CN104577982B - Current Transformer Secondary side output loop open loop protection circuit - Google Patents
Current Transformer Secondary side output loop open loop protection circuit Download PDFInfo
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- CN104577982B CN104577982B CN201510017353.7A CN201510017353A CN104577982B CN 104577982 B CN104577982 B CN 104577982B CN 201510017353 A CN201510017353 A CN 201510017353A CN 104577982 B CN104577982 B CN 104577982B
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Abstract
The invention discloses a kind of Current Transformer Secondary side output loop open loop protection circuits, belong to overvoltage crowbar technical field.It includes the secondary side output end with current transformer and the automatic protection circuit and manual protection mechanism for secondary side output loop open-circuit-protection connect; the automatic protection circuit includes at least one set of basic circuit, and every group of basic circuit includes a thyristor and perceive the secondary side output end both end voltage of mutual inductor and control the voltage-stabilizing device of turn on thyristors.Current transformer primary side current is avoided using this technology to be not zero and generate high pressure when output open circuit at open circuit, burn, smash the generations of the accidents such as equipment so as to avoid sparking, contact at open circuit, it is ensured that the safety of production, equipment debugging and maintenance convenience.In addition, manual protection mechanism is provided with, so that can also be used manual protection mechanism to be reliably shorted the output both ends of mutual inductor in equipment debugging, maintenance, to ensure the safety operated.
Description
Technical field
The present invention relates to overvoltage protections, more particularly to a kind of secondary side protective device of current transformer.
Background technique
In each link of electric system, including power generation, power transformation, transmission of electricity, distribution and electricity consumption, require to survey route
Amount, protection and control (hereinafter referred to as observing and controlling).However size of current great disparity in route, have from several peaces to tens of thousands of Andu, these electricity
Stream needs to be converted to the unified electric current of comparison, and in addition the voltage on route is generally relatively high, and such as direct observing and controlling is abnormally dangerous
's.The effect of current transformer (Current transformer, abbreviation CT) is the biggish primary current of numerical value can be passed through
Certain no-load voltage ratio is converted to the lesser secondary current of numerical value, for the purposes such as being protected, being measured.Such as the electricity that no-load voltage ratio is 400/5
Current transformer can be changed into the practical electric current for 400A the electric current of 5A.In addition to playing the role of current transformation, electricity is also acted as
Gas buffer action.
Current transformer is made of the iron core and winding being closed.Its first winding the number of turns is seldom, in practice often only
There is a circle, that is, punching and mistake, goes here and there in the route for the electric current for needing to measure, therefore it often there are whole electric current streams of route
It crosses, secondary side turn ratio is more, is serially connected in the equipment such as measuring instrumentss and protective loop.Current transformer in normal work,
Its secondary circuit is closure, therefore the impedance very little of measuring instrumentss and protective loop series coil, current transformer always
Working condition it is almost short-circuit.
For current transformer in the case where primary current is not zero, output end is not allow to open a way, because once opening a way,
Then can be in the voltage of the upper 1000V of mutual inductor output end generation, input terminal electric current is bigger, the turn ratio is bigger, and the voltage is higher, at this moment mutually
Sensor output end open circuit will cause following several destructions or loss:
One, it opens a way if it is being loosened at measuring and controlling equipment access terminal, it is likely that this high pressure can puncture equipment, cause
Equipment failure.
Two, the connecting terminal from mutual inductor output end to measuring and controlling equipment, any one intermediate route loosen or fall off, all can
Cause to strike sparks, burns contact, or even cause electrical fire.
