Fault arc detection device and method

Abstract

The invention discloses a fault arc detection device and method. The fault arc detection device comprises a signal filtering module, a signal pickup module, a signal conditioning module and a calculation and analysis module, the signal filtering module is used for filtering incoming line side signals of a plurality of frequency bands provided by an incoming line side signal end into filtering signals of a plurality of frequency bands; the third end of the signal pickup module is connected with the first end of the signal conditioning module; the signal pickup module is used for receiving the filtering signal and a load side signal provided by a load side signal end, and the signal conditioning module is used for generating multiple paths of conditioning signals based on the filtering signal and the load side signal; and the calculation and analysis module decodes the multiple paths of conditioning signals and detects fault arc signals of the power utilization loop according to a decoding result. The detection device provided by the invention can effectively solve the problem of misoperation caused by crosstalk signals and interference signals, and meanwhile, the technical effects of high sensitivity, low delay and low misoperation of the detection device can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of arc detection, and in particular to a fault arc detection device and method. Background Art

[0002] AC fault arc is a gas discharge phenomenon between conductors caused by poor insulation in AC power systems. Due to its irreversibility and high temperature characteristics, it is recognized as the primary cause of electrical fires.

[0003] The AC fault arc detection system is a solution for detecting and identifying fault arc signals in AC power circuits and performing tripping protection. The core technical difficulty lies in ensuring the comprehensive performance of low refusal rate and low false operation rate at the same time, that is, achieving high-sensitivity detection and low action delay in various scenarios and working conditions without causing false tripping.

[0004] Practice has proved that it is particularly important to improve the anti-false operation characteristics of the AC fault arc detection system while ensuring the detection sensitivity. Not only that, while ensuring the performance, the volume, power consumption and cost of the solution are also key factors in the overall competitiveness of the solution.

[0005] Although the crosstalk signal is usually attenuated by more power grid lines than the interference signal, generally speaking, the signal strength on the incoming line side is not as good as the signal generated by the circuit, but in actual applications, the complexity, diversity and frequent changes of the loads of adjacent power circuits are also important reasons for the misjudgment and malfunction of AC fault arc detection. From the reported literature, the existing technical solutions of AC fault arc detection systems all focus on preventing the malfunction caused by the load interference of the circuit, rarely involving the robustness of anti-crosstalk, and there are few countermeasures and feasible and effective technical solutions. Therefore, the so-called instability and easy false tripping of the existing detection systems and technical solutions in testing and actual applications are very easy and common. While eliminating the hidden dangers of fire accidents, this type of system has caused many other troubles and losses. The power accidents caused by its false operation (tripping that does not meet expectations) have become an important constraint on the application of such products and even the development of the industry. Therefore, an effective and low-cost anti-crosstalk fault arc detection solution has become a technical difficulty and key point that the industry must break through. Summary of the invention

[0006] The present invention provides a fault arc detection device and method, which detect the filter signals (including fault point signals) on each power circuit and the load side signals generated by the load signal end, generate multiple conditioning signals according to the filter signals and the load side signals, decode them by the calculation and analysis module, and detect the fault arc signals according to the decoding results. This can not only solve the false operation caused by the crosstalk signal and the interference signal, but also ensure that the detection device has the characteristics of high sensitivity, low action delay and low false operation, effectively improve the comprehensive performance, and has the characteristics of low cost and low power consumption.

[0007] According to a first aspect of the present invention, there is provided a fault arc detection device, which is applied to a power network having multiple power circuits, wherein the fault arc detection device is arranged in at least one of the power circuits; the fault arc detection device comprises: a signal filtering module, a signal pickup module, a signal conditioning module and a calculation and analysis module;

[0008] The first end of the signal filtering module is connected to the incoming line signal end, the second end of the signal filtering module is connected to the first end of the signal pickup module, and the signal filtering module is used to filter the incoming line signals of multiple frequency bands provided by the incoming line signal end into filtered signals of multiple frequency bands;

[0009] The second end of the signal pickup module is connected to the load side signal end, and the third end of the signal pickup module is connected to the first end of the signal conditioning module; the signal pickup module is used to receive the filter signal and the load side signal provided by the load side signal end, and transmit them to the signal conditioning module;

[0010] The second end of the signal conditioning module is connected to the first end of the calculation and analysis module; the signal conditioning module is used to generate a multi-channel conditioning signal based on the filter signal and the load side signal, and transmit it to the calculation and analysis module;

[0011] The calculation and analysis module decodes the multi-channel conditioning signal and detects the fault arc signal of the power circuit according to the decoding result; wherein the incoming line side signal includes interference signals from power circuits other than the target power circuit, and the load side signal includes interference signals.

[0012] Optionally, it also includes a tripping drive module, a tripping mechanism and a first switch;

[0013] The second end of the calculation and analysis module is connected to the first end of the tripping drive module, the second end of the tripping drive module is connected to the first end of the tripping mechanism, and the second end of the tripping mechanism is connected to the first switch;

[0014] The tripping driving module is used to drive the tripping mechanism to control the first switch to disconnect the power circuit where the fault arc signal is located when the calculation and analysis module determines that a fault arc signal appears in the power circuit.

[0015] Optionally, the signal conditioning module includes a plurality of frequency division filtering units and a plurality of signal conditioning units;

[0016] The number of the frequency division filtering units and the number of the signal conditioning units are the same;

[0017] The first ends of the plurality of frequency division filtering units are commonly connected to the third end of the signal pickup module, and the second ends of the plurality of frequency division filtering units are respectively connected to the first ends of the plurality of signal conditioning units; the frequency division filtering units are used to perform secondary filtering on the filter signals of the plurality of frequency bands;

[0018] The second ends of the plurality of signal conditioning units are commonly connected to the first end of the calculation and analysis module;

[0019] The plurality of signal conditioning units generate a plurality of conditioning signals according to the plurality of filtering signals and the load-side signals, and transmit the conditioned signals to the calculation and analysis module.

[0020] Optionally, the signal conditioning module includes an amplification unit, an analog-to-digital conversion unit, and a plurality of digital filtering units;

[0021] The first end of the amplifying unit is connected to the signal pickup module, the second end of the amplifying unit is connected to the first end of the analog-to-digital conversion unit, the first ends of the plurality of digital filtering units are commonly connected to the second end of the analog-to-digital conversion unit, and the second ends of the plurality of digital filtering units are commonly connected to the calculation and analysis module;

[0022] The amplifying unit is used to amplify the filtered signal and the load side signal and transmit them to the analog-to-digital conversion unit;

[0023] The analog-to-digital conversion unit generates a digital signal according to the filtered signal and the load-side signal and transmits the digital signal to the digital filtering unit;

[0024] The digital filtering unit filters the filtering signal and the load-side signal and transmits the filtered signal and the load-side signal to the calculation and analysis module.

[0025] Optionally, the signal conditioning module further includes a frequency scanning unit;

[0026] The first end of the amplifying unit is connected to the signal pickup module, the second end of the amplifying unit is connected to the first end of the frequency sweeping unit, and the second end of the frequency sweeping unit is connected to the first end of the analog-to-digital conversion unit;

[0027] The frequency sweep unit generates a first frequency band analog signal based on the filter signal and the load side signal and transmits the first frequency band analog signal to the analog-to-digital conversion unit;

[0028] The analog-to-digital conversion unit generates a second frequency band digital signal according to the first frequency band analog signal and transmits the generated second frequency band digital signal to the digital filtering unit; wherein the width of the first frequency band analog signal is smaller than the width of the second frequency band digital signal.

