CN202383238U - Power cable partial discharge on-line monitoring device based on electromagnetic wave and high frequency CT - Google Patents
Power cable partial discharge on-line monitoring device based on electromagnetic wave and high frequency CT Download PDFInfo
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- CN202383238U CN202383238U CN 201120502673 CN201120502673U CN202383238U CN 202383238 U CN202383238 U CN 202383238U CN 201120502673 CN201120502673 CN 201120502673 CN 201120502673 U CN201120502673 U CN 201120502673U CN 202383238 U CN202383238 U CN 202383238U
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Abstract
A power cable partial discharge on-line monitoring device based on electromagnetic wave and high frequency CT comprises broadband Rogowski coil current transformers arranged on various monitoring positions of a cable, the broadband Rogowski coil current transformers are connected with a corresponding signal amplification module, the signal amplification module is connected with a data acquisition card through a transmission optical fiber, ad the data acquisition card is connected with a computer. In the device, an optical fiber communication system is combined with an expert identification system, insulation status of the power cable can be accurately judged in real time, and validity of a distribution cable partial discharge on-line monitoring system can be verified. Safety of a power supply network can be enhanced, network cable accidents can be avoided, using costs of the network cable can be reduced, and the partial discharge one-line monitoring special matching device is an ideal device for realizing real-time monitoring of a power cable in a power supply network.
Description
Technical field
The utility model relates to the power supply network on-line monitoring technique, more particularly is about involving the power cable local discharge on-line monitoring device of high frequency CT to what power cable was monitored in real time based on electromagnetism in the supply network.
Background technology
Along with the further quickening of China's urban network reconstruction with the upgrading paces, power cable is increasing to be applied in the transmission line of electricity and power distribution network of various electric pressures.After putting into operation, owing in cable production, transportation, installation and operational process, introduce defectives such as impurity, bubble, burr, convexity, or receive the erosion infiltration of moisture, moisture, chemical substance for a long time, it is aging to cause cable insulation, influences cable operation life.At present, domestic High Voltage XLPE Power Cable insulation is detected carried out periodic withstand voltage test more, and this method is more effective to open defect, and it is powerless to develop the insulation thin spot that the several years just progressively manifests aging sign for those.
Shelf depreciation refers to occur in the non-penetrability electric discharge phenomena in cable body insulation or the annex.In the shelf depreciation process, the high molecular chemical bond of insulating material produces off-the-line, and the heating on point of discharge can reach very high temperature, makes insulating material burnt or melt at point of discharge; Temperature raises also can produce thermal cracking, and dielectric conductance and loss are increased, and quickens insulation ag(e)ing; The shelf depreciation process also can produce many active products, and the corrosion insulator makes the dielectric behavior deterioration; The discharge of continuous demolition property and the gases at high pressure of discharge generation all can make insulator produce fine fisssure, and it is aging to form electric branch.The research proof, cable local discharge amount and its insulation status are closely related, and the discharge capacity increase is indicating that possibly there is the defective that endangers cable running safety in cable insulation.Therefore, accurately measuring the cable local discharge amount is to judge cable insulation quality the most directly perceived, effective method.
Though work the research of having carried out about the cable insulation detection method for local discharge in the sixties abroad, and carried out long-term practice and groped, to the research of XLPE cable insulation ag(e)ing and detection technique thereof imperfection still.In addition, since 110 kV and 220 kV level XLPE cables in the world Application and Development the use experience of maturation more than 50 years is arranged and possesses perfect insulation ag(e)ing detection method unlike oil-filled cable so far only surplus in the of 30 year.Therefore, the measuring method of further investigation XLPE cable shelf depreciation, the reliable power supply of correct assessment cable insulation safe condition, guarantee electric system has important significance for theories and practical value.
