CN104577982A - Open circuit protective circuit for secondary side output circuit of current transformer - Google Patents
Open circuit protective circuit for secondary side output circuit of current transformer Download PDFInfo
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- CN104577982A CN104577982A CN201510017353.7A CN201510017353A CN104577982A CN 104577982 A CN104577982 A CN 104577982A CN 201510017353 A CN201510017353 A CN 201510017353A CN 104577982 A CN104577982 A CN 104577982A
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Abstract
The invention discloses an open circuit protective circuit for a secondary side output circuit of a current transformer, and belongs to the technical field of overvoltage protection circuits. The open circuit protective circuit for the secondary side output circuit of the current transformer comprises an automatic protective circuit and a manual protective mechanism, wherein the automatic protective circuit and the manual protective mechanism are connected with a secondary side output end of the current transformer in parallel and are used for open circuit protection of the secondary side output circuit. The automatic protective circuit comprises at least one basic circuit, and each basic circuit comprises a thyristor and a voltage stabilizer used for sensing voltages of the two ends of the secondary side output end of the current transformer and controlling the connecting and disconnecting of the thyristor. By the adoption of the open circuit protective circuit for the secondary side output circuit of the current transformer, the situation that high voltage is formed at the open circuit when primary side current of the current transformer is not equal to zero and the open circuit is formed at the output end is avoided, the accidents of arc striking at the open circuit, burning up of contacts, destroyed equipment and the like are further avoided, and production safety and equipment debugging and maintenance convenience are guaranteed. In addition, the manual protective mechanism is arranged, so that two output ends of the current transformer can be in reliable short splice through the manual protective mechanism in the process of equipment debugging and maintenance, and therefore operation safety is guaranteed.
Description
Technical field
The present invention relates to overvoltage protection, particularly relate to a kind of secondary side protective device of current transformer.
Background technology
In each link of electric power system, comprise generating, power transformation, transmission of electricity, distribution and electricity consumption, all need to measure circuit, protect and control (hereinafter referred to as observing and controlling).But size of current great disparity in circuit, have from a few peace to a little Wan An, these electric currents need to be converted to more unified electric current, and the voltage in addition on circuit is general all higher, if direct observing and controlling is breakneck.The effect of current transformer (Current transformer, be called for short CT) primary current larger for numerical value can be converted to the less secondary current of numerical value by certain no-load voltage ratio, is used for carrying out protecting, the purposes such as measurement.If no-load voltage ratio is the current transformer of 400/5, the current transitions that can be 400A reality is the electric current of 5A.Except the effect playing current transformation, also play electrical isolation effect.
Current transformer is made up of the iron core closed and winding.Its umber of turn is little, often only has a circle in reality, namely punching and mistake; go here and there in the circuit needing the electric current measured; therefore it often has whole electric currents of circuit to flow through, and secondary side turn ratio is more, is serially connected in the equipment such as measuring instrument and protective loop.Current transformer is when normally working, and its secondary circuit is closed all the time, and therefore the impedance of measuring instrument and protective loop series coil is very little, and the operating state of current transformer is close to short circuit.
Current transformer is when primary current is non-vanishing, output does not allow open circuit, because once open circuit, then can on instrument transformer output produces the voltage of 1000V, input electric current is larger, the turn ratio is larger, this voltage is higher, and at this moment instrument transformer output open circuit can cause following several destruction or loss:
One if get loose at measuring and controlling equipment access terminal place and open a way, and probably this high pressure can puncture equipment, causes equipment failure.
Two, from instrument transformer output to the binding post of measuring and controlling equipment, any one circuit middle loosens or comes off, and all can cause sparking, burn contact, even cause electrical fire.
