CN116593815A - SoC-based series alternating current arc fault detection method, positioning method and device - Google Patents
SoC-based series alternating current arc fault detection method, positioning method and device Download PDFInfo
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Abstract
The application discloses a series alternating current arc fault detection method, a positioning method and a device based on SoC. Firstly, acquiring voltage signals and current signals in a low-voltage distribution system through an arc fault detection SoC chip, respectively comparing the voltage signals and the current signals after wavelet decomposition with a set threshold value, judging whether an arc fault occurs according to a current domain comparison result, and judging fault branches according to the voltage domain comparison result. After determining that arc faults occur and determining fault branches, collecting and recording voltage signals and current signals of a source end and a load end of a distribution line through an SoC chip, performing FFT conversion respectively, substituting the voltage signals and the current signals into a positioning equation of the established serial arc fault position and the voltage signals and the current signals, determining a fault interval in a successive approximation manner, and finally determining a fault point according to the set precision of searching the fault point. The application has the characteristics of low cost and high integration level, and can be used for realizing the automation of a complex low-voltage power distribution system.
Description
Technical Field
The present application relates to the field of terminal technologies, and in particular, to a method and a device for detecting and locating a series ac arc fault based on an SoC.
Background
Conventional circuit breakers cannot effectively discriminate series fault arcs in time, and arc faults in the power system, if not detected, located and isolated in time, can cause significant damage to equipment, even electrical fires and personnel hazards. At present, a plurality of researches on arc fault detection are developed around an arc fault detection algorithm, and the existing arc fault signal front-end acquisition circuit and a board-level processor are utilized to complete calculation and data processing, so that the whole arc fault detection system is high in cost and poor in portability. In addition, the traditional fault locating method based on physical phenomena such as ultrasonic waves, electromagnetic wave radiation and the like is limited to fixed electric devices, and is not suitable for a low-voltage distribution system; the traveling wave method has the problem of transmission distortion, has higher requirements on equipment, and increases the cost of an arc fault positioning system.
Disclosure of Invention
In view of this, the embodiment of the application provides a series ac arc fault detection method, a positioning method and a device based on SoC, which can detect series ac arc faults in a low-voltage power distribution system in real time and judge fault branches, and position fault points in time.
According to a first aspect of an embodiment of the present application, there is provided a series ac arc fault detection method based on SoC, including:
acquiring voltage signals and current signals of different branches in a low-voltage distribution system through an arc fault detection SoC chip;
performing wavelet decomposition on the voltage signals and the current signals of the different branches respectively to obtain a high-frequency component of the voltage signals and a high-frequency component of the current signals after the wavelet decomposition;
comparing the high-frequency component of the voltage signal and the high-frequency component of the current signal with respective set thresholds;
and judging whether arc faults occur according to the comparison result in the current domain, and meanwhile judging fault branches according to the comparison result in the voltage domain.
Further, the performing wavelet decomposition on the voltage signal and the current signal of the different branches to obtain a high-frequency component of the voltage signal and a high-frequency component of the current signal after wavelet decomposition, includes:
performing discrete wavelet transformation on the voltage signals and the current signals of the different branches respectively;
and taking the high-frequency components of the voltage signal and the high-frequency components of the current signal after the first layer decomposition as the high-frequency components of the voltage signal and the high-frequency components of the current signal after the wavelet decomposition.
Further, determining whether an arc fault occurs according to the comparison result in the current domain, and simultaneously, determining the fault branch in combination with the comparison result in the voltage domain includes:
when the peak value of the high-frequency component of the current signal exceeds a set threshold value, judging that an arc fault occurs;
when the peak value of the high-frequency component of the voltage signal also exceeds a set threshold value, judging that an arc fault occurs at a place outside the branch;
when only the high frequency component of the current signal exceeds a set threshold, it is determined that an arc fault occurs in the branch.
