CN114280440A - Photovoltaic direct-current arc fault identification device and method and photovoltaic system - Google Patents
Photovoltaic direct-current arc fault identification device and method and photovoltaic system Download PDFInfo
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Abstract
The invention discloses a photovoltaic direct current arc fault identification device, a photovoltaic direct current arc fault identification method and a photovoltaic system, wherein the identification device comprises: the differential current detection module is used for acquiring a current signal on a branch between the output side of the photovoltaic array and the input side of the inverter by adopting a differential detection method; the signal processing module comprises a band-pass filter circuit, a logarithmic detection unit and an amplifying circuit, wherein the logarithmic detection unit is used for carrying out logarithmic processing on the filtered current signal, and the amplifying circuit is used for amplifying the signal output by the logarithmic detection unit; the fault processing unit analyzes the signal to be detected output by the signal processing module, and obtains the current working state of the signal to be detected according to the communication with the inverter so as to subtract an inverter interference signal from the signal to be detected and then judge the arc fault. The invention utilizes the logarithmic detection unit to collect high-frequency signals, the wide-band signal measurement range covers the panoramic characteristic of the direct current arc, and the accuracy of the arc fault detection result is improved on the premise of good economy.
Description
Technical Field
The invention relates to the field of power electronics, in particular to a photovoltaic direct-current arc fault identification device, a photovoltaic direct-current arc fault identification method and a photovoltaic system.
Background
With the rapid development of new energy technology, photovoltaic systems are more and more widely applied, but due to the aging of solar photovoltaic panels and other reasons, direct current arc faults are easily generated inside the solar photovoltaic panels to cause fire disasters, and the life and property safety of the masses are threatened, so that the detection of direct current arcs is necessary. The electrical characteristics of the direct current arc include current, voltage and the like, but because the arc generation position has randomness, the voltage signal of the arc is difficult to be acquired by a sensor, which causes difficulty in acquiring the arc voltage data, so that the method is usually adopted to acquire the direct current arc current data for processing and analyzing.
The sampling frequency of the existing direct current arc current detection technology is mostly 300kHz and below, namely, only the low-frequency part of an arc signal is analyzed, and the analysis of the high-frequency part is abandoned, so that the detection of the direct current arc has certain limitation. For example, a PCI data acquisition card is used for detecting and analyzing a current signal, and the sampling frequency of the PCI data acquisition card is set to be 10 kHz; or the arc detection part consists of a hardware filter circuit, an ADC sampling part and a DSP digital processing part, the hardware filter circuit filters signals below 20kHz to reduce the interference of noise of the inverter, an SM73201 sampling chip is used for arc data acquisition, the highest sampling rate of the chip is 250kHz, the sampling frequency in an experiment is set to be 180kHz, the sampling data in each time is 1024 data points, and the frequency spectrum obtained after Fourier transform processing is symmetrical by taking 90kHz as a boundary, so that the frequency spectrum below 90kHz is only used for analysis, and the detection requirement on the arc is basically met. However, when an arc occurs, the high frequency content in the current is increased, and when other current detection methods are adopted, the chip sampling rate of 250kHz may not meet the requirement. The time domain method is adopted to detect the current signal, the high sampling frequency of more than 1MHz is needed, and obviously, the SM73201 sampling chip is not suitable for time domain detection. If the high-frequency signals are directly collected, the requirement on hardware is high, and the cost is also increased.
U.S. patent application publication No. WO2021051401a1 by siemens corporation describes an arc detection method that utilizes a plurality of band pass filters and other modules to collect a plurality of narrow band signals in the arc signal. Because the frequency of the alternating current power supply is low (50-60 Hz) and has periodic characteristics, and the load types of the alternating current arc generating circuit are limited and are mostly power frequency loads, the alternating current arc signals have certain regularity, the interference generated by the alternating current power supply is concentrated on a low-frequency part, and whether the alternating current arc fault exists can be detected by collecting a plurality of narrow-band signals above 100 kHz; however, the direct current arc signals are disordered, the frequency band of the direct current arc signals and the interference frequency band have overlapped parts, only narrow-band signals are collected, the characteristics of the direct current arc cannot be accurately reflected, the load of the photovoltaic direct current arc generation circuit is mainly an inverter, the working frequency of the inverter is above 20kHz, a plurality of narrow-band signals are collected, although the noise interference of the inverter can be skillfully avoided, the characteristic frequency band of partial direct current arc is also ignored, and the arc detection method is suitable for the alternating current arc detection condition and is not suitable for the detection of the direct current arc.
At present, no economical direct current arc current detection solution exists.
Disclosure of Invention
The invention aims to provide an arc fault identification device and an arc fault identification method with better economical efficiency, which can comprehensively collect direct current arc current signals to complete the task of direct current arc current detection, improve the accuracy of arc fault detection and solve the problem that the existing direct current arc fault detection only collects low-frequency signals and abandons high-frequency signals or only collects narrow-band signals to cause incomplete arc characteristic detection.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a photovoltaic direct current arc fault identification device comprises a differential current detection module, a signal processing module and a fault processing unit, wherein the differential current detection module is configured to adopt a differential detection method to collect current signals on a branch between an output side of a photovoltaic array and an input side of an inverter;
the signal processing module is configured to process the current signal acquired by the differential current detection module to obtain a signal to be detected, and comprises a band-pass filter circuit and an amplification module, wherein the band-pass filter circuit is configured to filter the current signal acquired by the differential current detection module, the amplification module comprises a logarithmic detection unit and an amplification circuit, the logarithmic detection unit is configured to perform logarithmic processing on the filtered current signal, and the amplification circuit is configured to perform amplification processing on a signal output by the logarithmic detection unit;
the fault processing unit is configured to analyze the signal to be detected output by the signal processing module, and if it is determined that an arc fault exists, send a control instruction to the inverter, wherein the control instruction is configured to disconnect a grid-connected circuit of the inverter.