Three, current circuit wrong being found in measuring and controlling equipment debugging, or needing replacing measuring and controlling equipment, the output end of mutual inductor needs
It is disconnected with measuring and controlling equipment, so that the output open circuit of mutual inductor.And in this case, often test line is to be in work shape
State, primary current are not zero.However, carry out rewiring again after cannot many times having a power failure, especially for transformation project,
Even more so, because electrical equipment is all in operation, power failure can bring economic loss to user, as smelting equipment, ceramic device,
Large medical equipment cannot all have a power failure easily, according to measuring and calculating, a ceramic production line is restarted after power failure, needs to expend three or four
The expense of million RMB.Experienced staff can take certain mode to be shorted the output of mutual inductor, then connect again
Line, but this operation is that have very high unreliability and breakneck, does not pay attention to that slightly sparking, work will be caused
Personnel's electric shock.
The existing safeguard measure for solving Current Transformer Secondary side output loop open circuit, has following several substantially:
The first, using pressure cells such as varistor, gas-discharge tubes, when Current Transformer Secondary side, output loop is opened
Lu Shi once open-circuit voltage reaches the operation voltage of pressure-sensitive device, pressure-sensitive device conducting, and makes output voltage control in pressure-sensitive electricity
Pressure.
Second, when being opened a way using Current Transformer Secondary side output loop, once open-circuit voltage reaches certain value, by one
A coil for being attempted by two output ends attracts spring tripping mechanism, and tripping mechanism movement makes contact short, makees to reach protection
With.
The third, in output end one relay is installed, the contact of relay is connected to the both ends of output end, is filled by manipulation
It sets control relay to open and close, the protection of the output loop of current transformer is realized with this.
Above several schemes are clearly present such some shortcomings:
1, the conducting voltage of pressure-sensitive device high (more than ten volts or more), lasting conveyance capacity electric current that is small, and being used on route
Mutual inductor, rated output are substantially 5A, and the pressure-sensitive device under the prior art is only possible to hold in the range of millisecond (ms) grade
The so big electric current of continuous overcurrent, and current transformer output loop is once opened a way, the duration is unlikely to be ms grades.Therefore,
Pressure-sensitive device is protected, it is easy to be punctured and be formed permanent conducting, it is necessary to which mutual inductor output loop could be restored by replacing device
Normal work, or directly burn and do not have protective effect.
2, the above-mentioned second way, since coil is attempted by two output ends of mutual inductor, when mutual inductor works normally, coil
Itself inevitably to flow through the electric current of a part of mutual inductor secondary side, which does not flow through and should need to flow through
Detection device, to bring apparent error to detection device；Second, mechanical mechanism is slow in one's movements, and mutual inductor output open circuit
When, voltage rises quickly (us grades), it does not play a protective role also many times, and external accident already occurs.
3, the third above-mentioned mode, requires manual intervention completely, for unexpected open circuit, does not have protective effect at all.
4, when external fault is eliminated, the normal work shape of mutual inductor secondary side output end loop cannot be automatically restored to
State.
5, lack apparent eye-catching indicating fault.
Summary of the invention
For overcome the deficiencies in the prior art, the present invention provides a kind of Current Transformer Secondary side output open circuit protection electricity
Road, the purpose is to which circuit can be automatically formed when unexpected open circuit occurs for the secondary side output loop of current transformer, and when event
When barrier is eliminated, the normal operating conditions in circuit can be restored automatically；Simultaneously can also be when doing maintenance or replacement measuring and controlling equipment, it can be very
Easily, the reliablely and stablely output of artificial short circuit current mutual inductor, while guaranteeing again can be easily when restoring to work normally
Restore ortho states in ground.
In order to solve the above technical problems, a kind of basic technical scheme proposed by the present invention are as follows: Current Transformer Secondary
Side output loop open loop protection circuit, including the secondary side output end with current transformer and connect for secondary side output loop
The automatic protection circuit and manual protection mechanism of open-circuit-protection, the automatic protection circuit include at least one set of basic circuit, often
Group basic circuit includes the both end voltage an of thyristor and the secondary side output end for perceiving mutual inductor and controls brilliant lock
The voltage-stabilizing device of pipe conducting.
