CN206517032U - DC side earth-fault protection in DC power-supply system - Google Patents
DC side earth-fault protection in DC power-supply system Download PDFInfo
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- CN206517032U CN206517032U CN201720006854.XU CN201720006854U CN206517032U CN 206517032 U CN206517032 U CN 206517032U CN 201720006854 U CN201720006854 U CN 201720006854U CN 206517032 U CN206517032 U CN 206517032U
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- leakage current
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Abstract
The utility model discloses the DC side earth-fault protection in a kind of DC power-supply system; including D.C. contactor, leakage current sensor, sampling resistor, amplifying circuit, comparison circuit and exclusive circuit; D.C. contactor one end is connected with DC power output end, and the other end is connected by leakage current sensor with load；The output end of leakage current sensor is connected with sampling resistor；Amplifying circuit is connected with the output end of leakage current sensor, for leakage current signal to be amplified；Comparison circuit is used to receive the leakage current signal after the amplification of leakage current sensor transmission, and is compared with the threshold value of setting, forms comparator output；Locking circuit compares output for reception, and by comparing the switch of output control D.C. contactor.The utility model can carry out inverse time-lag protection according to the size of leakage current, so as to fully ensure that personal safety, it is possible to avoid misoperation, effectively raise earth leakage protective sensitivity and reliability.
Description
Technical field
The utility model is related to a kind of electric power system protection device, and in particular to the DC side in a kind of DC power-supply system
Earth-fault protection.
Background technology
Earth leakage protective is concerning personal safety, in high-voltage direct current, once occur earth fault, even if electric current is very micro-
It is small, it is still to cut off circuit as early as possible, in order to avoid cause personal injury accidents.Therefore during DC ground fault protection is high-voltage direct current
Indispensable protection.
Existing earth leakage protective is mainly used in AC system, when there is short trouble, by circuit breaker trip short circuit
Branch road, is protected, so as to ensure that the power supply of system other parts do not broken down is unaffected；When there is earth fault
When, protected by earth leakage circuit-breaker.When the effect of earth leakage circuit-breaker is the earth current for experiencing very little, you can do
Go out reaction, cut-out ground connection branch road, the main function of this protection is to ensure that personal safety；When human contact is to exchange live wire,
Live wire and the earth constitute loop by human body, and because human body resistance is larger, electric current is smaller in loop, but very little is flowed through on human body
Electric current just may be fatal, it is therefore desirable to be equipped with earth leakage circuit-breaker, flow to the electric current of the earth for detecting, electric current exists when normal
Live wire and it is leading between flow, electric current is not had and enters the earth, once finding there is the Weak current that flows to the earth, earth leakage protective is opened
Close with regard to starting protection, cut-out electric leakage branch road.
What it is due to detection earth current is an AC current transformer, is only able to detect alternating current.Work as electric power system
During for HVDC, what direct current anode or negative terminal were produced after human body grounding is DC current, such AC current transformer without
Method detects DC leakage electric current, causes earth leakage protective failure.
Application No. 201410059669.8 discloses a kind of DC leakage current detection and protection circuit and detection and protection
Method, using the detection circuit of output current and input current difference for detecting dc source, difference signal amplifies with being compared
Circuit, relay interlocking and IGCT (controllable silicon) control protection electric circuit, DC leakage protection test circuit.The utility model is carried
The method of confession is suitable only for the situation of low current and low-voltage.It is not appropriate for for the high-power circuit of high-voltage great-current.
Application No. 201520896813.3 discloses a kind of device for measuring DC line Ground leakage current, the device bag
Include electric current supercircuit, the first DC leakage current transformer, the second DC leakage current transformer, subtraction circuit and signal
Conversion module.Although the utility model expands application using sensor, then counted using the output of two sensors
The method error for calculating difference is larger.Compared to leakage current, line circuit is a very big value, and inspection is used as with two differences counted greatly
Result is surveyed, its error will be very big in theory, and this will directly affect it and protect result.
Utility model content
The utility model be in order to overcome in the prior art earth leakage protective it is not high in straight-flow system medium sensitivity and reliability
The problem of there is provided the DC side earth-fault protection in a kind of DC power-supply system, can be according to the size of leakage current
Inverse time-lag protection is carried out, so as to fully ensure that personal safety, it is possible to avoid misoperation, earth leakage protective spirit is effectively raised
Sensitivity and reliability.