Three, find current circuit wrong in measuring and controlling equipment debugging, or need to change measuring and controlling equipment, the output of instrument transformer need disconnect with measuring and controlling equipment, thus makes the output open circuit of instrument transformer.And in this case, often test line is in operating state, primary current is non-vanishing.But, rewiring is carried out again after many times can not having a power failure, especially for transformation project, all the more so, because power consumption equipment is all in operation, power failure can bring economic loss to user, as smelting equipment, ceramic device, large medical equipment, all can not have a power failure easily, according to measuring and calculating, restart a ceramic production line after power failure, need the expense expending three or four million people people's coin.Experienced staff, can take the output of certain mode short circuit instrument transformer, then rewiring, but this operation has very high unreliability, is also breakneck, does not slightly note causing sparking, staff's electric shock.
Solve the existing safeguard measure of Current Transformer Secondary side output loop open circuit, substantially have following several:
The first, adopt the pressure cell such as piezo-resistance, gas discharge tube, when Current Transformer Secondary side output loop is opened a way, once open circuit voltage reaches the operation voltage of pressure-sensitive device, pressure-sensitive device conducting, and make output voltage control at pressure sensitive voltage.
The second, when utilizing Current Transformer Secondary side output loop open circuit, once open circuit voltage reaches certain value, the coil being attempted by two outputs by attracts spring tripping mechanism, and tripping mechanism action makes contact short, thus reaches protective effect.
The third, at output, a relay is installed, the contact of relay is connected to the two ends of output, is opened and conjunction by actuation means control relay, realizes the protection of the output loop of current transformer with this.
Obviously there are such some shortcomings in several scheme above:
1, the conducting voltage of pressure-sensitive device high (more than tens volts), continue conveyance capacity little, and the current transformer that circuit uses, its specified output is substantially all 5A, pressure-sensitive device under prior art only may continue the so large electric current of overcurrent in the scope of millisecond (ms) level, and current transformer output loop is once open circuit, the duration can not be ms level.Therefore, pressure-sensitive device is protected, and is easy to puncture and forms permanent conducting, must change the normal work that device could recover instrument transformer output loop, or directly burns and do not have protective effect.
2, the above-mentioned second way, because coil is attempted by two outputs of instrument transformer, when instrument transformer normally works, coil itself inevitably will flow through the electric current of a part of instrument transformer secondary side, this portion of electrical current does not flow through the checkout equipment that should need to flow through, thus brings obvious error to checkout equipment; Its two, mechanical mechanism is slow in one's movements, and during instrument transformer output open circuit, and voltage rise very fast (us level), many times also do not play a protective role, and outside accident occurs already.
3, the third mode above-mentioned, needs manual intervention completely, for unexpected open circuit, does not have protective effect at all.
4, when external fault is eliminated, the normal operating conditions in instrument transformer secondary side output loop can not be automatically restored to.
5, significantly eye-catching faulty indication is lacked.
Summary of the invention
In order to overcome the deficiencies in the prior art, the invention provides a kind of Current Transformer Secondary side output open circuit protective circuit, the secondary side output loop that its objective is when current transformer meet accident open circuit time automatically can form loop, and when Failure elimination, the normal operating conditions in loop automatically can be recovered; Simultaneously also can when safeguarding or change measuring and controlling equipment, can easily, the output of reliablely and stablely artificial short circuit current instrument transformer, ensure to recover ortho states easily again when recovering normal work simultaneously.
In order to solve above-mentioned technical problem; the basic technical scheme that the present invention proposes is: a kind of Current Transformer Secondary side output loop open loop protection circuit; comprise with the secondary side output of current transformer and the automatic protection circuit for secondary side output loop open-circuit-protection connect and manual protection mechanism; described automatic protection circuit comprises at least one group of basic circuit, often organize basic circuit comprise a thyristor and for the secondary side output of perception instrument transformer both end voltage and control the voltage-stabilizing device of turn on thyristors.