Preferably, in Current Transformer Secondary side output loop open loop protection circuit of the present invention, automatic protection electricity
Road includes one group of basic circuit, and the pressure stabilizing conduction device is bi-directional voltage stabilizing diode D1 or two-way TVS pipe, the thyristor
For bidirectional thyristor Q1；One end of bi-directional voltage stabilizing diode D1 is connect with the gate pole G of bidirectional thyristor Q1；Bi-directional voltage stabilizing diode
The other end of D1 and the pole MT2 of bidirectional thyristor Q1 are connected to the first end in output end, the pole the MT1 connection of bidirectional thyristor Q1
The second end of output end.
Preferably, in Current Transformer Secondary side output loop open loop protection circuit of the present invention, bi-directional voltage stabilizing two
One end of pole pipe D1 connect the first auxiliary with the connecting line of the second end of the connecting line of the gate pole G of bidirectional thyristor Q1 and output end
Circuit is protected, which includes the resistance R1 and capacitor C1 being connected in parallel.
Preferably, in Current Transformer Secondary side output loop open loop protection circuit of the present invention, the resistance R1
Resistance value is between 1K Ω~2K Ω, and the capacitance of the capacitor C1 is between 0.01uF~0.1uF.
Preferably, in Current Transformer Secondary side output loop open loop protection circuit of the present invention, automatic protection electricity
Road includes that circuit structure is identical and be reversely attempted by the first basic circuit and the second basic circuit of secondary side output end；Wherein
The pressure stabilizing conduction device of one basic circuit is the zener diode D2 and rectifier diode D3 being connected in series, and the thyristor is can
Control silicon wafer brake tube Q2；Wherein the pole A of zener diode D2 and the pole G of Q2 connect, the pole K of the zener diode D2 and rectification two
The pole K of pole pipe D3 connects, and the pole A of rectifier diode D3 is extremely connected with the A of silicon controlled crystal brake pipe Q2 and to be connected to secondary side defeated
The first end of outlet, and the pole K of the silicon controlled crystal brake pipe Q2 is connected to the second end of secondary side output end.
Preferably, in Current Transformer Secondary side output loop open loop protection circuit of the present invention, at least one set of base
The connecting line of the second end of the connecting line and secondary side output end of the pole G of the pole A and Q2 of the zener diode D2 of this circuit is arranged
Second auxiliary protection circuit, second auxiliary circuit include the resistance R2 and capacitor C2 being connected in parallel.
Preferably, in Current Transformer Secondary side output loop open loop protection circuit of the present invention, the resistance R1
Resistance value is between 1K Ω~2K Ω, and the capacitance of the capacitor C1 is between 0.01uF~0.1uF.
Preferably, in Current Transformer Secondary side output loop open loop protection circuit of the present invention, secondary side output
End is also parallel with instruction auxiliary circuit, the instruction auxiliary circuit include series connection bi-directional voltage stabilizing diode D4 together and resistance R3 with
And the lamp L1 and lamp L2 being arranged in parallel.
Preferably, described two-way steady in Current Transformer Secondary side output loop open loop protection circuit of the present invention
It is the light emitting diode that power is 3W that the power for pressing diode D4, which is 3W, the lamp L1 and lamp L2, and its operating pressure drop is
1.8V~3.0V；The resistance value of resistance R3 is 10 Ω.
Preferably, in Current Transformer Secondary side output loop open loop protection circuit of the present invention, the manual guarantor
Protecting mechanism includes the static contact for being attempted by secondary side output end, elastically bendable moving contact and control mechanism, the control stick
Mechanism includes that the spring at moving contact end is arranged in the button being connected on lock and one.
The beneficial effects of the present invention are:
1, the automatic protection circuit of the invention with supper-fast response, automatic starting protection, restores normal condition automatically
Feature.Whether automatic monitoring mutual inductor secondary side output end loop opens a way, once open circuit, it can be with the sound that is exceedingly fast of ns (nanosecond) grade
Answer the automatic starting protection movement of speed；Once exporting end loop restores normal, guard mode can be automatically exited from.It ensures that
Current transformer primary side current be not zero and secondary side output loop open a way when high pressure will not be generated at open circuit, to avoid
The generation of the accidents such as equipment, electrical fire, personnel's electric shock is burnt, is smashed in sparking at open circuit, contact, it is ensured that the safety of production
Property, the safety of equipment, the safety of personnel.
