CN202794326U - Online monitoring device for grounding current of transformer core - Google Patents
Online monitoring device for grounding current of transformer core Download PDFInfo
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- CN202794326U CN202794326U CN 201220475402 CN201220475402U CN202794326U CN 202794326 U CN202794326 U CN 202794326U CN 201220475402 CN201220475402 CN 201220475402 CN 201220475402 U CN201220475402 U CN 201220475402U CN 202794326 U CN202794326 U CN 202794326U
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Abstract
The utility model discloses an online monitoring device for grounding current of a transformer core. The online monitoring device comprises a single chip microcomputer and an A/D (analog to digital) change-over circuit connected with the single chip microcomputer. The A/D change-over circuit is further connected to a current sensor through two current sampling circuits, the single chip microcomputer is further respectively connected with an LED digital display and a signal output unit, the two current sampling circuits are parallelly connected between the current sensor and the A/D change-over circuit, the current sensor comprises two secondary windings, a thicker core of one winding is used for measuring a small current signal of 0-1000mA, and a thinner core of the other winding is used for measuring a large current signal of 1-1000A. Real-time and continuous online monitoring and alarm for the grounding current of the transformer core are realized, and the failure rate of a transformer is reduced.
Description
Technical field
The utility model relates to current detection technology, specifically a kind of transformer iron core grounding current on-Line Monitor Device.
Background technology
Along with socioeconomic development, human more and more higher to the degree of dependence of electric power, accordingly power supply reliability is also had higher requirement.Transformer is one of visual plant of electric system, along with the in recent years fast development of extra-high voltage electric transmission and transformation technology, its status in electric system is also more and more important: cause power failure if break down for a certain reason, not only power department self is suffered heavy losses, and electricity consumption department also can suffer heavy economic losses, and visible transformer affects the reliability and safety of whole electric system.Data shows according to the relevent statistics, because of the accident that multipoint earthing of iron core causes, occupy the 3rd in the total accident of transformer, so the multipoint earthing of iron core of transformer fault can not be ignored.
Multipoint earthing of iron core of transformer is general property fault, although it can cause the local overheating of vicious cycle, the in the early stage loss that brings of ground current is very little, is difficult for realizing from open circuit loss.Just because of this, in order to find early the potential faults of transformer fe core inner, operation power department is the preventive trial project of the measurement of core insulation resistance as transformer.Facts have proved, the comprehensive diagnos that under this regular power failure, the off-line case power transformer is comprised the core insulation resistance test, really play certain effect of removing a hidden danger, but also have some obvious weak points, be mainly manifested in the following aspects:
1. the maintenance of stopping transport makes power department pay huge human and material resources cost, makes troubles not only for the electric energy user, also exists the problem of " maintenance is superfluous ";
Interval time between twice preventive trial longer, be difficult to find for paroxysmal insulation fault, have the problem of " maintenance is not enough ";
3. test condition and service condition have difference, and some off-line testing can not reflect the insulation status of equipment under service condition fully:
4. the people caused new equipment failure phenomenon also to happen occasionally when overhaul and power failure were tested.
The advantage of transformer iron core grounding current monitoring device is, can in time find the sign of initial failure, the operation maintenance personnel can be removed a hidden danger early by detection means when fault is in the embryonic stage, thereby avoid the generation of serious accident, improved repair quality and efficient.Development and application along with sensor technology, signal processing technology and computer technology, electrical equipment online monitoring technology as the repair based on condition of component basis has obtained develop rapidly, become an important component part in the insulation detection, it will remedy the weak point that only relies on regular preventive trial to bring aspect a lot.By the on-line monitoring to iron core grounding current, accurately judge the working condition of iron core, thereby that shoots the arrow at the target in time safeguards before iron core breaks down, not only effectively raise power supply reliability, also reduced the operating cost of electric system, the safe operation tool that ensures power transformer has been of great significance.
In addition, when transformer normally moves, because the no current loop forms, so the electric current on the ground wire is very little, be the milliampere level, generally be no more than O.1A; When having multipoint earthing, be equivalent to have the short circuit circle to exist around the iron core main flux, the circulation that flows through is decided by the relative position of trouble spot and normal earth point, and magnetic flux what namely surround in the short circuit circle, generally can reach tens amperes.Common current sensor can't guarantee enough measuring accuracy in so large scope, need to improve current sensor, to satisfy the measurement requirement of transformer iron core grounding current.
In view of this, for the problems referred to above, propose a kind of reasonable in design and effectively improve the transformer iron core grounding current on-Line Monitor Device of above-mentioned disappearance.
