CN108535606B - Fault arc detection method and device - Google Patents
Fault arc detection method and device Download PDFInfo
- Publication number
- CN108535606B CN108535606B CN201710129379.XA CN201710129379A CN108535606B CN 108535606 B CN108535606 B CN 108535606B CN 201710129379 A CN201710129379 A CN 201710129379A CN 108535606 B CN108535606 B CN 108535606B
- Authority
- CN
- China
- Prior art keywords
- value
- power
- frequency
- fault arc
- noise floor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Relating To Insulation (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The embodiment of the invention provides a fault arc detection method and device, wherein the fault arc detection method comprises the following steps: acquiring a current signal of a circuit; generating power spectrum data according to the acquired current signals; and determining whether a fault arc occurs according to the change trend of the power value in the preset frequency range in the power spectrum data. The fault arc detection method and the fault arc detection device provided by the embodiment of the invention can effectively and accurately detect the fault arc in the circuit, greatly improve the accuracy of fault arc detection, and can perform corresponding treatment in time when determining the fault arc in the circuit, thereby effectively reducing the occurrence of electric fire caused by the fault arc, improving the safety and stability of an electric system, ensuring the safe operation of the electric system and effectively reducing the property and personnel loss caused by the electric fire.
Description
Technical Field
The invention relates to the field of electrical systems, in particular to a fault arc detection method and device.
Background
Electrical fires represent a major part of today's urban fires, and existing commercial residual current protectors (RCDs) can effectively reduce the risk of fire by detecting leakage currents in electrical devices and arcing to ground caused by tracking currents. In practice, however, RCDs, fuses or Miniature Circuit Breakers (MCBs) cannot reduce the risk of electrical fires caused by series or parallel arcs between live conductors. When a series arc fault occurs, the RCD cannot detect such a fault since no leakage current to ground is generated. And the fault impedance of the series arc reduces the load current such that the current is below the trip threshold of the MCB or fuse. In the case of parallel arcs between the phase and neutral conductors, the current is limited only by the impedance of the device.
The most likely condition to initiate an electrical fire is a fault arc, which is generally referred to as a spark discharge or arc discharge due to a line or equipment fault. The fault arc belongs to one of the phenomena of gas insulation breakdown discharge. Arcing refers to: at atmospheric pressure, when the power supply capacity is sufficiently large, the gas, immediately after the spark discharge, develops to the opposite electrode, a very bright continuous arc occurs, which is called arcing. The arc discharge time is long, and the arc can be maintained even when the applied voltage is reduced to be lower than the initial voltage. The arc discharge current is large and the arc temperature is high. The fault arc is often accompanied by open flame and high temperature, which is very easy to cause electric fire.
Conventional circuit breakers are unable to detect the occurrence of a fault arc. Meanwhile, the temperature sensing alarm can only realize short-distance temperature detection and alarm, and the high temperature corresponding to a long low-voltage distribution line or a wall-buried line cannot play a role in protection. Thus, the prior art lacks methods and devices capable of effectively identifying a fault arc, and cannot provide effective protection against disasters caused by the fault arc. Therefore, whether the fault arc can be accurately identified becomes a key for solving the fault arc protection problem.
Disclosure of Invention
An aspect of the embodiments of the present invention provides a fault arc detection method and apparatus, which are used to solve the problem that the prior art cannot effectively detect a fault arc.
To achieve the above object, an embodiment of the present invention provides a fault arc detection method, including: acquiring a current signal of a circuit; generating power spectrum data according to the acquired current signals; and determining whether a fault arc occurs according to the change trend of the power value in the preset frequency range in the power spectrum data.
Optionally, in the foregoing fault arc detection method, determining whether a fault arc occurs according to a trend of a power value in a preset frequency range in the power spectrum data includes: if the power noise floor value of the power spectrum rises within a preset frequency range and the rise amplitude exceeds a predetermined floor rise rate threshold, and as the frequency rises, the power value exhibits an arc-like roll-off approximating the inverse of the frequency, a fault arc is determined to occur.
Optionally, in the foregoing fault arc detection method, determining whether a fault arc occurs according to a trend of a power value in a preset frequency range in the power spectrum data includes: dividing the preset frequency range into a plurality of equal-length frequency sub-segments, if the power noise base value of the power spectrum is increased in the plurality of frequency sub-segments, the increasing amplitude exceeds a preset base increasing rate threshold value, the increasing amplitude of the power noise base value of the frequency sub-segments gradually decreases along with the increase of the frequency, and the power value presents arc-shaped roll-off approximate to the inverse frequency along with the increase of the frequency, and then the fault arc is determined to occur.
Optionally, in the foregoing fault arc detection method, determining whether a fault arc occurs according to a trend of a power value in a preset frequency range in the power spectrum data includes: dividing a preset frequency range into a plurality of frequency sub-sections with equal length, if the power noise base value of the power spectrum is raised in the plurality of frequency sub-sections, the raising amplitude exceeds a preset base raising rate threshold value, and as the frequency is raised, the power value presents arc-shaped roll-off with approximate inverse frequency, and the reducing amplitude of the power noise base value of any frequency sub-section exceeds a preset amplitude change threshold value, determining that a fault arc occurs.