The utility model provides the DC side earth-fault protection in a kind of DC power-supply system, including direct current contact
Device, leakage current sensor, sampling resistor, amplifying circuit, comparison circuit and exclusive circuit, D.C. contactor one end and dc source
Output end is connected, and the other end is connected by leakage current sensor with load；The output end of leakage current sensor and sampling resistor phase
Even, for leakage current signal to be changed into magnitude of voltage；Amplifying circuit is connected with the output end of leakage current sensor, for that will leak electricity
Signal amplification is flowed, and the leakage current signal after amplification is sent to comparison circuit；Comparison circuit is used to receive leakage current sensor
Leakage current signal after the amplification of transmission, and compared with the threshold value of setting, comparator output is formed, and comparator is exported into transmission
To locking circuit；Locking circuit compares output for reception, and by comparing the switch of output control D.C. contactor.
DC side earth-fault protection in a kind of DC power-supply system described in the utility model, is used as preferred side
Formula, amplifying circuit is made up of the first operational amplifier, first resistor and second resistance；The positive input of first operational amplifier
It is grounded and is connected with sampling resistor one end, the reverse input end of the first operational amplifier is connected with the sampling resistor other end, first
The reverse input end of operational amplifier is grounded by first resistor, and the reverse input end of the first operational amplifier passes through second resistance
It is connected with the output end of the first operational amplifier, the output end of the first operational amplifier is connected with comparison circuit.
DC side earth-fault protection in a kind of DC power-supply system described in the utility model, is used as preferred side
Formula, comparison circuit is made up of the second operational amplifier, the 3rd operational amplifier, 3rd resistor and reference power source；Second computing is put
The big positive input of device is connected with the output end of the first operational amplifier and the 3rd operational amplifier reverse input end, the second fortune
The reverse input end for calculating amplifier is connected with reference power source positive pole, and the output end of the second operational amplifier is connected with 3rd resistor,
The output end of second operational amplifier is connected with exclusive circuit, positive input and the reference power source negative pole of the 3rd operational amplifier
It is connected, the reverse input end of the 3rd operational amplifier and the positive input of the second operational amplifier and the first operational amplifier
Output end is connected, and the output end of the 3rd operational amplifier is connected with exclusive circuit.
DC side earth-fault protection in a kind of DC power-supply system described in the utility model, is used as preferred side
Formula, exclusive circuit is by the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, the first metal-oxide-semiconductor, the 2nd MOS
Pipe, the 3rd metal-oxide-semiconductor, the first triode and the second triode composition；First G grades of metal-oxide-semiconductor is connected with comparison circuit output end, and first
D grades of metal-oxide-semiconductor is connected with by the 4th resistance with positive source, and the first D grades of metal-oxide-semiconductor passes through G grades of phases of the 5th resistance and the second metal-oxide-semiconductor
Even, the first S grade of metal-oxide-semiconductor ground connection, the first S grade of metal-oxide-semiconductor and the 3rd metal-oxide-semiconductor S-phase company, the first S grades of metal-oxide-semiconductor pass through the 6th resistance and the
Two D grades of metal-oxide-semiconductors are connected, and the second S grades of metal-oxide-semiconductor is connected with positive source, and the G levels of the second metal-oxide-semiconductor are connected with the first triode ground level,
The G levels of second metal-oxide-semiconductor with the 7th resistance with positive source by being connected, the D levels of the 3rd metal-oxide-semiconductor and the first triode ground level phase
Even, the emitting stage of the first triode ground connection, the ground level phase that the colelctor electrode of the first triode passes through the 8th resistance and the second triode
Even, the emitting stage of the second triode is connected with positive source, and the colelctor electrode of the second triode is connected with D.C. contactor.
The utility model uses the DC current sensor of Hall effect, positive-negative power line also cross sensor, this
The difference for the electric current on simply positive and negative two line that sample sensor is detected, that is, DC leakage current.In use, biography
The output of sensor enters filtering and amplifying circuit, and its alternating component is filtered out by low pass filter, and so remaining is exactly direct current leakage
Electric current, outputs it and accesses comparator anode through delay circuit, and the negative terminal of comparator connects rotection thresholds, is protected when leakage current value is more than
When protecting threshold value, comparator is output as height, protection act, and locks protection through exclusive circuit, until weight after manual reset or power-off
New upper electricity.
