CN104833867A - Signal enhanced pressure wave propagation model cable space charge test system - Google Patents
Signal enhanced pressure wave propagation model cable space charge test system Download PDFInfo
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- CN104833867A CN104833867A CN201510217559.4A CN201510217559A CN104833867A CN 104833867 A CN104833867 A CN 104833867A CN 201510217559 A CN201510217559 A CN 201510217559A CN 104833867 A CN104833867 A CN 104833867A
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- model cable
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Abstract
The invention discloses a signal enhanced pressure wave propagation model cable space charge test system. The wall of a metal shielding box (20) is provided with a light hole. A pulse laser (21) is arranged at the light hole. The outer semi-conductive shielding layer surface of a model cable (18) is coated with signal reinforcing agents (17). The light emitted by the pulse laser (21) can shine on the signal reinforcing agents (17) through the light hole. The invention provides a specific structure of the pressure wave propagation (PWP) model cable space charge test system. According to the invention, a waveguide tube is mounted at the entrance of a high-voltage lead, an interference removing resistor is serially connected in the high-voltage lead, and the metal shielding box is employed in the system, so that the influence on the space charge test system by external interference signals can be greatly reduced, and a signal-to-noise ratio of the system can be remarkably improved.
Description
Technical field
The invention belongs to model cable space charge technical field of measurement and test, be specifically related to the signal enhancement mode pressure wave method model cable space charge test macro for the test of model cable space charge.
Background technology
Under direct current high electric field, the subject matter that direct current cables faces can accumulate certain space charge in insulating medium or on interface, if space charge density is enough high, internal field even may exceed the breakdown electric field of insulating medium, causes dielectric breakdown.Space charge measuring technology, comprises electroacoustic pulse (pulsed electro-acoustic, PEA) method, pressure wave (Pressure wave propagation, PWP) method etc., has effectively promoted the research of space charge.At present, the cable insulation thickness for space charge test is 2 ~ 6 mm, is referred to as model cable, and model cable space charge to test normally used method be PEA method.
In the test of PEA method, plus high-pressure electric pulse can not be too high, and therefore test signal is less.In addition, in order to obtain electric impulse signal more accurately, the PVDF piezoelectric membrane in broadband need be adopted, but the sensitivity of this sensor is not high.So the signal that additional single electric pulse obtains in the ordinary course of things is difficult to analyze, usually needs additional hundreds of to thousands of electric pulses, then process is averaged to measured signal and just can obtain space charge signal.Meanwhile, in model cable insulating space electric charge test process, because signal attenuation is comparatively large, also need to utilize software to carry out data processing to fundamental space charge signal, space charge research can be used for.Like this, in the test of model cable space charge, there is certain randomness in the data that PEA method is surveyed, and there is certain distorted signals.In addition, be limited to the serviceability temperature of pvdf membrane, at the probe temperature of PEA method test macro generally below 70 DEG C, but due to the needs of research, often need the space charge performance of test model cable insulation more than 70 DEG C.Like this, in this link of probe temperature, there is certain limitation in PEA method.
Summary of the invention
The present invention proposes a kind of signal enhancement mode pressure wave method model cable space charge test macro, realize the test of PWP method model cable space charge, signal is stronger, the true and reliable property of test signal, without temperature limitations, can signal be strengthened, significantly improve signal to noise ratio (S/N ratio).
Technical solution of the present invention is as follows:
A kind of signal enhancement mode pressure wave method model cable space charge test macro, comprises DC generator, high-voltage connection, stress cone, waveguide, goes to disturb resistance, protective resistance, model cable, electric capacity, metallic shield case, pulsed laser, amplifier, oscillograph and grading ring.
