CN103066554B - Single-phase source leakage detection circuit for isolated neutral system - Google Patents
Single-phase source leakage detection circuit for isolated neutral system Download PDFInfo
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- CN103066554B CN103066554B CN201210536925.9A CN201210536925A CN103066554B CN 103066554 B CN103066554 B CN 103066554B CN 201210536925 A CN201210536925 A CN 201210536925A CN 103066554 B CN103066554 B CN 103066554B
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Abstract
The invention relates to a leakage detection circuit, in particular to a single-phase source leakage detection circuit applied to an isolated neutral system. Two electrodes of a single-phase source are respectively connected with a commutation diode, and a sampling unit is connected between the two commutation diodes and the ground. The output end of the sampling unit is connected with a comparison output unit. The comparison output unit is connected with a relay triggering unit. Through the adoption of the structure, a detection mutual inductor is saved, a voltage drive logic circuit of a leakage resistance in a half-wave rectifying circuit is utilized to achieve detection when a power source leaks electricity, and therefore cost is saved. In addition, misoperation caused by voltage floating is reduced, and the safety of mine power supply is improved.
Description
Technical field
The present invention relates to a kind of electric-leakage detection circuit, particularly a kind of electric-leakage detection circuit being applicable to isolated neutral system one-way electric power.
Background technology
Underground coal mine 127V power supply is used for illumination and communication apparatus is powered, and because subsurface environment is relatively severe, cable insulation reduction or electric leakage accident easily occurs and endangers personal safety.Therefore require more and more higher to the detection perform of comprehensive protection device, when particularly line voltage changes in-25% ~+20% scope, claimed device still can normal power supply, and when fault protector energy regular event.
Existing 127V earth leakage protective device mostly adopt detect instrument transformer detect insulation reduce or electric leakage time the zero sequence variable quantity that produces, then variable quantity is sent into Logic judgment or modulate circuit sends into single-chip microcomputer process again.Testing circuit is complicated, larger for device precision degree of dependence.More signal intensity number of times is had from detection instrument transformer to last process.Its metrical error may be there is in each device.Finally cause the amplification at double of error.The generation of protector malfunction or misaction when occurring to leak electricity or insulate reduction may be caused.
Summary of the invention
The technical issues that need to address of the present invention are to provide a kind of electric-leakage detection circuit of mine power supply.
For solving above-mentioned technical problem, described in isolated neutral system one-way electric power electric-leakage detection circuit of the present invention, the two poles of the earth of single phase poaer supply are respectively connected with a rectifier diode, described two are connected with sampling unit between rectifier diode and ground, the output of described sampling unit with compare output unit and be connected, the described output unit that compares is connected with relay trigger element;
Wherein, described sampling unit comprises the series circuit of sampling resistor and divider resistance, and described sampling resistor two ends are parallel with filter capacitor, and the tie point of described sampling resistor and divider resistance is sampled output;
The described output unit that compares comprises the first comparator, and the input of described first comparator is connected with sampled output;
Described relay trigger element comprises direct current relay and switch triode, and the collector electrode of described switch triode is connected with direct current relay, and the base stage of described switch triode is connected with the first comparator output terminal.
Further, described switch triode is connected with holding unit with comparing between output unit, and described holding unit is connected with triggering holding unit with comparing between output unit;
Described holding unit comprises the 3rd comparator, and the output of described 3rd comparator to be connected with input formation positive feedback by resistance;
Described triggering holding unit comprises the second comparator, and the input of described second comparator is connected with the first comparator output terminal, and the output of described second comparator is connected with the 3rd comparator input terminal.
Further, described triggering holding unit connects pole between output unit and has partition optocoupler with comparing.
Further, described direct current relay fly-wheel diode in parallel.
After adopting said structure, circuit of the present invention is directly by 127V voltage access baffle, and when cable insulation is normal, the rectification effective value of the rectification circuit in circuit is zero.When insulation variation occurs circuit, according to the change of cable insulation degree, the step-down produced on sample resistance in half-wave rectifying circuit constantly changes.Directly reflect the insulation situation of change of circuit.Sampling pressure drop taking-up and benchmark are compared, finally causes the upset of logic gates.Accurately, reliably, three linear variable quantities are had can to ensure the normal reliable upset of circuit in this circuit arrangement.A change being the change of cable insulation against ground degree and directly can making voltage on sample resistance.Also have a variable quantity being voltage floats can make the benchmark generation linear change of gate circuit.Last variable quantity being voltage floats can directly make sampling voltage change.So sampling aspect is the completely direct variable quantity obtaining insulation.Signal number of transitions is few, and almost without intermediate computations, error is little, and device precision degree of dependence is low.Make this circuit operation reliable.The more important thing is that solving voltage floats in situation, the accident for protector tripping and malfunction during cable leakage occurs.This circuit theory is simple, and reliable in action, detected value does not change by voltage fluctuation.Eliminate detection instrument transformer, when directly utilizing power supply that electric leakage occurs, the rectification changes in balance amount in circuit is carried out driving logic circuit and is completed detection, saves cost.Meanwhile, decrease the nonaction produced because voltage floats, improve the fail safe of mine power supply.