The utility model can carry out inverse time-lag protection according to the size of leakage current, so that personal safety is fully ensured that,
And misoperation can be avoided, effectively raise earth leakage protective sensitivity and reliability.
Brief description of the drawings
Fig. 1 is the DC side earth-fault protection schematic diagram in a kind of DC power-supply system.
Fig. 2 be a kind of DC power-supply system in DC side earth-fault protection amplifying circuit circuit diagram.
Fig. 3 be a kind of DC power-supply system in DC side earth-fault protection comparison circuit circuit diagram.
Fig. 4 be a kind of DC power-supply system in DC side earth-fault protection locking circuit circuit diagram.
Reference：U1, the first operational amplifier；U2, the second operational amplifier；U3, the 3rd operational amplifier；Vth, ginseng
Examine power supply；R1, first resistor；R2, second resistance；R3,3rd resistor；R4, the 4th resistance；R5, the 5th resistance；R6, the 6th electricity
Resistance；R7, the 7th resistance；R8, the 8th resistance；MOS1, the first metal-oxide-semiconductor；MOS2, the second metal-oxide-semiconductor；MOS3, the 3rd metal-oxide-semiconductor；Q1,
One triode；Q2, the second triode.
Embodiment
Embodiment 1
As shown in figures 1-4, the utility model provides the DC side earth-fault protection dress in a kind of DC power-supply system
Put, including D.C. contactor, leakage current sensor, sampling resistor, amplifying circuit, comparison circuit and exclusive circuit, direct current contact
Device one end is connected with DC power output end, and the other end is connected by leakage current sensor with load；Leakage current sensor it is defeated
Go out end with sampling resistor to be connected, for leakage current signal to be changed into magnitude of voltage；The output of amplifying circuit and leakage current sensor
End is connected, and comparison circuit is sent to for leakage current signal to be amplified, and by the leakage current signal after amplification；Comparison circuit is used for
The leakage current signal after the amplification of leakage current sensor transmission is received, and is compared with the threshold value of setting, comparator output is formed, and
Comparator output is sent to locking circuit；Locking circuit compares output for reception, and is connect by comparing output control direct current
The switch of tentaculum.
Amplifying circuit is made up of the first operational amplifier U1, first resistor R1 and second resistance R2；First operational amplifier
U1 positive input is grounded and is connected with sampling resistor one end, the first operational amplifier U1 reverse input end and sampling resistor
The other end is connected, and the first operational amplifier U1 reverse input end is grounded by first resistor R1, the first operational amplifier U1's
Reverse input end is connected by second resistance R2 with the first operational amplifier U1 output end, the first operational amplifier U1 output
End is connected with comparison circuit.
Comparison circuit is by the second operational amplifier U2, the 3rd operational amplifier U3,3rd resistor R3 and reference power source Vth groups
Into；The output end and the 3rd operational amplifier U3 of second operational amplifier U2 positive input and the first operational amplifier U1 are anti-
It is connected to input, the second operational amplifier U2 reverse input end is connected with reference power source Vth positive poles, the second operational amplifier
U2 output end is connected with 3rd resistor R3, and the second operational amplifier U2 output end is connected with exclusive circuit, and the 3rd computing is put
Big device U3 positive input is connected with reference power source Vth negative poles, the 3rd operational amplifier U3 reverse input end and the second fortune
The output end of the positive input and the first operational amplifier U1 of calculating amplifier U2 is connected, the 3rd operational amplifier U3 output end
It is connected with exclusive circuit.
