CN203747363U - DC arc fault detection circuit and protective device - Google Patents
DC arc fault detection circuit and protective device Download PDFInfo
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- CN203747363U CN203747363U CN201420086440.9U CN201420086440U CN203747363U CN 203747363 U CN203747363 U CN 203747363U CN 201420086440 U CN201420086440 U CN 201420086440U CN 203747363 U CN203747363 U CN 203747363U
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Abstract
The utility model discloses a DC arc fault detection circuit and a DC arc fault detection protective device. The DC arc fault detection protective device comprises a solid-state switch or a mechanical relay, an AC component detection circuit, a first AND gate and a DC arc fault detection circuit. The DC arc fault detection circuit and the DC arc fault detection protective device are simple in structure, fast in detection speed and high in reliability, can be implemented by just adopting analog and digital integrated circuits conveniently, and has low implementation and manufacturing costs. The DC arc fault detection circuit and the DC arc fault detection protective device can be widely applied to low-voltage and high-voltage power systems of aircrafts and vessels, photovoltaic cell systems and civil high-voltage DC power transmission and distribution systems.
Description
Technical field
The utility model relates to testing circuit and the protective device of arc fault in a kind of direct current power system, belongs to electrical technology field.
Background technology
Because the insulation property of electric wire are aging, damage in insulation and the arc fault that reason causes such as there was dampness in the air, splicing ear is loosening, easily directly or indirectly power supply-distribution system and power consumption equipment etc. are caused damage.Divide according to the character of the residing power-supply system of arc fault, can be divided into alternating current arc fault and direct-current arc fault.Arc fault is accompanied by spark, Mingguang City and high temperature, can cause the insulation of electric wire further to damage, and even causes electrical fire.
Direct-current arc fault signature and alternating current arc fault signature difference are very large: when alternating current arc current cycle and zero passage, have " Ling Xiu district "; Not periodically, there is not the concept of first-harmonic, and there is very strong randomness and non-stationary in direct current.Therefore the characteristic criterion of alternating current arc fault detect is not suitable for the detection of direct-current arc fault.Because direct-current arc does not exist zero crossing, is not easy arc extinguishing, as protected not in time, may there is long arcing in addition, cause fault to expand, so direct-current arc fault detect requires more accurately and be quick.
Theoretical and experimental study shows in a large number, and in direct-current arc fault generating process, the time domain of arc fault current and frequency domain character all have significant change: time domain generally shows as the sudden change of electric current, and current changing rate is higher; Frequecy characteristic shows as high fdrequency component and has significant increase.Therefore the direct-current arc fault detection method of routine has Fourier decomposition (FFT), wavelet analysis, the detection of arc current current changing rate etc. at present, or fully utilizes above method, feature.A kind of apparatus and method that detect arc current rate of change (di/dt) based on PCB air-core transformer are for example disclosed in patent CN103384446A.A kind of direct-current arc fault detection method and device based on the several characteristic frequency point features of Fourier decomposition disclosed in patent US2011/0141644.A kind of multicriterion detection method based on current changing rate absolute value and FFT electric arc high fdrequency component is disclosed in patent CN103245897A.
This class arc method for measuring and the equal more complicated of device above, generally must adopt digital microcomputer chip to realize arc fault detection algorithm as MCU, DSP or FPGA, and detection real-time and speed are slightly poor, realize cost also higher.
Summary of the invention
Technical problem to be solved in the utility model, is for the defect in aforementioned background art and deficiency, and a kind of direct-current arc failure detector circuit and protective device are provided.
The concrete technical scheme that the utility model adopts is as follows.
A kind of direct-current arc failure detector circuit, it is characterized in that comprising: modulate circuit, double limiting circuit, band pass filter, absolute value circuit, the first comparator, integrator, monostable flipflop, the second comparator, RS latch, the alternating current component of power circuit electric current is inputted double limiting circuit by modulate circuit, the output of double limiting circuit is connected in band pass filter, the output of band pass filter is connected in absolute value circuit, the output of absolute value circuit is connected in the integration input of the normal phase input end sum-product intergrator of the first comparator, the inverting input of the first comparator connects the first reference voltage, the output of the first comparator is connected in the input of monostable flipflop, the output of monostable flipflop is connected in the clear terminal of integrator, the output of integrator is connected in the inverting input of the second comparator, the normal phase input end of the second comparator connects the second reference voltage, the output of the second comparator is connected in the clear terminal of RS latch, the reset terminal of RS latch is as the reset terminal of direct-current arc failure detector circuit, the Q output of RS latch is as the electric arc fault protection signal output part of direct-current arc failure detector circuit.