The utility model content
The purpose of this utility model is to provide a kind of transformer iron core grounding current on-Line Monitor Device, has realized real-time continuous on-line monitoring and the warning of transformer iron core grounding current, has reduced the failure rate of transformer.
In order to reach above-mentioned purpose, the utility model provides following technical scheme: a kind of transformer iron core grounding current on-Line Monitor Device, comprise single-chip microcomputer and the A/D change-over circuit that is connected with single-chip microcomputer, described A/D change-over circuit also is connected to current sensor by current sampling circuit, and described single-chip microcomputer also is connected with signal output unit with the LED digital indicator separately respectively.
Described current sampling circuit is provided with two covers and is connected in parallel between current sensor and the A/D change-over circuit.
Described current sensor has 2 Secondary Winding, and the iron core of a winding is used for measuring the little current signal of 0 ~ 1000mA, and iron core is thicker; Another winding iron core is used for measuring the large current signal of 1 ~ 1000A, and iron core is thinner.
Described single-chip microcomputer is selected the input signal of the Secondary Winding of suitable current sensor automatically according to result and the amplifier multiple of A/D conversion.
Described A/D change-over circuit carries the programmable amplifier unit.
Described signal output unit 7 adopts CAN industrial bus output signal.
Compared to prior art, the utlity model has following beneficial effect:
Current sensor 1 is the sensor special of developing voluntarily, and its Secondary Winding has 2, and an iron core is thicker, is used for measuring the little current signal of 0 ~ 1000mA; Another iron core is thinner, is used for measuring the large current signal of 1 ~ 1000A.
A/D change-over circuit 4 adopts A/D conversion chip ADS1286U to add programmable amplifier chip PGA309 formation, can set the enlargement factor of amplifier according to the range of signal of inputting, and carries out the A/D conversion, to improve the sampled measurements precision again.
Single-chip microcomputer 5 adopts the AT89C52 chip to consist of, and has Intelligent Recognition range of signal function, can automatically select the input signal of the Secondary Winding of suitable current sensor according to result and the amplifier multiple of A/D conversion, guarantees the accuracy of measuring.
Led display unit adopts customization technical grade chip of LCD.
Signal output unit 7 adopts SN65HVD1050DR, realizes the output of CAN industrial bus signal, and antijamming capability is strong.
The utility model is applicable to the big-and-middle-sized transformer iron core grounding current monitoring with the end shield down conductor.
Description of drawings
Fig. 1 is the structural representation of a kind of transformer iron core grounding current on-Line Monitor Device of the present utility model.
Among the figure: 1, current sensor; 2, current sampling circuit; 3, current sampling circuit; 4, A/D change-over circuit; 5, single-chip microcomputer; 6, LED digital indicator; 7, signal output unit.
Embodiment
Relevant detailed description of the present utility model and technology contents cooperate description of drawings as follows, yet accompanying drawing only provides the usefulness of reference with explanation, and the utility model is limited.
According to shown in Figure 1, a kind of transformer iron core grounding current on-Line Monitor Device, by current sensor 1, current sampling circuit 2,3, A/D change-over circuit 4, single-chip microcomputer 5, the LED numeral shows 6, signal output unit 7 consists of.Wherein current sensor 1 winding passes the mounting hole of reserving in the current sensor by the ground connection end shield downlead single turn of transformer core and consists of; In the installation ground connection end shield downlead single turn of transformer core being passed current sensor 1 gets final product.The Secondary Winding of current sensor 1 has 2, and the output of these 2 Secondary Winding connects respectively current sampling circuit 2 and current sampling circuit 3; Current sampling circuit 2 is connected with current sampling circuit and is connected with A/D change-over circuit 4 simultaneously, current signal after the conversion is delivered to A/D change-over circuit 4 change digital signal into, A/D change-over circuit 4 is connected with single-chip microcomputer 5, single-chip microcomputer 5 is responsible for processing digital signal and is carried out analytical calculation, and iron core grounding current shown that by LED numeral 6 show, if iron core grounding current surpasses early warning value, then by signal output unit 7 output alarm signals.
Current sensor 1 is the sensor special of developing voluntarily, and its Secondary Winding has 2, and an iron core is thicker, is used for measuring the little current signal of 0 ~ 1000mA; Another iron core is thinner, is used for measuring the large current signal of 1 ~ 1000A.
A/D change-over circuit 4 adopts A/D conversion chip ADS1286U to add programmable amplifier chip PGA309 formation, can set the enlargement factor of amplifier according to the range of signal of inputting, and carries out the A/D conversion, to improve the sampled measurements precision again.
