CN205317883U - Current transformer secondary side winding short circuit open -circuit condition detection circuitry - Google Patents
Current transformer secondary side winding short circuit open -circuit condition detection circuitry Download PDFInfo
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- CN205317883U CN205317883U CN201520921521.0U CN201520921521U CN205317883U CN 205317883 U CN205317883 U CN 205317883U CN 201520921521 U CN201520921521 U CN 201520921521U CN 205317883 U CN205317883 U CN 205317883U
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Abstract
The utility model discloses a current transformer secondary side winding short circuit open -circuit condition detection circuitry, its is exportable can to reflect accurately that current transformer secondary side winding is in the short circuit, opens a way or normal condition's voltage to can judge current transformer secondary side winding the short circuit, open a way or normal condition. This current transformer secondary side winding short circuit open -circuit condition detection circuitry includes signal collection circuit, secondary side winding state judgement circuit for a constant -current source circuit of constant current source is provided, wherein, signal collection circuit is including connecting sampling resistor on current transformer secondary side winding in parallel, a plurality of diodes concatenate its positive pole of back connect serve sampling resistor first, its minus earth, the output of constant -current source circuit is connected and is served at the second of sampling resistor, provides operating voltage for signal collection circuit, the voltage at sampling resistor both ends is through secondary side winding state judgement circuit output voltage.
Description
Technical field
This utility model relates to a kind of Current Transformer Secondary side short circuit open-circuit condition measurement circuit design, particularly relates to a kind of circuit design with low cost high accuracy high efficient detection Current Transformer Secondary side short circuit open-circuit condition.
Background technology
Current transformer (Currenttransformer is called for short CT) can be converted to, by certain no-load voltage ratio, the secondary current that numerical value is less primary current bigger for numerical value. Therefore in the occasion being much applied to big electric current, it is required for using CT and realizes the functions such as protection, measurement. And having in the mode of connection of CT is connect by the form of connecting line greatly. Under this connected mode, it is possible to the failure conditions such as the secondary side winding short circuit of CT, open circuit occur. These faults can cause that the measuring circuit of rear class is measured abnormal on the one hand, also CT itself can be caused certain damage on the other hand. Therefore the short circuit open circuit detection to CT secondary side winding is a very necessary job. The secondary side winding that is mostly utilized in current testing circuit accesses a transformator again, and the square wave adding certain frequency in the weak side of transformator detects. Such method is all fairly cumbersome from hardware or software respective, does not all quite calculate from the aspect such as cost, development progress.
Utility model content
The purpose of this utility model is to carry a kind of Current Transformer Secondary side short circuit in winding open-circuit condition testing circuit, it is exportable can reflect that Current Transformer Secondary side winding is in short circuit exactly, the voltage of open circuit or normal condition, it is thus possible to judge the short circuit of Current Transformer Secondary side winding, open circuit or normal condition, do not affect the measurement of rear class measuring circuit simultaneously, and this testing circuit is compared existing method, all simplify many from hardware or software, it is achieved thereby that low cost high accuracy detects Current Transformer Secondary side short circuit open-circuit condition expeditiously.
For solving above-mentioned technical problem, the purpose of this utility model is achieved in that
A kind of current transformer short circuit open-circuit condition testing circuit, including signal sample circuit, secondary side winding status determination circuit, for providing the constant-current source circuit of constant current;Wherein, signal sample circuit includes the sampling resistor being connected in parallel on the winding of Current Transformer Secondary side, multiple diodes concatenation after its anode be connected on the first end of sampling resistor, its minus earth; The outfan of constant-current source circuit is connected on the second end of sampling resistor, provides running voltage for signal sample circuit; The voltage at sampling resistor two ends is through secondary side winding status determination circuit output voltage signal.
On the basis of such scheme and as the preferred version of such scheme: described diode is 3.
On the basis of such scheme and as the preferred version of such scheme: described secondary side winding status determination circuit includes the 6th resistance, one end of 6th resistance is connected on the in-phase input end of the 3rd operational amplifier, and the in-phase input end of the 3rd operational amplifier is through the second capacity earth; One end of 7th resistance is connected on the inverting input of the 3rd operational amplifier, the inverting input of the 3rd operational amplifier is connected on the outfan of the 3rd operational amplifier through the 8th resistance, and the outfan of the 3rd operational amplifier is through the 9th resistance output voltage signal; The other end of the 6th resistance is connected on the second end of sampling resistor, and the other end of the 7th resistance is connected on the first end of sampling resistor.