A kind of direct-current arc fault detect protective device, comprising: solid-state switch or mechanical relay, alternating current component testing circuit, first with and direct-current arc failure detector circuit, the alternating current component of alternating current component testing circuit detection power circuital current is also entered into direct-current arc failure detector circuit, the switch command of direct-current arc fault detect protective device connect first with input of door and the reset terminal of direct-current arc failure detector circuit, the electric arc fault protection signal output part of direct-current arc failure detector circuit be connected in first with door another input, it is characterized in that described direct-current arc failure detector circuit comprises: modulate circuit, double limiting circuit, band pass filter, absolute value circuit, the first comparator, integrator, monostable flipflop, the second comparator, RS latch, the alternating current component of power circuit electric current is inputted double limiting circuit by modulate circuit, the output of double limiting circuit is connected in band pass filter, the output of band pass filter is connected in absolute value circuit, the output of absolute value circuit is connected in the integration input of the normal phase input end sum-product intergrator of the first comparator, the inverting input of the first comparator connects the first reference voltage, the output of the first comparator is connected in the input of monostable flipflop, the output of monostable flipflop is connected in the clear terminal of integrator, the output of integrator is connected in the inverting input of the second comparator, the normal phase input end of the second comparator connects the second reference voltage, the output of the second comparator is connected in the clear terminal of RS latch, the reset terminal of RS latch is as the reset terminal of direct-current arc failure detector circuit, the Q output of RS latch is as the electric arc fault protection signal output part of direct-current arc failure detector circuit.
In the time period occurring due to arc fault, the high fdrequency component of arc current is compared normal current and is exceeded a lot, and therefore the utility model adopts the cumlative energy of alternating current component medium-high frequency component of the interior arc current of special time period as the foundation that judges whether to occur arc fault.Wherein the centre frequency of band pass filter is 10kHz left and right, and lower frequency limit is 1kHz left and right, and upper limiting frequency is 100kHz left and right.
Adopt the beneficial effect bringing after technical solutions of the utility model as follows:
(1) circuit structure is simple, and fault detect speed is fast;
(2) do not adopt digital microcomputer chip, reliability is high;
(3) can only adopt easily analog-and digital-integrated circuit to realize, the cost of realizing and manufacturing is low.
The technical solution of the utility model can be widely used in low pressure and high-voltage electric power system, photovoltaic cell system and the Civil High Pressure direct current transmission and distribution system on aircraft, naval vessel.
Brief description of the drawings
Fig. 1 is the theory diagram of direct-current arc fault detect protective device;
Fig. 2 is the theory diagram of direct-current arc failure detector circuit in the utility model;
Fig. 3 is the specific implementation circuit of direct-current arc failure detector circuit in the utility model.
Embodiment
Introduce in detail some related key technologies of the utility model below in conjunction with accompanying drawing, to support claim part.
Fig. 1 is the theory diagram of direct-current arc fault detect protective device.Direct-current arc failure detector circuit 5 is detected the alternating current component of relay or solid-state switch electric current and is input to direct-current arc failure detector circuit 5 by alternating current component testing circuit 3; alternating current component testing circuit 3 can adopt current transformer or current sense resistor; in the time that direct-current arc failure detector circuit 5 detects generation arc fault; its electric arc fault protection signal ArcFault step-down level; the switch command CMD that this low level signal acts on relay or solid-state switch by first with door 4, turn-offs relay or solid-state switch.The switch command CMD of relay or solid-state switch also connects the reset terminal of direct-current arc failure detector circuit 5.