[0029] Optionally, the signal filtering module includes at least one of the following: a bandpass filter, a band-stop filter, an inductor-capacitor-resistor passive filter, a circuit breaker switch inductor element, a circuit breaker switch dual-gold resistor, a safety capacitor element, an electromagnetic interference filter, a ceramic filter, a series active filter, a switch capacitor filter, a power supply filter, a magnetic bead filter element or a notch filter.

[0030] Optionally, the signal pickup module includes a current transformer.

[0031] Optionally, the first switch includes a miniature circuit breaker.

[0032] According to a second aspect of the present invention, there is provided a fault arc detection method, which is applicable to the fault arc detection device described in any one of the first aspects of the present invention and is applied to a power network having multiple power circuits, wherein the fault arc detection device is arranged in at least one of the power circuits; the fault arc detection method comprises:

[0033] The signal filtering module obtains the incoming line side signals of multiple frequency bands, and filters the incoming line side signals into filtered signals of multiple frequency bands;

[0034] The signal pickup module collects the filtered signal and the load side signal provided by the load side signal terminal;

[0035] The signal conditioning module generates a multi-channel conditioning signal according to the filtering signal and the load side signal;

[0036] The calculation and analysis module decodes the multi-channel conditioning signal and detects the fault arc signal of the power circuit according to the decoding result; wherein the incoming line side signal includes interference signals from power circuits other than the target power circuit, and the load side signal includes interference signals.

[0037] Optionally, the calculation and analysis module decodes the multi-channel conditioning signal, and detects the fault arc signal of the power circuit according to the decoding result, including:

[0038] When it is detected that the filter signal and / or the load-side signal is the fault arc signal, the calculation and analysis module drives the tripping mechanism to control the first switch to disconnect the power circuit where the fault arc signal is located.

[0039] The present invention discloses a fault arc detection device, which is applied to a power network with multiple power circuits. The fault arc detection device is arranged in at least one power circuit; the fault arc detection device comprises: a signal filtering module, a signal pickup module, a signal conditioning module and a calculation and analysis module; the first end of the signal filtering module is connected to the incoming line side signal end, the second end of the signal filtering module is connected to the first end of the signal pickup module, and the signal filtering module is used to filter the incoming line side signals of multiple frequency bands provided by the incoming line side signal end into filtered signals of multiple frequency bands; the second end of the signal pickup module is connected to the load side signal end, and the signal pickup module is connected to the load side signal end. The third end is connected to the first end of the signal conditioning module; the signal pickup module is used to receive the filter signal and the load side signal provided by the load side signal end, and transmit it to the signal conditioning module; the second end of the signal conditioning module is connected to the first end of the calculation and analysis module; the signal conditioning module is used to generate a multi-channel conditioning signal based on the filter signal and the load side signal, and transmit it to the calculation and analysis module; the calculation and analysis module decodes the multi-channel conditioning signal, and detects the fault arc signal of the power circuit according to the decoding result; wherein, the incoming line side signal includes a interference signal from a power circuit other than the target power circuit, and the load side signal includes an interference signal. The fault arc detection device and method provided by the present invention detect the filter signals (including fault point signals) on each power circuit and the load side signals generated by the load signal end, generate multiple conditioning signals according to the filter signals and the load side signals, decode them by the calculation and analysis module, and detect the fault arc signals according to the decoding results. This can not only solve the false operation caused by the crosstalk signal and the interference signal, but also ensure that the detection device has the characteristics of high sensitivity, low action delay and low false operation, effectively improve the comprehensive performance, and has the characteristics of low cost and low power consumption.

[0040] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 It is a schematic diagram of an electricity network with multiple electricity circuits;

[0043] Figure 2It is a structural schematic diagram of a fault arc detection device provided by an embodiment of the present invention;

[0044] Figure 3 It is a frequency waveform diagram of a signal filtering module in a fault arc detection device provided by an embodiment of the present invention;

[0045] Figure 4 It is a typical energy spectrum diagram of load working signal and fault arc signal;

[0046] Figure 5 is a schematic structural diagram of another fault arc detection device provided by an embodiment of the present invention;

[0047] Figure 6 is a schematic structural diagram of another fault arc detection device provided by an embodiment of the present invention;

[0048] Figure 7 is a schematic structural diagram of another fault arc detection device provided by an embodiment of the present invention;

[0049] Figure 8 is a schematic structural diagram of another fault arc detection device provided by an embodiment of the present invention;

[0050] Fig. 9 It is a system frequency band waveform diagram of another fault arc detection device provided by an embodiment of the present invention;

[0051] Fig.10 is a schematic structural diagram of another fault arc detection device provided by an embodiment of the present invention;

[0052] Fig.11 is a schematic structural diagram of another fault arc detection device provided by an embodiment of the present invention;

[0053] Fig.12 is a schematic structural diagram of another fault arc detection device provided by an embodiment of the present invention;

[0054] Fig.13 is a flow chart of another fault arc detection method provided by an embodiment of the present invention;

[0055] Fig.14 This is a flow chart of another fault arc detection method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0057] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0058] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0059] Figure 1 This is a schematic diagram of a power network with multiple power circuits. Figure 1 , the power network has three power circuits ( Figure 1 Only three power circuits are drawn as an example), including an upper adjacent power circuit 001, a target power circuit 002 and a lower adjacent power circuit 003; the fault arc detection device 102 provided in the embodiment of the present invention is installed in the target power circuit 002, the upper adjacent power circuit 001 includes a first fault point 301 and a first load 201; the target power circuit 002 includes a second fault point 302 and a second load 202; the lower adjacent power circuit 003 includes a third fault point 303 and a third load 203.

[0060] The false operation characteristics of the AC fault arc detection system are mainly affected by its own detection sensitivity and the power supply and use environment and scene interference. The detection sensitivity mainly complies with the requirements of the detection standard. Therefore, the key to preventing false operation is to avoid the influence of various interferences on the detection. The signal at any time can be divided into the incoming line side signal (401 and 402) and the load side signal (403 and 404). The incoming line side signal is derived from the signals generated by the upper adjacent power circuit 001, the lower adjacent power circuit 003 and other upper / lower adjacent power circuits transmitted to the power circuit through the power network, whether it is the interference signal (402) generated by all upper adjacent circuit loads and lower adjacent circuit loads such as the load (the first load 201 and the second load 202) or all upper adjacent circuits such as the first fault point 301 and the third fault point 303. The signals (401) generated by the fault point and the fault point of the next adjacent circuit are signals that should not be identified as fault arcs, because they will affect the judgment of fault arcs. This interference is called interference signal. If the interference is caused by a fault arc, it is called "arc interference", and the signal (404) generated by the second load 202 in the target power circuit 002 is called an interference signal. Only the signal (403) generated by the second fault point 302 in the target power circuit 002 is the target signal (i.e., fault arc signal) that the system really pays attention to and needs to distinguish. It should be noted that the type of fault arc generated by the arc fault point described here is not limited to a series fault arc, and can also refer to all fault arc types such as parallel or grounding.