On the basis of such scheme and as the preferred version of such scheme: described constant-current source circuit includes its negative electrode, with reference to the stabilivolt being connected on power supply, the anode of stabilivolt connects digitally through the first resistance, and the anode of stabilivolt is connected on the in-phase input end of the second operational amplifier by the second resistance simultaneously; Power supply is connected on the inverting input of the second operational amplifier through the 3rd resistance, the inverting input of the second operational amplifier is connected on the emitter stage of PNP triode simultaneously, the outfan of the 3rd operational amplifier is connected in the base stage of PNP triode through the 4th resistance, and the colelctor electrode of PNP triode is as the outfan of this constant-current source circuit.
On the basis of such scheme and as the preferred version of such scheme: also include circuitry for signal measurement, one end first electric capacity of sampling resistor connects described circuitry for signal measurement, and circuitry for signal measurement is for the voltage signal size at calculating sampling resistance two ends.
This utility model highlights and useful having the technical effect that compared to existing technology
Current Transformer Secondary side of the present utility model short circuit in winding open-circuit condition testing circuit, have employed signal sample circuit, secondary side winding status determination circuit and constant-current source circuit structure, the parallel relationship of sampling resistor summation current transformer secondary side winding, the short circuit of Current Transformer Secondary side winding, open circuit, normally all sampling resistor R5 can be produced different pressure drops, the voltage at sampling resistor R5 two ends has filtered through secondary side winding status determination circuit, amplify, with the different magnitude of voltage of the output when Current Transformer Secondary side winding is under different conditions, then the short circuit of CT is may determine that according to different magnitudes of voltage, open circuit, the state such as normal. when not affecting normal measurement, can quickly, efficiently, low cost, detect the short circuit of current transformer, open circuit, the state such as normal exactly, find the unusual condition that current transformer exists in time so that related personnel can take measures in time, it is prevented that unexpected generation.
Accompanying drawing explanation
Fig. 1 is circuit diagram of the present utility model.
Fig. 2 is the voltage signal figure that secondary side winding is corresponding when short circuit, open circuit, normal condition.
Detailed description of the invention
This utility model is further described with specific embodiment below in conjunction with accompanying drawing, referring to Fig. 1-Fig. 2;
It should be noted that, the term such as mentioned in the present embodiment " first ", " second ", " the 3rd ", " the 4th ", " the 6th ", " the 7th ", " the 8th ", " the 9th " is not to the restriction quantitatively of correlation technique feature, but the name made to distinguish correlation technique feature.
This gives a kind of current transformer short circuit open-circuit condition testing circuit, including signal sample circuit 2, secondary side winding status determination circuit 4 and constant-current source circuit 1. Wherein, signal sample circuit 2 includes the sampling resistor R5 being connected in parallel on the winding of Current Transformer Secondary side, multiple diodes concatenation after its anode be connected on first end of sampling resistor R5, its minus earth. Constant-current source circuit 1 is used for providing constant current, and its outfan is connected on second end of sampling resistor R5, provides running voltage for signal sample circuit 2; The voltage at sampling resistor R5 two ends is through secondary side winding status determination circuit 4 output voltage signal.
In the present embodiment, constant-current source circuit 1 includes stabilivolt U1, the first resistance R1, the second resistance R2, the 3rd resistance R3, the 4th resistance R4, the second operational amplifier U2, PNP triode Q1. Power supply connects negative electrode and the reference of stabilivolt U1, is used for providing a reference voltage. The anode of stabilivolt U1 connects digitally by the first resistance R1, the anode of stabilivolt U1 is connected to the in-phase input end of operational amplifier U2 by the second resistance R2 simultaneously, the inverting input of the second operational amplifier U2 is connected to one end of the 3rd resistance R3, and the other end of the 3rd resistance R3 is connected to power supply. R3 determines the size of current of constant-current source. The inverting input of the second operational amplifier U2 connects the emitter stage of PNP triode Q1 simultaneously, and the base stage of PNP triode Q1 connects the outfan of the second operational amplifier U2 by the 4th resistance R4. The colelctor electrode of PNP triode Q1 is as the outfan of this constant-current source circuit, and its output is the constant-current source of a current constant. In the present embodiment, the second operational amplifier adopts single supply to power.
