CN202663106U - Open-circuit prevention protective circuit for end screen grounding - Google Patents
Open-circuit prevention protective circuit for end screen grounding Download PDFInfo
- Publication number
- CN202663106U CN202663106U CN 201220295264 CN201220295264U CN202663106U CN 202663106 U CN202663106 U CN 202663106U CN 201220295264 CN201220295264 CN 201220295264 CN 201220295264 U CN201220295264 U CN 201220295264U CN 202663106 U CN202663106 U CN 202663106U
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- circuit
- open
- prevention protective
- end shield
- grounding
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- 230000001681 protective effect Effects 0.000 title abstract description 14
- 230000002265 prevention Effects 0.000 title abstract 8
- 230000001052 transient effect Effects 0.000 claims abstract description 12
- 238000009413 insulation Methods 0.000 abstract description 3
- 230000002159 abnormal effect Effects 0.000 abstract description 2
- 238000005259 measurement Methods 0.000 abstract 1
- 230000015556 catabolic process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000001066 destructive effect Effects 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
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- Emergency Protection Circuit Devices (AREA)
Abstract
The utility model discloses an open-circuit prevention protective circuit for end screen grounding. The open-circuit prevention protective circuit for end screen grounding comprises a pin which is lead out from an end screen and is characterized by comprising a gas discharge tube, a piezoresistor and a transient voltage suppressor diode which are connected in parallel between the end screen-lead pin and a ground end. The open-circuit prevention protective circuit protects the connection between the end screen and the ground, ensures the safety of a transformer, and prevents accidents caused by an open circuit of an end shield grounding cable. The open-circuit prevention protective circuit does not affect normal work of equipment in normal times, does not affect a normal flow direction of end shield current and does not affect normal measurement of the end shield current. If the grounding is abnormal, the open-circuit prevention protective circuit is conducted in different grades according to voltage classes, so that a large open circuit dynamic range is prevented; and the open-circuit prevention protective circuit is small in size and reliable, and convenient to install on site. The open-circuit prevention protective circuit is suitable for preventing the open circuit of all kinds of high voltage insulation grounding.
Description
Technical field
The utility model relates to a kind of protective circuit, especially the protective circuit of transformer high-voltage bushing end shield.
Background technology
During transformer high-voltage bushing end shield current monitoring, need to obtain the end shield electric current, generally be after going between out from transformer high-voltage bushing end shield pin, passes behind the transducer again ground connection.If the wiring loss, perhaps loose contact will cause end shield ground connection open circuit, and bushing shell for transformer inner heat, even the living economy that punctures to the security reliability of electrical network, also relates to electrical network of insulation breakdown bring destructive danger to equipment.The neutral grounding mode fault causes the transformer tripping operation, causes power grid accident.
The utility model content
The purpose of this utility model provides the anti-open loop protection circuit of a kind of end shield ground connection, and when transformer high-voltage bushing end shield earth connection wiring loss, perhaps during loose contact, circuit plays a protective role, and prevents the earth connection open circuit, avoids dangerous situation.
For reaching above-mentioned purpose, the technical solution of the utility model is:
A kind of end shield ground connection is prevented open loop protection circuit, and it comprises the pin that end shield is drawn, and characterized by further comprising:
Draw between pin and the earth terminal in described end shield by wire, and the gas discharge tube that connects, piezo-resistance and transient voltage twin zener dioder TVS.
The circuit of above structure; draw between pin and the ground and be connected to gas discharge tube, piezo-resistance and transient voltage twin zener dioder TVS in end shield; play the protective effect that end shield is connected with ground, guarantee the safety of transformer, prevent end shield earth cable open circuit and the accident of initiation.Have the following advantages:
1. add the normal operation of at ordinary times not impact of circuit equipment, do not affect end shield electric current normal flow direction, do not affect the end shield electric current and normally measure;
2. if there is the phenomenon such as ground connection is unusual, will be according to electric pressure classification conducting, the dynamic range that can prevent from opening a way is very large;
3. whole circuit board is small and exquisite, reliable, makes things convenient for the scene to install on the spot.
Description of drawings
Fig. 1 is circuit theory diagrams of the present utility model.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in further detail.
Shown in Figure 1, be circuit theory diagrams of the present utility model.As we know from the figure, prior art is drawn pin 2 in the end shield of bushing shell for transformer high-pressure side 1, has equivalent capacity C between the two, such as the left-hand broken line frame among the figure; End shield is drawn pin 2 and is connected with earth terminal 5 by cable 3.The technical solution of the utility model is to draw between pin 2 and the earth terminal 5 in end shield, and is connected to gas discharge tube G, piezo-resistance R and transient voltage twin zener dioder D, and makes circuit board 6, such as the dotted line frame on right side.Circuit board 6 volumes are little, the convenient installation.
