CN104316854A - Variable-frequency resonance testing circuit - Google Patents
Variable-frequency resonance testing circuit Download PDFInfo
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- CN104316854A CN104316854A CN201410620757.0A CN201410620757A CN104316854A CN 104316854 A CN104316854 A CN 104316854A CN 201410620757 A CN201410620757 A CN 201410620757A CN 104316854 A CN104316854 A CN 104316854A
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Abstract
The invention discloses a variable-frequency resonance testing circuit. The variable-frequency resonance testing circuit comprises a cable to be tested, a variable-frequency power supply, an exciting transformer, a wave trapper, a first voltage-dividing capacitor, a second voltage-dividing capacitor, a measurement impedor, a coupling capacitor, a voltmeter and a partial discharge detector, wherein a three-phase alternating-current power supply is connected to the input end of the variable-frequency power supply, and the output end of the variable-frequency power supply is connected to the primary side of the exciting transformer. One end of the wave trapper, the first voltage-dividing capacitor, the second voltage-dividing capacitor, the measurement impedor, the coupling capacitor and the other end of the wave trapper are sequentially connected in series. The coupling capacitor and the connecting end of the wave trapper and the second voltage-dividing capacitor and the connecting end of the measurement impedor are correspondingly connected to two ends of the secondary side of the exciting transformer in a one-to-one mode. The variable-frequency resonance testing circuit is simple in wiring, low in cost and capable of accurately judging the insulation defect of the cable to be tested.
Description
Technical field
The present invention relates to a kind of frequency conversion resonance experiment circuit, belong to the detection field that frequency conversion resonance vibration swings ripple detection streamer insulating property.
Background technology
The conductor wire core (single core or multicore) that cable is made up of high specific conductance material, and form heavy insulation course and protective seam by insulating material such as oil-paper, rubber, plastics, usually can be reduced to desirable coaxial capacitance structure.Cable reliability is high in theory, floor area is little, security is good and do not affect urban, thus in city neighborhood, industrial and mining enterprises and army use more and more many.Cable the sending out of electric system and each power station, join, generally use in electricity supplying and using system, and due to China populous, the particularly urban area of underground utilities complexity, the importance that cable is defeated, distribution line is safe is more outstanding, and insulation is the important criterion of cable quality quality.Local defect in insulating medium, under voltage effect, occur defect area repeat puncture, be called shelf depreciation, the medium-term and long-term shelf depreciation of cable insulation can make insulation defect constantly expand, and finally causes integral insulation to puncture, and causes insulation fault,
The test of AC voltage withstand test to insulation is very strict, an electrical equipment is exposed under the electric circumstance of very severe, as fruit product can also maintain normal condition under this severe electric circumstance, just can determine also necessarily can maintain very normal situation under normal environment.Effectively can find more dangerous centrality defect.It is qualification insulation of electrical installation intensity the most direct method, for judging that can electrical equipment put into operation and have decisive meaning, is also the important means ensureing apparatus insulated level, avoid generation insulation fault.
Cable ac voltage withstanding voltage test commonly uses the insulating property that frequency conversion resonance experiment carrys out detection streamer, frequency conversion resonance experiment generally needs to use capacitive divider, coupling condenser and detection impedance, separate between three, in order to meet condition of resonance, the numerous reactor arrangement connection in series-parallel of usual needs, equipment tissue put loaded down with trivial details, wiring is complicated, floor area is large, and cause metrical error large because the frequency of wiring is high, also easily affect testing result between each parts.
Summary of the invention
The object of the invention is to overcome the deficiencies in the prior art, providing a kind of frequency conversion resonance experiment circuit, its wiring is simple, and cost is low, can judge the insulation defect of cable under test quickly and accurately.
A kind of technical scheme realizing above-mentioned purpose is: a kind of frequency conversion resonance experiment circuit, external three-phase alternating-current supply, described frequency conversion resonance experiment circuit comprises cable under test, detector is put in variable-frequency power sources, exciting transformer, trap, the first voltage-dividing capacitor, the second voltage-dividing capacitor, measurement impedance, coupling condenser, voltage table drawn game, wherein:
Described three-phase alternating-current supply accesses the input end of described variable-frequency power sources, and the output terminal of described variable-frequency power sources receives the former limit of described exciting transformer;
The other end of one end of described trap, described first voltage-dividing capacitor, described second voltage-dividing capacitor, described measurement impedance, described coupling condenser and described trap is sequentially connected in series;
The end that connects of connect end and described second voltage-dividing capacitor and the described measurement impedance of described coupling condenser and described trap accesses the two ends of the secondary of described exciting transformer correspondingly;
The end that connects of described voltage table described first voltage-dividing capacitor of access and the second voltage-dividing capacitor;
The end that connects that detector accesses described measurement impedance and described coupling condenser is put in described office;
The connecting to holding of one end of described cable under test and described coupling condenser and described trap is connected, and the connecting to holding of the other end of described cable under test and described trap and described first voltage-dividing capacitor is connected;
The end ground connection that connects of described second voltage-dividing capacitor and described measurement impedance.