[0061] Figure 2 is a schematic diagram of a fault arc detection device provided by an embodiment of the present invention, with reference to Figure 1 and Figure 2 , an embodiment of the present invention provides a fault arc detection device, which is applied to a power network having multiple power circuits, for example, with reference to Figure 1 , including an upper adjacent power circuit 001, a target power circuit 002 and a lower adjacent power circuit 003, the arc fault detection device 102 is arranged in at least one power circuit (ie Figure 1In the target power circuit 002 in the circuit), the arc fault detection device 102 includes a signal filtering module 1, a signal pickup module 2, a signal conditioning module 3 and a calculation and analysis module 4; the first end of the signal filtering module 1 is connected to the incoming line side signal end, the second end of the signal filtering module 1 is connected to the first end of the signal pickup module 2, and the signal filtering module 1 is used to filter the incoming line side signals of multiple frequency bands provided by the incoming line side signal end into filtered signals of multiple frequency bands; the second end of the signal pickup module 2 is connected to the load side signal end, and the third end of the signal pickup module 2 is connected to the first end of the signal conditioning module 3; The signal picking module 2 is used to receive the filter signal and the load side signal provided by the load side signal terminal, and transmit it to the signal conditioning module 3; the second end of the signal conditioning module 3 is connected to the first end of the calculation and analysis module 4; the signal conditioning module 3 is used to generate a multi-channel conditioning signal based on the filter signal and the load side signal, and transmit it to the calculation and analysis module 4; the calculation and analysis module 4 decodes the multi-channel conditioning signal, and detects the fault arc signal of the power circuit according to the decoding result; wherein, the incoming line side signal includes interference signals from power circuits other than the target power circuit, and the load side signal includes interference signals.

[0062] Specifically, the first end of the signal filter module 1 is connected to the incoming line side signal end, the second end of the signal filter module 1 is connected to the signal pickup module 2, and the first end of the signal filter module 1 is connected to the incoming line side signal (ie Figure 2 The L end and the N end in the signal filtering module 1 are L and N ends, wherein the L line is the live line and the N line is the neutral line (or neutral line). The signal filtering module 1 is used to filter the incoming line side signals of multiple frequency bands provided by the incoming line side signal end into filtered signals of multiple frequency bands. It can be understood that the signal filtering module 1 can realize the frequency selection and filtering functions of the incoming line side signals, and can only perform frequency selection and filtering on the incoming line side signals transmitted by the L end, or can only perform frequency selection and filtering on the incoming line side signals transmitted by the N end. Preferably, the L end and the N end are filtered at the same time to generate filtered signals of multiple frequency bands.

[0063] Figure 3 is a frequency waveform diagram of a signal filtering module in a fault arc detection device provided by an embodiment of the present invention, with reference to Figure 3 , the signal filtering module 1 may be a low-pass filter (such as Figure 3 A), high-pass filter (as shown in Figure 3 As shown in B), bandpass filter (as Figure 3 C in the figure) or a band-stop filter (as shown in Figure 3 As shown in D), the bandpass filter can be regarded as a combination of a low-pass filter and a high-pass filter in series, and the bandstop filter can be regarded as a combination of a low-pass filter and a high-pass filter in parallel; the corner frequency of the amplitude-frequency characteristic of the low-pass filter is f L , the corner frequency of the high-pass filter amplitude-frequency characteristic is f H, the passband of the low-pass filter is 0~f L , the passband of the high-pass filter is f H ~Fs, Fs is the system sampling frequency. The passband of the bandpass filter is f H ~f L , center frequency f0=(f L -f H ) / 2, the stop band of the band-stop filter is f L ~f H , center frequency f0=(f H -f L ) / 2. The second end of the signal pickup module 2 is connected to the load side signal end (such as Figure 2 In the example, the second end of the signal pickup module 2 is connected to the second load 202 to receive the load side signal of the second load 202. The third end of the signal pickup module 2 is connected to the first end of the signal conditioning module 3. The signal pickup module 2 uses induction, coupling, voltage division, current shunting and other methods to obtain the filtered signals of multiple frequency bands transmitted by the signal filtering module 1. It can be understood that the filtered signals of multiple frequency bands include the signals coming from the incoming line side (including the upper adjacent power circuit 001 and the lower adjacent power circuit 003). The signal pickup module 2 also obtains the load side signal provided by the signal end on the second load 202 side (including the second load 202 and the second fault point 302 of the target power circuit 002). The signal obtained by the signal pickup module 2, no matter which side it comes from (that is, whether it is the upper adjacent power circuit 001, the lower adjacent power circuit 003, the load side signal of the second load 202, or the second fault point 302), the amplitude is generally weak, but all have a certain bandwidth. The signal bandwidth generated by the load operation is generally concentrated in the low frequency band less than MHz, and some loads will have a certain energy distribution in the frequency band of tens of MHz. The spectrum distribution of the fault arc signal is generally wider, and the signal energy can be observed in the frequency band from kHz to GHz. It can be said that the spectrum distribution characteristic of the wide frequency band is a typical feature of the fault arc signal. In short, the signal picked up by the signal pickup module 2 will be a multi-band or wide-band signal.

[0064] The second end of the signal conditioning module 3 is connected to the first end of the calculation and analysis module 4, and is used to distinguish and process the signal collected by the signal pickup module 2 into at least two frequency band components, including frequency selection filtering, amplification, amplitude adjustment, shaping, etc., outputting multi-channel conditioning signals of the corresponding frequency band, and transmitting them to the calculation and analysis module 4. If these signals are analog signals, their level represents the signal strength of the corresponding frequency band, and can be sampled and converted into digital signals by an analog-to-digital converter (ADC); if they are modulated digital signals, they can be processed by the algorithm and control unit of the post-stage calculation and analysis module. An independent analog-to-digital converter can be configured for each channel, or multiple channels can share an analog-to-digital converter, and time-sharing acquisition and conversion can be achieved through a multi-way switch. Because the frequency of the fault arc signal is 50Hz or 60Hz, and the period is at least 16ms, the frequency is very low relative to the conversion speed of the ADC, and time-sharing acquisition and conversion will hardly introduce signal distortion.

[0065] The calculation and analysis module 4 decodes the multi-channel conditioning signals and detects the fault arc signal of the power circuit according to the decoding results.

[0066] The calculation and analysis module 4 performs algorithmic operation processing and logical judgment on the multi-channel conditioning signals. The calculation and analysis module 4 can identify whether the multi-channel conditioning signals are derived from the adjacent power circuit on the incoming line side, or from the load side of the target power circuit, or identify whether the multi-channel conditioning signals belong to load working interference or fault arc signals. Only when it is identified that the multi-channel conditioning signals are derived from the fault arc signal of the target power circuit, will the tripping process be performed, thereby avoiding malfunctions caused by crosstalk signals or interference signals. Among them, the incoming line side signal includes the crosstalk signal from the power circuit other than the target power circuit, and the load side signal includes the interference signal.