Further, the amplifying module further comprises an a/D conversion module configured to process the filtered current signal and/or the current signal output by the amplifying circuit.
Further, the input end of the a/D conversion module is connected to one or more switches, and the amplification module further includes a control unit configured to control the one or more switches at the input end of the a/D conversion module to be turned on or off by:
if the amplitude of the current signal output by the amplifying circuit is between a preset first threshold and a preset second threshold, wherein the first threshold is higher than the second threshold, the control unit controls the conduction of a corresponding switch in one or more paths of switches at the input end of the A/D conversion module;
if the amplitude of the current signal output by the amplifying circuit is higher than the first threshold value or lower than the second threshold value, the control unit controls one or more switches at the input end of the A/D conversion module to be switched off.
Furthermore, the input end of the logarithm detection unit is connected with a multi-way switch, and the multi-way switch is matched with the photovoltaic panel sets of the photovoltaic array in series.
Further, the fault processing unit is in bidirectional communication with the inverter, and before the fault processing unit determines the arc fault, the fault processing unit acquires the current working state of the inverter from the inverter so as to match a preset interference signal corresponding to the current working state of the inverter;
and the fault processing unit removes an interference signal matched with the current working state of the inverter from the signal to be detected output by the signal processing module and then judges whether an arc fault exists or not.
Further, the step of analyzing the signal to be detected output by the signal processing module by the fault processing unit includes:
s1, the fault processing unit receives the signal to be detected output by the signal processing module;
s2, judging whether the sampling time of the signal to be detected reaches a preset time window threshold value, if so, executing S3-S7; otherwise, returning to execute S1-S2;
s3, processing the signal to be detected into one-dimensional current data;
s4, inquiring the current working state of the inverter, and removing an interference signal matched with the current working state of the inverter from the one-dimensional current data;
s5, extracting characteristic values of the current data after the interference signals are removed, and performing normalization processing on the extracted characteristic data;
s6, inputting the data after normalization processing into an arc detection model of a pre-trained one-dimensional convolutional neural network to obtain a detection result corresponding to the current time window, if the detection result is an arc fault, executing a self-increment algorithm on the flag bit value and updating the flag bit value after self-increment, and if not, executing a self-decrement algorithm on the flag bit value and updating the flag bit value after self-decrement;
s7, judging whether the current zone bit value reaches a preset zone bit threshold value, if so, executing S8, otherwise, resetting the sampling time to 0 and then returning to execute S1-S2;
s8, the fault processing unit sends a control instruction to the inverter, and the control instruction is configured to enable a grid-connected circuit of the inverter to be disconnected.
Furthermore, the differential current detection module comprises a current transformer, positive and negative buses are connected from the photovoltaic array, and both the positive and negative buses pass through the current transformer; alternatively, the first and second electrodes may be,
the differential current detection module comprises a first current transformer, a second current transformer and a differential module, and a positive bus and a negative bus are connected from the photovoltaic array, wherein the positive bus is connected to one end of the differential module after penetrating through the first current transformer, and the negative bus is connected to the other end of the differential module after penetrating through the second current transformer.
Further, the logarithmic detection unit is a logarithmic detection chip, and the signal bandwidth range of the logarithmic detection chip meets 1kHz to 10 MHz.
Further, the band-pass filter circuit is an active band-pass filter circuit including a resistor, a capacitor, and an operational amplifier, or,
the band-pass filter circuit is an RLC band-pass filter circuit.
According to another aspect of the invention, a photovoltaic system is provided, comprising a photovoltaic array, an inverter and a photovoltaic dc arc fault identification device as described above.
According to another aspect of the present invention, there is provided a photovoltaic dc arc fault identification method, including the steps of:
p1, collecting current signals on a branch between the output side of the photovoltaic array and the input side of the inverter by adopting a differential detection method;
p2, processing the current signal obtained by differential detection by the signal processing module to obtain a signal to be detected;
p3, analyzing the signal to be detected, wherein the analyzing step comprises the following steps S1-S6:
s1, the fault processing unit receives the signal to be detected output by the signal processing module;
s2, judging whether the sampling time of the signal to be detected reaches a preset time window threshold value, if so, executing S3-S6; otherwise, returning to execute S1-S2;
s3, processing the signal to be detected into one-dimensional current data;
s4, inquiring the current working state of the inverter, and removing an interference signal matched with the current working state of the inverter from the one-dimensional current data;
s5, extracting characteristic values of the current data after the interference signals are removed, and performing normalization processing on the extracted characteristic data;
s6, inputting the data after normalization processing into an arc detection model of a pre-trained one-dimensional convolutional neural network to obtain a detection result corresponding to the current time window; and
and the fault processing unit judges whether an arc fault exists according to the detection results corresponding to the time windows.
Further, the step of analyzing the signal to be detected in step P3 further includes: in step S6, if the detection result corresponding to the current time window is an arc fault, performing a self-increment algorithm on the flag bit value and updating the flag bit value stored after self-increment, otherwise performing a self-decrement algorithm on the flag bit value and updating the flag bit value stored after self-decrement, and then performing S7;
s7, judging whether the current zone bit value reaches a preset zone bit threshold value, if so, executing S8, otherwise, resetting the sampling time to 0 and then returning to execute S1-S2;
s8, the fault processing unit sends a control instruction to the inverter, and the control instruction is configured to enable a grid-connected circuit of the inverter to be disconnected.
Further, the extracting the characteristic value of the current data after the interference signal is removed in step S5 includes: and analyzing and extracting power spectral density characteristic information of the current data.
