CN203732639U - Arc fault detection protective device - Google Patents
Arc fault detection protective device Download PDFInfo
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- CN203732639U CN203732639U CN201320759635.0U CN201320759635U CN203732639U CN 203732639 U CN203732639 U CN 203732639U CN 201320759635 U CN201320759635 U CN 201320759635U CN 203732639 U CN203732639 U CN 203732639U
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- 238000001514 detection method Methods 0.000 title claims abstract description 38
- 230000001681 protective effect Effects 0.000 title claims abstract description 17
- 238000013519 translation Methods 0.000 claims description 10
- 230000010354 integration Effects 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 abstract description 2
- 230000000737 periodic effect Effects 0.000 abstract 2
- 238000009825 accumulation Methods 0.000 abstract 1
- 238000010891 electric arc Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000011002 quantification Methods 0.000 description 3
- 238000013461 design Methods 0.000 description 2
- 238000012795 verification Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 230000001932 seasonal effect Effects 0.000 description 1
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Abstract
The utility model relates to an arc fault detection protective device, comprising a current transformer, an I/V converting circuit, a rectifying circuit, an integrating circuit and a microprocessor. A current signal of a protected circuit is detected through the current transformer, the current signal is converted into a voltage signal through the I/V converting circuit on the secondary side of the transformer, the voltage signal is fed into the rectifying circuit through a voltage follower for rectifying, a waveform signal obtained after rectifying is provided to the integrating circuit, the integrating circuit provides the microprocessor a voltage level accumulation quantity on a predefined time period, the microprocessor captures a periodic integrating value through timed A/D conversion and stores the periodic integrating value, the current waveform change of the protected circuit is detected through an arc fault detection algorithm, and an arc fault is judged, so that whether the arc fault occurs or interference is caused by normal load start, power adjustment and the like can be effectively distinguished, the false tripping action of the device is reduced, and the reliability is higher.
Description
Technical field
The utility model relates to low-voltage distribution system arc fault detection field, is specifically related to a kind of arc fault detection protective device that running current wave form varies is disturbed that is not subject to.
Background technology
Along with improving constantly of socioeconomic develop rapidly and living standards of the people, electrifing degree is more and more higher, and power consumption is also in continuous increase.The generation of electrical fire event is more and more frequent, causes huge loss to the person and property.According to relevant statistics, the fire causing because of electric reason ranks first in all kinds of fire, accounts for 30%.Electrical fire incidence and the property loss causing occupy first of all kinds of cause of fire, and particularly, in these fire, particularly serious electrical fire happens occasionally.Arc fault be because loose contact, line are loosening, insulation ag(e)ing, fracture etc. cause.The feature of fault electric arc is that in circuit, electric current may reduce, but temperature is high, and fault is expanded rapidly, the initiation fire until light near combustible.So prevent this fire being caused by arc fault particularly important.
Traditional circuit-breakers for over-current protection and Aftercurrent protection circuit breaker extensively adopt, but it does not have the effect of fault electric arc protection in some occasions.At present domestic to domestic circuit arc fault field also in the research and development stage, although there is fewer companies, developed the arc-fault circuit interrupter for domestic circuit, but it does not also really start in circulation on the market, its reliability is also not yet well verified.
Although there has been at present Related product to be widely applied abroad, can detect and distinguish electric arc and normal load and disturb, also there will be false tripping phenomenon.As light modulator, electric drill, suction cleaner etc. are when normally working, in each semiperiod, produce the arc event of equal number, yet, conventional arc fault detection device often can not be distinguished this normal arc and arc fault reliably, thereby false tripping easily occurs.And these conventional equipments are often difficult to distinguish startup, power adjustments, shutdown and the arc fault of some load.Therefore, arc fault detection apparatus and method need further to improve, and avoid occurring erroneous judgement.