[0067] The fault arc detection device provided by the present invention can not only solve the false operation caused by the crosstalk signals and interference signals, but also ensure that the detection device has high sensitivity, low action delay and low false operation characteristics, effectively improve the overall performance, and has the characteristics of low cost and low power consumption.

[0068] The following describes how the calculation and analysis module 4 identifies the fault arc signal:

[0069] The type selected by the signal filter module 1 can be set according to the characteristics of the power network signal and the design requirements of the detection system, in conjunction with the frequency band division of the signal conditioning module 3. The setting principle is that the signal filter module 1 should attenuate and filter out the signal of at least one frequency band on the incoming line side, retaining only individual frequency bands or not retaining any incoming line side signal at all. At the same time, the signal conditioning module 3 should divide at least two frequency band channels and process and output the conditioned signals of the corresponding channels. The signal strength of one or more frequency bands filtered out by the signal filter module 1 is expressed by S ext_stop The signal strength of one or more frequency bands not filtered out by the signal filtering module 1 is represented by S ext_pass On this basis, the strategy for identifying signals is as follows:

[0070] When S ext_stop is less than the threshold, and S ext_pass When S is greater than the threshold, the signal is determined to be a jamming signal; ext_stop is greater than the threshold, and S ext_pass When it is greater than the threshold, the signal is determined to be a non-interference signal. ext_stop Frequency band f ext_stop It should be set to a frequency band where the signal is stronger when an arc fault occurs in the target power circuit. The setting of the threshold is a parameter that the interference judgment algorithm module needs to focus on and optimize. It is generally extracted and formed after analyzing the test data based on the fault arc signal law and network characteristics. Due to the filtering and frequency division characteristics of the present technical solution, the difference between the interference and non-interference signals is greatly enhanced, which is very conducive to the setting of the threshold. It is difficult to set similar parameter values ​​that meet a wide range of application scenarios and environments with previous technical solutions. This is a significant feature and advantage of the technical solution of the embodiment of the present invention.

[0071] Furthermore, in order to identify interference signals, the frequency band setting can be further subdivided based on the above strategy. According to the general characteristics of the working characteristics of the loop load (the second load 202), the interference signal energy caused by it is mainly concentrated in the low frequency. Figure 4 This is a typical load working signal and fault arc signal energy spectrum diagram. For example (when the bandwidth of the signal pickup module is not limited), the typical load working signal energy spectrum distribution is as follows: Figure 4 As shown, the typical energy distribution curve (601) of the load with greater interference shows that the energy is concentrated in the frequency band less than 1.5MHz, and there is still a certain intensity distribution in the range of 1.5MHz to 10MHz, a smaller intensity distribution above 10MHz, and no effect above 20MHz, which can be ignored; the typical energy distribution curve (602) of the load with less interference shows that except for the obvious energy distribution below 1.5MHz, the energy above 1.5MHz is almost at a negligible level.

[0072] The spectrum energy distribution curve (603) of the fault arc signal of this circuit shows that the energy distribution difference with frequency is relatively small, and the energy intensity distribution reaches the detection level within the range of tens of MHz. Obviously, in the frequency band of 1.5MHz~10MHz and the frequency band exceeding 10MHz, the bandpass and / or high-pass filter can be set in the signal conditioning module 3, so as to obtain the conditioning channel signal output with significant level and discrimination, and these signals also have advantages when setting the detection threshold, especially in the frequency band exceeding 10MHz, when setting the detection threshold, more accurate judgment can be obtained. Therefore, the typical three-way system frequency band setting can basically meet the above strategy application and judgment needs.

[0073] Considering the three-frequency system, for the convenience of description, the center frequency of the low frequency band is recorded as f 0—low <1.5MHz, the center frequency of the mid-band is f 0—mid (1.5MHz, 10MHz) and high frequency band f 0—high >10MHz. The signal strength is expressed as S 0—low , S 0—mid and S 0—high express.

[0074] Solution 1: Assume f 0—low f ext_stop , f 0—mid f ext_pass , f 0—high f ext_pass , the following measurements can be used to distinguish crosstalk from interference:

[0075]

[0076] The above three signals S 0—low , S 0—mid and S 0—high The corresponding thresholds may be different and may be set separately to achieve the best decision result.

[0077] Solution 2: Assumption f 0—low f ext_stop , f 0—mid f ext_stop , f 0—high f ext_pass , the following measurements can be used to distinguish between crosstalk and interference:

[0078]

[0079] The above three signals S 0—low , S 0—mid and S 0—highThe corresponding thresholds may be different and may be set separately to achieve the best decision result.

[0080] Scheme 3: Assumption f 0—low f ext_pass , f 0—mid f ext_pass , f 0—high f ext_stop , the following measurements can be used to distinguish between crosstalk and interference:

[0081] The above three signals S 0—low , S 0—mid and S 0—high The corresponding thresholds may be different and may be set separately to achieve the best decision result.

[0082] Theoretically, because the signal component in the high-frequency band is mainly contributed by the fault arc, and the fault arc interference signal generated by the adjacent circuit at the incoming line end also has the same frequency distribution characteristics, the third frequency band setting scheme is not as effective as the first two.

[0083] This is reflected in the crosstalk signal, especially the arc crosstalk signal, which is difficult to distinguish from the signal of this circuit.

[0084] However, no matter it is interference or jamming, the algorithm will block its tripping action when making judgment, so the false operation rate can also be reduced.

[0085] However, other means and methods are needed to distinguish arc interference from arc fault in this circuit.

[0086] In practical applications, considering that the fault arc interference signal generated by the adjacent circuit often passes through more lines and switches than the fault arc signal of the current circuit, especially the high-frequency signal, it is difficult to transmit to the current circuit over a long distance to cause substantial impact.

[0087] Taking this factor into consideration, the above frequency band decoding strategy can be modified as follows:

[0088] Modified plan three:

[0089]

[0090] It can be seen that the frequency band coding scheme can also eliminate the false operation caused by interference. In the absence of other conditions, the first two schemes are the preferred technical routes.

[0091] Scheme 4: Assumption f 0—low f ext_stop , f 0—mid f ext_ stop , f0—high f ext_stop , the following measurements can be used to distinguish between crosstalk and interference:

[0092] This solution is not limited to the above-mentioned frequency segmentation method. The number of frequency bands and the number of threshold parameters can be further increased, and the filter types and frequency band settings can be optimized and enriched to achieve more precise resolution and judgment, but the algorithm complexity and calculation amount will also increase accordingly. Practice has proved that two frequency bands combined with other arc detection algorithms can achieve effective crosstalk and interference discrimination effects, and the false operation rate is significantly improved; the division of three frequency bands can achieve more accurate judgment results, and the division of more than three frequency bands can significantly enhance the adaptability to multiple scenarios and environments. The principles of more frequency segmentation schemes are the same as above, and will not be repeated here.

[0093] Optional, reference Figure 2 , the fault arc detection device provided in the embodiment of the present invention further includes a tripping drive module 5, a tripping mechanism 6 and a first switch 7;

[0094] The second end of the calculation and analysis module 4 is connected to the first end of the tripping drive module 5, the second end of the tripping drive module 5 is connected to the first end of the tripping mechanism 6, and the second end of the tripping mechanism 6 is connected to the first switch 7; the tripping drive module 5 is used to drive the tripping mechanism 6 to control the first switch 7 to disconnect the power circuit where the fault arc signal is located when the calculation and analysis module determines that a fault arc signal appears in the power circuit.