Further, in step P1, a differential current detection module is used to collect a current signal on a branch between an output side of the photovoltaic array and an input side of the inverter, where the differential current detection module includes a current transformer, positive and negative buses are connected from the photovoltaic array, and both the positive and negative buses pass through the current transformer; alternatively, the first and second electrodes may be,
the differential current detection module comprises a first current transformer, a second current transformer and a differential module, and a positive bus and a negative bus are connected from the photovoltaic array, wherein the positive bus is connected to one end of the differential module after penetrating through the first current transformer, and the negative bus is connected to the other end of the differential module after penetrating through the second current transformer.
Further, the signal processing module includes a band-pass filter circuit and an amplifying module, wherein the band-pass filter circuit is configured to filter the current signal collected by the differential current detection module, the amplifying module includes a logarithmic detection unit, an amplifying circuit, a control unit and an a/D conversion module, the logarithmic detection unit is configured to perform logarithmic processing on the filtered current signal, and the amplifying circuit is configured to amplify the signal output by the logarithmic detection unit;
the A/D conversion module is configured to process the filtered current signal and/or the current signal output by the amplifying circuit;
the input end of the A/D conversion module is connected with one or more switches, and the control unit is configured to control the one or more switches at the input end of the A/D conversion module to be switched on or switched off in the following modes:
if the amplitude of the current signal output by the amplifying circuit is between a preset first threshold and a preset second threshold, wherein the first threshold is higher than the second threshold, the control unit controls the conduction of a corresponding switch in one or more paths of switches at the input end of the A/D conversion module;
if the amplitude of the current signal output by the amplifying circuit is higher than the first threshold value or lower than the second threshold value, the control unit controls one or more switches at the input end of the A/D conversion module to be switched off.
The technical scheme provided by the invention has the following beneficial effects:
a. the method comprises the steps that a differential detection method is adopted to collect current signals on a branch between the output side of a photovoltaic array and the input side of an inverter, so that common-mode current noise in positive and negative buses of the photovoltaic array can be effectively eliminated, and therefore direct-current arc fault signals are effectively extracted;
b. the detection frequency of the logarithmic detection unit can reach the MHz level, the measurement range can be greatly increased, the panoramic characteristic of the direct current electric arc is covered, the collection of high-frequency signals can not be abandoned on the premise of good economy, and the incomplete detection problem of the electric arc characteristic is avoided.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic diagram of a connection structure of a photovoltaic direct current arc fault identification device connected between a photovoltaic array and an inverter, according to an exemplary embodiment of the present invention;
fig. 2 is a schematic structural diagram of a signal processing module in a photovoltaic dc arc fault identification apparatus according to an exemplary embodiment of the present invention;
fig. 3 is a schematic structural diagram of an amplifying module in a signal processing module according to an exemplary embodiment of the present invention;
FIG. 4 is a schematic diagram of a circuit structure of a first differential current detection module according to an exemplary embodiment of the present invention;
FIG. 5 is a schematic circuit diagram of a second differential current detection module according to an exemplary embodiment of the present invention;
fig. 6 is a schematic diagram of an overall connection structure of a first band-pass filter circuit in a photovoltaic dc arc fault identification device in a signal processing module according to an exemplary embodiment of the present invention;
fig. 7 is a schematic diagram of a second band-pass filter circuit in a signal processing module provided by an exemplary embodiment of the present invention;
fig. 8 is a schematic flow chart of the fault processing unit of the photovoltaic dc arc fault identification apparatus provided by the exemplary embodiment of the present invention for determining an arc fault.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or device.
In the field of arc detection, a time domain method is adopted to detect a current signal, and a high sampling frequency of more than 1MHz is required, so that obviously, sampling chips such as SM73201 and the like are not suitable for time domain detection; if the high-frequency signal is directly collected, the requirement on hardware is high, and the cost is greatly increased. The invention aims to provide a solution which can simultaneously acquire a low-frequency signal and a high-frequency signal and has better economical efficiency to complete the task of detecting the direct current arc current.
In an embodiment of the present invention, there is provided a photovoltaic dc arc fault identification apparatus, as shown in fig. 1, which includes a differential current detection module, a signal processing module and a fault processing unit, and the differential current detection module, the signal processing module and the fault processing unit are described in detail below:
and the differential current detection module is configured to adopt a differential detection method to acquire a current signal on a branch between the output side of the photovoltaic array and the input side of the inverter, namely the photovoltaic array is used as a power supply, and the output direct current flows into the differential current detection module and then enters the inverter for grid-connected operation. The benefits of this are: in a photovoltaic system, when a direct current arc fault occurs, direct currents of a positive bus and a negative bus of a photovoltaic power supply simultaneously comprise a fault arc current signal and an inverter common mode current noise signal, wherein the inverter common mode current noise is related to a PWM control strategy, so that the common mode current noise generally has periodic repeatability within a certain time scale, and the direct current arc signal does not have the repetition rule. Therefore, the differential current detection method is adopted to carry out differential processing on the signals, so that common mode current noise in the positive bus and the negative bus can be effectively eliminated/reduced, and a direct current arc fault signal can be effectively extracted. The specific scheme has two embodiments: in one embodiment, referring to fig. 4, the differential current detection module includes a current transformer, and positive and negative bus bars are connected from the photovoltaic array, and both the positive and negative bus bars pass through the current transformer, and the principle is as follows: because the noise signal of the inverter has certain regularity, the magnetic field generated in the mutual inductor can be offset, the noise signal of the inverter in the current signal induced by the mutual inductor is greatly inhibited, the direct current arc signal is disordered, the magnetic field generated in the mutual inductor cannot be offset, and the current signal induced by the mutual inductor still contains the arc signal; in another embodiment, referring to fig. 5, the differential current detection module includes a first current transformer, a second current transformer, and a differential module, and positive and negative buses are connected from the photovoltaic array, wherein the positive bus is connected to one end of the differential module after passing through the first current transformer, and the negative bus is connected to the other end of the differential module after passing through the second current transformer, and the principle is as follows: because the noise signal of the inverter has certain regularity, the signal almost disappears after the subtraction, and the direct current arc signal is disordered, so the signal does not disappear after the subtraction, and the purpose of inhibiting the noise signal of the inverter is achieved.