Above-mentioned a kind of frequency conversion resonance experiment circuit, wherein, described measurement impedance comprises the electric capacity, resistance and the inductance that are in parallel, and described electric capacity, described resistance are connected with described coupling condenser with the first common port of described inductance, ground connection after the second common port is connected with described second voltage-dividing capacitor.
Above-mentioned a kind of frequency conversion resonance experiment circuit, wherein, the secondary of described exciting transformer connects lightning arrester in parallel.
A kind of frequency conversion resonance experiment circuit of the present invention beneficial effect is compared with prior art: wiring is simple, cost is low, can judge that cable under test exists with or without obvious shelf depreciation under operating voltage quickly and accurately, this frequency conversion resonance experiment circuit stability, reliability are high, voltage exports and rate-adaptive pacemaker is stablized, EMC Design is reasonable, and defencive function is perfect, has very strong overload capacity simultaneously; Automatic tuning capabilities is powerful, and cable under test length is restricted hardly.
Accompanying drawing explanation
Fig. 1 is the structural representation of a kind of frequency conversion resonance experiment circuit of the present invention.
Embodiment
The present inventor, in order to understand technical scheme of the present invention better, below by embodiment particularly, and is described in detail by reference to the accompanying drawings:
Refer to Fig. 1, embodiments of the invention, a kind of frequency conversion resonance experiment circuit, external three-phase alternating-current supply 1, frequency conversion resonance experiment circuit comprises cable under test X, detector 10 is put in variable-frequency power sources 2, exciting transformer 3, trap 4, first voltage-dividing capacitor 5, second voltage-dividing capacitor 6, measurement impedance 7, coupling condenser 8, voltage table 9 drawn game.
Three-phase alternating-current supply 1 accesses the input end of variable-frequency power sources 2, and the output terminal of variable-frequency power sources 2 receives the former limit of exciting transformer 3.
The other end of one end of trap 4, the first voltage-dividing capacitor 5, second voltage-dividing capacitor 6, measurement impedance 7, coupling condenser 8 and trap 4 is sequentially connected in series; The end that connects of connect end and the second voltage-dividing capacitor 6 and the measurement impedance 7 of coupling condenser 8 and trap 4 accesses the two ends of the secondary of exciting transformer 3 correspondingly.Voltage table 9 accesses the end that connects of the first voltage-dividing capacitor 5 and the second voltage-dividing capacitor 6; The end that connects that detector 10 accesses measurement impedance 7 and coupling condenser 8 is put in office; The connecting to holding of one end of cable under test X and coupling condenser 8 and trap 4 is connected, and the connecting to holding of the other end of cable under test X and trap 4 and the first voltage-dividing capacitor 5 is connected; The end ground connection that connects of the second voltage-dividing capacitor 6 and measurement impedance 7.The secondary of exciting transformer 3 connects lightning arrester 11 in parallel, and namely the two ends of the secondary of exciting transformer 3 are accessed at the two ends of lightning arrester 11 correspondingly.
Preferably, measurement impedance 7 comprises the electric capacity C, resistance R and the inductance L that are in parallel, electric capacity C, resistance R are connected with coupling condenser 8 with the first common port of inductance L, ground connection after second common port is connected with the second voltage-dividing capacitor 6, measurement impedance 7 adopts RLC type resonant tank, is Low ESR to power frequency, and the pulse detection of shelf depreciation is highly sensitive, frequency band is narrower, and noise level is lower.
The principle of work of a kind of frequency conversion resonance experiment circuit of the present invention: variable-frequency power sources 2 sent into by three-phase alternating-current supply, variable-frequency power sources 2 produces frequency within the scope of 4 ~ 1MHz, the standard sine wave voltage that voltage is adjustable in 0 ~ 350V sends into exciting transformer 3, the voltage that exciting transformer exports is added to the trap 4 be connected in series, first voltage-dividing capacitor 5, second voltage-dividing capacitor 6 both sides, regulate the frequency of variable-frequency power sources 2, exciting transformer 3 is utilized to excite resonant tank, the resonant tank of trap 4 and cable under test composition is made to be in resonant condition, resonance potential is the voltage of display on voltage table 9, namely be added to voltage on cable under test X.If the poor quality of cable under test X, there is insulation defect, when producing a shelf depreciation, the two ends of cable under test can produce an instantaneous voltage, now, are coupled on measurement impedance 7 through coupling condenser 8, a pulse current can be produced in frequency conversion resonance experiment circuit loop, office puts detector 10 and pulse current detected, can show insulation defect in real time, this makes it possible to judge that cable under test exists with or without obvious shelf depreciation under operating voltage quickly and accurately.
In sum, a kind of frequency conversion resonance experiment circuit connection of the present invention is simple, cost is low, can judge that cable under test exists with or without obvious shelf depreciation under operating voltage quickly and accurately, this frequency conversion resonance experiment circuit stability, reliability are high, and voltage exports and rate-adaptive pacemaker is stablized, and EMC Design is reasonable, defencive function is perfect, has very strong overload capacity simultaneously; Automatic tuning capabilities is powerful, and cable under test length is restricted hardly.