Summary of the invention
The object of the present invention is to provide a kind of ability to eliminate above-mentioned shortcoming; Have rational in infrastructure, simple to operate, safe and reliable, monitoring in time, accuracy of judgement, characteristics such as with low cost involve the power cable local discharge on-line monitoring device of high frequency CT based on electromagnetism; It combines optical fiber telecommunications system and expert's recognition system; Insulation status to power cable carries out accurately judging in real time that checking distribution cable office is placed on the validity of line monitoring system.Having improved the security of supply network widely, avoided the accident of netting twine to take place, lowered the use cost of netting twine, is the special-purpose assorted device of partial discharge monitoring of in the desirable supply network power cable being monitored in real time.
For realizing above-mentioned purpose, the utility model adopts following technical scheme:
A kind of power cable local discharge on-line monitoring device that involves high frequency CT based on electromagnetism; It comprises the broadband Rogowski coil current mutual inductor that is distributed in each monitoring location of cable; Broadband Rogowski coil current mutual inductor is connected with corresponding signal amplification module; The signal amplification module is through Transmission Fibers and data acquisition card connection, and data collecting card is connected with computing machine.Usually this computing machine can be the computing machine that is contained in backstage analysis expert system.
Said broadband Rogowski coil current mutual inductor is installed in cable splice, body or ground wire place, and pulse signal is put in induction office.
Said data collecting card is the multi-channel high-speed data capture card.
Said signal amplification module is the broadband signal amplification module.
Said broadband Rogowski coil current mutual inductor adopts the square-section ring skeleton of MnZn ferrite material, outer, internal diameter and highly be respectively 120,50 and 50mm, and the integrating resistor R of coil=50 Ω, number of turn N=10, the theoretical sensitivity of coil is 5V/A.
Said broadband Rogowski coil current mutual inductor is provided with the removable aluminum hull ring shielding of covers box, and thickness is 5mm.
The present invention has designed a kind of power cable office based on high frequency sensors and has been placed on line monitoring system, is applied to the operation of 10 kV cables, and cable local discharge is monitored and early warning.The cable local discharge on-line monitoring system mainly is made up of the broadband Rogowski coil current mutual inductor that is distributed in each monitoring location of cable, signal amplification module, Transmission Fibers, data collecting card and backstage analysis expert system, the functions such as collection, processing, conversion, transmission and display alarm of realization office discharge signal.
Rogowski coil (abbreviation Luo-coil) is processed by Ferrite Material, according to electromagnetic field couples principle measure local discharge pulse current signal.As shown in Figure 2, Luo-coil is the current transformer of 1:N, and annular Ferrite Material serves as former limit, is single-turn circular coil; Its secondary coil is the big and less N circle Circular Winding in cross section of a window area, and its structure and equivalent electrical circuit are shown in Fig. 3.
Among Fig. 2, Fig. 3, M is the mutual inductance of Luo-coil; Rs is the equivalent resistance of coil; Ls is the self-induction of coil; Cs is the equivalent stray capacitance of coil; R is the coil integrating resistor.The magnetic flux intersecting chain that coil secondary winding and former limit measured current I (t) are produced has following relation between the induced voltage U0 (t) of coil output and the measured current I (t)
[13]:
In the formula, M is the coefficient of mutual inductance between coil and current.
Because XLPE power cable partial discharge pulse's duration is short, signal amplitude is little, according to the current sensor equivalent electrical circuit, is fit to adopt high frequency small-signal shunt-resonant circuit theory that the cable local discharge signal is analyzed
[10]Choose different coil loads, Luo-coil can be divided into outer integration type again and from integration type.The load of outer integration type Luo-coil comprises integrating capacitor and integrating resistor, but because of receiving the integrator frequencies Effect on Performance, the frequency response of its measurement is restricted, and in the nanosecond current signal is measured, is difficult to use.And directly adopt integrating resistor from the integration type Luo-coil, and frequency response is high, is the desirable means of measuring the nanosecond pulse current signal, and the Luo-coil that this paper studied adopts from integration type.
Do not consider stray capacitance Cs, according to equivalent electrical circuit shown in Figure 1, its transport function is:
(2)
In the formula, R is an integrating resistor, and N is a coil turn.
