CN204330871U - A kind of low pressure parallel arc fault pick-up unit - Google Patents
A kind of low pressure parallel arc fault pick-up unit Download PDFInfo
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- CN204330871U CN204330871U CN201520011797.5U CN201520011797U CN204330871U CN 204330871 U CN204330871 U CN 204330871U CN 201520011797 U CN201520011797 U CN 201520011797U CN 204330871 U CN204330871 U CN 204330871U
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- 238000001514 detection method Methods 0.000 claims abstract description 11
- 238000012544 monitoring process Methods 0.000 claims abstract description 4
- 238000012360 testing method Methods 0.000 claims abstract description 4
- 238000010891 electric arc Methods 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 7
- 238000010205 computational analysis Methods 0.000 claims description 3
- 230000006698 induction Effects 0.000 claims description 3
- 230000001105 regulatory effect Effects 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 abstract description 3
- 230000015556 catabolic process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
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Abstract
A kind of low pressure parallel arc fault pick-up unit, comprise current transformer, differentiating circuit, microprocessor, and power circuit, zero cross detection circuit, biasing circuit, rectification circuit, sound light alarming circuit, the RS485 communicating circuit to be connected with microprocessor, test button and noise reduction button, wherein, differentiating circuit is connected with current transformer respectively with biasing circuit, and rectification circuit is connected with differentiating circuit.The utility model effectively can detect parallel arc fault by the signal of monitoring current size and sign current distortion, can provide the measuring ability not available for existing protective device.Effectively can avoid the interference of nonlinear load simultaneously.
Description
Technical field
The utility model relates to a kind of arc fault detection device.
Background technology
Along with socioeconomic develop rapidly and electrifing degree improve constantly, power consumption is also in continuous increase, and the generation of electrical fire event is more and more frequent, causes huge loss to the person and property.Arc fault is a kind of reason causing electrical fire be fully realized for various reasons in recent years, and parallel arc fault is one of principal mode in arc fault.When there is parallel arc, there is very high temperature, the combustible of surrounding of can igniting rapidly.Parallel arc electric current is less than short-circuit current, therefore, and the electrical fire that traditional overcurrent detecting device can not effectively prevent arc fault to cause.Because the domestic correlative study to arc fault is also in the starting stage, can effectively prevent arc fault initiation fire particularly important so develop a kind of device.
The feature of parallel arc electric current has the distortion that larger current amplitude and electric current occur at zero crossing.When detecting parallel arc, need to consider that some have the misoperation that may cause compared with the load of great start-up current.These loads are except having larger starting current, and its current waveform is the motor etc. of nonsinusoidal waveform, such as capacitor start.Therefore, require that detector can effectively distinguish between parallel arc fault and the load compared with great start-up current.
In prior art, by gathering current waveform signal, utilize the discrete wavelet coefficient of wavelet transformation decomposed signal.Calculate wavelet coefficient and, and to compare with threshold value, if be greater than threshold value, be then judged to be parallel arc.Due to the difference that domestic power distribution system source quality is more external, in power supply, harmonic content is large, and therefore, threshold value is difficult to choose, and computation process is comparatively complicated, and cost is high.
Summary of the invention
[0003] the utility model utilizes size of current and current distortion feature to detect, and can count parallel arc half-wave number accurately, effectively can avoid the interference of nonlinear load simultaneously.
A kind of low pressure parallel arc fault pick-up unit, comprise current transformer, differentiating circuit, microprocessor, and the power circuit to be connected with microprocessor, zero cross detection circuit, biasing circuit, rectification circuit, sound light alarming circuit, RS485 communicating circuit, test button and noise reduction button, wherein, differentiating circuit is connected with current transformer respectively with biasing circuit, and rectification circuit is connected with differentiating circuit, power circuit normally to work required D.C. regulated power supply for providing described pick-up unit, zero cross detection circuit is utilized to detect the zero crossing of distribution system alternating current, foundation is provided for the half-wave of alternating current is initial in arc-detection, current transformer is through the live wire of distribution system terminal, for the current signal in induction line, biasing circuit to described current signal carry out biased after, by microcontroller acquires current waveform, and calculate " flat shoulder " width, differentiating circuit is sent into rectification circuit after carrying out differential process to described current signal and is carried out rectification process to it, the rectified signal exported sends into microprocessor, microprocessor gathers the signal of the current signal after being biased and rectification circuit output respectively and carries out computational analysis, identify whether as electric arc, electric arc number in fixing moving time-window is added up simultaneously, if aggregate-value exceedes setting threshold value, be judged as parallel arc fault, then carry out being reported to the police by sound light alarming circuit, and be uploaded to monitoring backstage by RS485 communicating circuit.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the present invention is further detailed explanation.