Optionally, in the foregoing fault arc detection method, determining whether a fault arc occurs according to a trend of a power value in a preset frequency range in the power spectrum data includes: dividing a preset frequency range into a plurality of frequency sub-sections with equal length, if the power noise base value of the power spectrum is raised in the plurality of frequency sub-sections, the raising amplitude exceeds a preset base raising rate threshold value, the raising amplitude of the power noise base value of the frequency sub-sections gradually decreases along with the raising of the frequency, the power value presents arc-shaped roll-off with approximate inverse frequency along with the raising of the frequency, and the reducing amplitude of the power noise base value of any frequency sub-section exceeds a preset amplitude change threshold value, determining that a fault arc occurs.
Optionally, in the foregoing fault arc detection method, determining whether a fault arc occurs according to a trend of a power value in a preset frequency range in the power spectrum data includes: dividing a preset frequency range into a plurality of frequency sub-sections with equal length, if the power noise floor value of the power spectrum is raised in the plurality of frequency sub-sections, the raising amplitude exceeds a preset floor raising rate threshold value, and as the frequency is raised, the power value presents an arc-shaped roll-off approximating the inverse frequency, and the reducing amplitude of the power noise floor value of any frequency sub-section exceeds a preset amplitude change threshold value, and as the frequency is raised, the reducing amplitude of the power noise floor value of the frequency sub-section is gradually reduced, then the fault arc is determined to occur.
Optionally, in the foregoing fault arc detection method, determining whether a fault arc occurs according to a trend of a power value in a preset frequency range in the power spectrum data includes: dividing a preset frequency range into a plurality of frequency sub-sections with equal length, if the power noise floor value of the power spectrum is raised in the plurality of frequency sub-sections, the raised amplitude exceeds a preset floor raised rate threshold value, the raised amplitude of the power noise floor value of the frequency sub-sections gradually decreases along with the rise of the frequency, the power value presents arc-shaped roll-off approximate to the inverse frequency along with the rise of the frequency, the reduced amplitude of the power noise floor value of any frequency sub-section exceeds a preset amplitude change threshold value, and the reduced amplitude of the power noise floor value of the frequency sub-section gradually decreases along with the rise of the frequency, determining that a fault arc occurs.
Alternatively, in the foregoing fault arc detection method, the power spectrum data is generated from the acquired current signal by a fast fourier transform method.
Optionally, in the fault arc detection method, the preset frequency range is 0-250KHz.
Another aspect of the embodiments of the present invention provides a fault arc detection device, which is used for effectively detecting and accurately detecting a fault arc.
To achieve the above object, an embodiment of the present invention further provides a fault arc detection apparatus, configured to execute the foregoing detection method, including: a current signal acquisition unit for acquiring a current signal from the circuit; the power spectrum generating unit is used for generating power spectrum data according to the current signal acquired by the current signal acquiring unit; and the fault arc determining unit is used for determining whether fault arc occurs according to the change trend of the power value in the preset frequency range in the power spectrum data generated by the power spectrum generating unit.
The fault arc detection method and the fault arc detection device provided by the embodiment of the invention can effectively and accurately detect the fault arc in the circuit, greatly improve the accuracy of fault arc detection, and can perform corresponding treatment in time when determining the fault arc in the circuit, thereby effectively reducing the occurrence of electric fire caused by the fault arc, improving the safety and stability of an electric system, ensuring the safe operation of the electric system and effectively reducing the property and personnel loss caused by the electric fire.
Drawings
FIG. 1 shows a schematic diagram of a power spectrum waveform without a fault arc in a circuit;
FIG. 2 shows a schematic diagram of a power spectrum waveform in the event of a fault arc in a circuit;
FIG. 3 shows a flow chart of a fault arc detection method of an embodiment of the present invention;
fig. 4 is a flowchart showing a first embodiment of a fault arc detection method according to an embodiment of the present invention;
fig. 5 is a flowchart showing a second embodiment of a fault arc detection method according to an embodiment of the present invention;
fig. 6 shows a flowchart of a third implementation of the fault arc detection method according to an embodiment of the present invention;
fig. 7 is a flowchart showing a fourth embodiment of a fault arc detection method according to an embodiment of the present invention;
fig. 8 is a flowchart showing a fifth embodiment of a fault arc detection method according to an embodiment of the present invention;
fig. 9 shows a flowchart of a sixth embodiment of a fault arc detection method according to an embodiment of the present invention.
Detailed Description
The following describes a fault arc detection method and apparatus according to an embodiment of the present invention in detail with reference to fig. 1 to 9.
A waveform diagram of the power spectrum in a normal state (no fault arc) is shown in fig. 1; a waveform diagram of the power spectrum in the event of a fault arc in the circuit under the same load is shown in fig. 2. The inventor of the invention finds that when fault arc appears or does not appear in practice of the embodiment of the invention, the waveform diagrams of the two corresponding power spectrums have obvious differences, and the detection and the determination of the fault arc can be effectively and accurately realized by comparing the changes of the two waveform diagrams. How to effectively analyze and compare the changes of the two waveforms and thus accurately determine the occurrence of a fault arc, however, a need exists for efficient solutions.
To this end, fig. 3 shows a fault arc detection method according to an embodiment of the present invention, including: s1, acquiring a current signal of a circuit;
for example, the current signal of the acquisition circuit may be an analog signal obtained by a detection device such as a current transformer, and then the analog signal of the current signal is converted into a digital signal by an analog-to-digital conversion module. However, the present invention is not limited thereto, and any other method capable of acquiring a current signal may be employed. Analog signals typically include signals of the amplitude, frequency, etc. of the current. The circuit may be a power distribution circuit or a circuit of an electric device, but is not limited thereto.