Protective resistance, model cable, electric capacity are arranged in metallic shield case, and high-voltage connection is through the tank wall of described metallic shield case, and described waveguide is arranged on the tank wall place of high-voltage connection entrance, and in described high-voltage connection, series connection goes to disturb resistance; After removing interference resistive outer skin parcel autohension para tape, wrapped cable stress cone, DC generator, high-voltage connection are connected; Between high-voltage connection and protective resistance, protective resistance is connected respectively by grading ring with between model cable, electric capacity;
Model cable comprises near the first link of protective resistance, interlude and the second link away from protective resistance, and described first link and the second link are the two ends of the model cable peeling off certain length out semiconductor layer.
First link of model cable connects electric capacity by grading ring, and electric capacity, amplifier, oscillograph are linked in sequence successively; After second link connects grading ring, sky connects.
The tank wall of metallic shield case is provided with unthreaded hole, and described unthreaded hole place arranges pulsed laser, the out semiconductor layer surface smear signal reinforcing agent of the described interlude at model cable.
The utilizing emitted light of pulsed laser can be radiated on signal reinforcing agent by unthreaded hole.By using the effect of signal reinforcing agent, signal to noise ratio (S/N ratio) can be significantly improved.
More preferably, the interlude of model cable connects ground connection by metal fixture, wire, when metal fixture clamping, avoids signal reinforcing agent.
The out semiconductor layer thickness of model cable is 0.8 ~ 1.2mm;
Insulation thickness is 2 ~ 6 mm;
The strip length of the first link and the second link is 300 ~ 400 mm; Interlude length is 60 ~ 200 mm.
Electric capacity is connected with amplifier by the BNC connector on the tank wall of metallic shield case.
Between high-voltage connection and protective resistance, between protective resistance and model cable, electric capacity, the second link sky place of connecing is provided with grading ring.High-pressure uniform can be distributed in around assembly by grading ring, ensures that each tie point position does not exist electric discharge phenomena.
The resistance value disturbing resistance is gone to be 1000 Ω ~ 10 M Ω.Go interference resistance much larger than the wave impedance of high-voltage connection, the external interference signals introduced by high-voltage connection can be reduced widely.
Protective resistance is resistance value is 200 M Ω ~ 2 G Ω.Protective resistance not only can guard amplifier and oscillograph, can also remove DC generator and produce ripple voltage to the interference of test signal.
BNC connector is connected with amplifier by double layer screen signal wire.
Amplifier is connected by signal wire with oscillograph.
Withstand voltage 150 ~ 200 kV of electric capacity, electric capacity 0.5 ~ 2 nF.High direct voltage and secondary device (amplifier and oscillograph) are isolated by electric capacity 19, and coupled room charge signal preferably.
Protective resistance, electric capacity, model cable etc. carry out shielding and the electromagnetic interference signal stoped from the external world by metallic shield case.
Compared with prior art, the present invention includes following beneficial effect:
(1) the concrete structure of PWP method model cable space charge test macro is provided;
(2) pass through, at high-voltage connection entrance, waveguide is installed, connect in lead-in wire and go the measure such as interference resistance, use metallic shield case, the impact of external interference signals on space charge test macro can be reduced widely, and significantly improve system signal noise ratio;
(2) PWP method model cable space charge test macro signal is comparatively strong, solves the problem that PEA method model cable space charge test macro signal is more weak and signal to noise ratio (S/N ratio) is lower;
(3) PWP method model cable space charge test macro only needs to test and once can obtain stable space charge signal, solve PEA method model cable space charge test macro and need repeat the test of time even thousands of times of hundreds of and the stochastic problems that exists, ensure that the true and reliable property of test signal;
(4) PWP method model cable space charge test macro can be used for the space charge test of more than 70 DEG C, solves the limitation of PEA method probe temperature below 70 DEG C;
(5) utilize metallic shield case resistance, electric capacity, sample to be shielded, greatly reduce the electromagnetic interference (EMI) of outer bound pair test macro;
(6) high-voltage connection conductor series connection one resistance, and resistance is positioned at metallic shield case tank wall place, reduces the external electromagnetic interference introduced by high-voltage connection, improves the signal to noise ratio (S/N ratio) of system.
