CN105790215A - CT open-circuit protection device - Google Patents
CT open-circuit protection device Download PDFInfo
- Publication number
- CN105790215A CN105790215A CN201610115833.1A CN201610115833A CN105790215A CN 105790215 A CN105790215 A CN 105790215A CN 201610115833 A CN201610115833 A CN 201610115833A CN 105790215 A CN105790215 A CN 105790215A
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- Prior art keywords
- circuit
- open
- diode
- pressure cell
- protecting device
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
- H02H9/041—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage using a short-circuiting device
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Abstract
The invention discloses a CT open-circuit protection device. The device mainly comprises two field-effect triodes, a rectification filter circuit, a detection driving circuit and a protection circuit, wherein sources of the two field-effect triodes are both connected to a DC output negative electrode of the rectification circuit, drains of the two field-effect triodes are separately connected to two input ends of the protection device, gates of thee two field-effect triodes are both connected to the output end of the driving circuit, an AC input end of the rectification circuit is connected to the two input ends of the protection device, positive electrodes of two diodes of the protection circuit are separately connected with the sources of the two field-effect triodes, and negative electrodes of the two diodes are connected, are then connected in series with a pressure sensitive component and are connected with the gates of the two field-effect triodes. The CT open-circuit protection device has the advantages of working reliability, small size and low power consumption.
Description
Technical field
The present invention relates to a kind of protection device, particularly relate to the CT open-circuit protecting device of a kind of power system.
Background technology
nullThe CT of power system，Namely current transformer，Its secondary side is in operation open circuit，The voltage being likely to cause on secondary coil is increased to several kilovolts，Volts even up to ten thousand，This is by serious threat to personal safety and equipment safety，Therefore，In order to prevent the harm that CT second open circuit causes from occurring，Occur in that various CT open-circuit protecting device，But there is respective drawback，Chinese patent publication CN204858552U discloses a kind of Installation of Open-circuit Protection for Current Transformers，The fet of two differential concatenations that secondary side at current transformer is in parallel and drive circuit thereof，Rectification circuit when this protection device、Filter circuit、Testing circuit and drive circuit detect when high voltage occurs in CT open running，Drive the fet conducting of two differential concatenations，Inhibit the dangerous high voltage being likely to occur，This protection device volume is little，Cost is relatively low，But，This device is not turned at detection two fets of time period，Now by being connected in parallel on the two-way Transient Suppression Diode of CT secondary side to limit CT secondary voltage，Two fets of protection and other elements simultaneously，Restriction due to two-way Transient Suppression Diode self performance，When CT secondary current is bigger，The damage of two-way Transient Suppression Diode self and fet easily occurs.
Summary of the invention
It is an object of the invention to provide a kind of CT open-circuit protecting device; this device is not only able to when CT is operated in open circuit within the scope of rated current; CT secondary side can be effectively suppressed to produce dangerous high voltage, and when CT electric current is bigger during second open circuit, also can reliably working.
nullIn order to achieve the above object，The technical solution used in the present invention is: device mainly has two fets、Rectification circuit、Filter circuit and detection drive circuit composition，The source electrode of two fets is all connected to the direct current output negative pole of rectification circuit，The drain electrode of two fets is connected respectively to two inputs of protection device，The grid of two fets is all connected to the outfan of drive circuit，Two ac input ends of rectification circuit are connected respectively to two inputs of device，Consider wave circuit and connect DC output end positive pole and the negative pole of rectification circuit，It is further connected with two diodes between two inputs of protection device，And pressure cell，The positive pole of two diodes connects two inputs of protection device respectively，The negative pole of two diodes connects together，And be connected with the negative pole of pressure cell，The positive pole of pressure cell connects the grid of two fets，When this device is operated in the detection period，Although if now the secondary voltage of transformer has reached the setting voltage of testing circuit，But detection drive circuit drives the driving voltage of two fet conductings but without the output that is able to do in time，At this moment pressure cell punctures，The secondary voltage of transformer is delivered to the grid of two fets，When grid voltage exceedes its threshold voltage，Two fets begin to turn on，Thereby inhibiting bis-high voltages of CT.
Described pressure cell can adopt Zener diode.
Described pressure cell can also adopt Transient Suppression Diode.
Described Transient Suppression Diode can be unidirectional Transient Suppression Diode.
Described Transient Suppression Diode can also be two-way Transient Suppression Diode, and when adopting two-way Transient Suppression Diode, its closure is regardless of both positive and negative polarity.
Described pressure cell can also adopt varistor, and its closure is regardless of both positive and negative polarity.
Described two the diode preferred package being connected between two inputs common cathode composition element together.
In order to reduce the voltage that filter circuit bears, can connect between the DC output end of described rectification circuit and described filter circuit a buck diode, the negative pole of buck diode connects the DC output end positive pole of rectification circuit, and the positive pole of buck diode connects the positive pole of filter circuit.