S2, generating power spectrum data according to the acquired current signals;
for example, generating power spectrum data from the acquired current signal may employ a fast fourier transform to convert a digital signal of the current signal into power spectrum data. However, the method of conversion is not limited thereto, and any other conversion method suitable for converting time domain data into frequency domain data, such as discrete fourier transform, may be used. In addition, the present embodiment is not limited to converting the current signal into the power spectrum data, and a method of converting the current signal into the spectrum data or other domain data to determine may be adopted as long as the spectrum signal-to-noise ratio satisfies the requirement. Meanwhile, other algorithms, such as a wavelet transform algorithm, etc., can be also adopted in the method for converting the current signal into other domain data.
And step S3, determining whether a fault arc occurs according to the change trend of the power value in the preset frequency range in the power spectrum data.
The manner of determining whether or not a fault arc occurs based on the trend of the power value within the preset frequency range will be described in detail below, but is not limited to the following embodiments.
According to the fault arc detection method, power spectrum data are generated according to the acquired current signals, whether a fault arc occurs or not is determined by analyzing the change trend in the power spectrum data within the preset frequency range of the power value, and detection of the fault arc can be effectively and accurately achieved.
Several implementations of the fault arc detection method according to the embodiments of the present invention will be specifically described with reference to fig. 4 to 9. In the following embodiments, the same steps S1 and S2 will not be described in detail, and only step S3 will be described in detail.
Embodiment one: as shown in fig. 4, step S3 includes:
step S311, in a preset frequency range, determining whether a power noise base value of a power spectrum is raised, whether a raising amplitude exceeds a preset base raising rate threshold value, and determining whether a power value presents an arc-shaped roll-off approximate to the inverse frequency with the raising of the frequency;
if it is determined that the power noise floor value of the power spectrum increases with an increase in frequency and the increase amplitude exceeds a predetermined floor increase rate threshold, and the power value exhibits an arc-shaped roll-off approximating the inverse of the frequency with an increase in frequency, then it goes to step S312; otherwise, go to step S313.
Step S312, determining that a fault arc occurs;
step S313, determining that no fault arc occurs.
Specifically, in step S311, the preset frequency range may be divided into a plurality of equal-length frequency subsections; then finding out the average value of the power values of each frequency sub-segment and the average value of the power noise base value, and then determining the average value of each power value and the variation trend of the average value of each power noise base value; if the average value of the power noise floor values of the power spectra of all frequency sub-sections increases with increasing frequency and the increasing amplitude exceeds a predetermined floor increasing rate threshold value, and the average value of the power values of all frequency sub-sections exhibits an arc-shaped roll-off approximating the inverse frequency with increasing frequency, then a fault arc can be determined to occur.
In step S311, the compared values are not limited to the average value of the power values and the average value of the power noise floor values, and it may be determined whether a fault arc occurs or not according to the maximum value or the minimum value of the power in the frequency sub-segment and the maximum value or the minimum value of the power noise floor value, in the same manner as the average value.
Further, in another alternative, in step S311, it is determined whether the power noise floor value of the power spectrum is raised and whether the raising amplitude exceeds a predetermined floor raising ratio threshold, a determination may also be made according to whether the integrated area value of the power noise floor value of the power spectrum versus frequency is raised and whether the raising amplitude exceeds a predetermined area raising ratio threshold. If the integrated area value of the power noise floor value of the power spectrum over frequency increases and the increase amplitude exceeds a predetermined area increase rate threshold, the power noise floor value of the power spectrum may be considered to increase and the increase amplitude exceeds a predetermined floor increase rate threshold. But is not limited thereto, any method that can be used to identify an increase in the power noise floor value is within the limitations of the present embodiment.
The more the number of frequency sub-segments, the more accurate the determination result.
Embodiment two: as shown in fig. 5, step S3 includes:
step S321, dividing a preset frequency range into a plurality of equal-length frequency subsections;
step S322, determining, in a plurality of frequency sub-segments, whether a power noise floor value of the power spectrum rises, whether a rising amplitude exceeds a predetermined floor rising ratio threshold, and as the frequency rises, whether the amplitude of the rise of the power noise floor value of the frequency sub-segment gradually decreases, and as the frequency rises, whether the power value exhibits an arc-shaped roll-off approximating a reciprocal of the frequency;
if the power noise floor value of the power spectrum rises in a plurality of frequency sub-sections, the rising amplitude exceeds a predetermined floor rising ratio threshold, and the rising amplitude of the power noise floor value of the frequency sub-sections gradually decreases with the rising of the frequency, and the power value exhibits an arc roll-off approximating the inverse of the frequency with the rising of the frequency, then go to step S323, otherwise go to step S324;
step S323, determining that a fault arc occurs;
step S324, determining that no fault arc occurs.
Specifically, in step S322, the preset frequency range may be divided into a plurality of equal-length frequency subsections; then finding out the average value of the power values of each frequency sub-segment and the average value of the power noise base value, and then determining the average value of each power value and the variation trend of the average value of each power noise base value; if the average value of the power noise floor values of the power spectra of all the frequency sub-sections is raised in the plurality of frequency sub-sections, the raising amplitude exceeds a predetermined floor raising ratio threshold value, and the raising amplitude of the average value of the power noise floor values of the frequency sub-sections is gradually lowered with the raising of the frequency, and the average value of the power values of all the frequency sub-sections exhibits an arc-shaped roll-off approximating the inverse frequency with the raising of the frequency, it is determined that a fault arc occurs.
In step S322, the compared values are not limited to the average value of the power values and the average value of the power noise floor values, but may be determined according to the combination of the maximum value or the minimum value of the power in the frequency sub-segment and the maximum value or the minimum value of the power noise floor values, in which the specific determination manner is the same as the determination manner of the average value.