Exclusive circuit is by the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the 7th resistance R7, the 8th resistance R8, first
Metal-oxide-semiconductor MOS1, the second metal-oxide-semiconductor MOS2, the 3rd metal-oxide-semiconductor MOS3, the first triode Q1 and the second triode Q2 compositions；First MOS
Pipe MOS1 G levels are connected with comparison circuit output end, and the first metal-oxide-semiconductor MOS1 D levels are with passing through the 4th resistance R4 positive source phases
Even, the first metal-oxide-semiconductor MOS1 D levels are connected by the 5th resistance R5 with the second metal-oxide-semiconductor MOS2 G levels, the first metal-oxide-semiconductor MOS1 S
Level ground connection, the first metal-oxide-semiconductor MOS1 S levels connect with the 3rd metal-oxide-semiconductor MOS3 S-phase, and the first metal-oxide-semiconductor MOS S levels pass through the 6th resistance
R6 is connected with the second metal-oxide-semiconductor MOS2 D levels, and the second metal-oxide-semiconductor MOS2 S levels are connected with positive source, the second metal-oxide-semiconductor MOS2 G
Level be connected with the first triode Q1 ground level, the second metal-oxide-semiconductor MOS2 G levels by being connected with the 7th resistance R7 with positive source,
3rd metal-oxide-semiconductor MOS3 D levels are connected with the first triode Q1 ground level, the first triode Q1 emitting stage ground connection, the first three-level
Pipe Q1 colelctor electrode is connected by the 8th resistance R8 with the second triode Q2 ground level, the second triode Q2 emitting stage and power supply
Positive pole is connected, and the second triode Q2 colelctor electrode is connected with D.C. contactor.
In use, the output of leakage current sensor is connected on a sampling resistor the present embodiment, and leakage current is believed
Number it is changed into magnitude of voltage；Amplifying circuit is the discharge circuit of a dual power supply, leakage current signal can be amplified, due to leakage current
Direction may be for just, it is also possible to be negative, therefore dual power supply amplifier is used, it can be carried out amplification in positive and negative both direction；Electric leakage letter
Number comparison circuit is amplified into, comparison circuit is a window comparator, using dual power supply, and positive threshold is Vth, born
It is-Vth to threshold value, when leakage current is no more than threshold value, comparator is output as height；When leakage current exceedes threshold value, comparator is defeated
Go out to be low；The output of comparator enters exclusive circuit, and comparator is output as height when normal, and the output triode of exclusive circuit is in
Opening state, 24V power supplys are connected to D.C. contactor coil, contactor adhesive；When leakage current exceedes threshold value, comparator is reversed to
Low, output the first triode Q1 and the second triode Q2 shut-off of exclusive circuit, the 24V for being connected to D.C. contactor coil are cut
Disconnected, contactor disconnects, even if leakage current recovers normal afterwards, and comparator overturns as height again, due to the effect of exclusive circuit,
24V power supplys still can not be connected to D.C. contactor coil, therefore load supplying still can not recover.Only completely close system electricity
Source, then after restarting, can recover normal.
It is described above to be merely exemplary for the utility model, and nonrestrictive, those of ordinary skill in the art
Understand, in the case where not departing from the spirit and scope that claim is limited, any modification, change or the equivalent shape that can be made
Formula is fallen within the protection domain of utility model.
Claims (4)
1. the DC side earth-fault protection in a kind of DC power-supply system, it is characterised in that：Including D.C. contactor, leakage
Current sensor, sampling resistor, amplifying circuit, comparison circuit and exclusive circuit, described D.C. contactor one end and dc source
Output end is connected, and the other end is connected by the leakage current sensor with load；The output end of the leakage current sensor is with adopting
Sample resistance is connected, for leakage current signal to be changed into magnitude of voltage；The output of the amplifying circuit and the leakage current sensor
End is connected, and comparison circuit is sent to for leakage current signal to be amplified, and by the leakage current signal after amplification；The comparison circuit
The leakage current signal after amplification for receiving the leakage current sensor transmission, and compared with the threshold value of setting, formation is compared
Device is exported, and comparator output is sent into locking circuit；The locking circuit be used to receiving it is described compare output, and lead to
Cross the switch for comparing output control D.C. contactor.
2. the DC side earth-fault protection in a kind of DC power-supply system according to claim 1, its feature exists
In：The amplifying circuit is made up of the first operational amplifier (U1), first resistor (R1) and second resistance (R2)；First fortune
The positive input for calculating amplifier (U1) is grounded and is connected with described sampling resistor one end, first operational amplifier (U1)
Reverse input end is connected with the sampling resistor other end, and the reverse input end of first operational amplifier (U1) passes through described
First resistor (R1) is grounded, the reverse input end of first operational amplifier (U1) by the second resistance (R2) with it is described
The output end of first operational amplifier (U1) is connected, output end and the comparison circuit phase of first operational amplifier (U1)
Even.