[0095] Specifically, refer to Figure 2 When the calculation and analysis module 4 identifies the fault arc signal, the control instruction is sent to the tripping drive module 5, and the tripping drive module 5 controls the tripping mechanism 6 to issue a control instruction to the first switch 7 (generating a tripping action trigger), and the first switch 7 is controlled to accurately disconnect the power circuit where the fault arc signal is located. Exemplarily, the first switch 7 can be a circuit breaker switch, an external switch, etc. As long as it is a switch that can disconnect the power circuit, it is within the protection scope of the present invention.

[0096] Figure 5 is a schematic diagram of another fault arc detection device provided by an embodiment of the present invention, referring to Figure 5Optionally, the signal conditioning module 3 includes multiple frequency division filter units 31 and multiple signal conditioning units 32; the number of frequency division filter units 31 and the number of signal conditioning units 32 are the same; the first ends of the multiple frequency division filter units 31 are commonly connected to the third end of the signal pickup module 2, and the second ends of the multiple frequency division filter units 31 are respectively connected to the first ends of the multiple signal conditioning units 32; the frequency division filter unit 31 is used to perform secondary filtering on the filter signals of multiple frequency bands; the second ends of the multiple signal conditioning units 32 are commonly connected to the first end of the calculation and analysis module 4; the multiple signal conditioning units 32 generate multiple conditioning signals according to the multiple filter signals and the load side signals and transmit them to the calculation and analysis module 4.

[0097] Specifically, the signal conditioning module 3 includes multiple frequency division filtering units 31 and multiple signal conditioning units 32. The frequency division filtering unit 31 is used to receive the multi-band filtered signals and load side signals transmitted by the signal pickup module 2, and perform frequency selection and filtering. The signal conditioning unit 32 generates corresponding multi-channel conditioned signals according to the multiple filtered signals and load side signals, and transmits them to the calculation and analysis module 4.

[0098] If the multi-channel conditioning signal is an analog signal, it can be converted into an analog-to-digital converter ( Figure 5 ) performs analog-to-digital conversion to identify the fault arc signal;

[0099] If the multi-channel conditioned signals are digital signals, the signal processing and fault arc identification can be directly performed through the post-stage algorithm and control unit of the calculation and analysis module 4. An independent analog-to-digital converter can be configured for each channel, or multiple channels can share one analog-to-digital converter.

[0100] Figure 6 is a schematic diagram of another fault arc detection device provided by an embodiment of the present invention, referring to Figure 6 Optionally, the signal conditioning module includes an amplifying unit 33, an analog-to-digital conversion unit 34 and multiple digital filtering units 35; the first end of the amplifying unit 33 is connected to the signal pickup module 2, the second end of the amplifying unit 33 is connected to the first end of the analog-to-digital conversion unit 34, the first ends of the multiple digital filtering units 35 are commonly connected to the second end of the analog-to-digital conversion unit 34, and the second ends of the multiple digital filtering units 35 are commonly connected to the calculation and analysis module 4; the amplifying unit 33 is used to amplify the filtered signal and the load side signal and transmit them to the analog-to-digital conversion unit 34; the analog-to-digital conversion unit 34 generates a digital signal according to the filtered signal and the load side signal and transmits it to the digital filtering unit 35; the digital filtering unit 35 filters the filtered signal and the load side signal and transmits them to the calculation and analysis module 4.

[0101] Specifically, the signal conditioning module 3 in the embodiment of the present invention can also be implemented by an amplifying unit 33, an analog-to-digital conversion unit 34 and a plurality of digital filtering units 35. The amplifying unit 33 (which can be a low noise amplifier) ​​is used between the signal pickup module 2 and the digital filtering unit 35 to condition the signal, and then the signal is converted into a digital signal by the analog-to-digital conversion unit in the calculation and analysis module 4. There are certain requirements for the passband characteristics of the amplifying unit 33 and the analog-to-digital conversion unit, and the frequency band decoding function set by the subsequent calculation and analysis module should not be affected. When the accuracy, speed and other indicators of the analog-to-digital conversion unit are sufficient, the output of the signal pickup module 2 can also be directly quantized into a digital signal. Wideband signal sampling can be achieved to avoid the introduction of unnecessary distortion components.

[0102] Figure 7 is a schematic diagram of another fault arc detection device provided by an embodiment of the present invention, referring to Figure 7 Optionally, the signal conditioning module 3 also includes a frequency sweeping unit 36; the first end of the amplifying unit 33 is connected to the signal pickup module 2, the second end of the amplifying unit 33 is connected to the first end of the frequency sweeping unit 36, and the second end of the frequency sweeping unit 36 ​​is connected to the first end of the analog-to-digital conversion unit 34; the frequency sweeping unit 36 ​​generates a first frequency band analog signal based on the filtered signal and the load side signal and transmits it to the analog-to-digital conversion unit 34; the analog-to-digital conversion unit 34 generates a second frequency band digital signal based on the first frequency band analog signal and transmits it to the digital filtering unit 35; wherein the width of the first frequency band analog signal is smaller than the width of the second frequency band digital signal.

[0103] Specifically, the fault arc detection device provided in the embodiment of the present invention further includes a frequency sweeping unit 36, which generates a first frequency band analog signal based on the filtered signal amplified by the amplifier unit 33 and the load side signal, and transmits it to the analog-to-digital conversion unit 34, and the analog-to-digital conversion unit 34 converts the first frequency band analog signal into a second frequency band digital signal with a wider frequency band, and transmits it to the calculation and analysis module 4. The frequency sweeping unit 36 ​​in the embodiment of the present invention converts the signal to a specific intermediate frequency band through the frequency control of the local oscillator. The frequency sweeping speed depends on the bandwidth of the signal channel and the frequency sweeping speed of the local oscillator. Therefore, it is necessary to cooperate with the amplifier unit 33 to ensure that a frequency sweeping operation is completed in a sufficiently short time relative to the power frequency cycle. After the signal received by the frequency sweeping passes through the analog-to-digital conversion unit 34, it is converted into a digital signal with a wider frequency band, and then the frequency band is decoded by frequency band filtering. The realization of the local oscillator signal can also place the local oscillator in a phase-locked loop, which can significantly improve the stability and signal-to-noise ratio of the broadband signal obtained by the frequency sweeping detection.

[0104] Optionally, the signal filtering module 1 includes at least one of the following: a bandpass filter, a band-stop filter, an inductor-capacitor-resistor passive filter, a circuit breaker switch inductor element, a circuit breaker switch dual-gold resistor, a safety capacitor element, an electromagnetic interference filter, a ceramic filter, a series active filter, a switch capacitor filter, a power supply filter, a magnetic bead filter element or a notch filter.

[0105] Specifically, the embodiment of the present invention only lists the above three types of filters, and the embodiment of the present invention does not make an exhaustive list here. For example, in addition to the above filters, high-pass filters, low-pass filters, etc. may also be included.