Accompanying drawing explanation
Below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.
Fig. 1 is the circuit theory diagrams of the first execution mode of the present invention.
Fig. 2 is the circuit theory diagrams of the second execution mode of the present invention.
In figure: 1 is single phase poaer supply, 2 is sampling unit, and 3 for comparing output unit, and 4 for triggering holding unit, and 5 is holding unit, and 6 is relay trigger element, and 7 is the first comparator, and 8 is the second comparator, and 9 is the 3rd comparator
Embodiment
Execution mode one:
As shown in Figure 1, described in isolated neutral system one-way electric power electric-leakage detection circuit of the present invention, the two poles of the earth of single phase poaer supply 1 are respectively connected with a rectifier diode, i.e. rectifier diode V1 and V2 in Fig. 1, and single phase poaer supply 1 adopts down-hole 127V general AC power supply.Be connected with sampling unit 2 between described two rectifier diode V1 and V2 and ground, described sampling unit comprises the series circuit of sampling resistor R4 and divider resistance, and here in order to obtain the resistance needed, divider resistance is the series resistance of resistance R3 and R31.Described sampling resistor R4 two ends are parallel with filter capacitor, and filter capacitor is the shunt capacitance group of electrochemical capacitor C9 and C10, and the tie point of described sampling resistor R4 and resistance R31 is sampled output.
The output of described sampling unit with compare output unit 3 and be connected, the described output unit that compares comprises the first comparator 7, and the input 7 of described first comparator is connected with sampled output.The reference voltage of the first comparator 7 is the series connection dividing potential drop of resistance R5, R6 and power supply VJ, and the intermediate connection point of resistance R5 with R6 is connected with reference voltage input.
The described output unit 3 that compares is connected with relay trigger element 6; Described relay trigger element 6 comprises direct current relay KS1 and switch triode VT1, and the collector electrode of described switch triode VT1 is connected with direct current relay KS1, and the base stage of described switch triode is connected with the first comparator 7 output.
The operation principle of single-phase source leakage detection circuit of the present invention is as follows: when circuit leakproof, and two diode rectification balances, any change can not occur, and sampling unit 2 also can not obtain sampled signal.When Leaked Current of Line to Ground occurs in supply line, electric leakage place can produce leak resistance, and rectification circuit just becomes halfwave rectifier.Such R3, R4, R31 there will be the voltage drop of halfwave rectifier, this voltage drop is taken out in proportion as drive singal, drive singal rectification is direct current signal by filter capacitor C9, C10, is input to by this direct current signal compares input unit 3 as logic comparison signal.After comparing with the reference voltage of the first comparator 7, export high level, high level driving switch triode VT1, makes triode VT1 conducting, makes direct current relay KS1 adhesive like this, peripheral circuit is disconnected, protection peripheral circuit.
Further, in order to after electric leakage being detected, make relay remain on the state of adhesive, make the state that peripheral circuit remains open; Until be checked through electric leakage place and hand-reset after process.So need to be connected holding unit 5 at switch triode VT1 with comparing between output unit 3, described holding unit 5 triggers holding unit 4 with comparing to be connected with between output unit 3.
Described holding unit 5 comprises the 3rd comparator 9, and the output of described 3rd comparator to be connected with input formation positive feedback by resistance, and resistance is the series resistance of R17 and R18 here.Described triggering holding unit 4 comprises the second comparator 8, and the input of described second comparator 8 is connected with the first comparator 7 output, and the output of described second comparator 8 is connected with the 3rd comparator 9 input.The reference voltage of the second comparator 8 is the series connection dividing potential drop of resistance R11, R12 and power supply VC, and the intermediate connection point of resistance R11 with R12 is connected with the reference voltage input of the second comparator 8.The reference voltage of the 3rd comparator 9 is the series connection dividing potential drop of resistance R15, R16 and power supply VC, and the intermediate connection point of resistance R15 with R16 is connected with the reference voltage input of the 3rd comparator 9.From above, when electric leakage being detected, the output of the first comparator 7 is high level, after the high level that so the first comparator 7 exports is input to the second comparator 8, exporting also is high level, the effect triggering holding unit 4 is used on the one hand to trigger holding unit 5, is that the high level voltage for triggering holding unit 5 is stablized on the other hand.Be connected with the input of the 3rd comparator 9 of trigger element 5 after second comparator 8 exports high level, output like this with regard to triggering holding unit 5 is high level, because the output of the 3rd comparator 9 forms positive feedback by resistance R17 and R18, so just make the input of the 3rd comparator 9 keep high level, the output of holding unit 5 also keeps high level always.Such holding unit 5 just can maintained switch triode ON, makes direct current relay keep attracting state.
Further, because input ac power is high pressure, in order to high pressure and low pressure be separated, protection triggers holding unit 4 and follow-up low-voltage circuit thereof, to connect pole at described triggering holding unit 4 and has and cut off optocoupler G1 with comparing between output unit 3.