Preferably, in the output loop open loop protection circuit of Current Transformer Secondary side of the present invention, automatic protection circuit comprises one group of basic circuit, and described voltage stabilizing conduction device is bi-directional voltage stabilizing diode D1 or two-way TVS pipe, and described thyristor is bidirectional thyristor Q1; One end of bi-directional voltage stabilizing diode D1 is connected with the gate pole G of bidirectional thyristor Q1; The other end of bi-directional voltage stabilizing diode D1 and the MT2 pole of bidirectional thyristor Q1 are connected to the first end in output, and the MT1 pole of bidirectional thyristor Q1 connects the second end of output.
Preferably; in the output loop open loop protection circuit of Current Transformer Secondary side of the present invention; one end of bi-directional voltage stabilizing diode D1 is connected the first auxiliary protection circuit with the connecting line of the gate pole G of bidirectional thyristor Q1 with the connecting line of the second end of output, and this first auxiliary protection circuit comprises the resistance R1 and electric capacity C1 that are connected in parallel.
Preferably, in the output loop open loop protection circuit of Current Transformer Secondary side of the present invention, described resistance R1 resistance is between 1K Ω ~ 2K Ω, and the capacitance of described electric capacity C1 is between 0.01uF ~ 0.1uF.
Preferably, in the output loop open loop protection circuit of Current Transformer Secondary side of the present invention, it is identical and be oppositely attempted by the first basic circuit and second basic circuit of secondary side output that automatic protection circuit comprises circuit structure; Wherein the voltage stabilizing conduction device of the first basic circuit is the voltage stabilizing didoe D2 and rectifier diode D3 that are connected in series, and described thyristor is silicon controlled crystal brake pipe Q2; Wherein the A pole of voltage stabilizing didoe D2 is connected with the G pole of Q2, the K pole of described voltage stabilizing didoe D2 is connected with the K pole of rectifier diode D3, the A pole of this rectifier diode D3 is extremely connected with the A of silicon controlled crystal brake pipe Q2 and is connected to the first end of secondary side output, and the K pole of described silicon controlled crystal brake pipe Q2 is connected to the second end of secondary side output.
Preferably; in the output loop open loop protection circuit of Current Transformer Secondary side of the present invention; the connecting line of the connecting line of the A pole of the voltage stabilizing didoe D2 of at least one group of basic circuit and the G pole of Q2 and the second end of secondary side output arranges the second auxiliary protection circuit, and this second auxiliary circuit comprises the resistance R2 and electric capacity C2 that are connected in parallel.
Preferably, in the output loop open loop protection circuit of Current Transformer Secondary side of the present invention, described resistance R1 resistance is between 1K Ω ~ 2K Ω, and the capacitance of described electric capacity C1 is between 0.01uF ~ 0.1uF.
Preferably; in the output loop open loop protection circuit of Current Transformer Secondary side of the present invention; secondary side output is also parallel with instruction auxiliary circuit, and this instruction auxiliary circuit comprises series connection bi-directional voltage stabilizing diode D4 together and resistance R3 and the lamp L1 be arranged in parallel and lamp L2.
Preferably, in the output loop open loop protection circuit of Current Transformer Secondary side of the present invention, the power of described bi-directional voltage stabilizing diode D4 is 3W, the light-emitting diode of described lamp L1 and lamp L2 to be power be 3W, and its operating pressure drop is 1.8V ~ 3.0V; The resistance of resistance R3 is 10 Ω.
Preferably; in the output loop open loop protection circuit of Current Transformer Secondary side of the present invention; described manual protection mechanism comprises the fixed contact being attempted by secondary side output, elastically bendable moving contact and control mechanism, and this control mechanism comprises the spring that the button and be connected on snap close is arranged on moving contact end.
The invention has the beneficial effects as follows:
1, the automatic protection circuit of this invention, has supper-fast response, automatically starting protection, automatically recovers the feature of normal condition.Whether automatic monitoring instrument transformer secondary side output loop opens a way, once open circuit, and can with the automatic starting protection action of the response speed that is exceedingly fast of ns (nanosecond) level; Once output loop recovers normal, automatically guard mode can be exited.Thus ensure that current transformer primary side current non-vanishing and secondary side output loop open circuit time can not produce high pressure at open circuit place, thus avoid the generation that strike sparks in open circuit place, contact burns, smashes the accidents such as equipment, electrical fire, personnel's electric shock, ensure that the fail safe of production, the fail safe of equipment, the fail safe of personnel.