According to a second aspect of the embodiment of the present application, there is provided a method for locating a series ac arc fault, including:
executing the series alternating current arc fault detection method based on the SoC of the first aspect;
after the series alternating current arc fault detection method based on the SoC is completed, acquiring and recording voltage signals and current signals of a source end and a load end in a distribution line through the arc fault detection SoC chip, wherein the source end is a first fault distance in the distribution line, and the load end is a second fault distance in the distribution line;
performing FFT (fast Fourier transform) on the voltage signals and the current signals of the source end and the load end respectively to obtain frequency domain voltage signals and frequency domain current signals of the source end and the load end;
substituting the first fault distance, the second fault distance, the frequency domain voltage signals and the frequency domain current signals of the source end and the load end into a positioning equation of the serial arc fault position and the voltage signals and the current signals to obtain a fault current first fundamental frequency component difference value and a fault current second fundamental frequency component difference value; the fault current first fundamental frequency component difference value is obtained by substituting a first fault distance into a positioning equation of a series arc fault position and a voltage signal and a current signal, and the fault current second fundamental frequency component difference value is obtained by substituting a second fault distance into a positioning equation of the series arc fault position and the voltage signal and the current signal;
determining a fault interval in successive approximation mode according to the first fundamental frequency component difference value and the second fundamental frequency component difference value of the fault current;
and in the determined fault interval, determining the position of the arc fault point according to the set precision of searching the fault point.
Further, the determining the fault interval according to the fault current first fundamental frequency component difference value and the fault current second fundamental frequency component difference value in a successive approximation manner includes:
when the product of the first fundamental frequency component difference value and the second fundamental frequency component difference value of the fault current is smaller than zero, determining that the actual arc fault point is located between the first fault distance and the second fault distance;
taking an assumed arc fault point as a half of the first fault distance and the second fault distance, substituting the assumed arc fault point, the frequency domain voltage signals and the frequency domain current signals of the source end and the load end into a positioning equation of the serial arc fault position, the voltage signals and the current signals to obtain a fault point fundamental frequency component difference value;
if the product of the base frequency component difference value of the fault point and the second base frequency component difference value is smaller than zero, the actual arc fault point is located between the assumed arc fault point and the second fault distance, then the value of the assumed fault point is assigned to the first fault distance, and the first base frequency component difference value is recalculated; if the product of the base frequency component difference value of the fault point and the first base frequency component difference value is smaller than zero, the actual arc fault point is located between the first fault distance and the assumed arc fault point, then the value of the assumed arc fault point is assigned to the second fault distance, and the second base frequency component difference value is recalculated;
and continuing to iterate to assume that the arc fault point is half of the first fault distance and the second fault distance when the product of the first fundamental frequency component difference value and the second fundamental frequency component difference value is always smaller than zero.
Further, the determining the arc fault point position according to the set searching fault point accuracy in the determined fault interval includes:
and when the difference value between the first fault distance and the second fault distance is smaller than the set precision of searching the fault points in the fault interval process determined through successive approximation, obtaining the actual arc fault point which is half of the first fault distance and the second fault distance.
According to a third aspect of the embodiment of the present application, there is provided a series ac arc fault detection device based on SoC, including:
the signal acquisition unit is used for acquiring voltage signals and current signals of different branches in the low-voltage distribution system through the arc fault detection SoC chip;
the signal decomposition unit is used for respectively carrying out wavelet decomposition on the voltage signals and the current signals of the different branches to obtain a high-frequency component of the voltage signals and a high-frequency component of the current signals after the wavelet decomposition;
a comparison unit for comparing the high frequency component of the voltage signal and the high frequency component of the current signal with respective set thresholds;
and the fault judging unit is used for judging whether the arc fault occurs according to the comparison result in the current domain and judging the fault branch by combining the comparison result in the voltage domain.
According to a fourth aspect of an embodiment of the present application, there is provided a series ac arc fault locating device, including:
an arc fault detection unit, configured to perform the SoC-based series ac arc fault detection method according to the first aspect;
the system comprises a signal acquisition unit, a power distribution circuit and a power distribution circuit, wherein the signal acquisition unit is used for acquiring and recording voltage signals and current signals of a source end and a load end in the power distribution circuit through the arc fault detection SoC chip after a series alternating current arc fault detection method based on the SoC is completed, the source end is a first fault distance in the power distribution circuit, and the load end is a second fault distance in the power distribution circuit;
the signal conversion unit is used for performing FFT conversion on the voltage signals and the current signals of the source end and the load end respectively to obtain frequency domain voltage signals and frequency domain current signals of the source end and the load end;
the difference value calculation unit is used for substituting the first fault distance, the second fault distance, the frequency domain voltage signals and the frequency domain current signals of the source end and the load end into a positioning equation of the serial arc fault position and the voltage signals and the current signals to obtain a fault current first fundamental frequency component difference value and a fault current second fundamental frequency component difference value; the fault current first fundamental frequency component difference value is obtained by substituting a first fault distance into a positioning equation of a series arc fault position and a voltage signal and a current signal, and the fault current second fundamental frequency component difference value is obtained by substituting a second fault distance into a positioning equation of the series arc fault position and the voltage signal and the current signal;
the successive approximation unit is used for determining a fault interval in a successive approximation manner according to the first fundamental frequency component difference value and the second fundamental frequency component difference value of the fault current;
and the fault point determining unit is used for determining the arc fault point position according to the set searching fault point accuracy in the determined fault interval.