Utility model content
Fundamental purpose of the present utility model is the shortcoming that overcomes prior art; provide a kind of can effectively differentiation arc fault to occur or the arc fault detection protective device of the interference that load normally starts, power adjustments etc. causes; can monitor fault electric arc with higher reliability, reduce the de-action of mistake of device.
The utility model adopts following technical scheme:
Arc fault detection protective device, include the current transformer for detection of the AC current waveform signal of protected circuit, for the current signal of current transformer output being changed into the I/V translation circuit of AC voltage waveform signal, for the rectification circuit that AC voltage waveform signal is carried out to rectification, for to carrying out integration in the voltage waveform signal predetermined time cycle of rectification circuit output to obtain the integrating circuit of cycle integrated value and by catching the cycle integrated value of integrating circuit output the microprocessor that changes to carry out arc fault judgement with the current waveform of arc fault detection algorithm detection protected circuit, the primary side of described current transformer is connected on protected circuit, secondary side connects I/V translation circuit, described I/V translation circuit, rectification circuit, integrating circuit is connected in turn with microprocessor.
Further, described microprocessor signals output terminal connects trip circuit, trip circuit junctor electrical interface, and described electromechanical interface is coupled between the power input and power stage of protected circuit.
Further, between described I/V translation circuit and rectification circuit, be connected with for improving the voltage follower of load capacity.
Further, described I/V translation circuit is build-out resistor.
Further, described rectification circuit adopts precise rectification circuit.
Further, described integrating circuit adopts power frequency period integrating circuit.
Further, described arc fault detection protective device also includes the power circuit that is connected in microprocessor.
From above-mentioned to description of the present utility model, compared with prior art, the beneficial effects of the utility model are: microprocessor is by catching the cycle integrated value of integrating circuit output, can by arc fault detection algorithm show that the current waveform of protected circuit changes and set time window in current cycle integrated value monotonicity direction change frequency, the comprehensive many features of microprocessor are carried out arc fault Real-Time Monitoring, can effectively distinguish and arc fault occur or load normally starts, the interference that power adjustments etc. cause, can monitor fault electric arc with higher reliability, reduce thus the de-action of mistake of device.
Accompanying drawing explanation
Fig. 1 is the ware circuit schematic diagram of the arc fault detection protective device of the utility model embodiment;
Fig. 2 is the arc fault detection main program flow chart of the utility model embodiment;
Fig. 3 is the timing microprocessor interrupt routine process flow diagram of the utility model embodiment;
Fig. 4 is the process flow diagram of the arc fault detection algorithm of the utility model embodiment.
In figure: 1. current transformer, 2. build-out resistor, 3. voltage follower, 4. precise rectification circuit, 5. power frequency period integrating circuit, 6. microprocessor, 7. power circuit, 8. trip circuit, 9. electromechanical interface.
Embodiment
By embodiment, this arc fault detection algorithm is further described below.
With reference to Fig. 1, a kind of arc fault detection protective device, include the current transformer 1 for detection of the AC current waveform signal of protected circuit, for the current signal of current transformer 1 output being changed into the build-out resistor 2 of AC voltage waveform signal, for improving the voltage follower 3 of load capacity, for the precise rectification circuit 4 that the AC voltage waveform signal of voltage follower 3 outputs is carried out to rectification, for the voltage waveform signal of precise rectification circuit 4 outputs is carried out to integration to obtain the power frequency period integrating circuit 5 of power frequency period integrated value on power frequency period, by catching the cycle integrated value of power frequency period integrating circuit 5 output the power circuit 7 that changes to carry out the microprocessor 6 of arc fault judgement and be connected in microprocessor 6 with the current waveform of arc fault detection algorithm detection protected circuit, the primary side of described current transformer 1 is connected on protected circuit, secondary side matching connection resistance 2, described build-out resistor 2, voltage follower 3, precise rectification circuit 4, power frequency period integrating circuit 5 is connected in turn with microprocessor 6.Described microprocessor 6 signal output parts connect trip circuit 8, trip circuit 8 junctor electrical interfaces 9, and described electromechanical interface 9 is coupled between the power input and power stage of protected circuit.
