification
Signal.
In actual application, since the structure of conductor cable is different, the frequency of Partial Discharge Detection structure detection
Rate range is had nothing in common with each other, and the central frequency range of signal is accordingly changed the skill that can equally realize the present invention afterwards between H and L
Art effect.
First, which continues door, the second lasting door and third, continues the signal transmission of door to computer.
First, which continues door, the second lasting door and third, continues door and is connect with third signal receiving device；Third signal receives
Device is connect with selecting switch；Selecting switch is connected with A/D switches；A/D switches are connect with computer.
The effect of Noise gate is the noise signal that the signal that comparison calculus of finite differences device detects is coupled to antenna, by this
Corresponding signal is considered as noise signal and is rejected in the two.Continuing the effect of door is, is occurred according to discharge pulse signal
Frequent degree determines whether local discharge signal and exports the signal.The effect of NJ is the knot for exporting both sides Noise gate
Corresponding signal is considered as partial discharge pulse and exports the signal in fruit.
IJ1 and IJ2 is the acquisition signal at left and right sides of connector respectively, and NJ is opposite in the signal for exporting both sides Noise gate
The signal answered is considered as partial discharge pulse and exports the signal.
The effect of selecting switch is, selection is IJ1, that exports give A/D switches all the way for IJ2, NJ this 3 road signal, mainly
In order to reduce processing circuit cost.
Such as Fig. 2 to Fig. 6, high-tension cable Partial Discharge Detection structure here, including the first cable 1 and the second cable 2,
One cable 1 and the second cable 2 are connected by connector 3.First cable 1 outer surface of external screen layer at connector 3 is provided with first
Copper foil 4, the second cable 2 outer surface of external screen layer at connector 3 are provided with the second copper foil 5；First copper foil 4 and the second copper foil 5
Between be electrically connected with detection impedance 6.
It is provided with insulating cylinder 3a in connector 3, the metal screen layer of the first cable 1 and the second cable 2 is broken by insulating cylinder 3a
It opens.
Such as Fig. 2 to Fig. 6, Rc is the characteristic impedance of cable；C is the capacitance between conducting wire core wire and capacitance sensor copper foil；Cs
It is the stray capacitance of capacity coupler and metallic shield interlayer；Rs is the resistance between capacity coupler copper foil and shielded layer；Rf
It is the input impedance of measuring unit；C1 is the capacitance between the first metal foil 4 and cable；C2 be the first metal foil 4 and cable it
Between capacitance.
Capacitance is formed between copper foil and cable core, the detection impedance in 50 Europe is connected between two copper foil outputs.Detection resistance
Anti- to be just collected into the signal that Partial discharge signal acquires on two built-in capacitance sensors, this signal passes through differential amplification, turns through A/D
It changes the processing of input computer or input oscillograph is shown.The study found that Partial discharge signal frequency spectrum is in 1MHz-300MHz ranges
Interior, centre frequency is in 10MHz-20MHz, to-noise ratio highest.The measure loop of calculus of finite differences is similar to differential balance circuit, comes from
The noise signal of wire stylet, the both ends in detection impedance cannot generate pressure drop, thus can be very good to inhibit noise.And due to
There is copper foil to connect with the metal external screen layer of conducting wire, so external noise will not enter amplifier by signal input part, this is just more
Site environment noise is inhibited well.