Can find out that by formula (2) transport function of sieve formula coil is a constant, with frequency-independent; Response sensitivity is directly proportional with R, is inversely proportional to N.
But under high frequency, the influence of stray capacitance is very big, can not be left in the basket, and transport function is:
（3）
Each parameter interpretation and preceding text are together in the formula.
The working band of current sensor is used upper limit frequency f
hWith lower frequency limit f
lExpression; The working band of Luo-coil current sensor is seen formula (4), formula (5) among Fig. 3.
(4)
Analysis formula (2), formula (3) can know that the sensitivity of sensor is determined by inductance L s, resistance R s, coil stray capacitance Cs and the pull-up resistor R of cell winding jointly.Make transport function greatly then require to make Rs and Ls as far as possible little.And visible by formula (4), (5), for making sieve formula coil working frequency band enough wide, under the situation that core material and coil dimension are confirmed, should make its upper limiting frequency as far as possible greatly and lower frequency limit is as far as possible little, then require Rs and R as far as possible little, Ls is big as far as possible.But increase coil Ls, then turn number N should be big as far as possible.Increasing winding diameter and can reduce Rs, is mutual restriction but increase winding diameter with increasing turn number N.In addition, pull-up resistor R is all influential to bandwidth and response sensitivity.
Therefore, have the frequency band and the suitable sensitivity of broad in order to make coil, take all factors into consideration various factors after, sensor adopts the square-section ring skeleton of MnZn ferrite material, outer, internal diameter and highly be respectively 120,50 and 50mm.Select integrating resistor R=50 Ω of coil, number of turn N=10.The theoretical sensitivity that like this, can get coil is 5V/A.Receive external interference for coil is reduced as far as possible, Sensor Design the removable aluminum hull ring shielding of covers box, thickness is 5mm.After the shielding, sensor receives external electromagnetic field to disturb minimum (less than 1mV).
The beneficial effect of the utility model is: simple in structure, easy for installation, through cable body and cable splice are carried out on-line monitoring; Detection is put in the office of actual XLPE insulated cable show that this transducer sensitivity is higher; Can satisfy the requirement that monitoring is put in office, help arranging service work, and carry out defect processing targetedly; Minimizing takes place because of the sudden accident that mounting process or cable deterioration cause, and guarantees the urban power distribution network safe and reliable operation.
Description of drawings
Fig. 1: the power cable local discharge on-line monitoring device structural representation that involves high frequency CT based on electromagnetism;
Fig. 2: Rogowski coil current mutual inductor structural representation among Fig. 1;
The equivalent circuit diagram of Fig. 3: Fig. 2.
Wherein, 1. broadband Rogowski coil current mutual inductor, 2. signal amplification module, 3. Transmission Fibers, 4. data collecting card, 5. computing machine.
Embodiment
Further specify the structure of the utility model below in conjunction with accompanying drawing:
The power cable local discharge on-line monitoring device that involves high frequency CT based on electromagnetism as shown in the figure; It comprises the broadband Rogowski coil current mutual inductor 1 that is distributed in each monitoring location of cable; Broadband Rogowski coil current mutual inductor 1 is connected with corresponding signal amplification module 2; Signal amplification module 2 is connected with data collecting card 4 through Transmission Fibers 3, and data collecting card 4 is connected with computing machine 5.Data collecting card 4 is the multi-channel high-speed data capture card.Described broadband Rogowski coil current mutual inductor 1 is installed in cable splice, body or ground wire place, and pulse signal is put in induction office.Described signal amplification module 2 is the broadband signal amplification module.Described broadband Rogowski coil current mutual inductor 1 adopts the square-section ring skeleton of MnZn ferrite material; Internal diameter and highly be respectively 120,50 and 50mm outward; The integrating resistor R of coil=50 Ω, number of turn N=10, the theoretical sensitivity of coil is 5V/A.Broadband Rogowski coil current mutual inductor 1 is provided with the removable aluminum hull ring shielding of covers box, and thickness is 5mm.