2, the automatic protection circuit of the invention has the characteristics that lasting current-carrying capability is big.Thyristor is forced down because of electric conduction
(0.6V or so) continues current-carrying (more than ten peaces, tens Andu are conventional) greatly, big (the usually specified current-carrying of moment overload capacity
Ten times of ability), it completely can be with the output electric current of constant conduction mutual inductor (specified is 5A or 1A).
3, the automatic protection circuit of the invention has the characteristics that eye-catching protection act instruction.Indicate the red of auxiliary circuit
Light and shade flashes electric light instruction, it is easy to cause staff's note that instruction staff checks malfunction elimination problem, or refer to
Show that staff can trust operation.The control stick of manual protection mechanism is pressed or is bounced, and is indicated with will also recognize that manually
The state of protection.
4, the invention has the characteristics that simple production process, at low cost.The component of automatic protection circuit, and protect manually
The dynamic and static contact for protecting mechanism, can be attached on pcb board, good product consistency, high reliablity by the way that automated production is traditional thread binding.
Used component is all conventional use of technical grade device, is easily purchased, at low cost.
5, the invention has the characteristics that the simple using flexible of structure.Both it can be used as a component, and be directly placed at routine
The inside of current transformer, can also individually become a general protective device, and cooperation mutual inductor uses.
6, due to the presence of automatic protection circuit and manual protection mechanism, in equipment debugging or maintenance, operator can
With as needed arbitrarily disconnect mutual inductor secondary side output end and equipment connection, it is ensured that equipment debugging, maintenance convenience.
Detailed description of the invention
Fig. 1 is the circuit of the embodiment 1 of Current Transformer Secondary side output loop open loop protection circuit of the present invention
Schematic diagram；
Fig. 2 is the circuit diagram of the embodiment 2 of Current Transformer Secondary side output loop open loop protection circuit.
Specific embodiment
Below with reference to attached drawing 1 and attached drawing 2, the present invention is described further, but should not be of the invention to limit with this
Protection scope.
A kind of Current Transformer Secondary side output loop open loop protection circuit of the present invention, including secondary with current transformer
Side output end and the automatic protection circuit and manual protection mechanism for secondary side output loop open-circuit-protection connect, it is described automatic
Protecting circuit includes at least one set of basic circuit, every group of basic circuit include a thyristor and for perceiving mutual inductor two
The both end voltage of secondary side output end and the voltage-stabilizing device for controlling turn on thyristors.
This technology avoid current transformer primary side current be not zero and secondary side output loop open a way when at open circuit
Generate high pressure, so as to avoid at open circuit sparking, contact burn, smash equipment, electrical fire, personnel electric shock etc. accidents hair
It is raw, it is ensured that the safety of production, the safety of equipment, the safety of personnel, plant maintenance convenience.
Embodiment 1
The present embodiment include the secondary side output end with current transformer and connect for secondary side output loop open circuit protect
The automatic protection circuit 30 and manual protection mechanism 40 of shield.Automatic protection circuit 30 includes one group of basic circuit comprising two-way
Zener diode D1 and bidirectional thyristor Q1；The lower end of bi-directional voltage stabilizing diode D1 is connect with the gate pole G of bidirectional thyristor Q1；It is double
The pole MT2 of upper end and bidirectional thyristor Q1 to zener diode D1 is connected to the first end K1 in output end, bidirectional thyristor
The second end K2 of the pole the MT1 connection output end of Q1.