As shown in Figure 7 and Figure 8, it can realize a kind of high voltage cable partial discharge detection method using said detecting system, wrap
Include following steps：
1) two groups of local discharge signals are obtained on cable transmission line road
Two near joints of head and the tail set detection structure as claimed in claim 1 on cable transmission line road；Two detection structures
Connector between be in series with transition joint；The metal screen layer of transition joint both sides cable is connected as one；
The local discharge signal that two detection structures receive is respectively：
X1(t)=S1(t,r1)+n1(t) (1)
X2(t)=S1(t,r2)+n2(t) (2)
Wherein, X1(t) local discharge signal received for first group of detection structure of t moment；
S1(t,r1) it is t moment, apart from shelf depreciation distance r1Locate the signal observation that first group of detection structure obtains；
n1(t) random noise in the signal observation transmission process obtained for first group of detection structure；
r1For distance of first group of detection structure apart from shelf depreciation point；Detection structure capacitance only has 6 centimetres, 16 lis of overall length
Rice；It can regard as a little with respect to cable length；
X2(t) local discharge signal received for second group of detection structure of t moment；
S2(t,r2) it is t moment, apart from shelf depreciation distance r2Locate the signal observation that second group of detection structure obtains；
n2(t) random noise in the signal observation transmission process obtained for second group of detection structure；
r2For distance of second group of detection structure apart from shelf depreciation point；
2) the maximal correlation delay time τ for obtaining two groups of local discharge signals is calculatedm
Formula (1) and (2) using cosine signal are analyzed, enable the signal equation be：
S1(t,r1)=Ui e-ɑr1cos w0(t-r1/v) (3)
S2(t,r2)=Ui e-ɑr2cos w0(t-r2/v) (4)
The correlation function of the observation for the local discharge signal that two detection structures obtain is：
Wherein, X1(t) local discharge signal received for first group of detection structure of t moment；
X2(t+ τ) is the local discharge signal that second group of detection structure of t+ τ moment receives；
T is the signal period；
Amplitude for the cosine signal that first group of testing agency receives；
Amplitude for the cosine signal that second group of testing agency receives；
-aFor decay factor；
Formula (1) and (2) are substituted into formula (5) to obtain：
Wherein, S1(t,r1) it is t moment, apart from shelf depreciation distance r1Locate the signal observation that first group of detection structure obtains
Value；
n1(t) random noise in the signal observation transmission process obtained for first group of detection structure；
r1For distance of first group of detection structure apart from shelf depreciation point；
S2(t,r2) it is t moment, apart from shelf depreciation distance r2Locate the signal observation that second group of detection structure obtains；
n2(t) random noise in the signal observation transmission process obtained for second group of detection structure；
r2For distance of second group of detection structure apart from shelf depreciation point；
T is the signal period；
It is assumed that Partial discharge signal and noise are altogether irrelevant, (6) can be reduced to：
Wherein, S1(t,r1) it is t moment, apart from shelf depreciation distance r1Locate the signal observation that first group of detection structure obtains
Value；
n1(t) random noise in the signal observation transmission process obtained for first group of detection structure；
r1For distance of first group of detection structure apart from shelf depreciation point；
S2(t+ τ, r2) it is the t+ τ moment, apart from shelf depreciation distance r2Locate the signal observation that second group of detection structure obtains
Value；
n2(t) random noise in the signal observation transmission process obtained for second group of detection structure；
r2For distance of second group of detection structure apart from shelf depreciation point；
T is the signal period；
If noise signal n1 (t) and n2 (t) are altogether irrelevant, then Partial discharge signal is separated from noise, i.e.,：
Wherein, S1(t,r1) it is t moment, apart from shelf depreciation distance r1Locate the signal observation that first group of detection structure obtains
Value；
r1For distance of first group of detection structure apart from shelf depreciation point；
S2(t+ τ, r2) it is the t+ τ moment, apart from shelf depreciation distance r2Locate the signal observation that second group of detection structure obtains
Value；
r2For distance of second group of detection structure apart from shelf depreciation point；
T is the signal period；
If noise signal is concerned with local discharge signal, denoising is carried out to local discharge signal, suppresses noise
n1(t) and n2(t) interference obtains (8) formula；
Formula (8) is integrated in a cycle；The period of known Partial discharge signal isSo by formula (3) and
(4) formula (8) is substituted into, can be obtained by integration：
Wherein：
By (9) it is found that S1And S2The correlation function of two Partial discharge signals is by a special function(sinc function) with
One invariant k0Product form；The maximum of sinc function is：
So the maximum value of correlation function corresponds to：
Its value tends to 0 (11)
W0 can not possibly be 0, so：
Therefore,
Wherein, r1For distance of first group of detection structure apart from shelf depreciation point；
r2For distance of second group of detection structure apart from shelf depreciation point；
V is the transmission speed of local discharge signal in the cable；
τmMaximal correlation delay time for two groups of local discharge signals；
3) position of shelf depreciation point is determined
It can be obtained according to formula (13)：
r1=r2-ντm (14)
Wherein, r1For distance of first group of detection structure apart from shelf depreciation point；
r2For distance of second group of detection structure apart from shelf depreciation point；
V is the transmission speed of local discharge signal in the cable；
τmMaximal correlation delay time for two groups of local discharge signals；
If the distance of the first detection structure and the second detection structure is D, and r1=L, then r2=D-L can be obtained：
L=D-L- ν τm(15)
Then partial discharge point and the horizontal distance of the first detection structure are：
Wherein, τmIt is the maximal correlation delay that can be read from related partial discharge detection instrument record.