Gas discharge tube G, piezo-resistance R and transient voltage twin zener dioder D are prior art products,, on sale on the market.Wherein, the English of transient voltage twin zener dioder D is TRANSIENT VOLTAGE SUPPRESSOR, is abbreviated as TVS.TVS is a kind of new product that grows up on voltage-stabiliser tube technique basis, its circuit symbol is identical with common voltage stabilizing didoe, profile also is as good as with general-purpose diode, when the high energy impact events of moment is stood at TVS pipe two ends, it can reduce its impedance with high speed suddenly, absorbs simultaneously a large electric current, with the voltage clamp between its two ends on a predetermined numerical value, thereby the circuit element of guaranteeing the back is avoided the high-octane impact of transient state and is damaged.
The maximum characteristics of piezo-resistance R are the voltage above being added in it when being lower than its threshold values, and the electric current that flows through it is minimum, is equivalent to a valve that shuts, and when voltage surpassed threshold values, the electric current that flows through it increased sharply, and is equivalent to valve open.Utilize this function, can suppress the frequent abnormal overvoltage that occurs in the circuit, protective circuit is avoided superpotential infringement.
The operation principle of gas discharge tube G is gas discharge, namely when applied voltage increases to dielectric strength above gas, the gap of two interpolars is with discharge breakdown, be converted into conduction state by original state of insulation, the voltage after the conducting between discharge tube the two poles of the earth maintains the residual voltage level that electric arc channel determines of putting.
Operation principle of the present utility model is:
On the basis of existing technology, draw between pin 2 and the earth terminal 5 and be connected to gas discharge tube G, piezo-resistance R and transient voltage twin zener dioder D in end shield.End shield earth cable 3 contact is good or when damaging, gas discharge tube G and piezo-resistance R, not conducting of transient voltage twin zener dioder D, and the end shield earth current is normally drawn pin from end shield and is flowed through end shield earth cable 3 to large ground; When the damage of end shield earth connection or loose contact; electric current can't normally flow to the earth from earth cable 3; this moment, end shield drew that voltage can raise on the pin 2; gas discharge tube G and piezo-resistance R, transient voltage twin zener dioder D will be according to the voltage height; classification (500kV, 220kV, 35kV) conducting is flowed back to the earth again with earth current, plays the protective effect that is connected with ground; prevent the earth connection open circuit, guarantee the safety of transformer and sleeve pipe thereof.
Claims (1)
1. an end shield ground connection is prevented open loop protection circuit, and it comprises the pin that end shield is drawn, and characterized by further comprising:
Draw between pin (2) and the earth terminal (5) in described end shield by wire, and the gas discharge tube that connects (G), piezo-resistance (R) and transient voltage twin zener dioder (D).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220295264 CN202663106U (en) | 2012-06-22 | 2012-06-22 | Open-circuit prevention protective circuit for end screen grounding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220295264 CN202663106U (en) | 2012-06-22 | 2012-06-22 | Open-circuit prevention protective circuit for end screen grounding |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202663106U true CN202663106U (en) | 2013-01-09 |
Family
ID=47457985
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220295264 Expired - Fee Related CN202663106U (en) | 2012-06-22 | 2012-06-22 | Open-circuit prevention protective circuit for end screen grounding |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202663106U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103683259A (en) * | 2013-12-06 | 2014-03-26 | 四川联友电讯技术有限公司 | High-safety communication system |
| CN104410059A (en) * | 2014-11-27 | 2015-03-11 | 北方工业大学 | Discharge gap arc extinguishing method of intrinsically safe inductive circuit |
-
2012
- 2012-06-22 CN CN 201220295264 patent/CN202663106U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103683259A (en) * | 2013-12-06 | 2014-03-26 | 四川联友电讯技术有限公司 | High-safety communication system |
| CN104410059A (en) * | 2014-11-27 | 2015-03-11 | 北方工业大学 | Discharge gap arc extinguishing method of intrinsically safe inductive circuit |
| CN104410059B (en) * | 2014-11-27 | 2017-03-22 | 北方工业大学 | A discharge gap arc extinguishing method for an intrinsically safe inductive circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 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: 20130109 Termination date: 20150622 |
|
| EXPY | Termination of patent right or utility model |