In the present embodiment, signal sample circuit includes Current Transmit, sampling resistor R5, diode D1, D2, D3. Current Transmit secondary side winding is connected to sampling resistor R5. One end of sampling resistor R5 is connected to constant-current source, and after diode D1, D2, D3 series connection, anode is connected to the other end of sampling resistor R5, and negative electrode connects digitally. After D1, D2, D3 series connection, ground connection has raised level, is applied to late-class circuit. Certainly, the quantity of the diode for concatenating not only can adopt 3, it is possible to adopting 2,4 even more.
In the present embodiment, secondary side winding status determination circuit includes the 6th resistance R6, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, the second electric capacity C2, the 3rd operational amplifier U3. Second end of sampling resistor R5 is connected to the normal phase input end of the 3rd operational amplifier U3 by resistance R6, the normal phase input end of the 3rd operational amplifier U3 passes through the second electric capacity C2 ground connection, the other end of sampling resistor R5 is connected to the inverting input of the 3rd operational amplifier U3 by the 7th resistance R7, the inverting input of the 3rd operational amplifier U3 is connected to the outfan of the 3rd operational amplifier U3 by the 8th resistance R8, and the outfan of the 3rd operational amplifier U3 passes through the 9th resistance R9 output voltage signal. This voltage signal can change with the short circuit of Current Transmit secondary side winding, open circuit, the change of the state such as normal, and output voltage signal is as shown in Figure 2.Output voltage has three kinds of situations: between U1-U2, between U3-U4, between U5-U6, and the secondary side winding of corresponding current transformer CT is short-circuit respectively, CT is normal, CT open circuit. It can adopt interlock circuit to judge magnitude of voltage, draws current transformer CT secondary side winding current state. Preferably, the signal magnitude at circuitry for signal measurement 3 calculating sampling resistance R5 two ends is accessed by the first electric capacity C1 in one end of sampling resistor R5, oneth C1 is used for isolated DC signal, ensureing that only AC signal passes through, circuitry for signal measurement judges the state of Current Transmit first side winding by this AC signal.
During the work of this testing circuit, constant-current source circuit provides a constant-current source, and the size of constant-current source is determined by the 3rd resistance R3. Constant-current source flows through sampling resistor summation current transformer secondary side winding and produces pressure drop. Parallel relationship due to sampling resistor summation current transformer secondary side winding, the short circuit of Current Transformer Secondary side winding, open circuit, normal all sampling resistor R5 can be produced different pressure drops, the voltage at sampling resistor R5 two ends has filtered through secondary side winding status determination circuit, amplify, with the different magnitude of voltage of output when Current Transformer Secondary side winding is under different conditions, then may determine that the short circuit of Current Transmit secondary side winding, open circuit, the state such as normal according to different magnitudes of voltage.
Certainly, in order to the state of Current Transmit secondary side winding can be learnt more intuitively, the present embodiment also includes other functions such as display, communication to demonstrate the state of CT, specifically, output voltage is connected to MCU, MCU, by measuring the magnitude of voltage of input, then exports voltage three kinds different when being in three kinds of shapes according to secondary side winding, can directly judge the state of Current Transformer Secondary side winding whereby.
Above-described embodiment is only preferred embodiment of the present utility model, not limits protection domain of the present utility model according to this, therefore: all equivalence changes done according to structure of the present utility model, shape, principle, all should be covered by within protection domain of the present utility model.
Claims (5)
1. a Current Transformer Secondary side short circuit in winding open-circuit condition testing circuit, it is characterised in that: including signal sample circuit, secondary side winding status determination circuit, for providing the constant-current source circuit of constant current; Wherein, signal sample circuit includes the sampling resistor being connected in parallel on the winding of Current Transformer Secondary side, multiple diodes concatenation after its anode be connected on the first end of sampling resistor, its minus earth; The outfan of constant-current source circuit is connected on the second end of sampling resistor, provides running voltage for signal sample circuit; The voltage at sampling resistor two ends is through secondary side winding status determination circuit output voltage signal.
2. Current Transformer Secondary side according to claim 1 short circuit in winding open-circuit condition testing circuit, it is characterised in that: described diode is 3.