2, the automatic protection circuit of this invention, has the advantages that lasting current capacity is large.Thyristor forces down (about 0.6V) because of electric conduction, continue large (tens peaces of current-carrying, tens Andu are conventional), moment overload capacity large (being generally ten times of specified current capacity), completely can the output current (specified is 5A or 1A) of constant conduction instrument transformer.
3, the automatic protection circuit of this invention, has eye-catching protection act instruction feature.The red light and shade flicker electric light instruction of instruction auxiliary circuit, be easy to the attention causing staff, instruction staff checks malfunction elimination problem, or instruction staff can relievedly operate.The joystick of manual protection mechanism, it is pressed or upsprings, and also clearly indicates the state of manually protection.
4, this invention has the advantages that production technology is simple, cost is low.The components and parts of automatic protection circuit, and the dynamic and static contact of manual protection mechanism, can be attached on pcb board by automated production is traditional thread binding, good product consistency, reliability is high.The components and parts used, be all the conventional technical grade device used, easily purchase, cost is low.
5, this invention, has structure and simply uses feature flexibly.Both as parts, can directly be placed on the inside of conventional current instrument transformer, also can become separately a general protective device, and coordinate instrument transformer to use.
6, due to the existence of automatic protection circuit and manual protection mechanism, at equipment debugging or when safeguarding, operating personnel arbitrarily can disconnect the connection of instrument transformer secondary side output and equipment as required, ensure that the convenience of equipment debugging, maintenance.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of the embodiment 1 of Current Transformer Secondary side of the present invention output loop open loop protection circuit;
Fig. 2 is the circuit diagram of the embodiment 2 of Current Transformer Secondary side output loop open loop protection circuit.
Embodiment
Below with reference to accompanying drawing 1 and accompanying drawing 2, the present invention is described further, but should not limit the scope of the invention with this.
A kind of Current Transformer Secondary side of the present invention output loop open loop protection circuit; comprise with the secondary side output of current transformer and the automatic protection circuit for secondary side output loop open-circuit-protection connect and manual protection mechanism; described automatic protection circuit comprises at least one group of basic circuit, often organize basic circuit comprise a thyristor and for the secondary side output of perception instrument transformer both end voltage and control the voltage-stabilizing device of turn on thyristors.
This technology produces high pressure at open circuit place when avoiding current transformer primary side current non-vanishing and secondary side output loop open circuit, thus avoid the generation that strike sparks in open circuit place, contact burns, smashes the accidents such as equipment, electrical fire, personnel's electric shock, ensure that the fail safe of production, the fail safe of equipment, the fail safe of personnel, the convenience of plant maintenance.
Embodiment 1
The present embodiment comprises with the secondary side output of current transformer and the automatic protection circuit 30 for secondary side output loop open-circuit-protection connect and manual protection mechanism 40.Automatic protection circuit 30 comprises one group of basic circuit, and it comprises bi-directional voltage stabilizing diode D1 and bidirectional thyristor Q1; The lower end of bi-directional voltage stabilizing diode D1 is connected with the gate pole G of bidirectional thyristor Q1; The upper end of bi-directional voltage stabilizing diode D1 and the MT2 pole of bidirectional thyristor Q1 are connected to the first end K1 in output, and the MT1 pole of bidirectional thyristor Q1 connects the second end K2 of output.
Connecting line b place's extraction first auxiliary protection circuit 50 of the gate pole G of bi-directional voltage stabilizing diode D1 and bidirectional thyristor Q1; this first auxiliary protection circuit 50 comprises the resistance R1 and electric capacity C1 that are connected in parallel; described resistance R1 resistance is 1.0K Ω, and the capacitance of described electric capacity C1 is 0.1uF.This first auxiliary protection circuit 50 is applied to transient signal between the G pole of Q1 and MT1 pole and unstable voltage and current signal for filtering, avoids Q1 conducting under external disturbance.