Described buck diode can be Zener diode
Described buck diode can also be unidirectional Transient Suppression Diode.
Described buck diode can also is that two-way Transient Suppression Diode, and when adopting two-way Transient Suppression Diode, closure is regardless of both positive and negative polarity.
The invention has the beneficial effects as follows: 1. work is more reliable, owing to this device restrains high voltage in the detection time period also with two fets, and the two field effect transistor is the powerful field effect transistor selected, it is to avoid two-way transient state suppresses the problem that two poles are burnt because of overpower；2. cost is low, instead of expensive two-way transient state with cheap general-purpose diode and suppresses two poles, makes device holistic cost reduce；3. volume reduces further, and owing to general-purpose diode suppresses the volume of two poles little much than two-way transient state, therefore the volume of device also can reduce accordingly.
Accompanying drawing explanation
Fig. 1 is the electrical schematic diagram of first embodiment of the invention；
Fig. 2 is the electrical schematic diagram of another embodiment of the present invention.
In figure: Q1. fet, Q2. fet, Q3. audion, U1. adjustable precise shunt regulator, D1. diode, D2. diode, D3. rectification circuit, D4. buck diode, YM. pressure cell, C1. filter circuit, R1. resistance, R2. resistance, R3. resistance, R4. resistance, R5. resistance, R6. resistance.
Detailed description of the invention
Below in conjunction with drawings and Examples, the specific embodiment of the present invention being described in further detail, following example are used for illustrating the present invention, but are not limited to the scope of the present invention.
nullIn first shown in Fig. 1 embodiment，CT open-circuit protecting device mainly has two fet Q1、Q2、Rectification circuit D3、Filter circuit C1、And detection drive circuit composition，Two fet Q1、The source electrode of Q2 is all connected to the direct current output negative pole GND of rectification circuit D3，Two fet Q1、The drain electrode of Q2 is connected respectively to two input A of protection device、B，Two fet Q1、The grid of Q2 is all connected to the outfan D of drive circuit，Two ac input ends of rectification circuit D3 are connected respectively to two input A of device、B，Consider wave circuit C1 and meet the DC output end positive pole VCC and negative pole GND of rectification circuit D3，Two input A of protection device、Two diode D1 it are further connected with between B、D2 and pressure cell YM，Two diode D1、The positive pole of D2 meets two input A of protection device respectively、B，Two diode D1、The negative pole of D2 connects together，And be connected with the negative pole of pressure cell YM，The positive pole of pressure cell YM meets two fet Q1、The grid of Q2.
Detection drive circuit is made up of Q3, U1, R1, R2, R3, R4, R5 and R6, when voltage between DC output end positive pole VCC and the negative pole GND of rectification circuit D3 reaches certain value, Q3 turns on, D point output HIGH voltage, drives two fet Q1, Q2 conductings.
Described pressure cell YM can use Zener diode, unidirectional Transient Suppression Diode, two-way Transient Suppression Diode or varistor, and when adopting two-way Transient Suppression Diode or varistor, its closure is regardless of both positive and negative polarity.
Two diode D1, D2 preferred package common cathode diode combination together.
Another embodiment shown in Fig. 2, it is on the basis of first embodiment, connect buck diode D4 between the DC output end and described filter circuit C1 of described rectification circuit D3, the negative pole of buck diode D4 connects the DC output end positive pole of rectification circuit D3, the positive pole of buck diode D4 connects the positive pole of filter circuit C1, buck diode D4 can use Zener diode, unidirectional Transient Suppression Diode or two-way Transient Suppression Diode, and when adopting two-way Transient Suppression Diode, its closure is regardless of both positive and negative polarity.
Detection drive circuit can also adopt other circuit of prior art, exports high level when CT secondary voltage reaches setting value, transfers low level to when the voltage of filter circuit is reduced to and is unsuitable for driving field effect transistor conducting.
Claims (10)
- null1. a CT open-circuit protecting device，Mainly there are two fets (Q1)、(Q2)、Rectification circuit (D3)、Filter circuit (C1)、And detection drive circuit composition，Two fets (Q1)、(Q2) source electrode is all connected to the direct current output negative pole (GND) of rectification circuit (D3)，Two fets (Q1)、(Q2) drain electrode is connected respectively to two inputs (A) of protection device、(B)，Two fets (Q1)、(Q2) grid is all connected to the outfan (D) of drive circuit，Two ac input ends of rectification circuit (D3) are connected respectively to two inputs (A) of device、(B)，Consider wave circuit (C1) and connect DC output end positive pole (VCC) and the negative pole (GND) of rectification circuit (D3)，It is characterized in that: two inputs (A) of protection device、(B) two diodes (D1) it are further connected with between、And pressure cell (YM) (D2)，Two diodes (D1)、(D2) positive pole connects two inputs (A) of protection device respectively、(B)，Two diodes (D1)、(D2) negative pole connects together，And be connected with the negative pole of pressure cell (YM)，The positive pole of pressure cell (YM) connects two fets (Q1)、(Q2) grid.