The signal processing module is configured to process the current signal acquired by the differential current detection module to obtain a signal to be detected, referring to fig. 2, and the signal processing module comprises a band-pass filter circuit and an amplification module, wherein the band-pass filter circuit is configured to filter the current signal acquired by the differential current detection module, and the prior art acquires a plurality of sections of narrow-band current signals for analysis due to difficulty in removing noise interference of an inverter, so that although the noise frequency band of the inverter is avoided skillfully, a part of the characteristic frequency band of the direct current arc is ignored, and the accuracy of direct current arc detection is reduced; the current signal acquired by the differential current detection module acquires a broadband signal through the band-pass filter circuit, the broadband signal covers the panoramic characteristic of the direct current arc, and the condition that a part of the characteristic frequency band of the direct current arc is ignored is avoided, so that the accuracy of the direct current arc detection result in the embodiment is high. Referring to fig. 3, the amplification module includes a logarithmic detection unit and an amplification circuit, the logarithmic detection unit is configured to perform logarithmic processing on the filtered current signal, the logarithmic detection function of the embodiment is mainly realized by a logarithmic detection chip, the working voltage of the logarithmic detection chip satisfies 3.3V-5V, the signal bandwidth satisfies 1k-10MHz, the typical current value is 7.5mA, the measurement range is greatly increased, the sampling frequency reaches the MHz level, the power consumption is low, and the economic requirement is satisfied; the amplifying circuit is configured to amplify the signal output by the logarithmic detection unit; the differential current detection module is used for filtering data acquired by the differential current detection module through a band-pass filter circuit contained in the signal processing module, the amplification module is used for processing current signals, specifically, a logarithmic detection unit and an amplification circuit are adopted, the logarithmic detection unit acquires the current signals by utilizing the function of carrying out logarithmic processing on the filtered current data to enlarge the sampling range, the amplification circuit can enable the characteristics of the current signals to be more obvious, meanwhile, logarithmic detection can reflect the signal intensity, direct current arc faults can be identified quickly, the fault arc identification and protection speed is improved, the logarithmic detection method can reflect the current signal change trend, and the detection characteristics of the macroscopic level are represented. In one embodiment, the input end of the logarithmic detection unit is connected with a multi-way switch, the multi-way switch is matched with a plurality of photovoltaic panel sets of the photovoltaic array in series, circuits can be switched randomly through the multi-way switch, different circuits can be connected, the photovoltaic system can be better adapted to the situation that the photovoltaic system comprises a plurality of sets of photovoltaic panel sets, meanwhile, the purpose of respectively detecting multi-way current signals can be achieved by only adopting one-way logarithmic detection unit, and the economical efficiency is better. The band-pass filter circuit is the active band-pass filter circuit including resistance, electric capacity and operational amplifier, see fig. 6, and band-pass filter circuit and logarithm detection chip cooperate, more can improve direct current electric arc detection degree of accuracy: the current signals output by the differential current detection module are sent to an active band-pass filter circuit formed by C1, C2, R1, R2, R3, R4, R5 and an operational amplifier in fig. 6, and unnecessary signals are filtered; the active band-pass filter circuit needs to use an operational amplifier, and if the cost is further reduced, an RLC band-pass filter circuit can be used, as shown in fig. 7. Then the current flows into a logarithmic detection chip, the chip carries out logarithmic processing on the current signal, the current data output by the chip is amplified by an amplification module and then is sent to a fault processing unit to analyze the signal power spectral density so as to carry out preprocessing on the arc data, and then whether an arc exists or not is judged by using an algorithm, which is specifically referred to below.
And the fault processing unit is configured to analyze the signal to be detected output by the signal processing module, and if the arc fault is determined to exist, a control instruction is sent to the inverter, and the control instruction is configured to disconnect a grid-connected circuit of the inverter. In an embodiment of the invention, the fault processing unit adopts a single chip, that is, the single chip processing unit communicates with the inverter to obtain the current working state of the inverter, and because different states have different interferences, under the premise of obtaining the current working state of the inverter, an interference signal of the current working state of the inverter can be removed during signal processing, so as to facilitate the judgment of whether a direct current arc exists or not, for example, obtaining that the inverter is currently in a PWM modulation mode, the single chip processing unit inquires the interference frequency in the pre-stored PWM modulation mode, removes the interference signal matched with the current working state of the inverter from the signal to be detected processed by the signal processing module according to the interference frequency, and then judges whether the arc fault exists or not, so that the arc characteristics are comprehensively analyzed, the arc detection is well promoted, and the detection accuracy is improved, if the arc fault exists, the single chip sends an instruction to the inverter to disconnect the grid-connected circuit, so that the circuit is protected. The photovoltaic direct current arc fault identification method and device collect arc current signals.