Accompanying drawing explanation
Fig. 1 is the structural representation of signal enhancement mode pressure wave method model cable space charge test macro of the present invention;
Fig. 2 is not for use signal reinforcing agent space charge signal waveform;
Fig. 3 is the space charge signal wave using signal reinforcing agent;
Fig. 4 is model cable structural representation;
Fig. 5 is high-voltage connection, stress cone, waveguide, go interference resistance syndeton detailed schematic.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail.
As shown in Figure 1; a kind of signal enhancement mode pressure wave method model cable space charge test macro, comprises DC generator 11, high-voltage connection 12, stress cone 13, waveguide 14, goes to disturb resistance 15, protective resistance 16, model cable 18, electric capacity 19, metallic shield case 20, pulsed laser 21, amplifier 22, oscillograph 23.
As shown in Figure 5, protective resistance 16, model cable 18, electric capacity 19 are arranged in metallic shield case 20, high-voltage connection 12 is through the tank wall of described metallic shield case 20, and described waveguide 14 is arranged on the tank wall place of high-voltage connection 12 entrance, and in described high-voltage connection 12, series connection goes to disturb resistance 15; After removing interference resistance 15 outer layer covers autohension para tape, wrapped cable stress cone 13, DC generator 11, high-voltage connection 12 are connected; Between high-voltage connection 12 and protective resistance 16, protective resistance 16 is connected respectively by grading ring 30 with between model cable 18, electric capacity 19;
Model cable 18 comprises near the first link 1801 of protective resistance 16, interlude 1802 and the second link 1803 away from protective resistance 16, and described first link 1801 and the second link 1803 be the two ends of the model cable 18 of stripping certain length out semiconductor layer.In Fig. 4, interlude 1803 comprises out semiconductor layer (outermost layer), insulation course (middle layer) and wire, and the first link 1801 and the second link 1803 have peeled off out semiconductor layer.
First link 1801 of model cable 1 connects electric capacity 19, and electric capacity 19, amplifier 22, oscillograph 23 are linked in sequence successively; Second link 1803 sky connects.The interlude 1802 of the present embodiment model cable 18 connects ground connection by metal fixture, wire.Namely metal fixture is clamped on interlude 1802, and metal fixture passes through wired earth.
The tank wall of metallic shield case 20 is provided with unthreaded hole, and described unthreaded hole place arranges pulsed laser 21, the described out semiconductor layer surface smear signal reinforcing agent 17 at interlude 1802;
The utilizing emitted light of pulsed laser 21 can be radiated on signal reinforcing agent 17 by unthreaded hole.The constituent of signal reinforcing agent 17 is prior art, generally be made up of vaseline, alcohol, silicone grease, water, vaseline, alcohol, silicone grease, water form, and by using signal reinforcing agent, can significantly improve space charge signal intensity and significantly improving system signal noise ratio.By using the effect of signal reinforcing agent in the present embodiment, can significantly improve signal to noise ratio (S/N ratio), as shown in Figures 2 and 3, Fig. 2 is not for use signal reinforcing agent space charge signal waveform, and Fig. 3 is the space charge signal waveform using signal reinforcing agent.Compare with Fig. 2, the space charge signal of Fig. 3 about strengthens 7 times, and signal to noise ratio (S/N ratio) significantly improves.
The out semiconductor layer thickness of model cable 18 is 0.8 ~ 1.2mm.
Insulation thickness is 2 ~ 6 mm;
The strip length of the first link 1801 and the second link 1803 is 300 ~ 400 mm.Interlude 1802 length is 60 ~ 20 0mm.
Electric capacity 19 is connected with amplifier 22 by the BNC connector on the tank wall of metallic shield case 20.