Further, in another alternative, in step S322, when it is determined whether the power noise floor value of the power spectrum is raised and the raising amplitude exceeds a predetermined floor raising ratio threshold, it may also be determined whether the integrated area value of the power noise floor value of the power spectrum versus frequency is raised and the raising amplitude exceeds a predetermined area raising ratio threshold. If the integrated area value of the power noise floor value of the power spectrum over frequency increases and the increase amplitude exceeds a predetermined area increase rate threshold, the power noise floor value of the power spectrum may be considered to increase and the increase amplitude exceeds a predetermined floor increase rate threshold. But is not limited thereto, any method that can be used to identify an increase in the power noise floor value is within the limitations of the present embodiment.
Further, in another alternative, in step S322, when it is determined whether the magnitude of the increase in the power noise floor value of the frequency sub-section gradually decreases as the frequency increases, it may also be determined whether the magnitude of the increase in the integrated area value of the frequency is gradually decreased according to the power noise floor value of the frequency sub-section. If the magnitude of the increase in the integrated area value of the frequency over the power noise floor value of the frequency sub-segment gradually decreases with increasing frequency, the magnitude of the increase in the power noise floor value of the frequency sub-segment can be considered to gradually decrease. But is not limited thereto, any method that can be used to identify a magnitude reduction in the rise in power noise floor value is within the limitations of the present embodiment.
The more the number of frequency sub-segments, the more accurate the determination result.
Embodiment III: as shown in fig. 6, step S3 includes:
step S331, dividing a preset frequency range into a plurality of frequency subsections with equal length;
step S332, in a plurality of frequency sub-segments, determining whether a power noise floor value of the power spectrum is raised, whether a rise amplitude exceeds a predetermined floor rise rate threshold, and as the frequency is raised, determining whether a power value exhibits an arc-like roll-off approximating a reciprocal frequency, and determining whether a reduction amplitude of an amplitude of the power noise floor value of any frequency sub-segment exceeds a predetermined amplitude variation threshold, determining that a fault arc occurs.
If the power noise floor value of the power spectrum rises in a plurality of frequency sub-segments, the rising amplitude exceeds a predetermined floor rising rate threshold, and as the frequency rises, the power value exhibits an arc roll-off approximating the inverse frequency, and the decreasing amplitude of the power noise floor value of any frequency sub-segment exceeds a predetermined amplitude variation threshold, then go to step S333, otherwise go to step S334;
step S333, determining that a fault arc occurs;
step S334, determining that no fault arc occurs.
Specifically, in step S332, the preset frequency range may be divided into a plurality of equal-length frequency subsections; then find the average value of the power value, average value of the power noise base value and average value of the amplitude of the power noise base value of each frequency sub-section, then confirm the change trend of the average value of each power value, average value of each power noise base value and average value of the amplitude of each power noise base value; in the plurality of frequency sub-segments, an average value of power noise floor values of the power spectrum rises, a rising amplitude exceeds a predetermined floor rising ratio threshold, and as the frequency rises, an average value of power values of all the frequency sub-segments exhibits an arc-like roll-off approximating a reciprocal frequency, and a decreasing amplitude of an average value of amplitudes of power noise floor values of any of the frequency sub-segments exceeds a predetermined amplitude variation threshold, it can be determined that a fault arc occurs.
Optionally, in step S332, the compared values are not limited to the average value of the power values, the average value of the power noise floor values, and the average value of the amplitudes of the power noise floor values, and it may be determined whether a fault arc occurs according to a combination of the maximum value or the minimum value of the power in the frequency sub-segment, the maximum value or the minimum value of the power noise floor values, and the maximum value or the minimum value of the amplitudes of the power noise floor values, in the same manner as the determination of the average value.
Further, in another alternative, in step S332, it is determined whether the power noise floor value of the power spectrum is raised and whether the raising amplitude exceeds a predetermined floor raising ratio threshold, a determination may also be made according to whether the integrated area value of the power noise floor value of the power spectrum versus frequency is raised and whether the raising amplitude exceeds a predetermined area raising ratio threshold. If the integrated area value of the power noise floor value of the power spectrum over frequency increases and the increase amplitude exceeds a predetermined area increase rate threshold, the power noise floor value of the power spectrum may be considered to increase and the increase amplitude exceeds a predetermined floor increase rate threshold. But is not limited thereto, any method that can be used to identify an increase in the power noise floor value is within the limitations of the present embodiment.
The more the number of frequency sub-segments, the more accurate the determination result.
Embodiment four: as shown in fig. 7, step S3 includes:
step S341, dividing a preset frequency range into a plurality of frequency subsections with equal length;
step S342, in a plurality of frequency sub-sections, it is determined whether the power noise floor value of the power spectrum is raised, whether the raising amplitude exceeds a predetermined floor raising ratio threshold, and as the frequency is raised, it is determined whether the raising amplitude of the power noise floor value of the frequency sub-section is gradually lowered, and as the frequency is raised, it is determined whether the power value exhibits an arc-like roll-off approximating the inverse frequency, and it is determined whether the lowering amplitude of the power noise floor value of any frequency sub-section exceeds a predetermined amplitude variation threshold, then it is determined that a fault arc occurs.