Claims (6)
1. power cable local discharge on-line monitoring device that involves high frequency CT based on electromagnetism; It is characterized in that it comprises the broadband Rogowski coil current mutual inductor that is distributed in each monitoring location of cable; Broadband Rogowski coil current mutual inductor is connected with corresponding signal amplification module; The signal amplification module is through Transmission Fibers and data acquisition card connection, and data collecting card is connected with computing machine.
2. the power cable local discharge on-line monitoring device that involves high frequency CT based on electromagnetism as claimed in claim 1; It is characterized in that described broadband Rogowski coil current mutual inductor is installed in cable splice, body or ground wire place, pulse signal is put in induction office.
3. as claimed in claim 1ly involve the power cable local discharge on-line monitoring device of high frequency CT, it is characterized in that said data collecting card is the multi-channel high-speed data capture card based on electromagnetism.
4. as claimed in claim 1ly involve the power cable local discharge on-line monitoring device of high frequency CT, it is characterized in that said signal amplification module is the broadband signal amplification module based on electromagnetism.
5. the power cable local discharge on-line monitoring device based on electromagnetic wave and high frequency CT as claimed in claim 1; It is characterized in that said broadband Rogowski coil current mutual inductor adopts the square-section ring skeleton of MnZn ferrite material; Internal diameter and highly be respectively 120,50 and 50mm outward; The integrating resistor R of coil=50 Ω, number of turn N=10, the theoretical sensitivity of coil is 5V/A.
6. describedly involve the power cable local discharge on-line monitoring device of high frequency CT based on electromagnetism like claim 1 or 2 or 5, it is characterized in that said broadband Rogowski coil current mutual inductor is provided with the removable aluminum hull ring shielding of covers box, thickness is 5mm.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201120502673 CN202383238U (en) | 2011-12-06 | 2011-12-06 | Power cable partial discharge on-line monitoring device based on electromagnetic wave and high frequency CT |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201120502673 CN202383238U (en) | 2011-12-06 | 2011-12-06 | Power cable partial discharge on-line monitoring device based on electromagnetic wave and high frequency CT |
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| CN202383238U true CN202383238U (en) | 2012-08-15 |
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| CN 201120502673 Expired - Fee Related CN202383238U (en) | 2011-12-06 | 2011-12-06 | Power cable partial discharge on-line monitoring device based on electromagnetic wave and high frequency CT |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103197216A (en) * | 2013-04-12 | 2013-07-10 | 华北电力大学（保定） | Cable joint partial discharge monitoring system based on optical fiber transmission |
| CN105044579A (en) * | 2015-06-05 | 2015-11-11 | 北京兴迪仪器有限责任公司 | Measurement method for distributed partial discharge |
| CN109270411A (en) * | 2017-07-17 | 2019-01-25 | 广东电网有限责任公司佛山供电局 | A kind of partial discharge of power cable connector detection electromagnetic interference shielding device |
| CN112505483A (en) * | 2020-11-25 | 2021-03-16 | 山东科技大学 | Cable partial discharge positioning method based on online transfer function |
-
2011
- 2011-12-06 CN CN 201120502673 patent/CN202383238U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103197216A (en) * | 2013-04-12 | 2013-07-10 | 华北电力大学（保定） | Cable joint partial discharge monitoring system based on optical fiber transmission |
| CN105044579A (en) * | 2015-06-05 | 2015-11-11 | 北京兴迪仪器有限责任公司 | Measurement method for distributed partial discharge |
| CN109270411A (en) * | 2017-07-17 | 2019-01-25 | 广东电网有限责任公司佛山供电局 | A kind of partial discharge of power cable connector detection electromagnetic interference shielding device |
| CN112505483A (en) * | 2020-11-25 | 2021-03-16 | 山东科技大学 | Cable partial discharge positioning method based on online transfer function |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120815 Termination date: 20141206 |
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| EXPY | Termination of patent right or utility model |