[0106] When the signal filter module 1 uses the power filter, Figure 8 is a schematic diagram of another fault arc detection device provided by an embodiment of the present invention, referring to Figure 8 , by the mutual inductance and capacitance C x , capacitor C y The mutual inductance forms a π-type filter, with the same-direction and same-name ends, doubling the inductance and suppressing common-mode interference signals. x and capacitor C y Provides the elimination of common mode and differential mode interference to ensure compliance with safety regulations. The power filter can provide ideal high-frequency filtering characteristics for power lines and is a low-pass filter with high out-of-band suppression.

[0107] Typically, the amplitude characteristic of the power filter can be converted to the corner frequency f L Set to 10MHz, that is, f ext_pass For a frequency point less than 10MHz, only signals less than 10MHz will be sensed and collected by the subsequent signal pickup module 2; wherein, the signal filtering module 1 can not only be a power supply filter, a magnetic bead filter element or a trap filter, but any electrical element that can realize the filtering function is within the scope of protection of the embodiment of the present invention.

[0108] Optionally, the signal pickup module includes a current transformer.

[0109] The signal pickup module 2 needs to sense signals exceeding 10MHz, which can be achieved by using a sampling resistor or a current transformer, and the sensing position can be on the L line or the N line. Here, the current transformer N line sensing is taken as an example. In order to obtain a better high-frequency frequency response, high-frequency magnetic materials such as ferrite or amorphous nanocrystals can be used. The transformer coil 21 uses a smaller turn value, and its application frequency can generally reach a frequency band of tens of MHz. The output of the current transformer is connected in parallel with a resistor with a resistance of 50 ohms to realize the conversion of the current signal to the voltage signal, but the signal magnitude is in the range of uV~mV, and the subsequent signal conditioning module 3 is required to amplify and process the signal. The design principle of the amplification factor should be based on the strongest signal picked up after amplification close to the full scale of the data converter, and try to use a converter with higher conversion accuracy to ensure the dynamic range and signal-to-noise ratio indicators of signal processing. The embodiment of the present invention uses a 70dB amplification of the signal after each frequency division and filtering, a 12-bit digital-to-analog converter, and an effective number of bits reaches 10 bits.

[0110] The multi-band signal conditioning module adopts a two-band configuration. The first frequency division filter unit 3101 extracts the frequency point f 0—low f ext_pass For signals less than 10MHz, a low-pass filter or a band-pass filter can be used; and the second frequency division filter unit 3102 extracts the frequency point f 0—mid f ext_stop For signals greater than 10MHz, a high-pass filter or a band-pass filter can be used. In addition, in order to facilitate interference identification, a third frequency division filter unit 3103 can be added to extract the frequency point f 0—high f ext_stop For signals greater than 10MHz, for convenience, a bandpass filter is uniformly used here to implement three frequency division filters. The center frequencies of the first frequency division filter unit 3101, the second frequency division filter unit 3102 and the third frequency division filter unit 3103 are respectively f 0—low is 3MHz, f 0—mid is 16MHz, f 0—high is 25MHz.

[0111] Preferably, we can consider taking f 0—mid Greater than 3 times f 0—low and f 0—high Greater than 5 times f 0—low , which can avoid f 0—low Side lobe signal to f 0—mid and f 0—high Interference of the signal.

[0112] In addition, f 0—mid and f 0—high The frequency point should avoid f 0—low Integer multiples, especially odd harmonic positions, avoid f0—low The harmonic components of f 0—mid and f 0—high Interference is caused.

[0113] Fig. 9 is a system frequency band waveform diagram of another fault arc detection device provided by an embodiment of the present invention, referring to Fig. 9 , you can also choose f 0—low =3MHz, f 0—mid =16MHz and f 0—high =25MHz,

[0114] Signal characteristics in various scenarios may be as follows:

[0115] In the case of no crosstalk, no interference and no fault arc, the outputs of the first frequency division filter unit 3101, the second frequency division filter unit 3102 and the third frequency division filter unit 3103 are all small;

[0116] When there is no crosstalk but a fault arc occurs, the first frequency division filter unit 3101, the second frequency division filter unit 3102, the third frequency division filter unit 3103 and the signal conditioning module 3 all have output signal strengths exceeding a set threshold;

[0117] When there is no crosstalk but interference occurs, the first frequency division filter unit 3101 and the signal conditioning module 3 and the second frequency division filter unit 3102 and the signal conditioning module 3 will have outputs of a certain amplitude, while the outputs of the third frequency division filter unit 3103 and the signal conditioning module 3 are often smaller.

[0118] When crosstalk occurs, the crosstalk signal is low-pass filtered by the power filter after passing through the first switch 7 from the incoming line end, and the output signal is sensed and collected by the current transformer.

[0119] Then the output signal of the first frequency division filter unit 3101 and the signal conditioning module 3 is still relatively large, but the output signals of the second frequency division filter unit 3102 and the signal conditioning module 3 and the third frequency division filter unit 3103 and the signal conditioning module 3 will be much smaller than the threshold.

[0120] For specific decision strategies, please refer to the following interfering and interference decisions:

[0121] In implementation, it may also only include the first frequency division filter unit 3101 and the signal conditioning module 3 and the second frequency division filter unit 3102 and the signal conditioning module 3. The interference can be identified through the two conditioning signals. At the same time, the outputs of the two conditioning signals are used in conjunction with other arc and interference identification algorithms to identify fault arcs and interference, thereby simplifying the system.

[0122] Specifically, when the signal filtering module 1 uses the magnetic bead filter element 11, Fig.10 is a schematic diagram of another fault arc detection device provided by an embodiment of the present invention, referring to Fig.10 , waveform diagram reference Fig. 9 Magnetic beads are electronic filter components formed by wrapping magnetic components such as ferrite around wires. They are widely used to suppress high-frequency noise in circuits. By attenuating high-frequency energy, they reduce the mutual electromagnetic interference between the power supply and the system body. Magnetic beads have many types, various installation methods, low prices, and good filtering characteristics, and are more suitable for the implementation of the signal filtering module in the technical solution of the present invention.

[0123] Safety capacitors are usually used in conjunction with magnetic beads to filter out common-mode and differential-mode interference to ensure compliance with safety regulations. In this way, the magnetic beads and safety capacitors form a low-pass filter with high out-of-band suppression. Here, we can use the corner frequency f of the amplitude-frequency characteristic of the filter formed by the magnetic beads as L Set to 10MHz, only signals less than 10MHz will be sensed and collected by the subsequent signal pickup module.

[0124] The frequency band setting, the function of each unit module, the signal path, the detection process and the decision strategy logic of the system are similar to those of the first embodiment, and will not be repeated here. Similarly, only using two-way frequency division filtering and signal conditioning paths can also achieve good crosstalk, interference and fault arc discrimination.

[0125] Fig.11 is a schematic diagram of another fault arc detection device provided by an embodiment of the present invention, referring to Fig.11 Optionally, the first switch 7 includes a miniature circuit breaker.