Secondary side output is also parallel with instruction auxiliary circuit 60, this instruction auxiliary circuit 60 comprises series connection bi-directional voltage stabilizing diode D4 together and resistance R3 and the lamp L1 be arranged in parallel and lamp L2, the power of this bi-directional voltage stabilizing diode D4 is 3W, the light-emitting diode of described lamp L1 and lamp L2 to be power be 3W, and its operating pressure drop is 1.8V ~ 3.0V, the resistance of resistance R3 is 10 Ω, and the voltage stabilizing value Uz of bi-directional voltage stabilizing diode D4 selects 6.8V, and its maximum lasting electric current of voltage regulation is 220mA; In time indicating auxiliary circuit 60 to work, current instantaneous value If reaches 200mA, the voltage U z+R3*If+Uf=6.8+10*0.2+2.2=11V at these circuit two ends.
Manual protection mechanism 40 comprises the fixed contact 401, elastically bendable moving contact 402 and the control mechanism that are attempted by secondary side output, and this control mechanism comprises and is connected to the spring 405 that button on snap close 403 404 and is arranged on moving contact 402 end.Press the button 404, under the effect of spring 405, snap close 403 rotates, and enters latched position, and button 404 keeps down state, and under the effect of spring 405, moving contact 402 and fixed contact 401 close contact, and remain closed, make instrument transformer secondary side form loop.Again press the button 404, under the effect of spring 405, snap close 403 rotates again, and go out of lock position and upspringing, and moving contact 402 is upspring under its own resilient effect simultaneously, and moving contact 402 is separated with fixed contact 401, returns to the state of other circuit.Manually like this ensure that instrument transformer secondary side is closed when constructing, can the loop of disconnecting external, carry out other work; Construct complete, again press and recover.Meanwhile, the pressing and upspringing of button 404, just in time indicates the closed of moving contact 402 and fixed contact 401 and opens.
Below that the course of work of circuit is described, and as the components and parts such as bi-directional voltage stabilizing diode D1 and bidirectional thyristor Q1 directly will use replacements such as being called for short D1 and Q1 in following explanation, but should not think that this specification is unclear with this.
Its process is as follows: open a way in instrument transformer secondary side output loop, if now, secondary side current I2 exports from output K1, need from the backflow of K2 end, current instantaneous value increases from 0 gradually, and open circuit voltage Uac instantaneous value also increases gradually from 0, but because now output loop is open circuit, Uac rises very fast, once Uac reaches the operating voltage sum of voltage of voltage regulation Uz and L2 of D4, then D4 starts working, L2 is lit, electric current flows out from K1, crosses R3 after L2, then flow back to from K2 through D4.Along with electric current I 2 increases, the pressure drop Ude on R3 increases, and voltage U ac also increases thereupon, once Uac reaches the voltage of voltage regulation Uz of D1, then D1 starts working.The portion of electrical current of I2 crosses R1 through D1, then flows back to from K2.Along with this portion of electrical current increases, the pressure drop Ubc on R1 increases, and when Ubc is increased to the conducting voltage Ugt of Q1, and the electric current of gate pole G flowing into Q1 reaches the triggering and conducting electric current I gt of Q1, then Q1 is triggered forward conduction.After Q1 conducting, the voltage at the output two ends of instrument transformer is reduced to rapidly the conducting voltage of Q1, and D1, D4, L2 all end, and electric current all flows through Q1, and the voltage control of output is in the conducting voltage of Q1.When secondary side current I2 instantaneous value reduces gradually after crest, and gradually become zero by output K1 output, and then when oppositely increase is exported by K2, Q1 forward ends.Subsequently, along with the reverse increase of I2, open circuit voltage Uac instantaneous value also oppositely increases gradually from 0, but because of now output loop be open circuit, Uac rises very fast, once Uac reaches the operating voltage sum of voltage of voltage regulation Uz and L1 of D4, then D4 starts working, and L1 is lit, and electric current flows out from K2, cross R3 after D4 through L1, then flow back to from K1.Along with electric current