Fig. 2 is the theory diagram of direct-current arc failure detector circuit, first the alternating current component of detected power circuit electric current is connected to modulate circuit 6 as input variable, nurses one's health into the ac voltage signal I of OK range
aC, then pass through double limiting circuit 7 to this signal I
aCcarry out double limiting and obtain signal I
aCL, to reduce the impact of power circuit transient state switching process on subsequent integration circuit, I
aCLobtain signal I by band pass filter 8
aCLBP, the passband frequency range of band pass filter 8 is about 1kHz～100kHz, and centre frequency is 10kHz; Then calculate absolute value by absolute value circuit (or true rms circuit) 9 | I
aCLBP|.The output of absolute value circuit 9 is connected in the integration input of the normal phase input end sum-product intergrator 11 of the first comparator 10, the first reference voltage V th1 is connected in the inverting input of the first comparator 10, and the output of the first comparator 10 is connected in the input of the monostable flipflop 12 of rising edge triggering.Work as absolute value | I
aCLBP| while being greater than the first reference voltage V th1, the output of the first comparator 10 becomes high level from low level, monostable flipflop 12 is produced and hold time as the low level pulse of setting-up time section Δ T.The output of monostable flipflop 12 is connected in the clear terminal (high level is effective) of integrator 11, the absolute value that integrator 11 is exported absolute value circuit 9 within the Δ T time | I
aCLBP| carry out integration, calculate the cumlative energy of the band connection frequency component within the Δ T time.The output of integrator is connected in the inverting input of the second comparator 13; the normal phase input end of the second comparator 13 connects the second reference voltage V th2; the output of the second comparator 13 is connected in the clear terminal of RS latch 14; the reset terminal of RS latch 14 is as the reset terminal of direct-current arc failure detector circuit, and Q output is as the electric arc fault protection signal output part of direct-current arc failure detector circuit.In the time that the output of integrator 11 is greater than the second reference voltage V th2, the second comparator 13 output low levels, RS latch Q end is output as low level, arc fault detected.In integral process, work as absolute value | I
aCLBP| while being less than time>=Δ T of the first reference voltage V th1, integrator zero clearing.Wherein, the basis of design of Vth1 is: be approximately equal to 5%～10% of conditioning magnitude of voltage corresponding to load rating current fluctuation; The time of Δ T is taken as 5ms～10ms; The basis of design of Vth2 is: be approximately equal to the conditioning magnitude of voltage that the cumlative energy of arc fault current within the Δ T time is corresponding.
Fig. 3 is the specific implementation of direct-current arc failure detector circuit.As shown in Figure 4, the alternating current component of current transformer detection power circuital current, its output forms voltage through resistance R 0, after the double limiting of diode D1, D2, be connected in capacitor C 1, operational amplifier U1, capacitor C 1, resistance R 1 and R2 composition ac-coupled circuit, capacitor C 1 other end is connected in the positive polarity input of resistance R 1 and operational amplifier U1, the other end ground connection of resistance R 1, and resistance R 2 is connected in the output of operational amplifier U1.Operational amplifier U2, capacitor C 2 and C3, resistance R 3, R4 and R5 composition second-order bandpass filter, U1 output is connected in one end of resistance R 3, the R3 other end is connected in capacitor C 2, C3 and resistance R 4, capacitor C 2 other end ground connection, another termination of R4 U2 output, capacitor C 3 is connected in resistance R 5 and U2 positive polarity input, resistance R 6 one end ground connection, another termination U2 negative polarity input and resistance R 7, another termination of R7 U2 output, operational amplifier U3 and U4, resistance R 8, R9, R10, R11, R12, diode D3, D4, D5, D6 forms absolute value circuit, operational amplifier U2 output is connected to respectively resistance R 9, the anode of resistance R 9 another termination U3 negative polarity ends and R10 and diode D5, the negative electrode of diode D5 connects the output of U3, the output of U3 is connected in the anode of diode D6, the negative electrode of D6 is connected in the other end of R10, the positive polarity input of U3 is by resistance R 8 ground connection, operational amplifier U2 output is also connected in resistance R 12 one end, the other end of resistance R 12 