If the power noise floor value of the power spectrum increases in a plurality of frequency sub-sections, the increasing amplitude exceeds a predetermined floor increasing rate threshold, and the increasing amplitude of the power noise floor value of the frequency sub-sections gradually decreases with increasing frequency, and the power value exhibits an arc roll-off approximating the inverse frequency with increasing frequency, and the decreasing amplitude of the power noise floor value of any frequency sub-section exceeds a predetermined amplitude variation threshold, then go to step S343, otherwise go to step S344;
step S343, determining that a fault arc occurs;
step S344, determining that no fault arc occurs.
Specifically, in step S342, the preset frequency range may be divided into a plurality of equal-length frequency subsections; then find the average value of the power value, average value of the power noise base value and average value of the amplitude of the power noise base value of each frequency sub-section, then confirm the change trend of the average value of each power value, average value of each power noise base value and average value of the amplitude of each power noise base value; in the plurality of frequency sub-sections, an average value of power noise floor values of the power spectrum rises, a rising amplitude exceeds a predetermined floor rising ratio threshold, and as the frequency rises, the rising amplitude of the average value of the power noise floor values of the frequency sub-sections gradually decreases, and as the frequency rises, the average value of power values of all the frequency sub-sections exhibits an arc-shaped roll-off approximating a reciprocal of the frequency, and a decreasing amplitude of the average value of the amplitude of the power noise floor values of any one of the frequency sub-sections exceeds a predetermined amplitude variation threshold, it may be determined that a fault arc occurs.
Optionally, in step S342, the compared values are not limited to the average value of the power values, the average value of the power noise floor values, and the average value of the amplitudes of the power noise floor values, and it may be determined whether a fault arc occurs according to a combination of the maximum value or the minimum value of the power in the frequency sub-segment, the maximum value or the minimum value of the power noise floor values, and the maximum value or the minimum value of the amplitudes of the power noise floor values, in the same manner as the determination of the average value.
Further, in another alternative, in step S342, it is determined whether the power noise floor value of the power spectrum is raised and whether the raising amplitude exceeds a predetermined floor raising ratio threshold, it may also be determined whether the integrated area value of the power noise floor value of the power spectrum versus frequency is raised and whether the raising amplitude exceeds a predetermined area raising ratio threshold. If the integrated area value of the power noise floor value of the power spectrum over frequency increases and the increase amplitude exceeds a predetermined area increase rate threshold, the power noise floor value of the power spectrum may be considered to increase and the increase amplitude exceeds a predetermined floor increase rate threshold. But is not limited thereto, any method that can be used to identify an increase in the power noise floor value is within the limitations of the present embodiment.
Further, in another alternative, in step S342, when it is determined whether the magnitude of the increase in the power noise floor value of the frequency sub-section gradually decreases as the frequency increases, it may also be determined whether the magnitude of the increase in the integrated area value of the frequency is gradually decreased according to the power noise floor value of the frequency sub-section. If the magnitude of the increase in the integrated area value of the frequency over the power noise floor value of the frequency sub-segment gradually decreases with increasing frequency, the magnitude of the increase in the power noise floor value of the frequency sub-segment can be considered to gradually decrease. But is not limited thereto, any method that can be used to identify a magnitude reduction in the rise in power noise floor value is within the limitations of the present embodiment.
The more the number of frequency sub-segments, the more accurate the determination result.
Fifth embodiment: as shown in fig. 8, step S3 includes:
step S351, dividing a preset frequency range into a plurality of frequency subsections with equal length;
step S352, in a plurality of frequency sub-segments, determining whether a power noise floor value of the power spectrum rises, whether a rising amplitude exceeds a predetermined floor rising ratio threshold, and as the frequency rises, determining whether a power value exhibits an arc-like roll-off approximating a reciprocal frequency, and determining whether a decreasing amplitude of an amplitude of the power noise floor value of any frequency sub-segment exceeds a predetermined amplitude variation threshold, and as the frequency rises, determining whether the decreasing amplitude of the power noise floor value of the frequency sub-segment gradually decreases, then determining that a fault arc occurs.
If the power noise floor value of the power spectrum rises in a plurality of frequency sub-sections, the rising amplitude exceeds a predetermined floor rising rate threshold, and as the frequency rises, the power value exhibits an arc-like roll-off approximating the inverse frequency, and the decreasing amplitude of the power noise floor value of any frequency sub-section exceeds a predetermined amplitude variation threshold, and as the frequency rises, the decreasing amplitude of the power noise floor value of the frequency sub-section gradually decreases, then go to step S353, otherwise go to step S354;
step S353, determining that a fault arc occurs;
step S354, determining that no fault arc occurs.
Specifically, in step S352, the preset frequency range may be divided into a plurality of equal-length frequency subsections; then find the average value of the power value, average value of the power noise base value and average value of the amplitude of the power noise base value of each frequency sub-section, then confirm the change trend of the average value of each power value, average value of each power noise base value and average value of the amplitude of each power noise base value; in the plurality of frequency sub-sections, an average value of power noise floor values of the power spectrum rises, a rising amplitude exceeds a predetermined floor rising ratio threshold, and as the frequency rises, an average value of power values of all the frequency sub-sections exhibits an arc-shaped roll-off approximating a reciprocal of the frequency, and a decreasing amplitude of an average value of amplitude of power noise floor values of any one of the frequency sub-sections exceeds a predetermined amplitude variation threshold, and as the frequency rises, a decreasing amplitude of an average value of amplitude of power noise floor values of the frequency sub-sections gradually decreases, it can be determined that a fault arc occurs.