I 2 increases, the pressure drop Ude on R2 increases, and voltage U ac also increases thereupon, once Uac reaches the voltage of voltage regulation Uz of D1, then D1 starts working.The portion of electrical current of I2 crosses D1 through R1, then flows back to from K1.Along with this portion of electrical current increases, the pressure drop Ubc on R1 increases, and when Ubc is increased to the reverse turn-on voltages-Ugt of Q1, and the electric current flowing out the gate pole G of Q1 reaches the reverse triggering and conducting electric current-Igt of Q1, then Q1 is reversed triggering and conducting.After Q1 conducting, the voltage at the output two ends of instrument transformer is reduced to rapidly the conducting voltage of Q1, and D1, D4, L1 all end, and electric current all flows through Q1, and the voltage control of output is in the conducting voltage of Q1.When secondary side current I2 instantaneous value reduces gradually after trough, and gradually become zero by output K2 output, and then when oppositely increase is exported by K1, Q1 oppositely ends.Then this process is repeated.Such Current Transformer Secondary side output loop open circuit just obtains automatic protection.
When Current Transformer Secondary side, output loop is no longer opened a way; then after Q1 ends forward or backwards, because the condition of D1, D4, L1 or L2 work no longer exists, Q1 is conducting no longer; guard mode exits automatically, and Current Transformer Secondary side output loop recovers normal work.
Embodiment 2
It is identical and be oppositely attempted by the first basic circuit 101 and the second basic circuit 102 of secondary side output that the present embodiment and unique difference of embodiment 2 are that automatic protection circuit comprises circuit structure.Because the first basic circuit is identical with the circuit structure of the second basic circuit, therefore be only described for the first basic circuit herein, it comprises the voltage stabilizing didoe D2 and rectifier diode D3 that are connected in series, and the silicon controlled crystal brake pipe Q2 in parallel with this voltage stabilizing didoe D2 and rectifier diode D3, this silicon controlled crystal brake pipe Q2 is the thyristor of one-way conduction; Wherein the A pole of voltage stabilizing didoe D2 is connected with the G pole of Q2, the K pole of described voltage stabilizing didoe D2 is connected with the K pole of rectifier diode D3, the A pole of this rectifier diode D3 is extremely connected with the A of silicon controlled crystal brake pipe Q2 and is connected to the first end K1 of secondary side output, and the K pole of described silicon controlled crystal brake pipe Q2 is connected to the second end K2 of secondary side output.Arrange the second auxiliary protection circuit 70 between the connecting line d place of the A pole of voltage stabilizing didoe D2 and the G pole of Q2 and the second end K2, this second auxiliary circuit 70 is the same with the circuit structure of the first auxiliary circuit 50 in embodiment 1; Also be parallel with instruction auxiliary circuit 80 at secondary side output, this instruction auxiliary circuit 80 is identical with the circuit structure of the instruction auxiliary circuit 60 in embodiment 1.
The operation principle of the present embodiment is identical with the operation principle of embodiment 1, therefore no longer repeats.
The announcement of book and instruction according to the above description, those skilled in the art in the invention can also change above-mentioned execution mode and revise.Therefore, the present invention is not limited to embodiment disclosed and described above, also should fall in the protection range of claim of the present invention modifications and changes more of the present invention.In addition, although employ some specific terms in this specification, these terms just for convenience of description, do not form any restriction to the present invention.
Claims (10)
1. a Current Transformer Secondary side output loop open loop protection circuit; it is characterized in that: comprise with the secondary side output of current transformer and the automatic protection circuit for secondary side output loop open-circuit-protection connect and manual protection mechanism; described automatic protection circuit comprises at least one group of basic circuit, often organize basic circuit comprise a thyristor and for the secondary side output of perception instrument transformer both end voltage and control the voltage-stabilizing device of turn on thyristors.
