CN112234593B - Overcurrent protection circuit for CT induction power taking - Google Patents
Overcurrent protection circuit for CT induction power taking Download PDFInfo
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- CN112234593B CN112234593B CN202011024723.7A CN202011024723A CN112234593B CN 112234593 B CN112234593 B CN 112234593B CN 202011024723 A CN202011024723 A CN 202011024723A CN 112234593 B CN112234593 B CN 112234593B
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- rectifier bridge
- diode
- loop
- triode
- comparator
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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
- H02H9/045—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage adapted to a particular application and not provided for elsewhere
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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
- H02H7/04—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 for transformers
- H02H7/042—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 for transformers for current transformers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
- H02J7/04—Regulation of charging current or voltage
- H02J7/06—Regulation of charging current or voltage using discharge tubes or semiconductor devices
Abstract
The invention relates to an overcurrent protection circuit for CT induction power taking, which comprises a controlled silicon Q1, a triode Q2, a rectifier bridge D1, a comparator U11 and a CT loop; the triode Q2 drives the rectifier bridge D1, the rectifier bridge D1 drives the controllable silicon, and when the triode Q2 works and is conducted, the rectifier bridge D1 is conducted, and then the Q1 is triggered to conduct, so that redundant energy in a CT loop is discharged. The conduction of the bleeder circuit is controlled by a triode Q2, Q2 is controlled by the output of a comparator, when the voltage behind a rectifier bridge in the secondary circuit is higher than the reference voltage of the comparator, the output of the comparator is high, Q2 is conducted, the rectifier bridge Q1 is driven to be conducted, the redundant energy in the circuit is discharged, on the contrary, Q2 is cut off, and D1 is not conducted. The maximum transmission voltage value of the secondary circuit can be flexibly set only by setting different reference voltage values ref. The invention does not need to adopt a voltage-stabilizing tube to drive the controllable silicon and can flexibly set the maximum transmission voltage value of the secondary loop.
Description
Technical Field
The invention relates to the field of power transmission, power transformation and power distribution, in particular to an overcurrent protection circuit for CT induction power taking.
Background
CT induction electricity taking is commonly used for online monitoring devices in the fields of power transmission, power transformation, power distribution and the like, can provide real-time energy for the online monitoring devices, and can store redundant energy through a constant-voltage current-limiting charging management circuit to be used as a backup power supply. The CT induction electricity taking device is directly arranged on a primary circuit lead, can support cables of different types such as bare leads, insulated cables and the like, obtains energy from a circuit, and outputs the energy to a load for power supply after rectification and signal conditioning. The current range of the primary loop is very wide, usually 0-1500A, and when a primary line is just powered on or switched by a large load, the impact of a capacitive load in the line is taken into consideration in a more serious situation, the current in the primary loop can reach 30KA, and the load connected to the rear end of CT power taking is usually relatively fixed, so that a protection loop is needed to discharge redundant energy, and the voltage in a certain range is ensured to be output to supply power to a rear-stage load. At present, a conventional protection circuit is realized by adopting a mode of a voltage regulator tube and a thyristor, as shown in fig. 1. When the current in the primary loop is too large and the voltage in the secondary loop exceeds the breakdown voltage of the TVS1, the TVS1 is turned on, the controllable silicon TR1 is triggered, the TR1 triggers the TR2 again, the current in the loop is released into the CT, the saturation of the CT is accelerated, and the rear-stage circuit is protected. However, the circuit adopts a voltage-regulator tube protection scheme, the breakdown voltages of different voltage-regulator tubes are different, the types of the voltage-regulator tubes are limited, the breakdown voltage value of the voltage-regulator tube determines the output stable voltage value, and the voltage-regulator tube cannot be flexibly adjusted. The breakdown voltage of the voltage-stabilizing tube is high, the output voltage is also high, and the rear-end load bears larger pressure; low, the front end energy release is too fast to meet the requirements of the back end load. Therefore, the selection of the voltage regulator tube is very critical, and under certain specific occasions, the range of the input voltage of the rear-stage load is narrow, so that a proper TVS tube model cannot be selected.
Disclosure of Invention
In view of the above, an object of the present invention is to provide an overcurrent protection circuit for CT induction power extraction, which can flexibly set the maximum transmission voltage of a secondary circuit.
The invention is realized by adopting the following scheme: an overcurrent protection circuit for CT induction power taking comprises a controllable silicon Q1, a triode Q2, a rectifier bridge D1, a comparator U11 and a CT loop; the output end of the comparator U11 is connected with the base of the triode Q2, the collector of the triode Q2 is connected with one output end of the rectifier bridge D1, and the emitter of the triode Q2 is connected with the other output end of the rectifier bridge D1; one input end of the rectifier bridge is connected with a control electrode of the thyristor Q1, the other input end of the rectifier bridge D1 is connected with a cathode of the thyristor and is also connected with one input end of the CT loop, and an anode of the thyristor Q1 is connected with the other input end of the CT loop; the inverting input end of the comparator U11 is connected with a reference voltage ref, and the non-inverting input end of the comparator U11 is connected with the CT loop.