Optionally, in step S352, the compared values are not limited to the average value of the power values, the average value of the power noise floor values, and the average value of the amplitudes of the power noise floor values, and it may be determined whether a fault arc occurs or not according to a combination of the maximum value or the minimum value of the power in the frequency sub-segment, the maximum value or the minimum value of the power noise floor values, and the maximum value or the minimum value of the amplitudes of the power noise floor values, in the same manner as the determination of the average value.
Further, in another alternative, in step S352, when it is determined whether the power noise floor value of the power spectrum is raised and the raising amplitude exceeds a predetermined floor raising ratio threshold, it may also be determined whether the integrated area value of the power noise floor value of the power spectrum versus frequency is raised and the raising amplitude exceeds a predetermined area raising ratio threshold. If the integrated area value of the power noise floor value of the power spectrum over frequency increases and the increase amplitude exceeds a predetermined area increase rate threshold, the power noise floor value of the power spectrum may be considered to increase and the increase amplitude exceeds a predetermined floor increase rate threshold. But is not limited thereto, any method that can be used to identify an increase in the power noise floor value is within the limitations of the present embodiment.
The more the number of frequency sub-segments, the more accurate the determination result.
Embodiment six: as shown in fig. 9, step S3 includes:
step S361, dividing the preset frequency range into a plurality of equal-length frequency subsections;
step S362, in a plurality of frequency sub-segments, determining whether the power noise floor value of the power spectrum rises, whether the rising amplitude exceeds a predetermined floor rising ratio threshold, and as the frequency rises, determining whether the rising amplitude of the power noise floor value of the frequency sub-segment gradually decreases, and as the frequency rises, determining whether the power value exhibits an arc-like roll-off approximating the inverse frequency, and determining whether the decreasing amplitude of the power noise floor value of any frequency sub-segment exceeds a predetermined amplitude variation threshold, and as the frequency rises, determining whether the decreasing amplitude of the power noise floor value of the frequency sub-segment gradually decreases, then determining that a fault arc occurs.
If the power noise floor value of the power spectrum rises in a plurality of frequency sub-sections, the rising amplitude exceeds a predetermined floor rising ratio threshold, and the rising amplitude of the power noise floor value of the frequency sub-sections gradually decreases with the rising of the frequency, and the power value exhibits an arc roll-off approximating the inverse of the frequency with the rising of the frequency, and the decreasing amplitude of the power noise floor value of any frequency sub-section exceeds a predetermined amplitude variation threshold, and the decreasing amplitude of the power noise floor value of the frequency sub-sections gradually decreases with the rising of the frequency, then go to step S363, otherwise go to step S364;
step S363, determining that a fault arc occurs;
step S364, determining that no fault arc occurs.
Specifically, in step S362, the preset frequency range may be divided into a plurality of equal-length frequency subsections; then find the average value of the power value, average value of the power noise base value and average value of the amplitude of the power noise base value of each frequency sub-section, then confirm the change trend of the average value of each power value, average value of each power noise base value and average value of the amplitude of each power noise base value; in the plurality of frequency sub-sections, an average value of the power noise floor value of the power spectrum rises, the rising amplitude exceeds a predetermined floor rising ratio threshold, and as the frequency rises, the rising amplitude of the average value of the power noise floor value of the frequency sub-sections gradually decreases, and as the frequency rises, the average value of the power values of all the frequency sub-sections exhibits an arc-shaped roll-off approximating the inverse of the frequency, and a decreasing amplitude of the average value of the amplitude of the power noise floor value of any one of the frequency sub-sections exceeds a predetermined amplitude variation threshold, and as the frequency rises, the decreasing amplitude of the average value of the amplitude of the power noise floor value of the frequency sub-sections gradually decreases, it can be determined that a fault arc occurs.
Alternatively, in step S362, the compared values are not limited to the average value of the power values, the average value of the power noise floor values, and the average value of the amplitudes of the power noise floor values, and whether a fault arc occurs may be determined according to a combination of the maximum value or the minimum value of the power in the frequency sub-segment, the maximum value or the minimum value of the power noise floor values, and the maximum value or the minimum value of the amplitudes of the power noise floor values, in the same manner as the determination of the average value.
Further, in another alternative, in step S362, when it is determined whether the power noise floor value of the power spectrum is raised and the raising amplitude exceeds the predetermined floor raising ratio threshold, it may also be determined whether the integrated area value of the power noise floor value of the power spectrum versus frequency is raised and the raising amplitude exceeds the predetermined area raising ratio threshold. If the integrated area value of the power noise floor value of the power spectrum over frequency increases and the increase amplitude exceeds a predetermined area increase rate threshold, the power noise floor value of the power spectrum may be considered to increase and the increase amplitude exceeds a predetermined floor increase rate threshold. But is not limited thereto, any method that can be used to identify an increase in the power noise floor value is within the limitations of the present embodiment.
Further, in another alternative, in step S362, when it is determined whether the magnitude of the increase in the power noise floor value of the frequency sub-section gradually decreases as the frequency increases, it may also be determined whether the magnitude of the increase in the integrated area value of the frequency is gradually decreased according to the power noise floor value of the frequency sub-section. If the magnitude of the increase in the integrated area value of the frequency over the power noise floor value of the frequency sub-segment gradually decreases with increasing frequency, the magnitude of the increase in the power noise floor value of the frequency sub-segment can be considered to gradually decrease. But is not limited thereto, any method that can be used to identify a magnitude reduction in the rise in power noise floor value is within the limitations of the present embodiment.
The more the number of frequency sub-segments, the more accurate the determination result.