Those of ordinary skill in the art will be appreciated that, above embodiment is only used to the present invention is described, and be not used as limitation of the invention, as long as in spirit of the present invention, all will drop in Claims scope of the present invention the change of the above embodiment, modification.
Claims (3)
1. a frequency conversion resonance experiment circuit, external three-phase alternating-current supply, it is characterized in that, described frequency conversion resonance experiment circuit comprises cable under test, detector is put in variable-frequency power sources, exciting transformer, trap, the first voltage-dividing capacitor, the second voltage-dividing capacitor, measurement impedance, coupling condenser, voltage table drawn game, wherein:
Described three-phase alternating-current supply accesses the input end of described variable-frequency power sources, and the output terminal of described variable-frequency power sources receives the former limit of described exciting transformer;
The other end of one end of described trap, described first voltage-dividing capacitor, described second voltage-dividing capacitor, described measurement impedance, described coupling condenser and described trap is sequentially connected in series;
The end that connects of connect end and described second voltage-dividing capacitor and the described measurement impedance of described coupling condenser and described trap accesses the two ends of the secondary of described exciting transformer correspondingly;
The end that connects of described voltage table described first voltage-dividing capacitor of access and the second voltage-dividing capacitor;
The end that connects that detector accesses described measurement impedance and described coupling condenser is put in described office;
The connecting to holding of one end of described cable under test and described coupling condenser and described trap is connected, and the connecting to holding of the other end of described cable under test and described trap and described first voltage-dividing capacitor is connected;
The end ground connection that connects of described second voltage-dividing capacitor and described measurement impedance.
2. a kind of frequency conversion resonance experiment circuit according to claim 1, it is characterized in that, described measurement impedance comprises the electric capacity, resistance and the inductance that are in parallel, described electric capacity, described resistance are connected with described coupling condenser with the first common port of described inductance, ground connection after the second common port is connected with described second voltage-dividing capacitor.
3. a kind of frequency conversion resonance experiment circuit according to claim 1 and 2, is characterized in that, the secondary of described exciting transformer connects lightning arrester in parallel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410620757.0A CN104316854A (en) | 2014-11-06 | 2014-11-06 | Variable-frequency resonance testing circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410620757.0A CN104316854A (en) | 2014-11-06 | 2014-11-06 | Variable-frequency resonance testing circuit |
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| Publication Number | Publication Date |
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| CN104316854A true CN104316854A (en) | 2015-01-28 |
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| CN201410620757.0A Pending CN104316854A (en) | 2014-11-06 | 2014-11-06 | Variable-frequency resonance testing circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113625057A (en) * | 2021-08-11 | 2021-11-09 | 保定腾远电力科技有限公司 | Power cable dielectric loss testing device based on resonance characteristics |
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| CN202119866U (en) * | 2011-05-25 | 2012-01-18 | 黑龙江省安装工程公司 | Variable-frequency series resonance voltage withstanding test device |
| CN203054162U (en) * | 2012-12-10 | 2013-07-10 | 铜仁供电局 | Comprehensive tester for partial discharge of high-voltage cable |
| CN103267933A (en) * | 2013-05-02 | 2013-08-28 | 国家电网公司 | Method for measuring partial discharge in transformer induced voltage testing device |
| CN103605058A (en) * | 2013-12-03 | 2014-02-26 | 山东电力设备有限公司 | Device for carrying out partial discharge tests simultaneously on multiple sets of transformers |
| WO2014097006A1 (en) * | 2012-12-18 | 2014-06-26 | Koninklijke Philips N.V. | Problem detection in cable system |
| CN204166092U (en) * | 2014-11-06 | 2015-02-18 | 国网上海市电力公司 | A kind of frequency conversion resonance experiment circuit |
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2014
- 2014-11-06 CN CN201410620757.0A patent/CN104316854A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202119866U (en) * | 2011-05-25 | 2012-01-18 | 黑龙江省安装工程公司 | Variable-frequency series resonance voltage withstanding test device |
| CN203054162U (en) * | 2012-12-10 | 2013-07-10 | 铜仁供电局 | Comprehensive tester for partial discharge of high-voltage cable |
| WO2014097006A1 (en) * | 2012-12-18 | 2014-06-26 | Koninklijke Philips N.V. | Problem detection in cable system |
| CN103267933A (en) * | 2013-05-02 | 2013-08-28 | 国家电网公司 | Method for measuring partial discharge in transformer induced voltage testing device |
| CN103605058A (en) * | 2013-12-03 | 2014-02-26 | 山东电力设备有限公司 | Device for carrying out partial discharge tests simultaneously on multiple sets of transformers |
| CN204166092U (en) * | 2014-11-06 | 2015-02-18 | 国网上海市电力公司 | A kind of frequency conversion resonance experiment circuit |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113625057A (en) * | 2021-08-11 | 2021-11-09 | 保定腾远电力科技有限公司 | Power cable dielectric loss testing device based on resonance characteristics |
| CN113625057B (en) * | 2021-08-11 | 2022-04-12 | 保定腾远电力科技有限公司 | Power cable dielectric loss testing device based on resonance characteristics |
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