In an embodiment of the present invention, the amplifying module further includes a second processing mode, that is, the amplifying module further includes an a/D conversion module, the a/D conversion module can better retain signal details, and is configured to process the filtered current signal and/or the current signal output by the amplifying circuit, and the a/D conversion module can collect a real-time signal, can embody a change of the current signal in details, and represents a detection characteristic in a microscopic level. The former method using logarithmic detection unit and amplifying circuit embodies the detection characteristics of macroscopic level, when the fault characteristics are macroscopically detected, it is not necessary to select A/D conversion module, when the fault characteristics are macroscopically not detected, it is further selected, i.e. it is controlled whether the A/D conversion module is used or not according to the result of macroscopically detecting, as shown in fig. 3, the input end of A/D conversion module is connected with one or more switches, the amplifying module also includes control unit, if the A/D conversion module is needed, the control unit controls the one or more switches at the input end of A/D conversion module to be conducted; if the A/D conversion module is not needed, the control unit controls one or more switches at the input end of the A/D conversion module to be switched off. Specifically, if the amplitude of the current signal output by the amplifying circuit is between a preset first threshold and a preset second threshold, where the first threshold is higher than the second threshold, the control unit controls the conduction of a corresponding switch in one or more paths of switches at the input end of the a/D conversion module; if the amplitude of the current signal output by the amplifying circuit is higher than the first threshold value or lower than the second threshold value, the control unit controls one or more switches at the input end of the A/D conversion module to be switched off. The first threshold value may be selected to be about 33% higher than the current normal signal at the timing of the braking, and the second threshold value may be selected to be about 25% lower than the current normal signal at the timing of the braking. The control unit mainly judges whether the amplitude of the current signal reaches the range between the first threshold and the second threshold, and the judgment can be realized by a hardware circuit or a software mode. The multi-way switch can be connected in front of the A/D conversion module, lines can be switched randomly to enable a plurality of photovoltaic panel sets connected with the photovoltaic array to be connected, the photovoltaic system is better adapted to the condition that the photovoltaic system comprises a plurality of sets of photovoltaic panel sets, meanwhile, the aim of respectively detecting multi-way current signals can be achieved by only adopting one path of A/D conversion module, and the economy is good.
The single-chip microcomputer algorithm for photovoltaic direct-current arc detection has various algorithms, and in recent years, the artificial intelligence algorithm is widely applied to arc detection due to high accuracy, so the artificial intelligence algorithm is adopted for arc fault detection in the embodiment; and the single chip processing unit is communicated with the inverter to obtain the current working state of the inverter, and interference signals of the current working state of the inverter can be removed during signal processing, so that the existence of the direct current arc can be conveniently judged. Referring to fig. 8, the specific steps of analyzing the to-be-detected signal output by the signal processing module by the fault processing unit include:
s1, the fault processing unit receives the signal to be detected output by the signal processing module;
s2, judging whether the sampling time of the signal to be detected reaches a preset time window threshold value, wherein the time window threshold value is generally 5ms or 10ms, and if yes, executing S3-S7; otherwise, returning to execute S1-S2;
s3, processing the signal to be detected into one-dimensional current data;
s4, inquiring the current working state of the inverter, and removing an interference signal matched with the current working state of the inverter from the one-dimensional current data;
s5, extracting characteristic values of the current data after the interference signals are removed, and performing normalization processing on the extracted characteristic data; the photovoltaic direct current arc fault current waveform is characterized by random high-frequency burrs in the time domain, and is characterized by slightly increased spectrum amplitude in a specific frequency band in the frequency domain. When the photovoltaic inverter is subjected to pulse width modulation, high-frequency noise in a similar frequency band is generated, and the amplitude of the high-frequency noise may be the same as or even higher than that of an arc signal. Therefore, it is difficult to distinguish between normal operation and arc faults based on the difference in amplitude, which makes it difficult to perform algorithm analysis after generating a spectrogram by frequency domain transformation using a fast fourier transform method. In the embodiment, the arc data are preprocessed by analyzing the power spectral density of the signal, so that the power spectral density has high sensitivity to the change of the signal and can essentially reflect the objective rule of the change of the signal. Due to system inertia, the noise of the photovoltaic inverter can be regarded as a steady random signal in a short time slot (such as 10ms), however, the direct current arc does not follow the rule, so the normal operation state and the direct current arc fault state of the photovoltaic system can be distinguished according to the stationarity of the signal, and after preprocessing, an algorithm is used for judging whether an arc exists or not, so the power spectral density characteristic information of the current data is analyzed and extracted as the extracted characteristic type in the step S5.
And S6, inputting the data after normalization processing into an arc detection model of a pre-trained one-dimensional convolutional neural network to obtain a detection result corresponding to the current time window, training the arc detection model by using a large amount of arc data in advance, and putting the arc detection model into use after ensuring accuracy. If the detection result is the arc fault, executing a self-increasing algorithm on the flag bit value and updating the flag bit value stored after self-increasing, otherwise executing a self-decreasing algorithm on the flag bit value and updating the flag bit value stored after self-decreasing;
s7, judging whether the current zone bit value reaches a preset zone bit threshold value, if so, executing S8, otherwise, resetting the sampling time to 0 and then returning to execute S1-S2;
s8, that is, when the detection result of the plurality of time windows is an arc fault and the flag bit is greater than the set value, the fault processing unit sends a control command to the inverter, where the control command is configured to disconnect a grid-connected circuit of the inverter and protect the circuit.
In this way, the photovoltaic array, the inverter, and the photovoltaic dc arc fault identification apparatus provided in the above embodiments may constitute a photovoltaic system.