With reference to Fig. 1, Fig. 2, Fig. 3 and Fig. 4, a kind of method for detecting arc based on arc fault detection protective device of the present utility model, determines whether to produce arc fault by detecting the current waveform variation of protected circuit, comprises the following steps:
1. by the electric current of 1 pair of protected circuit of current transformer, sample, obtain AC current waveform signal; By being connected in the build-out resistor 2 of current transformer 1 secondary side, change this AC current waveform signal into AC voltage waveform signal again; The AC voltage waveform signal of build-out resistor 2 outputs carries out rectification by voltage follower 3 input precise rectification circuits 4; The voltage waveform signal obtaining after rectification obtains the voltage level semi-invariant of a power frequency period by power frequency period integrating circuit 5.
2. microprocessor 6 operation arc fault detection algorithms carry out fault verification:
1) microprocessor 6 is obtained the integrated value of 50 power frequency periods and is stored in the integrated value array of definition by timing A/D conversion, calculate the integrated value difference of adjacent two power frequency periods in this integrated value array, and set corresponding threshold value resulting difference is quantified as to-1,0,1, obtain corresponding one group and there is seasonal effect in time series and quantize array, and to add up in this quantification array be not 0 quantized value number Na, draw current waveform situation of change, specific algorithm is:
Define two variable m and n, m stores the cycle integrated value that current A/D gathers, n stores the power frequency period integrated value that previous A/D gathers, to the difference relation between adjacent current cycle integrated value set different threshold limits t1, t2 ,-t1 ,-t2 quantize, when the difference of m-n is more than or equal to setting value t1, difference is quantified as to 1, represents to increase progressively; When absolute difference is less than t2, difference is quantified as to 0,
Represent constant; When be less than or equal to-t1 of difference, be quantified as-1, represent to successively decrease.Define an array T[50 that length is 50] for storing adjacent power frequency period integration differential quantized value, timer interrupts, every 20 milliseconds, every of 0-48 element of array is moved to one to a high position, and the quantized value of current integrated value difference is stored in to the lowest order T[0 of array] in.Calculate array T[50] in be not 0 quantized value number Na.
2) when quantizing array T[50] in be not 0 quantized value number Na while surpassing setting threshold 8, further the monotonicity judgement by cycle integrated value is arc fault to occur or the interference that load normally starts, power adjustments etc. causes, specific algorithm is:
Further statistic quantification array T[50] in continuously for-1 or be 1 monotony interval number and the time span of each monotony interval continuously, and in statistic quantification array, by-1, change to 1 or change to-1 number of times by 1, i.e. the monotonicity direction change frequency Nb of current cycle integrated value in 50 power frequency periods.
3) microprocessor 6 determines whether generation arc fault by combination features, in sampling time window, current cycle integrated value monotonicity direction change frequency Nb is greater than the threshold k 2 setting, and when Na/Nb is greater than the threshold k 3 setting, be judged to be generation arc fault.
3. when microprocessor 6 is judged generation arc fault, microprocessor 6 triggers trip circuits 8, electromechanical interface 9 is threaded off, with timely disconnecting circuit.
With reference to Fig. 1, Fig. 2, Fig. 3 and Fig. 4, the algorithm routine that microprocessor 6 of the present utility model carries out arc fault detection comprises master routine, timer interrupt program and arc fault detection algorithm routine three parts, and its program operational scheme is as follows:
1. in master routine, timer is carried out to initialization, be configured to 20ms Interruption, program is in while circular wait interruption status;
2. timer is changed the integrated value gathering in power frequency period integrating circuit by A/D, and the integrator that resets, and integrated value is stored;
3. move arc fault detection algorithm, carry out fault verification.
Above are only an embodiment of the present utility model, but design concept of the present utility model is not limited to this, allly utilizes this design to carry out the change of unsubstantiality to the utility model, all should belong to the behavior of invading the utility model protection domain.