Therefore, the determination accuracy of fault arc can be increased, the occurrence of misjudgment is reduced, the reliability and the safety of equipment are improved, and the normal operation of the equipment is facilitated.
In the above embodiments, the meaning of "the power value represents the arc-shaped roll-off of the approximate inverse frequency" as the frequency increases, includes "the power value represents the arc-shaped roll-off of the inverse frequency (1/f) as the frequency increases, and the f is the frequency", and for example, one of the average value, the maximum value, and the minimum value of the power values of the plurality of frequency sub-segments represents the arc-shaped roll-off of the inverse frequency as the frequency increases may be used, but is not limited thereto. The meaning of "approximately" also includes a case of an arc-shaped roll-off that closely but inaccurately coincides with the inverse frequency, for example, but not limited to, a case in which one of an average value, a maximum value, and a minimum value of power values of a plurality of frequency sub-sections exhibits an arc-shaped roll-off that closely but inaccurately coincides with the inverse frequency as the frequency increases.
Alternatively, the preset frequency range in the above embodiment may be 0-250KHz. It should be noted that the preset frequency range of 0-250KHz is only an exemplary embodiment, but the embodiment of the present invention is not limited to this frequency range in practical implementation, and the preset frequency range may be suitable for use in the 0-GHz or even higher frequency band if the performance of the device allows. Selection of a particular frequency range may be based on cost considerations with accuracy and a particular tradeoff. The narrower the frequency range, the lower the cost and the accuracy is also reduced; the wider the frequency range, the higher the cost and the accuracy will also increase.
In addition, in the above embodiment, when the preset frequency range is divided into preset frequency subsections, the division method is not limited to the equal division method, and the division may be performed in an unequal manner, and any algorithm easy to implement may be used.
Another aspect of the present embodiment provides a fault arc detection apparatus for performing the fault arc detection method described in the present embodiment, including: a current signal acquisition unit for acquiring a current signal from the circuit; the power spectrum generating unit is used for generating power spectrum data according to the current signal acquired by the current signal acquiring unit; and the fault arc determining unit is used for determining whether fault arc occurs according to the change trend of the power value in the preset frequency range in the power spectrum data generated by the power spectrum generating unit.
The fault arc detection method and the fault arc detection device provided by the embodiment of the invention can effectively and accurately detect the fault arc in the circuit, greatly improve the accuracy of fault arc detection, and can perform corresponding treatment in time when determining the fault arc in the circuit, thereby effectively reducing the occurrence of electric fire caused by the fault arc, improving the safety and stability of an electric system, ensuring the safe operation of the electric system and effectively reducing the property and personnel loss caused by the electric fire.
The above embodiments are merely illustrative examples of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think about variations or substitutions within the technical scope of the present invention, and the invention should be covered. Therefore, the protection scope of the invention is subject to the protection scope of the claims.
Claims (4)
1. A fault arc detection method comprising:
acquiring a current signal of a circuit;
generating power spectrum data according to the acquired current signals;
determining whether a fault arc occurs according to the change trend of the power value in the preset frequency range in the power spectrum data;
determining whether a fault arc occurs according to the change trend of the power value in the preset frequency range in the power spectrum data comprises the following steps:
dividing the preset frequency range into a plurality of frequency subsections with equal length,
if the power noise floor value of the power spectrum increases in the plurality of frequency sub-segments by an amount exceeding a predetermined floor increase rate threshold, and the amount of increase in the power noise floor value of the frequency sub-segments gradually decreases as the frequency increases; and as the frequency increases, the power value presents an arc roll-off approximating the inverse of the frequency; and the amplitude of the power noise floor value of any frequency sub-segment is reduced to a smaller extent than the predetermined amplitude variation threshold value, and the amplitude of the power noise floor value of the frequency sub-segment is reduced gradually as the frequency increases; then a fault arc is determined to occur.
2. The detection method according to claim 1, wherein the generation of power spectrum data from the acquired current signal employs a fast fourier transform method.