The embodiment provides a photovoltaic direct current arc fault identification method, which comprises the following steps:
p1, collecting current signals on a branch between the output side of the photovoltaic array and the input side of the inverter by adopting a differential detection method;
p2, processing the current signal obtained by differential detection by the signal processing module to obtain a signal to be detected;
p3, analyzing the signal to be detected, wherein the analyzing step comprises the following steps S1-S6:
s1, the fault processing unit receives the signal to be detected output by the signal processing module;
s2, judging whether the sampling time of the signal to be detected reaches a preset time window threshold value, if so, executing S3-S6; otherwise, returning to execute S1-S2;
s3, processing the signal to be detected into one-dimensional current data;
s4, inquiring the current working state of the inverter, and removing an interference signal matched with the current working state of the inverter from the one-dimensional current data;
s5, extracting characteristic values of the current data after the interference signals are removed, and performing normalization processing on the extracted characteristic data;
s6, inputting the data after normalization processing into an arc detection model of a pre-trained one-dimensional convolutional neural network to obtain a detection result corresponding to the current time window; and
in order to improve the anti-interference capability of the model, the detection result of one time window is not used as the final output result, and it is necessary to determine whether there is an arc fault according to the detection results corresponding to the multiple time windows, specifically, the step of analyzing the to-be-detected signal in step P3 further includes: in step S6, if the detection result corresponding to the current time window is an arc fault, performing a self-increment algorithm on the flag bit value and updating the flag bit value stored after self-increment, otherwise performing a self-decrement algorithm on the flag bit value and updating the flag bit value stored after self-decrement, and then performing S7;
s7, judging whether the current zone bit value reaches a preset zone bit threshold value, if so, executing S8, otherwise, resetting the sampling time to 0 and then returning to execute S1-S2;
s8, the fault processing unit sends a control instruction to the inverter, and the control instruction is configured to enable a grid-connected circuit of the inverter to be disconnected.
Further, in step P1, a differential current detection module is used to collect a current signal on a branch between an output side of the photovoltaic array and an input side of the inverter, where the differential current detection module includes a current transformer, positive and negative buses are connected from the photovoltaic array, and both the positive and negative buses pass through the current transformer; alternatively, the first and second electrodes may be,
the differential current detection module comprises a first current transformer, a second current transformer and a differential module, and a positive bus and a negative bus are connected from the photovoltaic array, wherein the positive bus is connected to one end of the differential module after penetrating through the first current transformer, and the negative bus is connected to the other end of the differential module after penetrating through the second current transformer.
Further, the signal processing module in step P2 includes a band-pass filter circuit and an amplifying module, where the band-pass filter circuit is configured to filter the current signal collected by the differential current detection module, the amplifying module includes a logarithmic detection unit, an amplifying circuit, a control unit and an a/D conversion module, the logarithmic detection unit is configured to perform logarithmic processing on the filtered current signal, and the amplifying circuit is configured to perform amplification processing on the signal output by the logarithmic detection unit;
the A/D conversion module is configured to process the filtered current signal and/or the current signal output by the amplifying circuit;
the input end of the A/D conversion module is connected with one or more switches, and the control unit is configured to control the one or more switches at the input end of the A/D conversion module to be switched on or switched off in the following modes:
if the amplitude of the current signal output by the amplifying circuit is between a preset first threshold and a preset second threshold, wherein the first threshold is higher than the second threshold, the control unit controls the conduction of a corresponding switch in one or more paths of switches at the input end of the A/D conversion module;
if the amplitude of the current signal output by the amplifying circuit is higher than the first threshold value or lower than the second threshold value, the control unit controls one or more switches at the input end of the A/D conversion module to be switched off.
The embodiment of the photovoltaic direct-current arc fault identification method and the embodiment of the photovoltaic direct-current arc fault identification device belong to the same concept, and the whole content of the embodiment of the photovoltaic direct-current arc fault identification device is incorporated into the embodiment of the photovoltaic direct-current arc fault identification method in a reference mode, so that the details are not repeated.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The foregoing is directed to embodiments of the present application and it is noted that numerous modifications and adaptations may be made by those skilled in the art without departing from the principles of the present application and are intended to be within the scope of the present application.
Claims (15)
1. The photovoltaic direct-current arc fault identification device is characterized by comprising a differential current detection module, a signal processing module and a fault processing unit, wherein the differential current detection module is configured to acquire a current signal on a branch between an output side of a photovoltaic array and an input side of an inverter by adopting a differential detection method;
the signal processing module is configured to process the current signal acquired by the differential current detection module to obtain a signal to be detected, and comprises a band-pass filter circuit and an amplification module, wherein the band-pass filter circuit is configured to filter the current signal acquired by the differential current detection module, the amplification module comprises a logarithmic detection unit and an amplification circuit, the logarithmic detection unit is configured to perform logarithmic processing on the filtered current signal, and the amplification circuit is configured to perform amplification processing on a signal output by the logarithmic detection unit;
the fault processing unit is configured to analyze the signal to be detected output by the signal processing module, and if it is determined that an arc fault exists, send a control instruction to the inverter, wherein the control instruction is configured to disconnect a grid-connected circuit of the inverter.
2. The photovoltaic dc arc fault identification device of claim 1, wherein the amplification module further comprises an a/D conversion module configured to process the filtered current signal and/or the current signal output by the amplification circuit.
3. The apparatus according to claim 2, wherein the input end of the a/D conversion module is connected to one or more switches, and the amplifying module further comprises a control unit configured to control the one or more switches at the input end of the a/D conversion module to be turned on or off by:
if the amplitude of the current signal output by the amplifying circuit is between a preset first threshold and a preset second threshold, wherein the first threshold is higher than the second threshold, the control unit controls the conduction of a corresponding switch in one or more paths of switches at the input end of the A/D conversion module;
if the amplitude of the current signal output by the amplifying circuit is higher than the first threshold value or lower than the second threshold value, the control unit controls one or more switches at the input end of the A/D conversion module to be switched off.
4. The apparatus according to claim 1, wherein a multi-way switch is connected to an input of the logarithmic detection unit, and the multi-way switch is adapted to a plurality of photovoltaic panel strings of the photovoltaic array.