3. the DC side earth-fault protection in a kind of DC power-supply system according to claim 2, its feature exists
In：The comparison circuit is by the second operational amplifier (U2), the 3rd operational amplifier (U3), 3rd resistor (R3) and reference power source
(Vth) constitute；The positive input of second operational amplifier (U2) and the output end of first operational amplifier (U1)
It is connected with the 3rd operational amplifier (U3) reverse input end, the reverse input end of second operational amplifier (U2) and institute
State reference power source (Vth) positive pole to be connected, the output end of second operational amplifier (U2) is connected with the 3rd resistor (R3),
The output end of second operational amplifier (U2) is connected with the exclusive circuit, the forward direction of the 3rd operational amplifier (U3)
Input is connected with the reference power source (Vth) negative pole, the reverse input end of the 3rd operational amplifier (U3) and described the
The positive input of two operational amplifiers (U2) is connected with the output end of first operational amplifier (U1), the 3rd computing
The output end of amplifier (U3) is connected with the exclusive circuit.
4. the DC side earth-fault protection in a kind of DC power-supply system according to claim 3, its feature exists
In：The exclusive circuit is by the 4th resistance (R4), the 5th resistance (R5), the 6th resistance (R6), the 7th resistance (R7), the 8th resistance
(R8), the first metal-oxide-semiconductor (MOS1), the second metal-oxide-semiconductor (MOS2), the 3rd metal-oxide-semiconductor (MOS3), the first triode (Q1) and the two or three pole
Manage (Q2) composition；G grades of first metal-oxide-semiconductor (MOS1) is connected with the comparison circuit output end, first metal-oxide-semiconductor (MOS1)
D grades are connected with by the 4th resistance (R4) with positive source, D grades of first metal-oxide-semiconductor (MOS1) by the 5th resistance (R5) with
G grades of second metal-oxide-semiconductor (MOS2) is connected, described S grades of ground connection of first metal-oxide-semiconductor (MOS1), S grades of first metal-oxide-semiconductor (MOS1)
Connect with the 3rd metal-oxide-semiconductor (MOS3) S-phase, S grade of first metal-oxide-semiconductor (MOS1) passes through the 6th resistance (R6) and described the
D grades of two metal-oxide-semiconductors (MOS2) are connected, and S grades of second metal-oxide-semiconductor (MOS2) is connected with positive source, second metal-oxide-semiconductor (MOS2)
G levels be connected with the first triode (Q1) ground level, the G levels of second metal-oxide-semiconductor (MOS2) by with the 7th resistance
(R7) it is connected with positive source, the D levels of the 3rd metal-oxide-semiconductor (MOS3) are connected with the first triode (Q1) ground level, first
The emitting stage ground connection of triode (Q1), the colelctor electrode of first triode (Q1) passes through the 8th resistance (R8) and described the
The ground level of two triodes (Q2) is connected, and the emitting stage of second triode (Q2) is connected with positive source, the two or three pole
The colelctor electrode of pipe (Q2) is connected with the D.C. contactor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720006854.XU CN206517032U (en) | 2017-01-04 | 2017-01-04 | DC side earth-fault protection in DC power-supply system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720006854.XU CN206517032U (en) | 2017-01-04 | 2017-01-04 | DC side earth-fault protection in DC power-supply system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206517032U true CN206517032U (en) | 2017-09-22 |
Family
ID=59864346
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720006854.XU Active CN206517032U (en) | 2017-01-04 | 2017-01-04 | DC side earth-fault protection in DC power-supply system |
Country Status (1)
| Country | Link |
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| CN (1) | CN206517032U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106711932A (en) * | 2017-01-04 | 2017-05-24 | 山东中大电源科技有限公司 | DC side ground fault protection device in DC power supply system |
| CN112952748A (en) * | 2021-02-01 | 2021-06-11 | 重庆中车长客轨道车辆有限公司 | Leakage protection device |
-
2017
- 2017-01-04 CN CN201720006854.XU patent/CN206517032U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106711932A (en) * | 2017-01-04 | 2017-05-24 | 山东中大电源科技有限公司 | DC side ground fault protection device in DC power supply system |
| CN112952748A (en) * | 2021-02-01 | 2021-06-11 | 重庆中车长客轨道车辆有限公司 | Leakage protection device |
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