According to a fifth aspect of an embodiment of the present application, there is provided an electronic apparatus including:
one or more processors;
a memory for storing one or more programs;
the one or more programs, when executed by the one or more processors, cause the one or more processors to implement the method of the first or second aspect.
According to a sixth aspect of embodiments of the present application there is provided a computer readable storage medium having stored thereon computer instructions which when executed by a processor perform the steps of the method according to the first or second aspect.
The technical scheme provided by the embodiment of the application can comprise the following beneficial effects:
as can be seen from the above embodiments, the integration level and portability of the arc fault detection system are improved by integrating the fault signal acquisition unit, the fault signal determination unit and other units into the same SoC chip; meanwhile, thanks to the proposed voltage domain and current domain double-channel arc fault detection method, the application can also judge fault branches on the basis of realizing arc fault detection.
Because the positioning is realized based on the equivalent model of the series alternating current arc fault distribution line, expensive equipment is not needed, the positioning scene of fixed equipment is not limited, and the advantages of low cost are realized; meanwhile, the fault point can be rapidly determined by adopting a successive approximation fault positioning method.
The application realizes the detection and positioning of the series alternating current arc faults of the multi-branch complex low-voltage distribution system, has low system cost and high integration level, and is suitable for the occasions of automation of the complex low-voltage distribution system.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application as claimed.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.
Fig. 1 is a flowchart of a series ac arc fault detection method based on SoC according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a series AC arc fault detection circuit based on SoC according to an embodiment of the present application;
FIG. 3 is a flow chart of a method for locating a series AC arc fault in accordance with an embodiment of the present application;
FIG. 4 is a schematic diagram of an equivalent series AC arc fault distribution circuit according to an embodiment of the present application;
fig. 5 is a schematic diagram of a series ac arc fault detection device based on SoC according to an embodiment of the present application;
fig. 6 is a schematic diagram of a serial ac arc fault locating device based on SoC according to an embodiment of the present application;
fig. 7 is a schematic diagram of an application scenario of series arc fault detection and location in a multi-branch complex low-voltage power distribution system according to an embodiment of the present application.
Detailed Description
Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the application. Rather, they are merely examples of apparatus and methods consistent with aspects of the application as detailed in the accompanying claims.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.
It should be understood that although the terms first, second, third, etc. may be used herein to describe various information, these information should not be limited by these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the application. The word "if" as used herein may be interpreted as "at … …" or "at … …" or "responsive to a determination", depending on the context.
Fig. 1 is a flow chart illustrating a method of SoC-based series ac arc fault detection, as shown in fig. 1, according to an exemplary embodiment, the method may include the steps of:
s101, acquiring voltage signals and current signals of different branches in a low-voltage distribution system through an arc fault detection SoC chip.
In the method provided by the embodiment of the application, the voltage signals and the current signals of different branches in the low-voltage distribution system are acquired by utilizing the device for acquiring the voltage signals and the current signals based on the arc fault detection SoC chip.
S102, performing wavelet decomposition on the voltage signals and the current signals of the different branches respectively to obtain a high-frequency component of the voltage signals and a high-frequency component of the current signals after wavelet decomposition.
In the method provided by the embodiment of the application, after the voltage signals and the current signals of different branches in the low-voltage distribution system are obtained, discrete wavelet transformation is respectively carried out on the voltage signals and the current signals of the different branches to carry out multi-layer decomposition, and then the high-frequency components of the voltage signals and the high-frequency components of the current signals after the first layer decomposition are used as the high-frequency components of the voltage signals and the high-frequency components of the current signals after wavelet decomposition.
S103, comparing the high-frequency component of the voltage signal and the high-frequency component of the current signal with the set threshold values respectively.
S104, judging whether arc faults occur according to the comparison result in the current domain, and meanwhile judging fault branches according to the comparison result in the voltage domain.
Specifically, in the method provided by the embodiment of the application, when the peak value of the high-frequency component of the current signal after wavelet decomposition exceeds a set threshold value, arc faults are judged to occur;
when the peak value of the high-frequency component of the voltage signal also exceeds a set threshold value, judging that the arc fault occurs at a place outside the branch;
when only the peak value of the high frequency component of the current signal exceeds a set threshold value, it is determined that an arc fault occurs in the branch.
In another embodiment of the present application, a series ac arc fault detection circuit 230 based on SoC is provided, as shown in fig. 2, and may include:
an off-chip arc fault signal processing circuit 210 and an arc fault detection SoC chip 220. The off-chip arc fault signal processing circuit 210 is connected to the live and neutral lines in the low voltage distribution system for generating a fault voltage signal V and a fault current signal Δv; the arc fault detection SoC chip 220 is connected to the off-chip arc fault signal processing circuit 210 for acquiring and processing the fault voltage signal V and the fault current signal Δv.
The off-chip arc fault signal processing circuit 210 includes a voltage signal processing circuit 211 and a current signal processing circuit 212. In the current signal processing circuit 212, the current sensor is used for sensing the current in the main loop and reducing the current according to the turns ratio and the proportion, the common-mode voltage generating circuit is used for providing the common-mode voltage required by the circuit, the first resistor R1 and the second resistor R2 are respectively connected in series at the left end and the right end of the common-mode voltage point, and finally the current signal is converted into a differential voltage signal delta V; in the voltage signal processing circuit 211, a third resistor R3 and a fourth resistor R4 are connected in series between the hot and neutral wires to obtain a scaled voltage signal V.
The arc fault detection SoC chip 220 includes a voltage-current dual channel front end acquisition circuit 221 and an arc fault detection algorithm 222. The voltage and current dual-channel front end acquisition circuit 221 comprises a current signal acquisition circuit channel and a voltage signal acquisition circuit channel. The analog circuit portion of each channel is composed of PGA and SARADC. The PGA is used for amplifying and filtering the micro signal, and the SARADC samples the amplified and filtered signal and converts the sampled signal into a digital signal. The SARADC controller controls the sampling mode, the gating channel, the sampling rate and the like of the SARADC, and transmits and processes the sampled data. In the arc fault detection algorithm 222 portion, a wavelet transformation module and a fault analysis module are included. The digital signal output by the SAR ADC is subjected to wavelet decomposition through a wavelet transformation module to obtain a voltage signal high-frequency component and a current signal high-frequency component after wavelet decomposition, and the fault analysis module compares the voltage signal high-frequency component and the current signal high-frequency component with respective set thresholds. When the peak value of the high-frequency component of the current signal after wavelet decomposition exceeds a set threshold value, judging that an arc fault occurs; when the series fault arc occurs outside the load, the peak value of the high-frequency component of the voltage signal and the peak value of the high-frequency component of the current signal exceed a set threshold value; when a series arc fault occurs inside the load, then only the peak value of the high frequency component of the current signal exceeds a set threshold. Therefore, according to the abnormal conditions in the voltage domain and the current domain, the judgment of arc fault branches can be realized, namely, only the current domain generates a fault alarm signal on the branch with arc faults.
On the basis of the arc fault detection method, the embodiment of the application also provides a series alternating current arc fault positioning method, which is shown in fig. 3 and specifically comprises the following steps:
S101-S104 are used for arc fault detection and arc fault branch judgment. And respectively carrying out wavelet decomposition by acquiring voltage signals and current signals of different branches in the low-voltage distribution system to obtain a high-frequency component of the voltage signal and a high-frequency component of the current signal after wavelet decomposition. Comparing the high-frequency component of the voltage signal and the high-frequency component of the current signal with the set threshold values respectively, and judging that the arc fault occurs when the peak value of the high-frequency component of the current signal after wavelet decomposition exceeds the set threshold value; when the peak value of the high-frequency component of the voltage signal also exceeds a set threshold value, judging that the arc fault occurs at a place outside the branch; when only the peak value of the high frequency component of the current signal exceeds a set threshold value, it is determined that an arc fault occurs in the branch.
After the arc fault detection is completed, the arc fault positioning method is realized based on the equivalent model of the series alternating current arc fault distribution line.
Alternatively, in another embodiment of the present application, a series ac arc fault distribution line equivalent model diagram is shown in fig. 4.
Wherein the distribution line adopts a T-shaped equivalent model. Impedance Z of distribution line of unit length s ，Z s R+jωl, where r is the distribution line resistance value per unit length, and l is the distribution line inductance value per unit length. Admittance of distribution line of unit length Z p ，Z p Let g+jωc, where g is the distribution line conductance value per unit length and c is the distribution line capacitance value per unit length. Assuming that the total length of the distribution line from the power supply end to the load end is d meters, the fault position occurs at the position x meters away from the source end, and the equivalent series impedance is Z when the series arc fault occurs arc 。V 1 ，I 1 Respectively representing the source voltage and the current value, V 2 ，I 2 Respectively representing the voltage and current values of the load terminal, I 1a And I 2a Respectively representCurrent values flowing into and out of the fault point. According to kirchhoff voltage and current law, a positioning equation of the serial arc fault position and current and voltage signals is established as follows:
I 1a ＝-Z p xV 1 +(1+Z s Z p x 2 )I 1
I 2a ＝Z p (d-x)V 2 +(1+Z s Z p (d-x) 2 )I 2
s105, after the series alternating current arc fault detection method based on the SoC is completed, the arc fault detection SoC chip collects and records voltage signals and current signals of a source end and a load end in a distribution line; the source end is a first fault distance in the distribution line, and the load end is a second fault distance in the distribution line.
In the method provided by the embodiment of the application, the voltage signal V of the source end in the distribution line is collected by utilizing the SoC-based arc fault detection circuit shown in fig. 2 1 And current signal I 1 Voltage signal V at load end 2 And current signal I 2 The method comprises the steps of carrying out a first treatment on the surface of the The source end is a first fault distance in the distribution line, and the load end is a second fault distance in the distribution line.
S106, opposite source voltage signal V 1 And current signal I 1 Load terminal voltage signal V 2 And current signal I 2 And respectively performing FFT (fast Fourier transform) to obtain frequency domain voltage signals and frequency domain current signals of the source end and the load end.
S107, substituting the first fault distance, the second fault distance, the frequency domain voltage signals and the frequency domain current signals of the source end and the load end into a positioning equation of the serial arc fault position, the voltage signals and the current signals to obtain a fault current first fundamental frequency component difference value and a fault current second fundamental frequency component difference value; the fault current first fundamental frequency component difference value is obtained by substituting a first fault distance into a positioning equation of a series arc fault position and a voltage signal and a current signal, and the fault current second fundamental frequency component difference value is obtained by substituting a second fault distance into a positioning equation of the series arc fault position and the voltage signal and the current signal.
It should be noted that, in the method of this embodiment, the fundamental frequency is 50Hz, and the difference value of fundamental frequency components is the current value I flowing into the fault point 1a And the current value I of the outflow fault point 2a And (3) a difference.
S108, determining a fault interval in a successive approximation mode according to the first fundamental frequency component difference value and the second fundamental frequency component difference value of the fault current.
Optionally, the method provided by the embodiment of the application specifically includes:
when the product of the first fundamental frequency component difference value and the second fundamental frequency component difference value of the fault current is smaller than zero, determining that the actual arc fault point is located between the first fault distance and the second fault distance;
taking an assumed arc fault point as a half of a first fault distance and a second fault distance, substituting the assumed arc fault point, the frequency domain voltage signals and the frequency domain current signals of a source end and a load end into a positioning equation of a series arc fault position, the voltage signals and the current signals to obtain a fault point fundamental frequency component difference value;
if the product of the base frequency component difference value of the fault point and the second base frequency component difference value is smaller than zero, the actual arc fault point is located between the assumed arc fault point and the second fault distance, then the value of the assumed fault point is assigned to the first fault distance, and the first base frequency component difference value is recalculated; if the product of the base frequency component difference value of the fault point and the first base frequency component difference value is smaller than zero, the actual arc fault point is located between the first fault distance and the assumed arc fault point, then the value of the assumed arc fault point is assigned to the second fault distance, and the second base frequency component difference value is recalculated;
and continuing to iterate to assume that the arc fault point is half of the first fault distance and the second fault distance when the product of the first fundamental frequency component difference value and the second fundamental frequency component difference value is always smaller than zero.
And S109, determining the position of the arc fault point in the determined fault interval according to the set precision of searching the fault point.
In the method provided by the embodiment of the application, when the difference value between the first fault distance and the second fault distance is smaller than the set precision of searching the fault point in the fault interval determining process through successive approximation, the iteration process of determining the fault interval is ended, and the actual arc fault point is half of the first fault distance and the second fault distance.
Corresponding to the embodiment of the series alternating current arc fault detection method based on the SoC, the application also provides an embodiment of a series alternating current arc fault detection device based on the SoC.
Referring to fig. 5, an embodiment of the present application further provides a series ac arc fault detection device based on SoC, including:
the signal acquisition unit is used for acquiring voltage signals and current signals of different branches in the low-voltage distribution system through the arc fault detection SoC chip;
the signal decomposition unit is used for respectively carrying out wavelet decomposition on the voltage signals and the current signals of the different branches to obtain a high-frequency component of the voltage signals and a high-frequency component of the current signals after the wavelet decomposition;
a comparison unit for comparing the high frequency component of the voltage signal and the high frequency component of the current signal with respective set thresholds;
and the fault judging unit is used for judging whether the arc fault occurs according to the comparison result in the current domain and judging the fault branch by combining the comparison result in the voltage domain.
The application also provides an embodiment of the series ac arc fault locating device corresponding to the embodiment of the series ac arc fault locating method.
Referring to fig. 6, an embodiment of the present application further provides a device for locating a series ac arc fault, including:
an arc fault detection unit, configured to perform the SoC-based series ac arc fault detection method described above;
the system comprises a signal acquisition unit, a power distribution circuit and a power distribution circuit, wherein the signal acquisition unit is used for acquiring and recording voltage signals and current signals of a source end and a load end in the power distribution circuit through the arc fault detection SoC chip after a series alternating current arc fault detection method based on the SoC is completed, the source end is a first fault distance in the power distribution circuit, and the load end is a second fault distance in the power distribution circuit;
the signal conversion unit is used for performing FFT conversion on the voltage signals and the current signals of the source end and the load end respectively to obtain frequency domain voltage signals and frequency domain current signals of the source end and the load end;
the difference value calculation unit is used for substituting the first fault distance, the second fault distance, the frequency domain voltage signals and the frequency domain current signals of the source end and the load end into a positioning equation of the serial arc fault position and the voltage signals and the current signals to obtain a fault current first fundamental frequency component difference value and a fault current second fundamental frequency component difference value; the fault current first fundamental frequency component difference value is obtained by substituting a first fault distance into a positioning equation of a series arc fault position and a voltage signal and a current signal, and the fault current second fundamental frequency component difference value is obtained by substituting a second fault distance into a positioning equation of the series arc fault position and the voltage signal and the current signal;
the successive approximation unit is used for determining a fault interval in a successive approximation manner according to the first fundamental frequency component difference value and the second fundamental frequency component difference value of the fault current;
and the fault point determining unit is used for determining the arc fault point position according to the set searching fault point accuracy in the determined fault interval.
The specific manner in which the various modules perform the operations in the apparatus of the above embodiments have been described in detail in connection with the embodiments of the method, and will not be described in detail herein.
For the device embodiments, reference is made to the description of the method embodiments for the relevant points, since they essentially correspond to the method embodiments. The apparatus embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purposes of the present application. Those of ordinary skill in the art will understand and implement the present application without undue burden.
Correspondingly, the application also provides electronic equipment, which comprises: one or more processors; a memory for storing one or more programs; the one or more programs, when executed by the one or more processors, cause the one or more processors to implement a series ac arc fault detection method or a series ac arc fault localization method based on the SoC as described above.
Correspondingly, the application also provides a computer readable storage medium, wherein computer instructions are stored on the computer readable storage medium, and the instructions are executed by a processor to realize the series ac arc fault detection method or the series ac arc fault positioning method based on the SoC.
Fig. 7 is a schematic diagram of an application scenario of series ac arc fault detection and positioning based on SoC in a multi-branch complex low-voltage power distribution system according to an embodiment of the present application. F1 to F4 in the figure are fault points where arc faults may occur. The SoC-based series ac arc fault detection architecture 230 shown in fig. 2 is installed in both the electricity meter and the household load, wherein the SoC chip located in the electricity meter box is always in operation to enable real-time monitoring of arc faults, and the SoC located in the load waits for wake-up.
Firstly, according to the embodiment of the arc fault detection method shown in fig. 1, a SoC chip in an ammeter box collects and processes current signals I and voltage signals U of four channels, and if abnormal conditions are detected in the voltage and current signals of four branches, arc faults occur in places other than the four branches; if there is abnormality in the current signal of only the branch 3, it can be determined that an arc fault occurs in the branch 3, and a warning signal is issued; then, when a warning signal is sent out, the SoC chip in the load 3 is awakened, the SoC chip in the load 3 is used for sampling the voltage signal and the current signal of the load side of the load 3, the SoC chip in the ammeter box is used for collecting the source end voltage and the current signal of the branch 3, then the collected source end voltage signal and the collected load end current signal are recorded in the upper computer at the same time, and then the position of the arc fault point in the branch 3 is rapidly judged according to the specific execution process of S105 and later in fig. 3.
Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the application following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the application pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.
It is to be understood that the application is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the application is limited only by the appended claims.
Claims (10)
1. The serial alternating current arc fault detection method based on the SoC is characterized by comprising the following steps of:
acquiring voltage signals and current signals of different branches in a low-voltage distribution system through an arc fault detection SoC chip;
performing wavelet decomposition on the voltage signals and the current signals of the different branches respectively to obtain a high-frequency component of the voltage signals and a high-frequency component of the current signals after the wavelet decomposition;
comparing the high-frequency component of the voltage signal and the high-frequency component of the current signal with respective set thresholds;
and judging whether arc faults occur according to the comparison result in the current domain, and meanwhile judging fault branches according to the comparison result in the voltage domain.
2. The method according to claim 1, wherein the performing wavelet decomposition on the voltage signal and the current signal of the different branches to obtain a high-frequency component of the voltage signal and a high-frequency component of the current signal after wavelet decomposition includes:
performing discrete wavelet transformation on the voltage signals and the current signals of the different branches respectively;
and taking the high-frequency components of the voltage signal and the high-frequency components of the current signal after the first layer decomposition as the high-frequency components of the voltage signal and the high-frequency components of the current signal after the wavelet decomposition.
3. The method of claim 1, wherein determining whether an arc fault has occurred based on the comparison in the current domain, and wherein determining a fault branch in combination with the comparison in the voltage domain comprises:
when the peak value of the high-frequency component of the current signal exceeds a set threshold value, judging that an arc fault occurs;
when the peak value of the high-frequency component of the voltage signal also exceeds a set threshold value, judging that an arc fault occurs at a place outside the branch;
when only the high frequency component of the current signal exceeds a set threshold, it is determined that an arc fault occurs in the branch.
4. A method of locating a series ac arc fault comprising:
performing the SoC-based series ac arc fault detection method of claim 1;
after the series alternating current arc fault detection method based on the SoC is completed, acquiring and recording voltage signals and current signals of a source end and a load end in a distribution line through the arc fault detection SoC chip, wherein the source end is a first fault distance in the distribution line, and the load end is a second fault distance in the distribution line;
performing FFT (fast Fourier transform) on the voltage signals and the current signals of the source end and the load end respectively to obtain frequency domain voltage signals and frequency domain current signals of the source end and the load end;
substituting the first fault distance, the second fault distance, the frequency domain voltage signals and the frequency domain current signals of the source end and the load end into a positioning equation of the serial arc fault position and the voltage signals and the current signals to obtain a fault current first fundamental frequency component difference value and a fault current second fundamental frequency component difference value; the fault current first fundamental frequency component difference value is obtained by substituting a first fault distance into a positioning equation of a series arc fault position and a voltage signal and a current signal, and the fault current second fundamental frequency component difference value is obtained by substituting a second fault distance into a positioning equation of the series arc fault position and the voltage signal and the current signal;
determining a fault interval in successive approximation mode according to the first fundamental frequency component difference value and the second fundamental frequency component difference value of the fault current;
and in the determined fault interval, determining the position of the arc fault point according to the set precision of searching the fault point.