5. The apparatus according to claim 1, wherein the fault processing unit is in bidirectional communication with the inverter, and before the fault processing unit determines the arc fault, the fault processing unit obtains a current working state of the inverter to match a preset interference signal corresponding to the current working state of the inverter;
and the fault processing unit removes an interference signal matched with the current working state of the inverter from the signal to be detected output by the signal processing module and then judges whether an arc fault exists or not.
6. The apparatus according to claim 5, wherein the step of analyzing the signal to be detected output by the signal processing module by the fault processing unit comprises:
s1, the fault processing unit receives the signal to be detected output by the signal processing module;
s2, judging whether the sampling time of the signal to be detected reaches a preset time window threshold value, if so, executing S3-S7; otherwise, returning to execute S1-S2;
s3, processing the signal to be detected into one-dimensional current data;
s4, inquiring the current working state of the inverter, and removing an interference signal matched with the current working state of the inverter from the one-dimensional current data;
s5, extracting characteristic values of the current data after the interference signals are removed, and performing normalization processing on the extracted characteristic data;
s6, inputting the data after normalization processing into an arc detection model of a pre-trained one-dimensional convolutional neural network to obtain a detection result corresponding to the current time window, if the detection result is an arc fault, executing a self-increment algorithm on the flag bit value and updating the flag bit value after self-increment, and if not, executing a self-decrement algorithm on the flag bit value and updating the flag bit value after self-decrement;
s7, judging whether the current zone bit value reaches a preset zone bit threshold value, if so, executing S8, otherwise, resetting the sampling time to 0 and then returning to execute S1-S2;
s8, the fault processing unit sends a control instruction to the inverter, and the control instruction is configured to enable a grid-connected circuit of the inverter to be disconnected.
7. The photovoltaic dc arc fault identification device of claim 1, wherein the differential current detection module comprises a current transformer through which positive and negative bus bars are connected from the photovoltaic array; alternatively, the first and second electrodes may be,
the differential current detection module comprises a first current transformer, a second current transformer and a differential module, and a positive bus and a negative bus are connected from the photovoltaic array, wherein the positive bus is connected to one end of the differential module after penetrating through the first current transformer, and the negative bus is connected to the other end of the differential module after penetrating through the second current transformer.
8. The apparatus according to claim 1, wherein the logarithmic detection unit is a logarithmic detection chip, and the signal bandwidth of the logarithmic detection chip is in a range of 1kHz to 10 MHz.
9. The photovoltaic direct current arc fault identification device of claim 1, wherein the band-pass filter circuit is an active band-pass filter circuit comprising a resistor, a capacitor and an operational amplifier, or,
the band-pass filter circuit is an RLC band-pass filter circuit.
10. A photovoltaic system comprising a photovoltaic array, an inverter and a photovoltaic dc arc fault identification apparatus as claimed in any one of claims 1 to 9.
11. A photovoltaic direct current arc fault identification method is characterized by comprising the following steps:
p1, collecting current signals on a branch between the output side of the photovoltaic array and the input side of the inverter by adopting a differential detection method;
p2, processing the current signal obtained by differential detection by the signal processing module to obtain a signal to be detected;
p3, analyzing the signal to be detected, wherein the analyzing step comprises the following steps S1-S6:
s1, the fault processing unit receives the signal to be detected output by the signal processing module;
s2, judging whether the sampling time of the signal to be detected reaches a preset time window threshold value, if so, executing S3-S6; otherwise, returning to execute S1-S2;
s3, processing the signal to be detected into one-dimensional current data;
s4, inquiring the current working state of the inverter, and removing an interference signal matched with the current working state of the inverter from the one-dimensional current data;
s5, extracting characteristic values of the current data after the interference signals are removed, and performing normalization processing on the extracted characteristic data;
s6, inputting the data after normalization processing into an arc detection model of a pre-trained one-dimensional convolutional neural network to obtain a detection result corresponding to the current time window; and
and the fault processing unit judges whether an arc fault exists according to the detection results corresponding to the time windows.
12. The method for identifying a photovoltaic direct current arc fault as claimed in claim 11, wherein the step of analyzing the signal to be detected in step P3 further comprises: in step S6, if the detection result corresponding to the current time window is an arc fault, performing a self-increment algorithm on the flag bit value and updating the flag bit value stored after self-increment, otherwise performing a self-decrement algorithm on the flag bit value and updating the flag bit value stored after self-decrement, and then performing S7;
s7, judging whether the current zone bit value reaches a preset zone bit threshold value, if so, executing S8, otherwise, resetting the sampling time to 0 and then returning to execute S1-S2;
s8, the fault processing unit sends a control instruction to the inverter, and the control instruction is configured to enable a grid-connected circuit of the inverter to be disconnected.
13. The method for identifying the photovoltaic direct-current arc fault as claimed in claim 11, wherein the step S5 of extracting the characteristic value of the current data after the interference signal is removed includes: and analyzing and extracting power spectral density characteristic information of the current data.
14. The pv dc arc fault identification method according to claim 11, wherein in step P1, a differential current detection module is used to collect current signals on a branch between an output side of the pv array and an input side of the inverter, wherein the differential current detection module comprises a current transformer, positive and negative buses are connected from the pv array, and both the positive and negative buses pass through the current transformer; alternatively, the first and second electrodes may be,
the differential current detection module comprises a first current transformer, a second current transformer and a differential module, and a positive bus and a negative bus are connected from the photovoltaic array, wherein the positive bus is connected to one end of the differential module after penetrating through the first current transformer, and the negative bus is connected to the other end of the differential module after penetrating through the second current transformer.
15. The method according to claim 14, wherein the signal processing module comprises a band-pass filter circuit and an amplification module, wherein the band-pass filter circuit is configured to filter the current signal collected by the differential current detection module, the amplification module comprises a logarithmic detection unit, an amplification circuit, a control unit and an a/D conversion module, the logarithmic detection unit is configured to logarithmically process the filtered current signal, and the amplification circuit is configured to amplify the signal output by the logarithmic detection unit;
the A/D conversion module is configured to process the filtered current signal and/or the current signal output by the amplifying circuit;
the input end of the A/D conversion module is connected with one or more switches, and the control unit is configured to control the one or more switches at the input end of the A/D conversion module to be switched on or switched off in the following modes:
if the amplitude of the current signal output by the amplifying circuit is between a preset first threshold and a preset second threshold, wherein the first threshold is higher than the second threshold, the control unit controls the conduction of a corresponding switch in one or more paths of switches at the input end of the A/D conversion module;
if the amplitude of the current signal output by the amplifying circuit is higher than the first threshold value or lower than the second threshold value, the control unit controls one or more switches at the input end of the A/D conversion module to be switched off.
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Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103245897A (en) * | 2013-05-02 | 2013-08-14 | 复旦大学 | Detection method for photovoltaic system direct current fault arc by using multicriterion |
| CN103457238A (en) * | 2013-08-22 | 2013-12-18 | 南京集能易新能源技术有限公司 | Method for detecting and protecting direct-current arc of photovoltaic power generation system and circuit |
| WO2014056707A2 (en) * | 2012-10-11 | 2014-04-17 | Bender Gmbh & Co. Kg | Differential current monitoring device with arc detection |
| CN104793112A (en) * | 2015-04-03 | 2015-07-22 | 莱茵斯（厦门）科技有限公司 | Low-voltage arc fault detection method and device |
| US20160282398A1 (en) * | 2015-03-25 | 2016-09-29 | Delta Electronics (Shanghai) Co., Ltd | Method and Device for ARC Fault Detection for Photovoltaic Inverter and Photovoltaic Inverter Using the Same |
| JP2017190996A (en) * | 2016-04-13 | 2017-10-19 | 富士電機機器制御株式会社 | Arc failure detection device |
| CN108075728A (en) * | 2016-11-15 | 2018-05-25 | 上海英孚特电子技术有限公司 | A kind of photovoltaic system DC side arc fault type identification and protective device |
| KR20190059455A (en) * | 2017-11-23 | 2019-05-31 | 전자부품연구원 | Detection device and method of direct current arc in sunlight power generation system |
| CN110417351A (en) * | 2019-08-01 | 2019-11-05 | 上海理工大学 | Photovoltaic system DC side arc fault detection systems and detection method |
| CN111123048A (en) * | 2019-12-23 | 2020-05-08 | 温州大学 | Series fault arc detection device and method based on convolutional neural network |
| CN111512511A (en) * | 2017-12-29 | 2020-08-07 | 华为技术有限公司 | Method and device for processing direct current arc |
| CN114127567A (en) * | 2019-09-20 | 2022-03-01 | 西门子股份公司 | Arc detection device, arc fault protection electrical appliance and method for manufacturing arc detection device |
-
2022
- 2022-03-04 CN CN202210207032.3A patent/CN114280440B/en active Active
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014056707A2 (en) * | 2012-10-11 | 2014-04-17 | Bender Gmbh & Co. Kg | Differential current monitoring device with arc detection |
| US20150309104A1 (en) * | 2012-10-11 | 2015-10-29 | Bender Gmbh & Co. Kg | Differential current monitoring device with arc detection |
| CN103245897A (en) * | 2013-05-02 | 2013-08-14 | 复旦大学 | Detection method for photovoltaic system direct current fault arc by using multicriterion |
| CN103457238A (en) * | 2013-08-22 | 2013-12-18 | 南京集能易新能源技术有限公司 | Method for detecting and protecting direct-current arc of photovoltaic power generation system and circuit |
| CN106154120A (en) * | 2015-03-25 | 2016-11-23 | 台达电子企业管理（上海）有限公司 | The method for detecting arc of photovoltaic DC-to-AC converter, device and photovoltaic DC-to-AC converter |
| US20160282398A1 (en) * | 2015-03-25 | 2016-09-29 | Delta Electronics (Shanghai) Co., Ltd | Method and Device for ARC Fault Detection for Photovoltaic Inverter and Photovoltaic Inverter Using the Same |
| CN104793112A (en) * | 2015-04-03 | 2015-07-22 | 莱茵斯（厦门）科技有限公司 | Low-voltage arc fault detection method and device |
| JP2017190996A (en) * | 2016-04-13 | 2017-10-19 | 富士電機機器制御株式会社 | Arc failure detection device |
| CN108075728A (en) * | 2016-11-15 | 2018-05-25 | 上海英孚特电子技术有限公司 | A kind of photovoltaic system DC side arc fault type identification and protective device |
| KR20190059455A (en) * | 2017-11-23 | 2019-05-31 | 전자부품연구원 | Detection device and method of direct current arc in sunlight power generation system |
| CN111512511A (en) * | 2017-12-29 | 2020-08-07 | 华为技术有限公司 | Method and device for processing direct current arc |
| CN110417351A (en) * | 2019-08-01 | 2019-11-05 | 上海理工大学 | Photovoltaic system DC side arc fault detection systems and detection method |
| CN114127567A (en) * | 2019-09-20 | 2022-03-01 | 西门子股份公司 | Arc detection device, arc fault protection electrical appliance and method for manufacturing arc detection device |
| CN111123048A (en) * | 2019-12-23 | 2020-05-08 | 温州大学 | Series fault arc detection device and method based on convolutional neural network |
Non-Patent Citations (1)
| Title |
|---|
| 吴春华等: "光伏系统直流微弱电弧信号检测研究", 《中国电机工程学报》 * |
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