Further, the CT loop includes a first diode D6, a second diode D7, a third diode D8, a fourth diode D9, a capacitor C3 and a TVS tube; the cathode of the first diode D6 is connected to the anode of the second diode D7 and serves as another input terminal of the CT loop, and the anode of the third diode D8 is connected to the cathode of the fourth diode D9 and serves as an input terminal of the CT loop; the cathode of the second diode D7 is respectively connected to the cathode of the third diode D8, the non-inverting input terminal of the comparator U11, one end of the capacitor C3 and one end of the TVS tube, and are all connected to a power supply; the anode of the first diode D6 is connected with the anode of the fourth diode D9 and grounded; the other end of the capacitor C3 is connected with the other end of the TVS tube and is grounded.
Further, the invention also provides a working method of the over-current protection circuit for CT induction power taking, which is characterized in that: the triode Q2 drives a rectifier bridge D1, the rectifier bridge D1 drives a thyristor Q1, the triode Q2 is controlled by the output of a comparator U11, when the triode Q2 works and is conducted, the rectifier bridge D1 is conducted, and then the thyristor Q1 is triggered to be conducted, so that redundant energy in a CT loop is discharged; when the direct-current voltage of the rectifier bridge D1 is higher than the reference voltage of the comparator, the output of the comparator U11 is high, the triode Q2 is conducted, the rectifier bridge D1 is driven to be conducted, redundant energy in the loop is discharged, otherwise, the Q2 is cut off, and the D1 is not conducted; setting the maximum transmission voltage value of the secondary circuit is realized by setting different reference voltage values ref.
Compared with the prior art, the invention has the following beneficial effects:
the invention can flexibly set the output voltage value and solves the problem that the conduction voltage value can not be flexibly set when a voltage-regulator tube is used as a trigger circuit in the conventional circuit.
Drawings
Fig. 1 is a schematic diagram of a CT inductive power-taking protection circuit according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a protection circuit according to an embodiment of the invention.
Detailed Description
The invention is further explained below with reference to the drawings and the embodiments.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
As shown in fig. 2, the embodiment provides an overcurrent protection circuit for CT induction power taking, which is characterized in that: the circuit comprises a controlled silicon Q1, a triode Q2, a rectifier bridge D1, a comparator U11 and a CT loop; the output end of the comparator U11 is connected with the base of the triode Q2, the collector of the triode Q2 is connected with one output end of the rectifier bridge D1, and the emitter of the triode Q2 is connected with the other output end of the rectifier bridge D1; one input end of the rectifier bridge is connected with a control electrode of the thyristor Q1, the other input end of the rectifier bridge D1 is connected with a cathode of the thyristor and is also connected with one input end of the CT loop, and an anode of the thyristor Q1 is connected with the other input end of the CT loop; the inverting input end of the comparator U11 is connected with a reference voltage ref, and the non-inverting input end of the comparator U11 is connected with the CT loop.
In the present embodiment, the CT loop includes a first diode D6, a second diode D7, a third diode D8, a fourth diode D9, a capacitor C3, and a TVS tube; the cathode of the first diode D6 is connected to the anode of the second diode D7 and serves as the other input end of the CT loop, and the anode of the third diode D8 is connected to the cathode of the fourth diode D9 and serves as the one input end of the CT loop; the cathode of the second diode D7 is respectively connected to the cathode of the third diode D8, the non-inverting input terminal of the comparator U11, one end of the capacitor C3 and one end of the TVS tube, and are all connected to a power supply; the anode of the first diode D6 is connected with the anode of the fourth diode D9 and grounded; the other end of the capacitor C3 is connected with the other end of the TVS tube and is grounded.
Preferably, the embodiment further provides a working method of the over-current protection circuit for CT induction power taking, the triode Q2 drives the rectifier bridge D1, the rectifier bridge D1 drives the thyristor Q1, and the triode Q2 is controlled by the output of the comparator U11, when the triode Q2 is switched on, the rectifier bridge D1 is switched on, and then the thyristor Q1 is triggered to be switched on, so as to discharge the excess energy in the CT loop; the conduction of the bleeder circuit is controlled by a triode Q2, a triode Q2 is controlled by the output of a comparator U11, when the direct-current voltage of a rectifier bridge D1 in the secondary circuit is higher than the reference voltage of the comparator, the output of the comparator U11 is high, a triode Q2 is conducted, the rectifier bridge D1 is driven to be conducted, the redundant energy in the circuit is discharged, otherwise, the Q2 is cut off, and the D1 is not conducted; setting the maximum transmission voltage value of the secondary circuit is realized by setting different reference voltage values ref.
In this embodiment, the reference voltage ref ranges from 0 to Vcc.
Preferably, the embodiment does not need to adopt a voltage regulator tube to drive the controllable silicon, and the maximum transmission voltage value of the secondary loop can be flexibly set.