3. The detection method according to claim 1, wherein the preset frequency range is 0-250KHz.
4. A fault arc detection apparatus for performing the detection method of any of claims 1-3, comprising:
a current signal acquisition unit for acquiring a current signal from the circuit;
the power spectrum generating unit is used for generating power spectrum data according to the current signal acquired by the current signal acquiring unit;
the fault arc determining unit is used for determining whether fault arc occurs according to the change trend of the power value in the preset frequency range in the power spectrum data generated by the power spectrum generating unit;
determining whether a fault arc occurs according to the change trend of the power value in the preset frequency range in the power spectrum data comprises the following steps: dividing a preset frequency range into a plurality of frequency sub-sections with equal length, if the power noise floor value of the power spectrum is raised in the plurality of frequency sub-sections, the raised amplitude exceeds a preset floor raised rate threshold value, the raised amplitude of the power noise floor value of the frequency sub-sections gradually decreases along with the rise of the frequency, the power value presents arc-shaped roll-off approximate to the inverse frequency along with the rise of the frequency, the reduced amplitude of the power noise floor value of any frequency sub-section exceeds a preset amplitude change threshold value, and the reduced amplitude of the power noise floor value of the frequency sub-section gradually decreases along with the rise of the frequency, determining that a fault arc occurs.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710129379.XA CN108535606B (en) | 2017-03-06 | 2017-03-06 | Fault arc detection method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710129379.XA CN108535606B (en) | 2017-03-06 | 2017-03-06 | Fault arc detection method and device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108535606A CN108535606A (en) | 2018-09-14 |
| CN108535606B true CN108535606B (en) | 2023-10-13 |
Family
ID=63489382
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710129379.XA Active CN108535606B (en) | 2017-03-06 | 2017-03-06 | Fault arc detection method and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108535606B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11329471B2 (en) * | 2017-10-27 | 2022-05-10 | Panasonic Intellectual Property Management Co., Ltd. | Arc detection circuit, breaker system, connection box system, power conditioner, micro inverter, DC optimizer, and arc detection method |
| CN110174602B (en) * | 2019-05-09 | 2021-01-08 | 山东大学 | Nonlinear load series arc fault determination method and application |
| CN110854821B (en) * | 2019-11-15 | 2021-09-24 | 上海红檀智能科技有限公司 | Self-adaptive electric arc light protection method based on current and arc light change trend |
| CN110988454B (en) * | 2019-12-31 | 2021-07-06 | 山东计保电气有限公司 | Method for monitoring small current by apparent power and real-time disposal |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5359293A (en) * | 1993-06-03 | 1994-10-25 | Bell Communications Research, Inc. | Electrical cable arcing fault detection by monitoring power spectrum in distribution line |
| CN105223427A (en) * | 2014-06-17 | 2016-01-06 | 西门子公司 | The detection method of fault electric arc and pick-up unit |
| CN105259446A (en) * | 2015-11-04 | 2016-01-20 | 北京腾锐视讯科技有限公司 | Wide-spectrum rapid high-sensitivity fault arc detection sensor and protector |
| CN105445611A (en) * | 2014-05-30 | 2016-03-30 | 西门子公司 | Fault arc detection method and device |
-
2017
- 2017-03-06 CN CN201710129379.XA patent/CN108535606B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5359293A (en) * | 1993-06-03 | 1994-10-25 | Bell Communications Research, Inc. | Electrical cable arcing fault detection by monitoring power spectrum in distribution line |
| CN105445611A (en) * | 2014-05-30 | 2016-03-30 | 西门子公司 | Fault arc detection method and device |
| CN105223427A (en) * | 2014-06-17 | 2016-01-06 | 西门子公司 | The detection method of fault electric arc and pick-up unit |
| CN105259446A (en) * | 2015-11-04 | 2016-01-20 | 北京腾锐视讯科技有限公司 | Wide-spectrum rapid high-sensitivity fault arc detection sensor and protector |
Non-Patent Citations (3)
| Title |
|---|
| Arc Fault Current Signal’s Power Spectrum Characteristics and Diagnosis Based on Welch Algorithm;Hongli Guan等;《International Journal of Engineering Science and Computing》;20160831;第6卷(第8期);正文第I-VII节 * |
| MichałDOŁĘGOWSKI等.Mechanisms of electric arc detection based on current waveform spectrum and incremental decomposition analysis.《PRZEGLĄD ELEKTROTECHNICZNY》.2016,59-62. * |
| 基于Welch算法故障电弧电流信号功率谱的特征与电弧故障诊断;管红立等;《电器与能效管理技术》;20161231(第24期);正文第1-5节 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108535606A (en) | 2018-09-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108535606B (en) | Fault arc detection method and device | |
| US9025287B2 (en) | Arc fault detection equipment and method using low frequency harmonic current analysis | |
| US7366622B1 (en) | Arc fault identification using model reference estimation | |
| US11435409B2 (en) | Temporary overvoltage and ground fault overvoltage protection based on arrester current measurement and analysis | |
| Ashrafian et al. | Hyperbolic S-transform-based method for classification of external faults, incipient faults, inrush currents and internal faults in power transformers | |
| US9366716B2 (en) | Sub-harmonic arc fault detection system and method | |
| US9829530B2 (en) | Method for adapting an arc sensor | |
| KR20100080453A (en) | Parallel arc detection using discrete wavelet transforms | |
| KR20120036804A (en) | Method and system for transient and intermittent earth fault detection and direction determination in a three phase median voltage electric power distribution system | |
| Cheng et al. | Series arc fault detection and implementation based on the short-time fourier transform | |
| Kim et al. | Clearing series AC arc faults and avoiding false alarms using only voltage waveforms | |
| CN103155329A (en) | Method and system for online ferroresonance detection | |
| US8355882B2 (en) | Method for detecting high impedance faults by analyzing a local deviation from a regularization | |
| CN110854809B (en) | Detection method of transformer neutral point protection device and protection device | |
| US11650264B2 (en) | Capacitance-coupled voltage transformer monitoring | |
| de Alvarenga Ferreira et al. | A novel high impedance arcing fault detection based on the discrete wavelet transform for smart distribution grids | |
| Ozansoy et al. | Volatility diagnosis in phase-to-phase fault detection for branch across wire faults | |
| KR101308003B1 (en) | Mehthod of arc detection based on wavelet | |
| KR102453119B1 (en) | Arc detecting device of power supply system and arc detecting method using the same | |
| US11187727B2 (en) | Capacitance-coupled voltage transformer monitoring | |
| KR102519681B1 (en) | Apparatus and method for detecting arc fault using weighted sum of arc noise signal | |
| Kachesov et al. | Monitoring in 6–35 kV power networks, location of single-phase ground fault and detection of fault feeder | |
| Xu et al. | Identification of series fault arc of low-voltage power cables in substation based on wavelet transform | |
| Banjanin et al. | Experimental registration and numerical simulation of the transient overvoltages caused by single phase intermittent arc earth fault in 35 kV network with isolated neutral | |
| US11411390B2 (en) | Secure and dependable restricted earth fault protection for electric power generators and transformers |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |