CN214958677U - Protection device for adjustable open-circuit voltage of current transformer - Google Patents
Protection device for adjustable open-circuit voltage of current transformer Download PDFInfo
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- CN214958677U CN214958677U CN202120661100.4U CN202120661100U CN214958677U CN 214958677 U CN214958677 U CN 214958677U CN 202120661100 U CN202120661100 U CN 202120661100U CN 214958677 U CN214958677 U CN 214958677U
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- resistor
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- current transformer
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Abstract
The invention discloses a protection device for a current transformer capable of adjusting open-circuit voltage, which comprises a bidirectional thyristor, an adjustable resistor, a charging resistor, a discharging resistor, a charging and discharging capacitor and a bidirectional trigger diode, wherein the bidirectional thyristor is connected with the charging resistor; the first anode of the bidirectional thyristor is connected with one end of an adjustable resistor, the second anode of the bidirectional thyristor is connected with one end of a charging and discharging capacitor, the other end of the adjustable resistor is connected with one end of a current-limiting resistor, the other end of the current-limiting resistor is respectively connected with one end of a discharging resistor and the other end of the charging and discharging capacitor, the other end of the discharging resistor is connected with one end of a bidirectional trigger diode, and the other end of the bidirectional trigger diode is connected with the control electrode of the bidirectional thyristor. The protection device for the adjustable open-circuit voltage of the current transformer, provided by the invention, does not need an auxiliary power supply, has a simple topological structure, high reliability, wider application range and easy popularization, and can conveniently adjust the open-circuit protection voltage value.
Description
Technical Field
The invention relates to the field of current transformer application, in particular to a protective device for a current transformer capable of adjusting open-circuit voltage.
Background
Nowadays, current transformer mainly uses the occasion that alternating current ammeter range is less than the actual measurement alternating current, and is different from voltage transformer, and current transformer does not allow the operation of opening a way, and current transformer opens a way the consequence seriously, mainly shows: high peak voltage is generated between a secondary side winding and an open circuit point of the current transformer, so that the insulation of equipment and the personal safety are threatened; the loss of the iron core is increased, the heating is serious, and the insulation can be burned out; residual magnetism is generated in the iron core, so that the transformation ratio and the phase angle error of the current transformer are increased, and the metering accuracy is influenced, so that the secondary side open circuit protection of the current transformer is important.
The inventor finds that most of the current transformer open-circuit protection devices adopted at the present stage need auxiliary power supplies, are relatively complex in topological structure and low in reliability, are inconvenient to adjust open-circuit protection voltage values, and are relatively narrow in application range in the implementation process of the invention.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a protective device for a current transformer capable of adjusting open-circuit voltage, which has the specific technical scheme that: the bidirectional thyristor K, the adjustable resistor RW1, the charging resistor R2, the discharging resistor R3, the charging and discharging capacitor C1 and the bidirectional trigger diode D1 are included; the adjustable resistor RW1 is a two-port device, a first anode T1 of the bidirectional thyristor K is connected with one end of the adjustable resistor RW1, the end is used for being connected with one end of the secondary side of the current transformer, a second anode T2 of the bidirectional thyristor K is connected with one end of the charging and discharging capacitor C1, the end is used for being connected with the other end of the secondary side of the current transformer, the other end of the adjustable resistor RW1 is connected with one end of the charging resistor R2, the other end of the charging resistor R2 is connected with one end of the discharging resistor R3 and the other end of the charging and discharging capacitor C1 respectively, the other end of the discharging resistor R3 is connected with one end of the bidirectional trigger diode D1, and the other end of the bidirectional trigger diode D1 is connected with the control electrode G of the bidirectional thyristor K.
Further, the adjustable resistor RW1 may be replaced by an adjustable resistor RW2 of a three-port device, that is, one fixed end of the adjustable resistor RW2 is connected to the adjustable end thereof, the end is connected to the first anode T1 of the triac K, and the other fixed end of the adjustable resistor RW2 is connected to one end of the charging resistor R2.
Compared with the prior art, the protection device for the current transformer capable of adjusting the open-circuit voltage has the advantages that an auxiliary power supply is not needed, the topological structure is simple, the reliability is high, the open-circuit protection voltage value can be conveniently adjusted, the application range is wide, and the popularization is easy.
Drawings
Fig. 1 is a typical schematic diagram of a protection device for a current transformer capable of adjusting an open-circuit voltage according to the present invention.
Fig. 2 is a typical schematic diagram of another protection device for a current transformer capable of adjusting open-circuit voltage according to the invention.
Fig. 3 is a specific embodiment of a protection device for an adjustable open-circuit voltage of a current transformer according to the present invention.
Detailed Description
In order that the above objects, features and advantages of the present invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.