- 2. CT open-circuit protecting device according to claim 1, it is characterised in that: described pressure cell (YM) is Zener diode.
- 3. CT open-circuit protecting device according to claim 1, it is characterised in that: described pressure cell (YM) is Transient Suppression Diode.
- 4. CT open-circuit protecting device according to claim 3, it is characterised in that: described pressure cell (YM) is unidirectional Transient Suppression Diode.
- 5. CT open-circuit protecting device according to claim 3, it is characterised in that: described pressure cell (YM) is two-way Transient Suppression Diode, and its closure is regardless of both positive and negative polarity.
- 6. CT open-circuit protecting device according to claim 1, it is characterised in that: described pressure cell (YM) is varistor, and its closure is regardless of both positive and negative polarity.
- 7. the CT open-circuit protecting device according to claim 1,2,4,5 or 6; it is characterized in that: between DC output end and the described filter circuit (C1) of described rectification circuit (D3), be also in series with buck diode (D4); the negative pole of buck diode (D4) connects the DC output end positive pole of rectification circuit (D3), and the positive pole of buck diode (D4) connects the positive pole of filter circuit (C1).
- 8. CT open-circuit protecting device according to claim 7, it is characterised in that: described buck diode (D4) is Zener diode.
- 9. CT open-circuit protecting device according to claim 7, it is characterised in that: described buck diode (D4) is unidirectional Transient Suppression Diode.
- 10. CT open-circuit protecting device according to claim 7, it is characterised in that: described buck diode (D4) is two-way Transient Suppression Diode.Its closure is regardless of both positive and negative polarity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610115833.1A CN105790215B (en) | 2016-03-02 | 2016-03-02 | CT open-circuit protecting devices |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610115833.1A CN105790215B (en) | 2016-03-02 | 2016-03-02 | CT open-circuit protecting devices |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105790215A true CN105790215A (en) | 2016-07-20 |
| CN105790215B CN105790215B (en) | 2018-03-09 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610115833.1A Active CN105790215B (en) | 2016-03-02 | 2016-03-02 | CT open-circuit protecting devices |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108966435A (en) * | 2018-09-26 | 2018-12-07 | 江苏优为视界科技有限公司 | The protection circuit of low ripple LED control device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2082908U (en) * | 1991-03-07 | 1991-08-14 | 长春市宽城区奋进电器设备厂 | Secondary circuit disconnection protective device of current transformer |
| US20050201033A1 (en) * | 2004-03-09 | 2005-09-15 | Samsung Measuring Instruments Co., Ltd. | Apparatus for monitoring open state of the secondary terminals of a current transformer |
| CN104577982A (en) * | 2015-01-12 | 2015-04-29 | 深圳市普元电力技术有限公司 | Open circuit protective circuit for secondary side output circuit of current transformer |
| CN204858552U (en) * | 2015-08-06 | 2015-12-09 | 华电北瑞电气(北京)有限公司 | Current transformer open circuit protection device |
| CN205489460U (en) * | 2016-03-02 | 2016-08-17 | 闫堂锁 | CT open circuit protection device |
-
2016
- 2016-03-02 CN CN201610115833.1A patent/CN105790215B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2082908U (en) * | 1991-03-07 | 1991-08-14 | 长春市宽城区奋进电器设备厂 | Secondary circuit disconnection protective device of current transformer |
| US20050201033A1 (en) * | 2004-03-09 | 2005-09-15 | Samsung Measuring Instruments Co., Ltd. | Apparatus for monitoring open state of the secondary terminals of a current transformer |
| CN104577982A (en) * | 2015-01-12 | 2015-04-29 | 深圳市普元电力技术有限公司 | Open circuit protective circuit for secondary side output circuit of current transformer |
| CN204858552U (en) * | 2015-08-06 | 2015-12-09 | 华电北瑞电气(北京)有限公司 | Current transformer open circuit protection device |
| CN205489460U (en) * | 2016-03-02 | 2016-08-17 | 闫堂锁 | CT open circuit protection device |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108966435A (en) * | 2018-09-26 | 2018-12-07 | 江苏优为视界科技有限公司 | The protection circuit of low ripple LED control device |
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| Publication number | Publication date |
|---|---|
| CN105790215B (en) | 2018-03-09 |
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Effective date of registration: 20191129 Address after: 3031, building C, Xinyuan Science Park, No. 97, Changping Road, Changping District, Beijing 102200 Patentee after: Huadian Beirui Electric (Beijing) Co., Ltd. Address before: 050400, Hebei, Pingshan County, Pingshan Town, Dongchuan street, No. 14, south alley west gate Patentee before: Yan Tangsuo |
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