CN203967748U - Secondary over-voltage protector for current transformer - Google Patents
Secondary over-voltage protector for current transformer Download PDFInfo
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- CN203967748U CN203967748U CN201420370019.0U CN201420370019U CN203967748U CN 203967748 U CN203967748 U CN 203967748U CN 201420370019 U CN201420370019 U CN 201420370019U CN 203967748 U CN203967748 U CN 203967748U
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Abstract
The utility model discloses a kind of secondary over-voltage protector for current transformer, between described sampling input, be parallel to the two ends of current transformer, between sampling input, be connected with bidirectional triode thyristor, photoelectric isolated driver connects bidirectional triode thyristor through resistance the 3rd resistance; Between sampling input, be also connected to rectifier bridge, the DC output end of rectifier bridge connects electric capacity, TVS pipe, the first resistance, the second resistance and the second optocoupler through gas discharge tube, and described the second resistance is managed in parallel with described the first resistance, described electric capacity, described TVS after connecting with described the second optocoupler.The utility model has the following advantages compared to existing technology: the utility model adopts gas discharge tube to replace piezo-resistance, it is less that gas discharge tube has parasitic capacitance, the advantage that insulation resistance is large, thus greatly reduce the size of leakage current, increase fail safe and the useful life of product.
Description
Technical field
The utility model relates to voltage protector, in particular a kind of secondary over-voltage protector for current transformer.
Background technology
Known current transformer (hereinafter to be referred as CT), in electric power system, is widely used in one-shot measurement and control.In normal work, instrument transformer secondary side is in approximate short-circuit condition, and output voltage is very low.In the situation of actual motion, if one time winding flows through abnormal current (as thunder-strike current, resonance current, capacitor charging electric current, inductance starting current etc.), also all can produce at secondary side the overvoltage of thousands of volts volts even up to ten thousand, not only to secondary side, insulation works the mischief for this, can be also that instrument transformer is too drastic and burn, even jeopardize staff's life security.
CT secondary side overvoltage protection device is mainly divided into the overvoltage (as thunderbolt etc.) of moment transient state, and its feature is the energy large (kA level) producing, but the duration short (Microsecond grade).Next is the overvoltage (as second open circuit) of stable state, and his feature is that the energy producing is less, but the duration is long.
Existing product is taking piezo-resistance as voltage sample device, makes like this place circuit leakage current larger, and in the aging reduction useful life of aggravation electronic devices and components, the parasitic capacitance of piezo-resistance is also larger, is unfavorable for the protection to High-Frenquency Electronic Circuit.
Utility model content
The purpose of this utility model is to overcome the deficiencies in the prior art, a kind of secondary over-voltage protector for current transformer is provided, it is characterized in that: between described sampling input, (Ua, Un) is parallel to the two ends of current transformer, between sampling input (Ua, Un), be connected with bidirectional triode thyristor (T1), photoelectric isolated driver (U1) connects bidirectional triode thyristor (T1) through resistance the 3rd resistance (R1); Between sampling input, (Ua, Un) is also connected to rectifier bridge (D1), the DC output end of rectifier bridge (D1) connects electric capacity (C1), TVS through gas discharge tube (GDT2) and manage (D7), the first resistance (R13), the second resistance (R14) and the second optocoupler (U7), and described the second resistance (R14) is connected afterwards with described the first resistance (R13), described electric capacity (C1) with described the second optocoupler (U7), that described TVS manages (D7) is in parallel.
The utility model is achieved through the following technical solutions:
The utility model has the following advantages compared to existing technology: existing product is taking piezo-resistance as voltage sample device; make like this place circuit leakage current larger; the aging reduction useful life of aggravation electronic devices and components; the parasitic capacitance of piezo-resistance is also larger, is unfavorable for the protection to High-Frenquency Electronic Circuit.The utility model adopts gas discharge tube to replace piezo-resistance, and that gas discharge tube has parasitic capacitance is less, the advantage that insulation resistance is large, thus greatly reduce the size of leakage current, increase fail safe and the useful life of product.