Between high-voltage connection 12 and protective resistance 16, between protective resistance 16 and model cable 18, electric capacity 19, the second link sky place of connecing is provided with grading ring.In the present embodiment, between protective resistance 16 and model cable 18, be provided with grading ring between protective resistance 16 and electric capacity 19, the tail end (sky connects end) of the second link of model cable 18 arranges grading ring.In accompanying drawing 1, circle represents grading ring.Comprise altogether three grading rings 30 in the present embodiment, namely between high-voltage connection 12 and protective resistance 16, on three's tie point of protective resistance 16, first link 1802, electric capacity 19, the sky place of connecing of the second link 1803 arranges a grading ring respectively.
The resistance value disturbing resistance 15 is gone to be 1000 Ω ~ 10 M Ω.Go interference resistance 15 much larger than the wave impedance of high-voltage connection, the external interference signals introduced by high-voltage connection can be reduced widely.
Protective resistance is resistance value is 200 M Ω ~ 2 G Ω.Protective resistance 16 not only can guard amplifier and oscillograph, can also remove DC generator and produce ripple voltage to the interference of test signal.
BNC connector is connected with amplifier 22 by double layer screen signal wire.
Amplifier is connected by signal wire with oscillograph.
Withstand voltage 150 ~ 200 kV of electric capacity 19, electric capacity 0.5 ~ 2 nF.High direct voltage and secondary device (amplifier and oscillograph) are isolated by electric capacity 19, and coupled room charge signal preferably.
Protective resistance, electric capacity, model cable etc. carry out shielding and the electromagnetic interference signal stoped from the external world by metallic shield case 20.
Particularly, in the present embodiment, component parameter is:
(1) DC generator, voltage 80 ~ 200, ripple factor≤0.5%, maximum current 1 ~ 10 mA;
(2) high-voltage connection, withstand voltage >=150 kV, external diameter 10 ~ 15 mm;
(3) go to disturb resistance, resistance 1000 ~ 10 M Ω;
(4) protective resistance, resistance 200 M Ω ~ 2 G Ω;
(5) model cable, inside and outside semi-conductive screen layer thickness 0.8 ~ 1.2, insulation thickness 2 ~ 6 mm, length
650 ~ 900 mm, two ends outer semiconducting layer strip length 300 ~ 400 mm, remaining outer semiconducting layer is long
Degree 6 ~ 20 mm;
(6) electric capacity, withstand voltage 150 ~ 200 kV, electric capacity 0.5 ~ 2 nF;
(7) metallic shield case, material is stainless steel or aluminium alloy, thick 2 ~ 4 mm of case, long 1700 ~ 2000 mm,
Wide 700 ~ 900 mm, high 700 ~ 1000 mm;
(8) pulsed laser, wavelength 1064 nm, pulsewidth 5 ~ 8 ns, energy 500 ~ 900 mJ;
(9) amplifier, enlargement factor 40 ~ 60 dB, bandwidth 40 ~ 200 MHz, input impedance 50 Ω;
(10) oscillograph, bandwidth 100 ~ 500 MHz, sampling rate 1 ~ 5 GSa.s-1, input impedance 50 Ω.
Those skilled in the art can change the present invention or modification design but do not depart from thought of the present invention and scope.Therefore, if these amendments of the present invention and modification belong within the claims in the present invention and equivalent technical scope thereof, then the present invention is also intended to comprise these change and modification.