Fig. 1 is the hardware block diagram of parallel arc fault pick-up unit of the present utility model.
Fig. 2 is according to the utility model, during parallel arc fault, and the output waveform of current transformer.
Fig. 3 is according to the utility model, the waveform that the output waveform of current transformer exports after differentiating circuit.
Fig. 4 is according to the utility model, motor start-up waveform.
Embodiment
In order to better understand the technical solution of the utility model, describe below in conjunction with accompanying drawing the embodiment that the utility model provides in detail.
When low pressure parallel arc fault occurs, it is comparatively large that its flame current is characterized as current amplitude, but be less than the electric current of short circuit, and waveform is incomplete sine wave, as shown in Figure 2.Therefore, effectively, accurately parallel arc can be identified by size of current and current waveform distortion characteristics.Wherein current distortion feature as: need the gap between certain electromotive force breakdown electrode between two electrodes due to electric arc, therefore, when current zero-crossing point, interelectrode electromotive force increases along with voltage and increases, can gap between breakdown electrode time, electric current sharply rises.In this example, by " flat shoulder " width when the differential output of collection current waveform and calculating current zero crossing, (described " put down and take on " is when electric arc occurs, the current over-zero stage can keep certain hour, size of current is now zero or is approximately zero) detect the distortion of current waveform, reach the object detecting parallel arc fault.Simultaneously, in order to avoid some nonlinear load has similar parallel arc Current Waveform Characteristics instantaneously in startup, when principium identification is arc fault, the current amplitude variation characteristic in front several cycle is identified, if amplitude variation characteristic meets nonlinear load starting current waveform, so be determined as non-parallel arc fault, do not report to the police.
Figure 1 shows that the hardware block diagram of low pressure parallel arc fault pick-up unit, these pick-up unit inlet wire terminals are connected to zero line in distribution system and live wire, and the leading-out terminal of this pick-up unit is load power source.Pick-up unit internal hardware comprises power circuit, zero cross detection circuit, current transformer, biasing circuit, differentiating circuit, rectification circuit, microprocessor, sound and light alarm, test button and noise reduction button and RS485 communicating circuit etc.The power circuit of pick-up unit inside normally to work required D.C. regulated power supply for providing pick-up unit.The generation of electric arc is relevant with the positive and negative cyclical variation of the alternating current of load, utilizes zero cross detection circuit to detect the zero crossing of distribution system alternating current, provides foundation for the half-wave of alternating current is initial in arc-detection.Current transformer, through the live wire of distribution terminal, for the current waveform in induction line, is illustrated in figure 2 sensed parallel arc current waveform.Current waveform respectively through two different signal processing circuits, on the one hand, to current waveform carry out biased after, by microcontroller acquires current waveform, and calculate " flat shoulder " width.On the other hand, carry out differential process to current signal, and carry out rectification process, the rectified signal exported can characterize current waveform distortion degree size, if Fig. 3 is the waveform obtained after differential.Waveform after the width of " flat shoulder " and differential can characterize the sudden change of current waveform, can be used in identifying parallel arc.Microprocessor gathers current waveform signal and rectification circuit respectively and outputs signal and carry out computational analysis, identify whether as electric arc, adds up the electric arc number in fixing moving time-window simultaneously.If aggregate-value exceedes setting threshold value, be judged as arc fault, carry out sound and light alarm, and be uploaded to monitoring backstage by RS485 communication.
As the startup waveform that Fig. 4 is high power motor (being greater than 2KW), its current amplitude starting moment is about 7 times when normally working, and waveform has certain distortion.Therefore, in order to avoid the interference of the higher magnitude that load starts, the variation characteristic of current amplitude is identified.If meet the current amplitude variation characteristic of startup, even if be identified as electric arc, also do not report to the police.