is connected in the positive polarity input of U4, the negative polarity input of U4 is connected in one end of anode and the R11 of diode D3, the negative electrode of diode D1 is connected in the output of U4 and the anode of diode D4, the negative electrode of D4 is connected in the other end of resistance R 11, the negative electrode of diode D6, resistance R 16, the positive polarity input of comparator U5, the negative polarity input of U5 is connected in resistance R 13 and R14 simultaneously, resistance R 13 other ends are connected in power supply VCC, resistance R 14 other end ground connection, the output of comparator U5 is pulled to power supply VCC by resistance R 15, the output of comparator U5 is also connected in that in monostable flipflop U7(figure, to select model be MC14528 simultaneously) rising edge trigger end (A end), the Cx/Rx end of U7 is connected in resistance R 24 and capacitor C 6, another termination power VCC of resistance R 24, the other end ground connection of capacitor C 5, trailing edge trigger end (B end) and the clear terminal of U7
meet power supply VCC, U7's
the control end of output termination analog switch S, resistance R 16, R17, R18, R19, capacitor C 4, operational amplifier U6 and U8 composition integrator, the negative polarity input of another termination operational amplifier U6 of R16, the positive polarity input end grounding of U6, switch S, R17, capacitor C 4 parallel connections, the negative polarity input of U6 is connected in capacitor C 4, a parallel connected end of resistance R 17 and switch S, capacitor C 4, another parallel connected end of resistance R 17 and switch S is connected in the output of U6, the output of U6 is connected in resistance R 18, the other end of R18 is connected in negative polarity input and the resistance R 19 of U8, the positive polarity input end grounding of U8, the other end of resistance R 19 is connected in the output of U8, the output of U8 is connected in the negative polarity input of comparator U9 through resistance R 20, the positive polarity of U8 is relatively held and is connected in resistance R 21 and resistance R 22, the other end of resistance R 21 is connected in power supply VCC, the other end ground connection of resistance R 22, the output of comparator U9 is pulled to power supply VCC through resistance R 23, the output of U9 is also connected in the clear terminal of RS latch U10
the set end of RS latch U10
be connected in the reset of switch command CMD for arcing fault signal output terminals A rcFault, the Q output of RS latch is as the arcing fault signal output terminals A rcFault of direct-current arc failure detector circuit.
Above embodiment is only explanation technological thought of the present utility model; can not limit protection range of the present utility model with this; every technological thought according to the utility model proposes, any change of doing on technical scheme basis, within all falling into the utility model protection range.
Claims (4)
1. a direct-current arc failure detector circuit, it is characterized in that comprising: modulate circuit (6), double limiting circuit (7), band pass filter (8), absolute value circuit (9), the first comparator (10), integrator (11), monostable flipflop (12), the second comparator (13), RS latch (14), the alternating current component of power circuit electric current is by modulate circuit (6) input double limiting circuit (7), the output of double limiting circuit (7) is connected in band pass filter (8), the output of band pass filter (8) is connected in absolute value circuit (9), the output of absolute value circuit (9) is connected in the integration input of the normal phase input end sum-product intergrator (11) of the first comparator (10), the inverting input of the first comparator (10) connects the first reference voltage, the output of the first comparator (10) is connected in the input of monostable flipflop (12), the output of monostable flipflop (12) is connected in the clear terminal of integrator (11), the output of integrator is connected in the inverting input of the second comparator (13), the normal phase input end of the second comparator (13) connects the second reference voltage, the output of the second comparator (13) is connected in the clear terminal of RS latch (14), the reset terminal of RS latch (14) is as the reset terminal of direct-current arc failure detector circuit, the Q output of RS latch is as the electric arc fault protection signal output part of direct-current arc failure detector circuit.
2. a kind of direct-current arc failure detector circuit as claimed in claim 1, the centre frequency that it is characterized in that band pass filter is 10kHz, and lower frequency limit is 1kHz, and upper limiting frequency is 100kHz.