Further, described direct current relay fly-wheel diode V3 in parallel.Because direct current relay can produce back-emf when disconnecting, impact or component damage circuit, fly-wheel diode V3 can well not be damaged by protective circuit components and parts.
Execution mode two:
As shown in Figure 2, the single phase poaer supply of single-phase source leakage detection circuit of the present invention may connect multiple output, in order to when electric leakage being detected, each output branch road can be controlled to disconnect.Other parts of execution mode two are identical with execution mode one, the output that difference is triggering holding unit 4 is parallel with multiple holding unit, be connected with relay trigger element after each holding unit, the output of each holding unit is connected with the switch triode base stage of relay trigger element.
Although the foregoing describe the specific embodiment of the present invention, those of skill in the art in the art should be appreciated that these only illustrate, can make various changes or modifications, and do not deviate from principle of the present invention and essence to these execution modes.Scope of the present invention only has appended claims to limit.
Claims (3)
1. an isolated neutral system single-phase source leakage detection circuit, it is characterized in that: the two poles of the earth of described single phase poaer supply are respectively connected with a rectifier diode, sampling unit is connected with between two described rectifier diodes and ground, the output of described sampling unit with compare output unit and be connected, the described output unit that compares is connected with relay trigger element;
Wherein, described sampling unit comprises the series circuit of sampling resistor and divider resistance, and described sampling resistor two ends are parallel with filter capacitor, and the tie point of described sampling resistor and divider resistance is sampled output;
The described output unit that compares comprises the first comparator, and the input of described first comparator is connected with sampled output;
Described relay trigger element comprises direct current relay and switch triode, and the collector electrode of described switch triode is connected with direct current relay, and the base stage of described switch triode is connected with the first comparator output terminal, the grounded emitter of switch triode;
Described switch triode is connected with holding unit with comparing between output unit, and described holding unit is connected with triggering holding unit with comparing between output unit;
Described holding unit comprises the 3rd comparator, and the output of described 3rd comparator to be connected with input formation positive feedback by resistance;
Described triggering holding unit comprises the second comparator, and the input of described second comparator is connected with the first comparator output terminal, and the output of described second comparator is connected with the 3rd comparator input terminal.
2. according to isolated neutral system single-phase source leakage detection circuit according to claim 1, it is characterized in that: described triggering holding unit is connected with partition optocoupler with comparing between output unit.
3. according to isolated neutral system single-phase source leakage detection circuit according to claim 1, it is characterized in that: described direct current relay fly-wheel diode in parallel.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210536925.9A CN103066554B (en) | 2012-12-12 | 2012-12-12 | Single-phase source leakage detection circuit for isolated neutral system |
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| CN201210536925.9A CN103066554B (en) | 2012-12-12 | 2012-12-12 | Single-phase source leakage detection circuit for isolated neutral system |
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| CN103066554A CN103066554A (en) | 2013-04-24 |
| CN103066554B true CN103066554B (en) | 2015-02-25 |
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| CN108594074A (en) * | 2018-04-28 | 2018-09-28 | 三电电缆股份有限公司 | A kind of cable automatic double surface gluer |
| CN110780224A (en) * | 2018-07-11 | 2020-02-11 | 西门子股份公司 | Ground fault detection circuit and device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2191487Y (en) * | 1994-06-14 | 1995-03-08 | 张宝明 | residual current action protector |
| JP3452445B2 (en) * | 1996-07-23 | 2003-09-29 | 株式会社日立産機システム | Earth leakage breaker |
| CN101182956A (en) * | 2007-11-10 | 2008-05-21 | 杨发生 | Intelligent type omnibearing protection, auto-reclosing, multipurpose flowing water type electric water heater |
| CN202586267U (en) * | 2012-03-01 | 2012-12-05 | 张永清 | On-line phase voltage monitoring device |
| CN202957571U (en) * | 2012-12-12 | 2013-05-29 | 常州联力自动化科技有限公司 | Electric leakage detection circuit for single-phase power supply of isolated neutral system |
-
2012
- 2012-12-12 CN CN201210536925.9A patent/CN103066554B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2191487Y (en) * | 1994-06-14 | 1995-03-08 | 张宝明 | residual current action protector |
| JP3452445B2 (en) * | 1996-07-23 | 2003-09-29 | 株式会社日立産機システム | Earth leakage breaker |
| CN101182956A (en) * | 2007-11-10 | 2008-05-21 | 杨发生 | Intelligent type omnibearing protection, auto-reclosing, multipurpose flowing water type electric water heater |
| CN202586267U (en) * | 2012-03-01 | 2012-12-05 | 张永清 | On-line phase voltage monitoring device |
| CN202957571U (en) * | 2012-12-12 | 2013-05-29 | 常州联力自动化科技有限公司 | Electric leakage detection circuit for single-phase power supply of isolated neutral system |
Non-Patent Citations (1)
| Title |
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| 低压综合保护器的漏电保护实现;马星河等;《煤矿机电》;20100630(第3期);第4－7页 * |
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