[0126] When the signal filtering module is a trap, the first switch 7 is a miniature circuit breaker, which can maximize the savings in materials, costs and space. The two-in-one solution of the fault arc detection device and the miniature circuit breaker is a common product form at present. It reuses the switch mechanism and components in the miniature circuit breaker, so that the product not only has the fault arc detection and protection capabilities, but also has the short circuit and overload protection functions of the traditional miniature circuit breaker. The miniature circuit breaker and core components include a switch mechanism, an arc extinguishing device, an electromagnet and a bimetallic element. When the current passing through the electromagnet exceeds the set value, especially when a short circuit occurs, the electromagnet will act instantly to drive the tripping mechanism to disconnect the line. The bimetallic element is a thermal sensing element. When the line is overloaded, the bimetallic element will heat up and bend until the contacts on the element are disconnected. In the product form of miniature circuit breakers and composite functions, the signal filtering module in the technical solution of the present invention can be cleverly constructed by using the inductor element in the miniature circuit breaker and the safety capacitor in the electronic circuit.

[0127] The electromagnet inductance and safety capacitor in the miniature circuit breaker form an inductor-capacitor series resonant filter, which is a typical notch filter. Since the electromagnet inductance in the miniature circuit breaker is designed according to the specifications of the miniature circuit breaker, its parameters cannot be adjusted at will. Therefore, for a specific miniature circuit breaker, the electromagnet inductance included is a fixed value, and the common inductance is in the order of hundreds of nH. Therefore, the capacity of the safety capacitor needs to be carefully selected in the system design to make the overall inductor-capacitor series resonant frequency .

[0128] Without loss of generality, the center frequency of the notch filter can be set to f 0_linefilter If it is set to 3MHz, the value of Cx is in the order of nF to 10nF. It should be noted that the bandwidth of the band-stop filter is slightly wide, ensuring that the passband of the frequency division filter unit corresponding to the subsequent multi-band signal conditioning unit does not overlap with the stopband of the band-stop filter under the specified environment and use conditions, so as to ensure the effectiveness of frequency band encoding and decoding.

[0129] Similarly, the signal pickup module can be implemented with a sampling resistor or a current transformer. In order to obtain a better high-frequency frequency response, high-frequency magnetic materials such as ferrite or amorphous nanocrystalline can be used. The transformer coil 21 uses a smaller turn value, and its application frequency can generally reach a frequency band of tens of MHz. The output of the current transformer is connected in parallel with a 50 ohm resistor to realize the conversion of current signal to voltage signal.

[0130] The multi-band signal conditioning module 3 can be configured with two frequency bands. The first frequency division filter unit 3101 is a bandpass filter. 0—mid =f 0_linefilter =5.5MHz signal, its bandwidth should be smaller than the bandwidth of the notch filter, and the signal strength is S 0—mid The second frequency division filter unit 3102 takes out the frequency point f 0—low f ext—stop For signals less than 1.5MHz, a low-pass filter or a band-pass filter can be used, and the signal strength is S 0—low In addition, in order to facilitate interference identification, a third frequency division filter unit can be added to extract the frequency point f 0—high f ext—stop For signals greater than 10MHz, a bandpass filter or a high-pass filter can be used. 0—low =1MHz and f 0—high =22.5MHz, preferably, f 0—mid >3 times f 0—low and f 0—high >5 times f 0—low , which can avoid f 0—low Side lobe signal to f 0—mid and f 0—highIn addition, f 0—mid and f 0—high The frequency point should avoid f 0—low Integer multiples, especially odd harmonic positions, avoid f 0—low The harmonic components of f 0—mid and f 0—high Interference is caused.

[0131] In the case of no crosstalk, no interference and no fault arc, the outputs of the first frequency division filter unit 3101, the second frequency division filter unit 3102 and the third frequency division filter unit 3103 are all small;

[0132] When there is no crosstalk but a fault arc occurs, the first frequency division filter unit 3101, the second frequency division filter unit 3102, the third frequency division filter unit 3103 and the signal conditioning module all have output signal strengths exceeding a set threshold;

[0133] When there is no crosstalk but interference occurs, the first frequency division filter unit 3101 and the signal conditioning module and the second frequency division filter unit 3102 and the signal conditioning module will have a certain amplitude output, while the third frequency division filter unit 3103 and the signal conditioning module output is often smaller. When crosstalk occurs, the crosstalk signal is filtered out by the notch filter after passing through the first switch 7 from the incoming line end. 0_linefilter The output signal of the signal near the frequency point is sensed and collected by the current transformer, and the output signal after the first frequency division filter unit 3101 and the signal conditioning module will be much smaller than the threshold, but the output signal of the second frequency division filter unit 3102 and the signal conditioning module and the third frequency division filter unit 3103 and the signal conditioning module will be much smaller than the threshold. The specific decision strategy will not be repeated here.

[0134] In practice, it may also only include the first frequency division filter unit 3101 and the signal conditioning module and the second frequency division filter unit 3102 and the signal conditioning module. The interference can be identified through the two conditioning signals. At the same time, the outputs of the two conditioning signals are used in conjunction with other arc and interference identification algorithms to identify fault arcs and interference, thereby simplifying the system.

[0135] Fig.12 is a schematic diagram of another fault arc detection device provided by an embodiment of the present invention, referring to Fig.12 In the embodiment of the present invention, the signal pickup module is replaced by a sampling resistor, and the working principle and judgment method are the same as those described above, which will not be described in detail here.

[0136] According to the same inventive concept, an embodiment of the present invention provides a fault arc detection method, which is applicable to the fault arc detection device in any of the above-mentioned invention embodiments, and is applied to a power network having multiple power circuits, wherein the fault arc detection device is arranged in at least one power circuit; Fig.13is another flow chart of a fault arc detection method provided by an embodiment of the present invention, refer to Figure 1 , Figure 2 and Fig.13 , the arc fault detection method includes:

[0137] S101. A signal filtering module obtains incoming line side signals of multiple frequency bands, and filters the incoming line side signals into filtered signals of multiple frequency bands.

[0138] Specifically, the signal filtering module obtains the incoming line side signals of multiple frequency bands from the upper adjacent power circuit 001 and the lower adjacent power circuit 003, and filters the incoming line side signals into filtered signals of multiple frequency bands (ie, frequency selection and filtering).

[0139] S102: The signal pickup module collects the filtered signal and the load side signal provided by the load side signal terminal.

[0140] Specifically, the signal pickup module collects the filtered signals of multiple frequency bands generated by the signal filtering module and the load-side signal from the second load 202 in the target power circuit 002, and transmits them to the signal conditioning module.

[0141] S103: The signal conditioning module generates multiple conditioning signals according to the filtered signal and the load side signal.

[0142] Specifically, the signal conditioning module generates corresponding multi-channel conditioning signals according to the filter signals and load-side signals collected in the above step S102, and transmits the signals to the calculation and analysis module.

[0143] S104, the calculation and analysis module decodes the multi-channel conditioning signals, and detects the fault arc signal of the power circuit according to the decoding results; wherein the incoming line side signal includes the interference signal from the power circuit other than the target power circuit, and the load side signal includes the interference signal.

[0144] Specifically, the calculation and analysis module decodes the multi-channel conditioning signals generated in the above step S103, and detects the fault arc signal according to the decoding result. The specific determination process is described in detail above and will not be repeated here.

[0145] Fig.14 is another flow chart of a fault arc detection method provided by an embodiment of the present invention, refer to Fig.14 ,

[0146] S101. A signal filtering module obtains incoming line side signals of multiple frequency bands, and filters the incoming line side signals into filtered signals of multiple frequency bands.