Claims (9)
1. signal enhancement mode pressure wave method model cable space charge test macro, is characterized in that,
Comprise DC generator (11), high-voltage connection (12), stress cone (13), waveguide (14), remove interference resistance (15), protective resistance (16), model cable (18), electric capacity (19), metallic shield case (20), pulsed laser (21), amplifier (22), oscillograph (23) and grading ring (30);
Described protective resistance (16), model cable (18), electric capacity (19) are arranged in metallic shield case (20), high-voltage connection (12) is through the tank wall of described metallic shield case (20), described waveguide (14) is arranged on the tank wall place of high-voltage connection (12) entrance, and in described high-voltage connection (12), interference resistance (15) is gone in series connection; After removing interference resistance (15) outer layer covers autohension para tape, wrapped cable stress cone (13); DC generator (11), high-voltage connection (12) are connected; Between high-voltage connection (12) and protective resistance (16), protective resistance (16) is connected respectively by grading ring (30) with between model cable (18), electric capacity (19);
Described model cable (18) comprise near first link (1801) of protective resistance (16), interlude (1802) and away from protective resistance (second link (1803) of 16, described first link (1801) and the second link (1803) they are the two ends of the model cable (18) of stripping certain length out semiconductor layer;
First link (1801) of described model cable (18) connects electric capacity (19) by grading ring, and electric capacity (19), amplifier (22), oscillograph (23) are linked in sequence successively; Described second link (1803) connection grading ring (30) afterwards sky connects;
The tank wall of described metallic shield case (20) is provided with unthreaded hole, and described unthreaded hole place arranges pulsed laser (21), described out semiconductor layer surface smear signal reinforcing agent (17) at interlude (1802);
The utilizing emitted light of described pulsed laser (21) can be radiated on signal reinforcing agent (17) by unthreaded hole.
2. signal enhancement mode pressure wave method model cable space charge test macro according to claim 1, is characterized in that, the interlude (1802) of described model cable (18) connects ground connection by metal fixture, wire.
3. signal enhancement mode pressure wave method model cable space charge test macro according to claim 1, is characterized in that,
The out semiconductor layer thickness of described model cable (18) is 0.8 ~ 1.2mm;
Insulation thickness is 2 ~ 6 mm;
The strip length of described first link (1801) and the second link (1803) is 300 ~ 400 mm;
Described interlude (1802) length is 60 ~ 200 mm.
4. signal enhancement mode pressure wave method model cable space charge test macro according to claim 1, is characterized in that,
Described electric capacity (19) is connected with amplifier (22) by the BNC connector on the tank wall of metallic shield case (20).
5. signal enhancement mode pressure wave method model cable space charge test macro according to claim 1, is characterized in that,
Described resistance value of going interference resistance (15) is 1000 Ω ~ 10 M Ω.
6. signal enhancement mode pressure wave method model cable space charge test macro according to claim 1, is characterized in that,
Protective resistance (16) for resistance value be 200 M Ω ~ 2 G Ω.
7. signal enhancement mode pressure wave method model cable space charge test macro according to claim 4, is characterized in that,
Described BNC connector is connected with amplifier (22) by double layer screen signal wire.
8. signal enhancement mode pressure wave method model cable space charge test macro according to claim 1, it is characterized in that, described amplifier (22) is connected by signal wire with oscillograph (23).
9. signal enhancement mode pressure wave method model cable space charge test macro according to claim 1, is characterized in that, withstand voltage 150 ~ 200 kV of electric capacity (19), electric capacity 0.5 ~ 2 nF.
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| CN201510217559.4A CN104833867B (en) | 2015-04-30 | 2015-04-30 | Signal enhancing type pressure wave method model cable space charge test system |
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| CN201510217559.4A CN104833867B (en) | 2015-04-30 | 2015-04-30 | Signal enhancing type pressure wave method model cable space charge test system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109633292A (en) * | 2018-12-07 | 2019-04-16 | 南瑞集团有限公司 | A kind of cable shield processing method for the test of pressure wave method cable space charge |
| CN109669082A (en) * | 2019-01-28 | 2019-04-23 | 国网天津市电力公司电力科学研究院 | Cable body space charge test macro based on temperature gradient field and alternating voltage |
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| CN109669082A (en) * | 2019-01-28 | 2019-04-23 | 国网天津市电力公司电力科学研究院 | Cable body space charge test macro based on temperature gradient field and alternating voltage |
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Address after: Nan Shui Road Gulou District of Nanjing city of Jiangsu Province, No. 8 210003 Patentee after: NARI Group Corp. Address before: Nan Shui Road Gulou District of Nanjing city of Jiangsu Province, No. 8 210003 Patentee before: NARI Group CORPORATION STATE GRID ELECTRIC POWER INSTITUTE |