3. Current Transformer Secondary side according to claim 1 short circuit in winding open-circuit condition testing circuit, it is characterized in that: described secondary side winding status determination circuit includes the 6th resistance, one end of 6th resistance is connected on the in-phase input end of the 3rd operational amplifier, and the in-phase input end of the 3rd operational amplifier is through the second capacity earth; One end of 7th resistance is connected on the inverting input of the 3rd operational amplifier, the inverting input of the 3rd operational amplifier is connected on the outfan of the 3rd operational amplifier through the 8th resistance, and the outfan of the 3rd operational amplifier is through the 9th resistance output voltage signal; The other end of the 6th resistance is connected on the second end of sampling resistor, and the other end of the 7th resistance is connected on the first end of sampling resistor.
4. Current Transformer Secondary side according to claim 1 short circuit in winding open-circuit condition testing circuit, it is characterized in that: the stabilivolt that described constant-current source circuit includes its negative electrode, reference is connected on power supply, the anode of stabilivolt connects digitally through the first resistance, and the anode of stabilivolt is connected on the in-phase input end of the second operational amplifier by the second resistance simultaneously;Power supply is connected on the inverting input of the second operational amplifier through the 3rd resistance, the inverting input of the second operational amplifier is connected on the emitter stage of PNP triode simultaneously, the outfan of the 3rd operational amplifier is connected in the base stage of PNP triode through the 4th resistance, and the colelctor electrode of PNP triode is as the outfan of this constant-current source circuit.
5. Current Transformer Secondary side according to claim 1 short circuit in winding open-circuit condition testing circuit, it is characterized in that: also include circuitry for signal measurement, one end first electric capacity of sampling resistor connects described circuitry for signal measurement, and circuitry for signal measurement is for the voltage signal size at calculating sampling resistance two ends.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520921521.0U CN205317883U (en) | 2015-11-13 | 2015-11-13 | Current transformer secondary side winding short circuit open -circuit condition detection circuitry |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520921521.0U CN205317883U (en) | 2015-11-13 | 2015-11-13 | Current transformer secondary side winding short circuit open -circuit condition detection circuitry |
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| CN205317883U true CN205317883U (en) | 2016-06-15 |
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| CN201520921521.0U Expired - Fee Related CN205317883U (en) | 2015-11-13 | 2015-11-13 | Current transformer secondary side winding short circuit open -circuit condition detection circuitry |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105486971A (en) * | 2015-11-13 | 2016-04-13 | 浙江涵普电力科技有限公司 | Short circuit and open circuit state detection circuit for secondary side winding of current transformer |
| CN109061373A (en) * | 2018-09-28 | 2018-12-21 | 中国船舶重工集团公司第七0七研究所九江分部 | A kind of short-circuit automatic detection circuit device of four terminal potential device signals broken string |
| CN109870667A (en) * | 2019-03-19 | 2019-06-11 | 中国石油大学(华东) | A kind of current transducer signal conditioning circuit with short circuit and breakage detection function |
| CN109975733A (en) * | 2017-12-28 | 2019-07-05 | 国网江苏省电力公司常州供电公司 | Electromagnetic current transducer secondary circuit safety monitoring assembly |
| CN110988575A (en) * | 2019-12-30 | 2020-04-10 | 国家电网有限公司 | Electric power terminal electric quantity acquisition warning system |
-
2015
- 2015-11-13 CN CN201520921521.0U patent/CN205317883U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105486971A (en) * | 2015-11-13 | 2016-04-13 | 浙江涵普电力科技有限公司 | Short circuit and open circuit state detection circuit for secondary side winding of current transformer |
| CN109975733A (en) * | 2017-12-28 | 2019-07-05 | 国网江苏省电力公司常州供电公司 | Electromagnetic current transducer secondary circuit safety monitoring assembly |
| CN109061373A (en) * | 2018-09-28 | 2018-12-21 | 中国船舶重工集团公司第七0七研究所九江分部 | A kind of short-circuit automatic detection circuit device of four terminal potential device signals broken string |
| CN109061373B (en) * | 2018-09-28 | 2024-02-13 | 中国船舶重工集团公司第七0七研究所九江分部 | Automatic detection circuit device for signal broken line and short circuit of four-terminal potentiometer |
| CN109870667A (en) * | 2019-03-19 | 2019-06-11 | 中国石油大学(华东) | A kind of current transducer signal conditioning circuit with short circuit and breakage detection function |
| CN110988575A (en) * | 2019-12-30 | 2020-04-10 | 国家电网有限公司 | Electric power terminal electric quantity acquisition warning system |
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| 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: 20160615 Termination date: 20181113 |
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| CF01 | Termination of patent right due to non-payment of annual fee |