The above description is only a preferred embodiment of the present invention, and all the equivalent changes and modifications made according to the claims of the present invention should be covered by the present invention.
Claims (2)
1. The utility model provides an overcurrent protection circuit for CT induction electricity-taking which characterized in that: the circuit comprises a controlled silicon Q1, a triode Q2, a rectifier bridge D1, a comparator U11 and a CT loop; the output end of the comparator U11 is connected with the base of the triode Q2, the collector of the triode Q2 is connected with one output end of the rectifier bridge D1, and the emitter of the triode Q2 is connected with the other output end of the rectifier bridge D1; one input end of the rectifier bridge is connected with a control electrode of the thyristor Q1, the other input end of the rectifier bridge D1 is connected with a cathode of the thyristor and is also connected with one input end of the CT loop, and an anode of the thyristor Q1 is connected with the other input end of the CT loop; the inverting input end of the comparator U11 is connected with a reference voltage ref, and the non-inverting input end of the comparator U11 is connected with the CT loop;
the CT loop comprises a first diode D6, a second diode D7, a third diode D8, a fourth diode D9, a capacitor C3 and a TVS tube; the cathode of the first diode D6 is connected to the anode of the second diode D7 and serves as the other input end of the CT loop, and the anode of the third diode D8 is connected to the cathode of the fourth diode D9 and serves as the one input end of the CT loop; the cathode of the second diode D7 is respectively connected to the cathode of the third diode D8, the non-inverting input terminal of the comparator U11, one end of the capacitor C3 and one end of the TVS tube, and are all connected to a power supply; the anode of the first diode D6 is connected with the anode of the fourth diode D9 and is grounded; the other end of the capacitor C3 is connected with the other end of the TVS tube and is grounded.
2. The operating method of the over-current protection circuit for CT induction power taking according to claim 1, characterized in that: the triode Q2 drives a rectifier bridge D1, the rectifier bridge D1 drives a thyristor Q1, the triode Q2 is controlled by the output of a comparator U11, when the triode Q2 works and is conducted, the rectifier bridge D1 is conducted, and then the thyristor Q1 is triggered to be conducted, so that redundant energy in a CT loop is discharged; when the direct-current voltage of the rectifier bridge D1 is higher than the reference voltage of the comparator, the output of the comparator U11 is high, the triode Q2 is conducted, the rectifier bridge D1 is driven to be conducted, redundant energy in the loop is discharged, on the contrary, the Q2 is cut off, and the D1 is not conducted; the maximum power transmission voltage value of the secondary circuit of the power taking CT is set by setting different reference voltage values ref.
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CN202011024723.7A CN112234593B (en) | 2020-09-25 | 2020-09-25 | Overcurrent protection circuit for CT induction power taking |
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CN202011024723.7A CN112234593B (en) | 2020-09-25 | 2020-09-25 | Overcurrent protection circuit for CT induction power taking |
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CN112234593B true CN112234593B (en) | 2022-07-15 |
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Citations (3)
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CN2681445Y (en) * | 2004-03-25 | 2005-02-23 | 西安森宝电气工程有限公司 | Thyristor automatic voltage regulator |
CN105375435A (en) * | 2015-11-30 | 2016-03-02 | 深圳市中电电力技术股份有限公司 | Self-power protection device and self-power protection device on the basis of power and tripping induction of three-phase current |
CN107345978A (en) * | 2017-06-23 | 2017-11-14 | 沈阳工程学院 | The packaged type of power plant or intelligent substation controls power supply and control method |
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WO1997013391A1 (en) * | 1995-10-03 | 1997-04-10 | Pal Sandor | Improvements in or relating to an electronic ballast for fluorescent lamps |
CN2503653Y (en) * | 2001-08-22 | 2002-07-31 | 孟付元 | Universal overcurrent relay protecter |
US7561396B2 (en) * | 2004-03-09 | 2009-07-14 | Samsung Measuring Instruments Co., LTD | Apparatus for monitoring open state of the secondary terminals of a current transformer |
US9842709B2 (en) * | 2015-03-20 | 2017-12-12 | Eaton Corporation | Electronic trip units powered by current transformers and circuit breakers comprising the same |
CN107645180B (en) * | 2017-08-09 | 2019-09-10 | 东北电力大学 | A kind of low starting current power-supply circuit for cable monitoring |
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2020
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Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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CN2681445Y (en) * | 2004-03-25 | 2005-02-23 | 西安森宝电气工程有限公司 | Thyristor automatic voltage regulator |
CN105375435A (en) * | 2015-11-30 | 2016-03-02 | 深圳市中电电力技术股份有限公司 | Self-power protection device and self-power protection device on the basis of power and tripping induction of three-phase current |
CN107345978A (en) * | 2017-06-23 | 2017-11-14 | 沈阳工程学院 | The packaged type of power plant or intelligent substation controls power supply and control method |
Non-Patent Citations (2)
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