2. Current Transformer Secondary side as claimed in claim 1 output loop open loop protection circuit, it is characterized in that: automatic protection circuit comprises one group of basic circuit, described voltage stabilizing conduction device is bi-directional voltage stabilizing diode D1 or two-way TVS pipe, and described thyristor is bidirectional thyristor Q1; One end of bi-directional voltage stabilizing diode D1 is connected with the gate pole G of bidirectional thyristor Q1; The other end of bi-directional voltage stabilizing diode D1 and the MT2 pole of bidirectional thyristor Q1 are connected to the first end in output, and the MT1 pole of bidirectional thyristor Q1 connects the second end of output.
3. Current Transformer Secondary side as claimed in claim 2 output loop open loop protection circuit; it is characterized in that: one end of bi-directional voltage stabilizing diode D1 is connected the first auxiliary protection circuit with the connecting line of the gate pole G of bidirectional thyristor Q1 with the connecting line of the second end of output, this first auxiliary protection circuit comprises the resistance R1 and electric capacity C1 that are connected in parallel.
4. Current Transformer Secondary side as claimed in claim 3 output loop open loop protection circuit, is characterized in that: described resistance R1 resistance is between 1K Ω ~ 2K Ω, and the capacitance of described electric capacity C1 is between 0.01uF ~ 0.1uF.
5. Current Transformer Secondary side as claimed in claim 1 output loop open loop protection circuit, is characterized in that: it is identical and be oppositely attempted by the first basic circuit and second basic circuit of secondary side output that automatic protection circuit comprises circuit structure; Wherein the voltage stabilizing conduction device of the first basic circuit is the voltage stabilizing didoe D2 and rectifier diode D3 that are connected in series, and described thyristor is silicon controlled crystal brake pipe Q2; Wherein the A pole of voltage stabilizing didoe D2 is connected with the G pole of Q2, the K pole of described voltage stabilizing didoe D2 is connected with the K pole of rectifier diode D3, the A pole of this rectifier diode D3 is extremely connected with the A of silicon controlled crystal brake pipe Q2 and is connected to the first end of secondary side output, and the K pole of described silicon controlled crystal brake pipe Q2 is connected to the second end of secondary side output.
6. Current Transformer Secondary side as claimed in claim 5 output loop open loop protection circuit; it is characterized in that: the connecting line of the connecting line of the A pole of the voltage stabilizing didoe D2 of at least one group of basic circuit and the G pole of Q2 and the second end of secondary side output arranges the second auxiliary protection circuit, this second auxiliary circuit comprises the resistance R2 and electric capacity C2 that are connected in parallel.
7. Current Transformer Secondary side as claimed in claim 6 output loop open loop protection circuit, is characterized in that: described resistance R1 resistance is between 1K Ω ~ 2K Ω, and the capacitance of described electric capacity C1 is between 0.01uF ~ 0.1uF.
8. the Current Transformer Secondary side output loop open loop protection circuit as described in one of claim 1 to 7; it is characterized in that: secondary side output is also parallel with instruction auxiliary circuit, this instruction auxiliary circuit comprises series connection bi-directional voltage stabilizing diode D4 together and resistance R3 and the lamp L1 be arranged in parallel and lamp L2.
9. Current Transformer Secondary side as claimed in claim 8 output loop open loop protection circuit, is characterized in that: the light-emitting diode of described lamp L1 and lamp L2 to be power be 3W, and its operating pressure drop is 1.8V ~ 3.0V; The resistance of resistance R3 is 10 Ω.
10. the Current Transformer Secondary side output loop open loop protection circuit as described in one of claim 1 to 7; it is characterized in that: described manual protection mechanism comprises the fixed contact being attempted by secondary side output, elastically bendable moving contact and control mechanism, this control mechanism comprises the spring that the button and be connected on snap close is arranged on moving contact end.