Claims (7)
1. arc fault detection protective device, it is characterized in that: include the current transformer for detection of the AC current waveform signal of protected circuit, for the current signal of current transformer output being changed into the I/V translation circuit of AC voltage waveform signal, for the rectification circuit that AC voltage waveform signal is carried out to rectification, for to carrying out integration in the voltage waveform signal predetermined time cycle of rectification circuit output to obtain the integrating circuit of cycle integrated value and by catching the cycle integrated value of integrating circuit output the microprocessor that changes to carry out arc fault judgement with the current waveform of arc fault detection algorithm detection protected circuit, the primary side of described current transformer is connected on protected circuit, secondary side connects I/V translation circuit, described I/V translation circuit, rectification circuit, integrating circuit is connected in turn with microprocessor.
2. arc fault detection protective device as claimed in claim 1; it is characterized in that: described microprocessor signals output terminal connects trip circuit; trip circuit junctor electrical interface, described electromechanical interface is coupled between the power input and power stage of protected circuit.
3. arc fault detection protective device as claimed in claim 1, is characterized in that: between described I/V translation circuit and rectification circuit, be connected with for improving the voltage follower of load capacity.
4. arc fault detection protective device as claimed in claim 3, is characterized in that: described I/V translation circuit is build-out resistor.
5. arc fault detection protective device as claimed in claim 3, is characterized in that: described rectification circuit adopts precise rectification circuit.
6. arc fault detection protective device as claimed in claim 1, is characterized in that: described integrating circuit adopts power frequency period integrating circuit.
7. arc fault detection protective device as claimed in claim 1, is characterized in that: also include the power circuit that is connected in microprocessor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320759635.0U CN203732639U (en) | 2013-11-26 | 2013-11-26 | Arc fault detection protective device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320759635.0U CN203732639U (en) | 2013-11-26 | 2013-11-26 | Arc fault detection protective device |
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| CN203732639U true CN203732639U (en) | 2014-07-23 |
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| CN201320759635.0U Expired - Lifetime CN203732639U (en) | 2013-11-26 | 2013-11-26 | Arc fault detection protective device |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103592550A (en) * | 2013-11-26 | 2014-02-19 | 华侨大学 | Arc fault detection method and protection device |
| CN104793165A (en) * | 2015-04-03 | 2015-07-22 | 莱茵斯（厦门）科技有限公司 | Labview-based AFDD (arc fault detection device) test equipment and method thereof |
| CN104831027A (en) * | 2014-02-12 | 2015-08-12 | Emag控股有限公司 | Method for monitoring device for inductive heating |
| CN114076903A (en) * | 2020-08-21 | 2022-02-22 | 黑龙江电卫士电气科技发展有限公司 | Arc short circuit fault type judgment method |
-
2013
- 2013-11-26 CN CN201320759635.0U patent/CN203732639U/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103592550A (en) * | 2013-11-26 | 2014-02-19 | 华侨大学 | Arc fault detection method and protection device |
| CN103592550B (en) * | 2013-11-26 | 2018-11-23 | 华侨大学 | A kind of method for detecting arc and protective device |
| CN104831027A (en) * | 2014-02-12 | 2015-08-12 | Emag控股有限公司 | Method for monitoring device for inductive heating |
| CN104793165A (en) * | 2015-04-03 | 2015-07-22 | 莱茵斯（厦门）科技有限公司 | Labview-based AFDD (arc fault detection device) test equipment and method thereof |
| CN104793165B (en) * | 2015-04-03 | 2018-01-02 | 莱茵斯（厦门）科技有限公司 | It is a kind of that arc fault detection device AFDD test equipments and its method are used for based on Labview |
| CN114076903A (en) * | 2020-08-21 | 2022-02-22 | 黑龙江电卫士电气科技发展有限公司 | Arc short circuit fault type judgment method |
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