The preferred embodiment of the present invention described in detail above.It should be appreciated that those of ordinary skill in the art without
Creative work is needed according to the present invention can to conceive and makes many modifications and variations.Therefore, all technologies in the art
Personnel are available by logical analysis, reasoning, or a limited experiment on the basis of existing technology under this invention's idea
Technical solution, all should be in the protection domain being defined in the patent claims.
Claims (3)
1. a kind of high-tension cable PD On-Line Measurement System, it is characterized in that：Including high-tension cable Partial Discharge Detection structure；
Transition joint is in series between the connector of two detection structures；The metal screen layer of transition joint both sides cable is connected as
Integral structure；
First group of detection structure is connect with the first signal receiving device；The near joints of first group of detection structure are provided with first day
Line；The first antenna is connect with first signal receiving device；First signal receiving device and the first frequency-selecting are amplified
Device connects；The first frequency-selecting amplifying device is connect by four road signal outputs with the first modulator；First modulator
First demodulator is connected with by optical fiber；First demodulator is provided with four road signals outputs, wherein two paths of signals output with
First Noise gate connects, and another two paths of signals output is connect with the second Noise gate；First Noise gate continues door with first and connect；
Second Noise gate is connect with NJ；Described NJ continues door with second and connect；
Second group of detection structure is connect with second signal reception device；The near joints of second group of detection structure are provided with second day
Line；Second antenna is connect with the second signal reception device；The second signal reception device is amplified with the second frequency-selecting
Device connects；The second frequency-selecting amplifying device is connect by four road signal outputs with the second modulator；Second modulator
Second demodulator is connected with by optical fiber；Second demodulator is provided with four road signals outputs, wherein two paths of signals output with
Third Noise gate connects, and another two paths of signals output is connect with the 4th Noise gate；The third Noise gate is connect with described NJ；Institute
It states the 4th Noise gate and continues door with third and connect；
Described first, which continues door, the second lasting door and third, continues the signal transmission of door to computer.
2. high-tension cable PD On-Line Measurement System as claimed in claim 2, it is characterized in that：Described first lasting door,
Second lasting door and third continue door and are connect with third signal receiving device；The third signal receiving device connects with selecting switch
It connects；The selecting switch is connected with A/D switches；The A/D switches are connect with computer.
3. high-tension cable PD On-Line Measurement System as described in claim 1, it is characterized in that：Including the first cable (1)
With the second cable (2)；First cable (1) and the second cable (2) are connected by connector (3)；It is characterized in that：First electricity
Cable (1) is provided with the first metal foil (4) close to the outer surface of external screen layer at the connector (3)；Second cable (2) is close to institute
The outer surface for stating external screen layer at connector (3) is provided with the second metal foil (5)；First metal foil (4) and the second metal foil (5)
Between be electrically connected with detection impedance (6)；
Insulating cylinder (3a) is provided in the connector (3)；The metal screen layer of first cable (1) and the second cable (2) leads to
Cross the insulating cylinder (3a) disconnection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810091790.7A CN108169644A (en) | 2018-01-30 | 2018-01-30 | A kind of high-tension cable PD On-Line Measurement System |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810091790.7A CN108169644A (en) | 2018-01-30 | 2018-01-30 | A kind of high-tension cable PD On-Line Measurement System |
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| CN108169644A true CN108169644A (en) | 2018-06-15 |
Family
ID=62512758
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| CN201810091790.7A Pending CN108169644A (en) | 2018-01-30 | 2018-01-30 | A kind of high-tension cable PD On-Line Measurement System |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112180218A (en) * | 2020-09-30 | 2021-01-05 | 北京神州泰岳软件股份有限公司 | Partial discharge monitoring method, system and device |
| WO2021138569A1 (en) * | 2019-12-31 | 2021-07-08 | 3M Innovative Properties Company | Monitoring system for evaluating a condition of an electrical grid |
-
2018
- 2018-01-30 CN CN201810091790.7A patent/CN108169644A/en active Pending
Non-Patent Citations (1)
| Title |
|---|
| 李华春: ""电缆局部放电在线检侧方法的分析比较"", 《电力设备》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021138569A1 (en) * | 2019-12-31 | 2021-07-08 | 3M Innovative Properties Company | Monitoring system for evaluating a condition of an electrical grid |
| CN112180218A (en) * | 2020-09-30 | 2021-01-05 | 北京神州泰岳软件股份有限公司 | Partial discharge monitoring method, system and device |
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