3. a direct-current arc fault detect protective device, comprising: solid-state switch or mechanical relay (2), alternating current component testing circuit (3), first and door (4) and direct-current arc failure detector circuit (5), the alternating current component of alternating current component testing circuit (3) detection power circuital current is also entered into direct-current arc failure detector circuit (5), the switch command of direct-current arc fault detect protective device connect first with input of door (4) and the reset terminal of direct-current arc failure detector circuit (5), the electric arc fault protection signal output part of direct-current arc failure detector circuit (5) be connected in first with door (4) another input, it is characterized in that described direct-current arc failure detector circuit (5) comprising: modulate circuit (6), double limiting circuit (7), band pass filter (8), absolute value circuit (9), the first comparator (10), integrator (11), monostable flipflop (12), the second comparator (13), RS latch (14), the alternating current component of power circuit electric current is by modulate circuit (6) input double limiting circuit (7), the output of double limiting circuit (7) is connected in band pass filter (8), the output of band pass filter (8) is connected in absolute value circuit (9), the output of absolute value circuit (9) is connected in the integration input of the normal phase input end sum-product intergrator (11) of the first comparator (10), the inverting input of the first comparator (10) connects the first reference voltage, the output of the first comparator (10) is connected in the input of monostable flipflop (12), the output of monostable flipflop (12) is connected in the clear terminal of integrator (11), the output of integrator is connected in the inverting input of the second comparator (13), the normal phase input end of the second comparator (13) connects the second reference voltage, the output of the second comparator (13) is connected in the clear terminal of RS latch (14), the reset terminal of RS latch (14) is as the reset terminal of direct-current arc failure detector circuit (5), the Q output of RS latch is as the electric arc fault protection signal output part of direct-current arc failure detector circuit (5).
4. a kind of direct-current arc fault detect protective device as claimed in claim 3, the centre frequency that it is characterized in that band pass filter is 10kHz, and lower frequency limit is 1kHz, and upper limiting frequency is 100kHz.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420086440.9U CN203747363U (en) | 2014-02-27 | 2014-02-27 | DC arc fault detection circuit and protective device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420086440.9U CN203747363U (en) | 2014-02-27 | 2014-02-27 | DC arc fault detection circuit and protective device |
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| CN203747363U true CN203747363U (en) | 2014-07-30 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103812081A (en) * | 2014-02-27 | 2014-05-21 | 南京航空航天大学 | Direct-current arc fault detection protection method and method and detection circuit |
| CN106405309A (en) * | 2016-08-31 | 2017-02-15 | 武汉海奥电气有限公司 | System and method for rapidly determining single phase earth fault |
| CN107994866A (en) * | 2017-12-07 | 2018-05-04 | 厦门科华恒盛股份有限公司 | Method, apparatus, equipment and the storage medium of direct current arc fault detection |
| CN108885237A (en) * | 2016-03-03 | 2018-11-23 | Abb瑞士股份有限公司 | Method and apparatus for detecting the arc fault in electrical system |
| CN117074889A (en) * | 2023-10-16 | 2023-11-17 | 天津科林电气有限公司 | DC arc detection method and device |
-
2014
- 2014-02-27 CN CN201420086440.9U patent/CN203747363U/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103812081A (en) * | 2014-02-27 | 2014-05-21 | 南京航空航天大学 | Direct-current arc fault detection protection method and method and detection circuit |
| CN103812081B (en) * | 2014-02-27 | 2016-06-08 | 南京航空航天大学 | A kind of direct-current arc fault detect guard method and device and testing circuit |
| CN108885237A (en) * | 2016-03-03 | 2018-11-23 | Abb瑞士股份有限公司 | Method and apparatus for detecting the arc fault in electrical system |
| CN106405309A (en) * | 2016-08-31 | 2017-02-15 | 武汉海奥电气有限公司 | System and method for rapidly determining single phase earth fault |
| CN107994866A (en) * | 2017-12-07 | 2018-05-04 | 厦门科华恒盛股份有限公司 | Method, apparatus, equipment and the storage medium of direct current arc fault detection |
| CN107994866B (en) * | 2017-12-07 | 2019-10-08 | 科华恒盛股份有限公司 | Method, apparatus, equipment and the storage medium of direct current arc fault detection |
| CN117074889A (en) * | 2023-10-16 | 2023-11-17 | 天津科林电气有限公司 | DC arc detection method and device |
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