The utility model, by effectively detecting parallel arc fault to the signal (" flat shoulder " width, differential value etc.) of size of current and sign current distortion, can provide the measuring ability not available for existing protective device (electric leakage, overcurrent protective device).Effectively can avoid the interference of nonlinear load simultaneously.
Above embodiment is the one of the utility model more preferably embodiment, and the usual change that those skilled in the art carry out within the scope of the technical program and replacing should be included in protection domain of the present utility model.
Claims (1)
1. a low pressure parallel arc fault pick-up unit, comprise current transformer, differentiating circuit, microprocessor, and the power circuit to be connected with microprocessor, zero cross detection circuit, biasing circuit, rectification circuit, sound light alarming circuit, RS485 communicating circuit, test button and noise reduction button, wherein, differentiating circuit is connected with current transformer respectively with biasing circuit, and rectification circuit is connected with differentiating circuit, power circuit normally to work required D.C. regulated power supply for providing described pick-up unit, zero cross detection circuit is utilized to detect the zero crossing of distribution system alternating current, foundation is provided for the half-wave of alternating current is initial in arc-detection, current transformer is through the live wire of distribution system terminal, for the current signal in induction line, biasing circuit to described current signal carry out biased after, by microcontroller acquires current waveform, and calculate " flat shoulder " width, differentiating circuit is sent into rectification circuit after carrying out differential process to described current signal and is carried out rectification process to it, the rectified signal exported sends into microprocessor, microprocessor gathers the signal of the current signal after being biased and rectification circuit output respectively and carries out computational analysis, identify whether as electric arc, electric arc number in fixing moving time-window is added up simultaneously, if aggregate-value exceedes setting threshold value, be judged as parallel arc fault, then carry out being reported to the police by sound light alarming circuit, and be uploaded to monitoring backstage by RS485 communicating circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520011797.5U CN204330871U (en) | 2015-01-08 | 2015-01-08 | A kind of low pressure parallel arc fault pick-up unit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520011797.5U CN204330871U (en) | 2015-01-08 | 2015-01-08 | A kind of low pressure parallel arc fault pick-up unit |
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| CN204330871U true CN204330871U (en) | 2015-05-13 |
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| CN201520011797.5U Expired - Fee Related CN204330871U (en) | 2015-01-08 | 2015-01-08 | A kind of low pressure parallel arc fault pick-up unit |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104614608A (en) * | 2015-03-04 | 2015-05-13 | 刘岩 | Detection device and method for low voltage parallel electric arc fault |
| CN106159876A (en) * | 2016-07-10 | 2016-11-23 | 珠海派诺科技股份有限公司 | Electric fireproof current-limiting type protector and fault current detection method |
| CN106199347A (en) * | 2016-06-23 | 2016-12-07 | 福州大学 | Fault arc detection method based on interference fingerprint identification and detection device |
| CN106771898A (en) * | 2016-11-27 | 2017-05-31 | 福州大学 | Series fault arc detection device and its method based on Higher Order Cumulants identification |
-
2015
- 2015-01-08 CN CN201520011797.5U patent/CN204330871U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104614608A (en) * | 2015-03-04 | 2015-05-13 | 刘岩 | Detection device and method for low voltage parallel electric arc fault |
| CN104614608B (en) * | 2015-03-04 | 2017-07-04 | 珠海派诺科技股份有限公司 | A kind of low pressure parallel arc fault detection means and method |
| CN106199347A (en) * | 2016-06-23 | 2016-12-07 | 福州大学 | Fault arc detection method based on interference fingerprint identification and detection device |
| CN106199347B (en) * | 2016-06-23 | 2019-02-22 | 福州大学 | Fault arc detection method and detection device based on interference fingerprint identification |
| CN106159876A (en) * | 2016-07-10 | 2016-11-23 | 珠海派诺科技股份有限公司 | Electric fireproof current-limiting type protector and fault current detection method |
| CN106771898A (en) * | 2016-11-27 | 2017-05-31 | 福州大学 | Series fault arc detection device and its method based on Higher Order Cumulants identification |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150513 |