[0147] S102: The signal pickup module collects the filtered signal and the load side signal provided by the load side signal terminal.

[0148] S103: The signal conditioning module generates multiple conditioning signals according to the filtered signal and the load side signal.

[0149] S104, the calculation and analysis module decodes the multi-channel conditioning signals, and detects the fault arc signal of the power circuit according to the decoding results.

[0150] S205: When it is detected that the filter signal and / or the load-side signal is a fault arc signal, the calculation and analysis module drives the tripping mechanism to control the circuit breaker to disconnect the power circuit where the fault arc signal is located.

[0151] Specifically, when the calculation and analysis module detects that the filter signal and / or the load side signal is a fault arc signal (refer to the above for the specific judgment process), the calculation and analysis module sends a control instruction to the tripping mechanism to disconnect the circuit breaker to accurately control the power circuit where the fault arc signal is located.

[0152] S206: When it is detected that the filter signal and / or the load-side signal is a crosstalk signal and / or an interference signal, the calculation and analysis module does not take action.

[0153] Specifically, when the calculation and analysis module detects that the filter signal and / or the load-side signal is a crosstalk signal and / or an interference signal, the calculation and analysis module will not act and will continue to detect the signals generated by each power circuit of the power network.

[0154] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A fault arc detection device, characterized in that: Applicable to a power network having multiple power circuits, the arc fault detection device is arranged in at least one of the power circuits; the arc fault detection device comprises: a signal filtering module, a signal pickup module, a signal conditioning module and a calculation and analysis module; The first end of the signal filtering module is connected to the incoming line signal end, the second end of the signal filtering module is connected to the first end of the signal pickup module, and the signal filtering module is used to filter the incoming line signals of multiple frequency bands provided by the incoming line signal end into filtered signals of multiple frequency bands; The second end of the signal pickup module is connected to the load side signal end, and the third end of the signal pickup module is connected to the first end of the signal conditioning module; the signal pickup module is used to receive the filter signal and the load side signal provided by the load side signal end, and transmit them to the signal conditioning module; The second end of the signal conditioning module is connected to the first end of the calculation and analysis module; the signal conditioning module is used to generate a multi-channel conditioning signal based on the filter signal and the load side signal, and transmit it to the calculation and analysis module; The calculation and analysis module decodes the multi-channel conditioning signal and detects the fault arc signal of the power circuit according to the decoding result; wherein the incoming line side signal includes interference signals from power circuits other than the target power circuit, and the load side signal includes interference signals.

2. The arc fault detection device according to claim 1, characterized in that: It also includes a tripping drive module, a tripping mechanism and a first switch; The second end of the calculation and analysis module is connected to the first end of the tripping drive module, the second end of the tripping drive module is connected to the first end of the tripping mechanism, and the second end of the tripping mechanism is connected to the first switch; The tripping driving module is used to drive the tripping mechanism to control the first switch to disconnect the power circuit where the fault arc signal is located when the calculation and analysis module determines that a fault arc signal appears in the power circuit.

3. The arc fault detection device according to claim 1, characterized in that: The signal conditioning module includes a plurality of frequency division filtering units and a plurality of signal conditioning units; The number of the frequency division filtering units and the number of the signal conditioning units are the same; The first ends of the plurality of frequency division filtering units are commonly connected to the third end of the signal pickup module, and the second ends of the plurality of frequency division filtering units are respectively connected to the first ends of the plurality of signal conditioning units; the frequency division filtering units are used to perform secondary filtering on the filter signals of the plurality of frequency bands; The second ends of the plurality of signal conditioning units are commonly connected to the first end of the calculation and analysis module; The plurality of signal conditioning units generate a plurality of conditioning signals according to the plurality of filtering signals and the load-side signals, and transmit the conditioned signals to the calculation and analysis module.

4. The arc fault detection device according to claim 1, characterized in that: The signal conditioning module includes an amplification unit, an analog-to-digital conversion unit and a plurality of digital filtering units; The first end of the amplifying unit is connected to the signal pickup module, the second end of the amplifying unit is connected to the first end of the analog-to-digital conversion unit, the first ends of the plurality of digital filtering units are commonly connected to the second end of the analog-to-digital conversion unit, and the second ends of the plurality of digital filtering units are commonly connected to the calculation and analysis module; The amplifying unit is used to amplify the filtered signal and the load side signal and transmit them to the analog-to-digital conversion unit; The analog-to-digital conversion unit generates a digital signal according to the filtered signal and the load-side signal and transmits the digital signal to the digital filtering unit; The digital filtering unit filters the filtering signal and the load-side signal and transmits the filtered signal and the load-side signal to the calculation and analysis module.

5. The arc fault detection device according to claim 4, characterized in that: The signal conditioning module also includes a frequency scanning unit; The first end of the amplifying unit is connected to the signal pickup module, the second end of the amplifying unit is connected to the first end of the frequency sweeping unit, and the second end of the frequency sweeping unit is connected to the first end of the analog-to-digital conversion unit; The frequency sweep unit generates a first frequency band analog signal based on the filter signal and the load side signal and transmits the first frequency band analog signal to the analog-to-digital conversion unit; The analog-to-digital conversion unit generates a second frequency band digital signal according to the first frequency band analog signal and transmits the generated second frequency band digital signal to the digital filtering unit; wherein the width of the first frequency band analog signal is smaller than the width of the second frequency band digital signal.

6. The arc fault detection device according to claim 1, characterized in that: The signal filtering module includes at least one of the following: a bandpass filter, a band-stop filter, an inductor-capacitor-resistor passive filter, a circuit breaker switch inductor element, a circuit breaker switch dual-gold resistor, a safety capacitor element, an electromagnetic interference filter, a ceramic filter, a series active filter, a switch capacitor filter, a power supply filter, a magnetic bead filter element or a notch filter.

7. The arc fault detection device according to claim 1, characterized in that: The signal pickup module includes a current transformer.

8. The arc fault detection device according to claim 2, characterized in that: The first switch includes a miniature circuit breaker.

9. A fault arc detection method, characterized in that: The arc fault detection device according to any one of claims 1 to 8 is applied to a power network having multiple power circuits, wherein the arc fault detection device is arranged in at least one of the power circuits; The arc fault detection method comprises: The signal filtering module obtains the incoming line side signals of multiple frequency bands, and filters the incoming line side signals into filtered signals of multiple frequency bands; The signal pickup module collects the filtered signal and the load side signal provided by the load side signal terminal; The signal conditioning module generates a multi-channel conditioning signal according to the filtering signal and the load side signal; The calculation and analysis module decodes the multi-channel conditioning signal and detects the fault arc signal of the power circuit according to the decoding result; wherein the incoming line side signal includes interference signals from power circuits other than the target power circuit, and the load side signal includes interference signals.

10. The arc fault detection method according to claim 9, characterized in that: The calculation and analysis module decodes the multi-channel conditioning signal and detects the fault arc signal of the power circuit according to the decoding result, including: When it is detected that the filter signal and / or the load-side signal is the fault arc signal, the calculation and analysis module drives the tripping mechanism to control the first switch to disconnect the power circuit where the fault arc signal is located.

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