Single-chip microcomputer 5 adopts the AT89C52 chip to consist of, and has Intelligent Recognition range of signal function, can automatically select the input signal of the Secondary Winding of suitable current sensor according to result and the amplifier multiple of A/D conversion, guarantees the accuracy of measuring.
Led display unit adopts customization technical grade chip of LCD.
Signal output unit 7 adopts SN65HVD1050DR, realizes the output of CAN industrial bus signal, and antijamming capability is strong.
The above only is preferred embodiment of the present utility model, and non-in order to limit claim of the present utility model, other use the equivalence of patent spirit of the present utility model to change, and all should all belong to claim of the present utility model.
Claims (6)
1. transformer iron core grounding current on-Line Monitor Device, comprise single-chip microcomputer and the A/D change-over circuit that is connected with single-chip microcomputer, it is characterized in that, described A/D change-over circuit also is connected to current sensor by current sampling circuit, and described single-chip microcomputer also is connected with signal output unit with the LED digital indicator separately respectively.
2. a kind of transformer iron core grounding current on-Line Monitor Device according to claim 1 is characterized in that, described current sampling circuit is provided with two covers and is connected in parallel between current sensor and the A/D change-over circuit.
3. a kind of transformer iron core grounding current on-Line Monitor Device according to claim 1 is characterized in that, described current sensor has 2 Secondary Winding, and the iron core of a winding is used for measuring the little current signal of 0 ~ 1000mA, and iron core is thicker; Another winding iron core is used for measuring the large current signal of 1 ~ 1000A, and iron core is thinner.
4. a kind of transformer iron core grounding current on-Line Monitor Device according to claim 3 is characterized in that, described single-chip microcomputer is selected the input signal of the Secondary Winding of suitable current sensor automatically according to result and the amplifier multiple of A/D conversion.
5. a kind of transformer iron core grounding current on-Line Monitor Device according to claim 1 is characterized in that, described A/D change-over circuit carries the programmable amplifier unit.
6. a kind of transformer iron core grounding current on-Line Monitor Device according to claim 1 is characterized in that, described signal output unit adopts CAN industrial bus output signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220475402 CN202794326U (en) | 2012-09-18 | 2012-09-18 | Online monitoring device for grounding current of transformer core |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220475402 CN202794326U (en) | 2012-09-18 | 2012-09-18 | Online monitoring device for grounding current of transformer core |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202794326U true CN202794326U (en) | 2013-03-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220475402 Expired - Fee Related CN202794326U (en) | 2012-09-18 | 2012-09-18 | Online monitoring device for grounding current of transformer core |
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| Country | Link |
|---|---|
| CN (1) | CN202794326U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103163364A (en) * | 2013-03-21 | 2013-06-19 | 辽宁省电力有限公司电力科学研究院 | Wireless monitoring device and monitoring method for grounding current of transformer core/clamp |
| CN103197178A (en) * | 2013-03-21 | 2013-07-10 | 辽宁省电力有限公司电力科学研究院 | Device and method of on-line monitoring of transformer direct current magnetic bias |
| CN103575970A (en) * | 2013-11-14 | 2014-02-12 | 国家电网公司 | Transformer grounding current monitoring device and system |
| CN110441577A (en) * | 2019-08-16 | 2019-11-12 | 大连世有电力科技有限公司 | A kind of highly integrated transformer iron core grounding current intelligent online monitoring device |
-
2012
- 2012-09-18 CN CN 201220475402 patent/CN202794326U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103163364A (en) * | 2013-03-21 | 2013-06-19 | 辽宁省电力有限公司电力科学研究院 | Wireless monitoring device and monitoring method for grounding current of transformer core/clamp |
| CN103197178A (en) * | 2013-03-21 | 2013-07-10 | 辽宁省电力有限公司电力科学研究院 | Device and method of on-line monitoring of transformer direct current magnetic bias |
| CN103197178B (en) * | 2013-03-21 | 2015-08-05 | 辽宁省电力有限公司电力科学研究院 | Transformer DC magnetic bias on-Line Monitor Device and monitoring method thereof |
| CN103575970A (en) * | 2013-11-14 | 2014-02-12 | 国家电网公司 | Transformer grounding current monitoring device and system |
| CN110441577A (en) * | 2019-08-16 | 2019-11-12 | 大连世有电力科技有限公司 | A kind of highly integrated transformer iron core grounding current intelligent online monitoring device |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130313 Termination date: 20150918 |
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| EXPY | Termination of patent right or utility model |