Brief description of the drawings
Fig. 1 is the circuit diagram of secondary over-voltage protector for current transformer of the present utility model.
Embodiment
Below embodiment of the present utility model is elaborated; the present embodiment is implemented under taking technical solutions of the utility model as prerequisite; provided detailed execution mode and concrete operating process, but protection range of the present utility model is not limited to following embodiment.
Referring to Fig. 1, it is the circuit diagram of secondary over-voltage protector for current transformer of the present utility model.Between sampling input Ua and Un, be parallel to the two ends of current transformer, between sampling input Ua and Un, be connected with bidirectional triode thyristor T1.
Photoelectric isolated driver U1 connects bidirectional triode thyristor T1 through resistance the 3rd resistance R 1; Between sampling input Ua and Un, be also connected to rectifier bridge D1, the DC output end of rectifier bridge D1 connects capacitor C 1, TVS pipe D7, the first resistance R 13, the second resistance R 14 and the second optocoupler U7 through gas discharge tube GDT2.The second resistance R 14 is connected with the second optocoupler U7, and D7 is in parallel with the first resistance R 13, capacitor C 1, TVS pipe afterwards.
When work, in the time that the overvoltage signal of transient state is come, gas discharge tube GDT2 punctures rapidly conducting, makes the second optocoupler U7 work in circuit, completes once sampling; Photoelectric isolated driver U1 work simultaneously, makes bidirectional triode thyristor T1 conducting, sample like this input Ua and Un short circuit.
Secondary over-voltage protector for current transformer of the present utility model; adopt gas discharge tube to replace piezo-resistance; and that gas discharge tube has parasitic capacitance is less; the advantage that insulation resistance is large; thereby greatly reduce the size of leakage current, increased fail safe and the useful life of secondary over-voltage protector for current transformer.
The foregoing is only preferred embodiment of the present utility model; not in order to limit the utility model; all any amendments of doing within spirit of the present utility model and principle, be equal to and replace and improvement etc., within all should being included in protection range of the present utility model.
Claims (1)
1. a secondary over-voltage protector for current transformer, it is characterized in that: between described sampling input, (Ua, Un) is parallel to the two ends of current transformer, between sampling input (Ua, Un), be connected with bidirectional triode thyristor (T1), photoelectric isolated driver (U1) connects bidirectional triode thyristor (T1) through resistance the 3rd resistance (R1); Between sampling input, (Ua, Un) is also connected to rectifier bridge (D1), the DC output end of rectifier bridge (D1) connects electric capacity (C1), TVS through gas discharge tube (GDT2) and manage (D7), the first resistance (R13), the second resistance (R14) and the second optocoupler (U7), and described the second resistance (R14) is connected afterwards with described the first resistance (R13), described electric capacity (C1) with described the second optocoupler (U7), that described TVS manages (D7) is in parallel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420370019.0U CN203967748U (en) | 2014-07-04 | 2014-07-04 | Secondary over-voltage protector for current transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420370019.0U CN203967748U (en) | 2014-07-04 | 2014-07-04 | Secondary over-voltage protector for current transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203967748U true CN203967748U (en) | 2014-11-26 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420370019.0U Expired - Fee Related CN203967748U (en) | 2014-07-04 | 2014-07-04 | Secondary over-voltage protector for current transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203967748U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105652063A (en) * | 2015-06-26 | 2016-06-08 | 广州供电局有限公司 | Insulator leakage current monitoring system used for laboratory |
-
2014
- 2014-07-04 CN CN201420370019.0U patent/CN203967748U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105652063A (en) * | 2015-06-26 | 2016-06-08 | 广州供电局有限公司 | Insulator leakage current monitoring system used for laboratory |
| CN105652063B (en) * | 2015-06-26 | 2019-04-23 | 广州供电局有限公司 | Insulator leakage current for laboratory monitors system |
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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: 20141126 Termination date: 20200704 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |