CN102684141A - Shock current identifying method and aftercurrent protecting device - Google Patents
Shock current identifying method and aftercurrent protecting device Download PDFInfo
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Abstract
The invention discloses a shock current separating method, and relates to the field of electrical engineering technology. The shock current separating method includes the steps: S1, performing wavelet multi-resolution decomposition and reconstruction on the total leaked current acquired by means of real-time monitoring and acquiring the reconstructed low frequency signal; and S2, acquiring M periodic low frequency signals as current operating windows, sequentially moving the current operating windows, using the difference between the rear M/2 periodic low frequency signals and the front M/2 periodic low frequency signals as a separating current for separating, and wherein the M is an even number. By the aid of the shock current separating method shock current can be accurately separated from the total leaked current by means of sliding windows and based on wavelet, whether tripping is needed or not can be judged according to the amplitude of the shock current, problems that whether tripping is needed or not is judged by the total leaked current can cause misoperation and non-operation are avoided.
Description
Technical field
The present invention relates to the electrical engineering technical field, particularly a kind of method for protecting residual current and device.
Background technology
Aftercurrent protecting equipment prevents that in rural low voltage network the person from getting an electric shock and avoid causing because of leakage current aspect such as electric equipment damage to play an important role.Aftercurrent protecting equipment at present commonly used has two types of amplitude discrimination formula and amplitude discrimination phase discriminator types, its operating criterion normally the amplitude of the total leakage current in low-voltage power supply loop greater than certain setting value, or always little increment of leakage current greater than certain setting.Operating experience shows, present Aftercurrent protecting equipment is the real current signal of identification human electric shock branch road mostly, closes not brake application when big load usually occurring, can't correctly put into operation; Or under the wet weather condition, because of the electric loop insulation level significantly reduces, cause earth leakage current to increase, and then the phenomenon of misoperation occurs.Its main cause is that electrical shock protective device is inreal difference normal leakage electric current and human electric shock's electric current on principle.
Summary of the invention
The technical problem that (one) will solve
The technical problem that the present invention will solve is: how to distinguish normal leakage electric current and shock current exactly.
(2) technical scheme
For solving the problems of the technologies described above, the invention provides a kind of shock current separation method, may further comprise the steps:
S1: the total leakage current that real-time monitors carried out the wavelet multiresolution rate is decomposed and reconstruct, obtain the low frequency signal after the reconstruct;
S2: the said low frequency signal in M cycle as current computing window, is moved said window successively, and as the shock current that separates, M is an even number with the difference of back M/2 cycle and the low frequency signal in a preceding M/2 cycle.
Wherein, adopt the female small echo of db11 in the Daubechies system that the total leakage current that real-time monitors is carried out the decomposition of wavelet multiresolution rate among the step S1.
Wherein, among the said step S1, carry out the wavelet multiresolution rate and decompose, decomposition scale is 6.
Wherein, said M is 8.
Wherein, when moving said window successively, move 1 cycle at every turn.
The present invention also provides a kind of Aftercurrent protecting equipment; Comprise: single chip circuit and executive circuit; Said single chip circuit is used for isolating shock current by above-mentioned each described shock current separation method from the total leakage current that receives, and when said shock current amplitude surpasses specified operating value, sends the tripping operation execution command to said executive circuit.
Send the tripping operation execution command to said executive circuit when wherein, said single chip circuit detects three isolated shock currents of continuous moving window and all surpasses said specified operating value.
Wherein, also comprise the pattern configurations circuit, connect said single chip circuit, be used to dispose the mode of operation of said single-chip microcomputer.
Wherein, also comprise: the display circuit that is used for display parameters that is connected with said single chip circuit.
Wherein, also comprise: what be connected with said single chip circuit is used for the communication interface circuit with compunication.
(3) beneficial effect
The present invention is through having realized from total leakage current, isolating exactly shock current based on small echo and sliding window mode; And need to judge whether tripping operation according to the amplitude of this shock current, avoided according to total leakage current size judge whether to trip the protective device malfunction that causes or the problem of tripping.
Description of drawings
Fig. 1 is a kind of shock current separation method flow chart of the embodiment of the invention;
Fig. 2 is a kind of Aftercurrent protecting equipment structural representation of the embodiment of the invention;
Fig. 3 is the device workflow sketch map among Fig. 2.
Embodiment
Below in conjunction with accompanying drawing and embodiment, specific embodiments of the invention describes in further detail.Following examples are used to explain the present invention, but are not used for limiting scope of the present invention.
Shock current separation method idiographic flow provided by the invention is as shown in Figure 1, comprising:
Step S1 carries out the wavelet multiresolution rate to the total leakage current that real-time monitors and decomposes, and obtains the low frequency signal after the reconstruct.Specifically adopt the female small echo of db11 in the Daubechies system that the total leakage current
that real-time monitors is carried out the decomposition of wavelet multiresolution rate; Selecting decomposition scale is 6 to decompose; Can keep low frequency signal effectively like this; Denoising effectively (removing high-frequency signal) again; And because the fault oscillograph sample frequency of using in the electric shock Physical Experiment platform is 10000Hz; Satisfy the requirement of 50Hz for the signal that makes reconstruct; Therefore, original total leakage current
is proceeded to many 6 layers of decomposition.Through a large amount of experimental verifications, female small echo is selected the female ripple of the db11 in the Daubechies system.
Step S2; To the data in M cycle as current computing window; Moving window successively, with the window one-period that moves forward, the data in a back M/2 cycle and the difference in a preceding M/2 cycle are as identified signal; And carry out error analysis and similarity analysis, and then isolate shock current with actual test value.Wherein, the value of M is relevant with the operate time of Aftercurrent protecting equipment.Usually should require operate time smaller or equal to 0.1 second; Therefore; The data in 8 cycles are as current computing window among the M desirable
; 8 cycles are the reflected waveform state fully, can satisfy requirement operate time again.Move the computing window successively, owing in time-domain, describe a signal, its base unit is one-period, in order to guarantee the precision of isolated shock current, each preferred moving 1 cycle that is spaced apart.In current window, as shock current, and then isolate shock current with the difference of back 4 cycles and preceding 4 cycle low frequency signals.The normal leakage current of electrical network and power consumption equipment changes along with change of time, but its variation is slowly.From a stable state to another stable state, the transformation period of leakage current maybe for several seconds, somewhat, or even several hours, as because the humidity of atmosphere changes the leakage current that the variation that causes insulation resistance etc. causes changes.Most of fault leakage current then can be at several cycles, or even have greatly changed in several milliseconds, like person electric shock etc., therefore can isolate shock current exactly as stated above.
The present invention also provides a kind of Aftercurrent protecting equipment that utilizes said method to realize; This device has realized from total leakage current, isolating exactly shock current through said method; And the amplitude of this shock current need to judge whether tripping operation, avoided according to total leakage current size judge whether to trip the protective device malfunction that causes or the problem of tripping.The concrete structure sketch map is as shown in Figure 2, and this device comprises:
The zero sequence current mutual inductor of signal conditioning circuit, single chip circuit, executive circuit, power circuit and the total leakage current of real-time monitoring.Single chip circuit is the core of this invention, is responsible for image data is handled, and isolates shock current, and the operation of control executive circuit reaches the protection effect.Single chip circuit specifically comprises: reconfiguration unit and separative element.Reconfiguration unit is used for the total leakage current that real-time monitors carried out that the wavelet multiresolution rate is decomposed and reconstruct, obtains the low frequency signal after the reconstruct; Separative element is used for said low frequency signal to M cycle as current computing window, moves said window successively, and as the shock current that separates, M is an even number with the difference of back M/2 cycle and the low frequency signal in a preceding M/2 cycle.
Particularly, zero sequence current mutual inductor passes A, B, C phase line and the neutral line of distribution line, and the output of zero sequence current mutual inductor links to each other with the signal conditioning circuit input; The signal conditioning circuit output links to each other in single chip circuit, and the signal conditioning circuit timesharing is that digital signal is sent in the single chip circuit with the analog signal conversion of instrument transformer; The single chip circuit record acquisition has arrived data, and adopts above-mentioned small echo to combine the decomposition algorithm of sliding window to isolate shock current from total leakage current with this; Finally; Single-chip microcomputer through send the tripping operation execution command to coupled executive circuit, is realized tripping operation with the action foundation of shock current as device; Avoided existing Aftercurrent protecting equipment problem, the problem includes: tripping, malfunction problem have improved the protective device reliability of operation.
The execution of the executive circuit of this device requires smaller or equal to 0.1 second operate time; Promptly in back 5 cycles of electric shock, must accomplish the trip protection action; Therefore; M gets the data in 8 cycles in
as current computing window; Moving window moves 1 cycle that is spaced apart at every turn successively.In current window, as identified signal, and carry out error analysis and similarity analysis with the difference of back 4 cycles and preceding 4 cycle low frequency signals, and then isolate the amplitude of shock current with actual test value.
In order to improve the reliability of algorithm; The present invention is provided with a flag bit Flag in the program of single chip circuit; The Flag initial value is 0, has only when moving continuously that three cycles, isolated shock current all surpassed specified operating value, and promptly Flag equals at 3 o'clock; Just can confirm as electric shock accidents, so just avoid because the misoperation that some sampling errors of test macro possibly cause.
Further, Aftercurrent protecting equipment of the present invention has still kept existing mode of operation, and promptly this Aftercurrent protecting equipment is provided with two kinds of mode of operations, and a kind of is general mode, and a kind of is the divergence type pattern.General mode; It is the function of traditional Aftercurrent protecting equipment; When being chosen as this pattern; The rated current default setting of system is 30mA, and when residual current
size surpasses 30mA, equipment will move.The divergence type pattern is promptly sent the new model of trip command according to the amplitude of shock current, device identifies shock current and makes the protection action according to corresponding criterion.The mode of operation of device acquiescence is a divergence type.And under some special environment, as: bathroom, the operating current of this device more generally speaking should be less, therefore need be configured desired action current and operate time.
In order to realize to mode of operation and the configuration of desired action current and operate time; This device also comprises: the pattern configurations circuit that connects single chip circuit; Like the keyboard circuit among Fig. 2; The user can pass through the keyboard associative operation, and mode of operation is set, and corresponding desired action current and operate time are set.This function can improve the stability and the adaptability of this cover system.
Further; In order to realize better man-machine interaction; This device also comprises display circuit, like LCD etc., can show at display screen the residual current of actual measurement current value and magnitude of voltage, the shock current value that identifies, whether get an electric shock, Working mode set, setting value setting etc.And the three-phase and four-line electric power system measured three-phase current, zero-sequence current 4 road current signals, three-phase voltage and residual voltage 4 road signals, and isolated shock current signal shown that real-time storage is selected the signal waveform data of period.
Further, this device also comprises communication interface circuit, as: serial ports, can sampled data be sent to PC through serial ports, be convenient to sampled data is done further to analyze.
The part hardware device that Aftercurrent protecting equipment of the present invention adopts is following:
The chip L7805CV of power circuit and LM1117 are adjustable three terminal regulator.Ui is the 9V voltage after the AC/DC conversion; After L7805CV and LM1117 conversion; Obtain 5V and 3.3V galvanic current pressure respectively at VDD and VCC place; Both satisfied of the requirement of modules such as serial communication, relay output, and also can power supply be provided for single chip circuit and LCD, serial storage module to power supply.
Signal conditioning circuit comprises that altogether signal amplifies and filter circuit two parts, and the chip of selecting for use is the precision operational-amplifier OPA4374 that Texas Instrument produces, and this amplifier input bias current is 10pA, and input offset voltage is 5mV, adopts single power supply.
Single chip circuit is selected the MSP430F149 into American TI Company for use; This chip internal contains the 2kBRAM district, can be used for the quick storage sampled data, under the driving of 8MHz crystal; Realize the instruction cycle of 125ns; Carry 12 analog-to-digital conversion modules (ADC12), can realize the analog-to-digital conversion of 12 precision, sample rate reaches as high as 200kbps.
The chip that liquid crystal display circuit adopts is the graphical dots configuration LCD YLF12232 that Beijing friend Li Fa scientific & trading Co., Ltd. produces.
As shown in Figure 3, be Aftercurrent protecting equipment workflow diagram of the present invention, this device gets into system initialization in the back that powers on; After the initialization of each module is accomplished smoothly, get into the main program circulation in the single chip circuit, the mode of operation of system confirms through the associative operation of button, acquiescence be the divergence type pattern.When being chosen as the divergence type pattern, system will get into data acquisition, data processing, separation algorithm supervisor, finally isolate the shock current amplitude; When shock current during, continue the circulation of main program less than the operating value set; When shock current during greater than the operating value set, system sends trip command, end loop.When being chosen as general modfel, system will be according to the operation principle operation of the Aftercurrent protecting equipment of routine, and when residual current surpassed 30mA, system sent trip command, end loop, otherwise, then continue the circulation of main program.Shock current amplitude that above button operation, the leakage current of surveying and branch are managed out and device action situation can show in LCDs through the liquid crystal display program.
Above execution mode only is used to explain the present invention; And be not limitation of the present invention; The those of ordinary skill in relevant technologies field under the situation that does not break away from the spirit and scope of the present invention, can also be made various variations and modification; Therefore all technical schemes that are equal to also belong to category of the present invention, and scope of patent protection of the present invention should be defined by the claims.
Claims (10)
1. a shock current separation method is characterized in that, may further comprise the steps:
S1: the total leakage current that real-time monitors carried out the wavelet multiresolution rate is decomposed and reconstruct, obtain the low frequency signal after the reconstruct;
S2: the said low frequency signal in M cycle as current computing window, is moved said window successively, and as the shock current that separates, M is an even number with the difference of back M/2 cycle and the low frequency signal in a preceding M/2 cycle.
2. shock current separation method as claimed in claim 1 is characterized in that, adopts the female small echo of db11 in the Daubechies system that the total leakage current that real-time monitors is carried out the decomposition of wavelet multiresolution rate among the step S1.
3. shock current separation method as claimed in claim 1 is characterized in that, among the said step S1, carries out the wavelet multiresolution rate and decomposes, and decomposition scale is 6.
4. shock current separation method as claimed in claim 1 is characterized in that, said M is 8.
5. shock current separation method as claimed in claim 1 is characterized in that, when moving said window successively, moves 1 cycle at every turn.
6. Aftercurrent protecting equipment; Comprise: single chip circuit and executive circuit; It is characterized in that; Said single chip circuit is used for from the total leakage current that receives, isolating shock current by each described shock current separation method of claim 1～5, and when said shock current amplitude surpasses specified operating value, sends the tripping operation execution command to said executive circuit.
7. Aftercurrent protecting equipment as claimed in claim 6 is characterized in that, sends the tripping operation execution command to said executive circuit when said single chip circuit detects three isolated shock currents of continuous moving window and all surpasses said specified operating value.
8. Aftercurrent protecting equipment as claimed in claim 6 is characterized in that, also comprises the pattern configurations circuit, connects said single chip circuit, is used to dispose the mode of operation of said single-chip microcomputer.
9. Aftercurrent protecting equipment as claimed in claim 6 is characterized in that, also comprises: the display circuit that is used for display parameters that is connected with said single chip circuit.
10. Aftercurrent protecting equipment as claimed in claim 6 is characterized in that, also comprises: what be connected with said single chip circuit is used for the communication interface circuit with compunication.
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Cited By (8)
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| CN102904209A (en) * | 2012-11-01 | 2013-01-30 | 四川省电力公司资阳公司 | Digital signal processing (DSP)-based current separation motion type electric leakage protection device and method |
| CN103825245A (en) * | 2014-01-27 | 2014-05-28 | 广东南冠电气有限公司 | Intelligent circuit breaker capable of distinguishing electric shock signal and leakage signal |
| CN104638612A (en) * | 2015-02-13 | 2015-05-20 | 西安交通大学 | Method for recognizing and protecting human body electric shock accident |
| CN105956242A (en) * | 2016-04-25 | 2016-09-21 | 中国农业大学 | Multiport impedance model construction method based on living body electric shock impedance parameter calculation |
| CN107276029A (en) * | 2017-06-20 | 2017-10-20 | 安徽南瑞继远电网技术有限公司 | Anti- personal electrical shock circuit breaker control method and system based on Waveform Identification Technology |
| CN112906389A (en) * | 2021-02-04 | 2021-06-04 | 云南电网有限责任公司昆明供电局 | Fault trip discrimination method based on multi-dimensional data analysis |
| CN112952753A (en) * | 2021-03-15 | 2021-06-11 | 国网福建省电力有限公司南平供电公司 | Low-voltage power grid electric shock accident detection method and system based on threshold value self-adaptive adjustment |
| CN113325028A (en) * | 2021-06-07 | 2021-08-31 | 中国核动力研究设计院 | Boiling critical experiment device for unstable flow of natural circulation system and control method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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| CN107276029A (en) * | 2017-06-20 | 2017-10-20 | 安徽南瑞继远电网技术有限公司 | Anti- personal electrical shock circuit breaker control method and system based on Waveform Identification Technology |
| CN107276029B (en) * | 2017-06-20 | 2019-04-16 | 安徽南瑞继远电网技术有限公司 | Anti- personal electrical shock circuit breaker control method and system based on Waveform Identification Technology |
| CN112906389A (en) * | 2021-02-04 | 2021-06-04 | 云南电网有限责任公司昆明供电局 | Fault trip discrimination method based on multi-dimensional data analysis |
| CN112952753A (en) * | 2021-03-15 | 2021-06-11 | 国网福建省电力有限公司南平供电公司 | Low-voltage power grid electric shock accident detection method and system based on threshold value self-adaptive adjustment |
| CN113325028A (en) * | 2021-06-07 | 2021-08-31 | 中国核动力研究设计院 | Boiling critical experiment device for unstable flow of natural circulation system and control method |
| CN113325028B (en) * | 2021-06-07 | 2022-05-24 | 中国核动力研究设计院 | Boiling critical experiment device for unstable flow of natural circulation system and control method |
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