The first auxiliary protection circuit is drawn at the connecting line b of the gate pole G of bi-directional voltage stabilizing diode D1 and bidirectional thyristor Q1
50, which includes the resistance R1 and capacitor C1 being connected in parallel, and the resistance R1 resistance value is 1.0K Ω, institute
The capacitance for stating capacitor C1 is 0.1uF.First auxiliary protection circuit 50 is applied between the pole G of Q1 and the pole MT1 for filtering out
Transient signal and unstable voltage and current signal, avoid Q1 from being connected under external disturbance.
Secondary side output end is also parallel with instruction auxiliary circuit 60, which includes series connection together two-way
The power of the zener diode D4 and resistance R3 and lamp L1 and lamp L2 being arranged in parallel, bi-directional voltage stabilizing diode D4 are 3W, institute
It states lamp L1 and lamp L2 is the light emitting diode that power is 3W, and its operating pressure drop is 1.8V~3.0V, the resistance value of resistance R3 is
The pressure stabilizing value Uz of 10 Ω, bi-directional voltage stabilizing diode D4 select 6.8V, and it is 220mA that maximum, which continues electric current of voltage regulation,；When instruction assists
When circuit 60 works, current instantaneous value If reaches 200mA, the voltage Uz+R3*If+Uf=6.8+10* at the circuit both ends
0.2+2.2=11V.
Manual protection mechanism 40 includes static contact 401, the elastically bendable moving contact for being attempted by secondary side output end
402 and control mechanism, which includes that the button 404 being connected on lock 403 and one are arranged at 402 end of moving contact
Spring 405.By lower button 404, under the action of spring 405,403 rotation of lock, into latched position, button 404 is kept
Down state, and under the action of spring 405, moving contact 402 and static contact 401 are in close contact, and are remained closed, and mutual inductor is made
Secondary side forming circuit.Lower button 404 is pressed again, and under the action of spring 405, lock 403 rotates again, is detached from latched position
And bounce, while moving contact 402 bounces under own resilient effect, moving contact 402 and static contact 401 separate, and are restored to other
The state of circuit.It manually being ensured in this way in construction, mutual inductor secondary side is closure, external circuit can be disconnected, into
Other work of row；Construction finishes, and presses and restores again.At the same time, button 404 being pressed and bouncing, and just indicates dynamic
The closure and opening of contact 402 and static contact 401.
It is to be illustrated to the course of work of circuit below, and below in explanation such as bi-directional voltage stabilizing diode D1 and two-way
The components such as thyristor Q1 will be replaced directly using abbreviation D1 and Q1 etc., but should not think that this specification is unclear with this
's.
Its process is as follows: mutual inductor secondary side exports end loop open circuit, if at this point, secondary side current I2 is exactly from defeated
Outlet K1 output needs to flow back from the end K2, and current instantaneous value gradually increases from 0, and open-circuit voltage Uac instantaneous value also gradually increases from 0
Greatly, but because output loop at this time is open circuit, Uac rises quickly, once Uac reaches the work electricity of the voltage of voltage regulation Uz and L2 of D4
The sum of pressure, then D4 starts to work, and L2 is lit, and electric current is flowed out from K1, crosses R3 through D4 and flows back to after L2, then from K2.With electric current
I2 increases, and the pressure drop Ude on R3 increases, and voltage Uac is consequently increased, once Uac reaches the voltage of voltage regulation Uz of D1, then D1 starts
Work.The portion of electrical current of I2 crosses R1 through D1, then flows back to from K2.As the portion of electrical current increases, the pressure drop Ubc on R1 increases, when
Ubc increases to the conducting voltage Ugt of Q1, and the electric current for flowing into the gate pole G of Q1 reaches the triggering and conducting electric current Igt of Q1, then Q1 quilt
Trigger forward conduction.After Q1 conducting, the voltage at the output both ends of mutual inductor is rapidly decreased to the conducting voltage of Q1, D1, D4, L2
It is turned off, electric current all flows through Q1, and the voltage of output end controls the conducting voltage in Q1.When secondary side current I2 instantaneous value passes through