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| CN105790215A (en) * | 2016-03-02 | 2016-07-20 | 闫堂锁 | CT open-circuit protection device |
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| CN106532640A (en) * | 2016-10-26 | 2017-03-22 | 国网重庆市电力公司电力科学研究院 | Secondary side open circuit protection device of current transformer |
| CN106684820A (en) * | 2016-11-09 | 2017-05-17 | 国网天津市电力公司 | Open circuit automatic protection device for secondary circuit of high voltage current transformer |
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| CN110649566A (en) * | 2019-10-12 | 2020-01-03 | 北京恒源利通电力技术有限公司 | Overvoltage protection device for current transformer |
| CN113163549A (en) * | 2021-03-25 | 2021-07-23 | 深圳市恒耀光电科技有限公司 | LED driving power supply starting method and circuit thereof |
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| CN104953547A (en) * | 2015-07-07 | 2015-09-30 | 安徽瑞宏信息科技有限公司 | Secondary side open-circuit protector circuit adopting windings and used for intelligent selection current transformer |
| CN105790215A (en) * | 2016-03-02 | 2016-07-20 | 闫堂锁 | CT open-circuit protection device |
| CN105790215B (en) * | 2016-03-02 | 2018-03-09 | 闫堂锁 | CT open-circuit protecting devices |
| CN106371049A (en) * | 2016-08-31 | 2017-02-01 | 贵州电网有限责任公司贵阳供电局 | Current transformer secondary open circuit identification method |
| CN106371049B (en) * | 2016-08-31 | 2023-09-26 | 贵州电网有限责任公司贵阳供电局 | Current transformer secondary open circuit identification method |
| CN106532640B (en) * | 2016-10-26 | 2018-11-27 | 国网重庆市电力公司电力科学研究院 | Secondary side open circuit protecting equipment of current mutual inductor |
| CN106532640A (en) * | 2016-10-26 | 2017-03-22 | 国网重庆市电力公司电力科学研究院 | Secondary side open circuit protection device of current transformer |
| CN106684820A (en) * | 2016-11-09 | 2017-05-17 | 国网天津市电力公司 | Open circuit automatic protection device for secondary circuit of high voltage current transformer |
| CN107727991A (en) * | 2017-10-30 | 2018-02-23 | 珠海易赛特电子科技有限公司 | A kind of anti-observation circuit and the anti-open circuit monitoring devices of CT of opening a way of CT |
| CN107785869A (en) * | 2017-11-08 | 2018-03-09 | 河南森源电气股份有限公司 | A kind of current transformer and its secondary side protective arrangement for limiting output voltage |
| CN107785870A (en) * | 2017-11-11 | 2018-03-09 | 河南森源电气股份有限公司 | A kind of current transformer and its secondary side open-circuit protecting device |
| CN107785870B (en) * | 2017-11-11 | 2023-11-24 | 河南森源电气股份有限公司 | Current transformer and secondary side open circuit protection device thereof |
| CN108776303A (en) * | 2018-06-08 | 2018-11-09 | 上海金艺检测技术有限公司 | Asynchronous motor supplied with variable frequency signal dynamics time-sharing acquisition device in groups |
| CN110412459A (en) * | 2019-08-01 | 2019-11-05 | 国网浙江省电力有限公司检修分公司 | A kind of secondary loop of mutual inductor is switched fast operating mechanism |
| CN110649566A (en) * | 2019-10-12 | 2020-01-03 | 北京恒源利通电力技术有限公司 | Overvoltage protection device for current transformer |
| CN113163549A (en) * | 2021-03-25 | 2021-07-23 | 深圳市恒耀光电科技有限公司 | LED driving power supply starting method and circuit thereof |
| CN113740792A (en) * | 2021-08-27 | 2021-12-03 | 保定北特电气设备制造有限公司 | Electric leakage metering system and method after secondary open circuit of current transformer |
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