5. The method of claim 4, wherein the successively approximation determining the fault interval from the fault current first fundamental frequency component difference and the second fundamental frequency component difference comprises:
when the product of the first fundamental frequency component difference value and the second fundamental frequency component difference value of the fault current is smaller than zero, determining that the actual arc fault point is located between the first fault distance and the second fault distance;
taking an assumed arc fault point as a half of the first fault distance and the second fault distance, substituting the assumed arc fault point, the frequency domain voltage signals and the frequency domain current signals of the source end and the load end into a positioning equation of the serial arc fault position, the voltage signals and the current signals to obtain a fault point fundamental frequency component difference value;
if the product of the base frequency component difference value of the fault point and the second base frequency component difference value is smaller than zero, the actual arc fault point is located between the assumed arc fault point and the second fault distance, then the value of the assumed fault point is assigned to the first fault distance, and the first base frequency component difference value is recalculated; if the product of the base frequency component difference value of the fault point and the first base frequency component difference value is smaller than zero, the actual arc fault point is located between the first fault distance and the assumed arc fault point, then the value of the assumed arc fault point is assigned to the second fault distance, and the second base frequency component difference value is recalculated;
and continuing to iterate to assume that the arc fault point is half of the first fault distance and the second fault distance when the product of the first fundamental frequency component difference value and the second fundamental frequency component difference value is always smaller than zero.
6. The method of claim 4, wherein determining the arc fault point location based on the set search fault point accuracy within the determined fault interval comprises:
and when the difference value between the first fault distance and the second fault distance is smaller than the set precision of searching the fault points in the fault interval process determined through successive approximation, obtaining the actual arc fault point which is half of the first fault distance and the second fault distance.
7. A series ac arc fault detection device based on a SoC, comprising:
the signal acquisition unit is used for acquiring voltage signals and current signals of different branches in the low-voltage distribution system through the arc fault detection SoC chip;
the signal decomposition unit is used for respectively carrying out wavelet decomposition on the voltage signals and the current signals of the different branches to obtain a high-frequency component of the voltage signals and a high-frequency component of the current signals after the wavelet decomposition;
a comparison unit for comparing the high frequency component of the voltage signal and the high frequency component of the current signal with respective set thresholds;
and the fault judging unit is used for judging whether the arc fault occurs according to the comparison result in the current domain and judging the fault branch by combining the comparison result in the voltage domain.
8. A tandem ac arc fault locating device, comprising:
an arc fault detection unit for performing the SoC-based series ac arc fault detection method of claim 1;
the system comprises a signal acquisition unit, a power distribution circuit and a power distribution circuit, wherein the signal acquisition unit is used for acquiring and recording voltage signals and current signals of a source end and a load end in the power distribution circuit through the arc fault detection SoC chip after a series alternating current arc fault detection method based on the SoC is completed, the source end is a first fault distance in the power distribution circuit, and the load end is a second fault distance in the power distribution circuit;
the signal conversion unit is used for performing FFT conversion on the voltage signals and the current signals of the source end and the load end respectively to obtain frequency domain voltage signals and frequency domain current signals of the source end and the load end;
the difference value calculation unit is used for substituting the first fault distance, the second fault distance, the frequency domain voltage signals and the frequency domain current signals of the source end and the load end into a positioning equation of the serial arc fault position and the voltage signals and the current signals to obtain a fault current first fundamental frequency component difference value and a fault current second fundamental frequency component difference value; the fault current first fundamental frequency component difference value is obtained by substituting a first fault distance into a positioning equation of a series arc fault position and a voltage signal and a current signal, and the fault current second fundamental frequency component difference value is obtained by substituting a second fault distance into a positioning equation of the series arc fault position and the voltage signal and the current signal;
the successive approximation unit is used for determining a fault interval in a successive approximation manner according to the first fundamental frequency component difference value and the second fundamental frequency component difference value of the fault current;
and the fault point determining unit is used for determining the arc fault point position according to the set searching fault point accuracy in the determined fault interval.
9. An electronic device, comprising:
one or more processors;
a memory for storing one or more programs;
the one or more programs, when executed by the one or more processors, cause the one or more processors to implement the method of any of claims 1-6.
10. A computer readable storage medium having stored thereon computer instructions which, when executed by a processor, implement the steps of the method according to any of claims 1-6.
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| CN117148049A (en) * | 2023-10-31 | 2023-12-01 | 锦浪科技股份有限公司 | Direct current arc discharge fault detection system, method and photovoltaic grid-connected system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117148049A (en) * | 2023-10-31 | 2023-12-01 | 锦浪科技股份有限公司 | Direct current arc discharge fault detection system, method and photovoltaic grid-connected system |
| CN117148049B (en) * | 2023-10-31 | 2024-01-26 | 锦浪科技股份有限公司 | Direct current arc discharge fault detection system, method and photovoltaic grid-connected system |
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