Be gradually reduced after wave crest, and gradually become zero by output end K1 output, and then it is reversed increase when being exported by K2, Q1 forward direction is cut
Only.Then, inversely increasing with I2, open-circuit voltage Uac instantaneous value are also gradually inversely increased from 0, but because of output loop at this time
It is open circuit, Uac rises quickly, once Uac reaches the sum of the operating voltage of the voltage of voltage regulation Uz and L1 of D4, then D4 starts work
Make, L1 is lit, and electric current is flowed out from K2, is crossed R3 through L1 and is flowed back to after D4, then from K1.As electric current I2 increases, the pressure drop on R2
Ude increases, and voltage Uac is consequently increased, once Uac reaches the voltage of voltage regulation Uz of D1, then D1 starts to work.The portion of electrical current of I2
D1 is crossed through R1, then is flowed back to from K1.As the portion of electrical current increases, the pressure drop Ubc on R1 increases, when Ubc increases to the reversed of Q1
Conducting voltage-Ugt, and the electric current for flowing out the gate pole G of Q1 reaches the reversed triggering and conducting electric current-Igt of Q1, then Q1 is reversed triggering
Conducting.After Q1 conducting, the voltage at the output both ends of mutual inductor is rapidly decreased to the conducting voltage of Q1, and D1, D4, L1 are turned off,
Electric current all flows through Q1, and the voltage of output end controls the conducting voltage in Q1.When secondary side current I2 instantaneous value is after trough
Be gradually reduced, and gradually become zero by output end K2 output, and then it is reversed increase when being exported by K1, Q1 reversely ends.Then
Repeat this process.Current Transformer Secondary side output loop open circuit so has just obtained automatic protection.
When Current Transformer Secondary side, output loop is no longer opened a way, then after Q1 ends forward or backwards, due to D1, D4,
The condition of L1 or L2 work no longer exists, and Q1 is no longer turned on, and guard mode automatically exits from, Current Transformer Secondary side output loop
Restore to work normally.
Embodiment 2
The present embodiment and unique difference of embodiment 2 be automatic protection circuit include circuit structure it is identical and it is reversed simultaneously
Connect the first basic circuit 101 and the second basic circuit 102 in secondary side output end.Substantially due to the first basic circuit and second
The circuit structure of circuit is identical, therefore is only illustrated by taking the first basic circuit as an example herein comprising the pressure stabilizing of series connection
Diode D2 and rectifier diode D3, and the silicon controlled crystal brake pipe in parallel with zener diode D2 and rectifier diode D3
Q2, silicon controlled crystal brake pipe Q2 are the thyristor of one-way conduction；Wherein the pole A of zener diode D2 and the pole G of Q2 connect, described
The pole K of zener diode D2 is connect with the pole K of rectifier diode D3, the pole A of rectifier diode D3 and silicon controlled crystal brake pipe Q2
A be extremely connected and be connected to the first end K1 of secondary side output end, and the pole K of the silicon controlled crystal brake pipe Q2 is connected to
The second end K2 of secondary side output end.It is arranged between second end K2 at the connecting line d of the pole G of the pole A and Q2 of zener diode D2
Second auxiliary protection circuit 70, second auxiliary circuit 70 is as the circuit structure of the first auxiliary circuit 50 in embodiment 1；
It is also parallel with instruction auxiliary circuit 80 in secondary side output end, the instruction in the instruction auxiliary circuit 80 and embodiment 1 assists electricity
The circuit structure on road 60 is identical.
The working principle of the present embodiment is identical as the working principle of embodiment 1, therefore is no longer repeated.
According to the disclosure and teachings of the above specification, those skilled in the art in the invention can also be to above-mentioned embodiment party
Formula is changed and is modified.Therefore, the invention is not limited to the specific embodiments disclosed and described above, to of the invention
Some modifications and changes should also be as falling into the scope of the claims of the present invention.In addition, although being used in this specification
Some specific terms, these terms are merely for convenience of description, does not limit the present invention in any way.