As shown in fig. 1, a typical schematic diagram of a protection device for an adjustable open-circuit voltage of a current transformer according to the present invention includes a triac K, an adjustable resistor RW1, a charging resistor R2, a discharging resistor R3, a charging/discharging capacitor C1, and a diac D1; the adjustable resistor RW1 is a two-port device, a first anode T1 of the bidirectional thyristor K is connected with one end of the adjustable resistor RW1, the end is used for being connected with one end of the secondary side of the current transformer, a second anode T2 of the bidirectional thyristor K is connected with one end of the charging and discharging capacitor C1, the end is used for being connected with the other end of the secondary side of the current transformer, the other end of the adjustable resistor RW1 is connected with one end of the charging resistor R2, the other end of the charging resistor R2 is connected with one end of the discharging resistor R3 and the other end of the charging and discharging capacitor C1 respectively, the other end of the discharging resistor R3 is connected with one end of the bidirectional trigger diode D1, and the other end of the bidirectional trigger diode D1 is connected with the control electrode G of the bidirectional thyristor K.
Referring to fig. 2, which is a typical schematic diagram of another protection device for an adjustable open-circuit voltage of a current transformer according to the present invention, as can be seen from fig. 1, the adjustable resistor RW1 may be replaced by an adjustable resistor RW2 of a three-port device, that is, a fixed end of the adjustable resistor RW2 is connected to an adjustable end thereof, the adjustable end is connected to the first anode T1 of the triac K, and another fixed end of the adjustable resistor RW2 is connected to one end of the charging resistor R2.
As shown in fig. 3, in an embodiment of the protection device for an adjustable open-circuit voltage of a current transformer of the present invention, a diac D1 is 1N5758, and a triac K is BT 134; the adjustable resistor has a resistance range of 0-100K omega, the charging resistor R2 has a resistance of 1K omega, and the discharging resistor R3 has a resistance of 100 omega; the value of the charge and discharge capacitance C1 is 0.1 muF; the charging and discharging capacitor C1, the discharging resistor R3 and the bidirectional trigger diode D1 form a discharging branch circuit; in addition, the adjustable resistor RW1, the charging resistor R2 and the charging and discharging capacitor C1 form a charging branch; the sum of the adjustable resistor RW1 and the charging resistor R2 and the product of the sum and the charging and discharging capacitor C1 form a time constant;
when a TA secondary circuit of the current transformer is in an open-circuit state, the device does not act, a short-circuit power channel cannot be provided for the secondary side of the current transformer, and the alternating current ammeter can normally display the short-circuit power channel;
when the secondary circuit of the current transformer TA is in an open circuit state, the time constant can be changed by adjusting the value of the adjustable resistor RW1, namely, the charging speed of the charging and discharging capacitor C1 is adjusted, the turn-on voltage of the bidirectional thyristor K can be adjusted, the function of adjusting the open circuit protection voltage of the secondary side of the current transformer is realized, once the bidirectional thyristor K is conducted, a short-circuit power channel can be provided for the secondary side of the current transformer, an alternating current ammeter is bypassed, and the purpose of adjusting the open circuit protection voltage of the secondary side of the current transformer is also achieved.
Claims (2)
1. A protection device for an adjustable open-circuit voltage of a current transformer is characterized by comprising a bidirectional thyristor K, an adjustable resistor RW1, a charging resistor R2, a discharging resistor R3, a charging and discharging capacitor C1 and a bidirectional trigger diode D1; the adjustable resistor RW1 is a two-port device, a first anode T1 of the bidirectional thyristor K is connected with one end of the adjustable resistor RW1, the end is used for being connected with one end of the secondary side of the current transformer, a second anode T2 of the bidirectional thyristor K is connected with one end of the charging and discharging capacitor C1, the end is used for being connected with the other end of the secondary side of the current transformer, the other end of the adjustable resistor RW1 is connected with one end of the charging resistor R2, the other end of the charging resistor R2 is connected with one end of the discharging resistor R3 and the other end of the charging and discharging capacitor C1 respectively, the other end of the discharging resistor R3 is connected with one end of the bidirectional trigger diode D1, and the other end of the bidirectional trigger diode D1 is connected with the control electrode G of the bidirectional thyristor K.
2. The protection device for the adjustable open-circuit voltage of the current transformer according to claim 1, wherein the adjustable resistor RW1 is replaced by an adjustable resistor RW2 of a three-port device, that is, a fixed end of the adjustable resistor RW2 is connected to an adjustable end thereof, the adjustable end is connected to the first anode T1 of the triac K, and the other fixed end of the adjustable resistor RW2 is connected to one end of the charging resistor R2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120661100.4U CN214958677U (en) | 2021-04-01 | 2021-04-01 | Protection device for adjustable open-circuit voltage of current transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120661100.4U CN214958677U (en) | 2021-04-01 | 2021-04-01 | Protection device for adjustable open-circuit voltage of current transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN214958677U true CN214958677U (en) | 2021-11-30 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120661100.4U Expired - Fee Related CN214958677U (en) | 2021-04-01 | 2021-04-01 | Protection device for adjustable open-circuit voltage of current transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN214958677U (en) |
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2021
- 2021-04-01 CN CN202120661100.4U patent/CN214958677U/en not_active Expired - Fee Related
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|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20211130 |
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| CF01 | Termination of patent right due to non-payment of annual fee |