Claims (8)
1. a kind of Current Transformer Secondary side output loop open loop protection circuit, it is characterised in that: including with current transformer
Secondary side output end and the automatic protection circuit and manual protection mechanism for secondary side output loop open-circuit-protection connect, it is described
Automatic protection circuit includes one group of basic circuit, and basic circuit includes a thyristor and the secondary side for perceiving mutual inductor
The both end voltage of output end and the voltage-stabilizing device for controlling turn on thyristors；
Automatic protection circuit include one group of basic circuit, the voltage-stabilizing device be bi-directional voltage stabilizing diode D1 or two-way TVS pipe,
The thyristor is bidirectional thyristor Q1；One end of bi-directional voltage stabilizing diode D1 is connect with the door G of bidirectional thyristor Q1；It is two-way steady
The pole MT2 of the other end and bidirectional thyristor Q1 of pressing diode D1 is connected to the first end in output end, bidirectional thyristor Q1's
The second end of the pole MT1 connection output end；
Secondary side output end is also parallel with instruction auxiliary circuit, which includes two pole of bi-directional voltage stabilizing of series connection together
The pipe D4 and resistance R3 and lamp L1 and lamp L2 being arranged in parallel；Wherein, one end of bi-directional voltage stabilizing diode D4 and bi-directional voltage stabilizing two
The other end of pole pipe D1 connects, and the other end of bi-directional voltage stabilizing diode D4 is connect with one end of resistance R3, the other end of resistance R3
It is connect respectively with the anode of the cathode of lamp L1 and lamp L2, the anode of lamp L1 is connected with the cathode of lamp L2；
The lamp L1 and lamp L2 is the light emitting diode that power is 3W, and its operating pressure drop is 1.8V~3.0V；Resistance R3's
Resistance value is 10 Ω, and the pressure stabilizing value Uz of bi-directional voltage stabilizing diode D4 selects 6.8V, and it is 220mA that maximum, which continues electric current of voltage regulation,；Work as instruction
When auxiliary circuit works, the voltage at the instruction auxiliary circuit both ends is 11V；
Wherein, the work of the burning voltage and lamp L1 or lamp L2 that gradually increase to bi-directional voltage stabilizing diode D4 from 0 when open-circuit voltage
When pressure drop, lamp L1 or lamp L2 are lit, and bi-directional voltage stabilizing diode D1 does not work；Reach bi-directional voltage stabilizing when open-circuit voltage gradually increases
When the burning voltage of diode D1, bi-directional voltage stabilizing diode D1 work.
2. Current Transformer Secondary side output loop open loop protection circuit as described in claim 1, it is characterised in that: two-way steady
One end of diode D1, the connecting line of gate pole G of bidirectional thyristor Q1 and the connecting line of second end of output end is pressed to be all connected to
First auxiliary protection circuit, first auxiliary protection circuit include the resistance R1 and capacitor C1 being connected in parallel.
3. Current Transformer Secondary side output loop open loop protection circuit as claimed in claim 2, it is characterised in that: the electricity
R1 resistance value is hindered between 1K Ω~2K Ω, and the capacitance of the capacitor C1 is between 0.01uF~0.1uF.
4. the Current Transformer Secondary side output loop open loop protection circuit as described in one of claims 1 to 3, feature exist
In: the manual protection mechanism includes the static contact for being attempted by secondary side output end, elastically bendable moving contact and control stick
Mechanism, the control mechanism include that the spring at moving contact end is arranged in the button being connected on lock and one.
5. a kind of Current Transformer Secondary side output loop open loop protection circuit, it is characterised in that: including with current transformer
Secondary side output end and the automatic protection circuit and manual protection mechanism for secondary side output loop open-circuit-protection connect, automatically
Protection circuit includes that circuit structure is identical and be reversely attempted by the first basic circuit and the second basic circuit of secondary side output end；
Wherein, the voltage-stabilizing device of the first basic circuit is the zener diode D2 and rectifier diode D3 being connected in series, thyristor
For silicon controlled crystal brake pipe Q2；Wherein zener diode D2 anode connect with the pole G of Q2, the cathode of the zener diode D2 and
The cathode of rectifier diode D3 connects, and the anode of rectifier diode D3 is extremely connected and is connected to the A of silicon controlled crystal brake pipe Q2
The first end of secondary side output end, and the pole K of the silicon controlled crystal brake pipe Q2 is connected to the second end of secondary side output end；
Secondary side output end is also parallel with instruction auxiliary circuit, which includes two pole of bi-directional voltage stabilizing of series connection together
The pipe D4 and resistance R3 and lamp L1 and lamp L2 being arranged in parallel；Wherein, one end of bi-directional voltage stabilizing diode D4 and rectifier diode
The anode connection of D3, the other end of bi-directional voltage stabilizing diode D4 connect with one end of resistance R3, the other end of resistance R3 respectively with
The anode connection of the cathode and lamp L2 of lamp L1, the anode of lamp L1 are connected with the cathode of lamp L2；
The lamp L1 and lamp L2 is the light emitting diode that power is 3W, and its operating pressure drop is 1.8V~3.0V；Resistance R3's
Resistance value is 10 Ω, and the pressure stabilizing value Uz of bi-directional voltage stabilizing diode D4 selects 6.8V, and it is 220mA that maximum, which continues electric current of voltage regulation,；Work as instruction
When auxiliary circuit works, the voltage at the instruction auxiliary circuit both ends is 11V；
Wherein, the work of the burning voltage and lamp L1 or lamp L2 that gradually increase to bi-directional voltage stabilizing diode D4 from 0 when open-circuit voltage
When pressure drop, lamp L1 or lamp L2 are lit, and zener diode D2 does not work；Reach zener diode D2 when open-circuit voltage gradually increases
Burning voltage when, zener diode D2 work.
6. Current Transformer Secondary side output loop open loop protection circuit as claimed in claim 5, it is characterised in that: at least one
The connecting line of the second end of the anode of the zener diode D2 of group basic circuit, the connecting line of the pole G of Q2 and secondary side output end
It is all set to the second auxiliary protection circuit, which includes the resistance R2 and capacitor C2 being connected in parallel.
7. Current Transformer Secondary side output loop open loop protection circuit as claimed in claim 6, it is characterised in that: the electricity
R2 resistance value is hindered between 1K Ω~2K Ω, and the capacitance of the capacitor C2 is between 0.01uF~0.1uF.
8. the Current Transformer Secondary side output loop open loop protection circuit as described in one of claim 5 to 7, feature exist
In: the manual protection mechanism includes the static contact for being attempted by secondary side output end, elastically bendable moving contact and control stick
Mechanism, the control mechanism include that the spring at moving contact end is arranged in the button being connected on lock and one.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510017353.7A CN104577982B (en) | 2015-01-12 | 2015-01-12 | Current Transformer Secondary side output loop open loop protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510017353.7A CN104577982B (en) | 2015-01-12 | 2015-01-12 | Current Transformer Secondary side output loop open loop protection circuit |
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| CN104577982B true CN104577982B (en) | 2019-03-15 |
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Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
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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 |
| CN105790215B (en) * | 2016-03-02 | 2018-03-09 | 闫堂锁 | CT open-circuit protecting devices |
| 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 |
| 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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| 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 |
| 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 |
| CN110412459B (en) * | 2019-08-01 | 2024-08-16 | 国网浙江省电力有限公司检修分公司 | Quick switching operating mechanism for secondary circuit of current transformer |
| 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 |
| CN113740792B (en) * | 2021-08-27 | 2024-09-20 | 保定北特电气设备制造有限公司 | Current transformer secondary open circuit post-leakage metering system and method |
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