阅读说明：本技术 一种智能用电插排及其故障电弧的检测方法 (Intelligent power utilization socket and fault arc detection method thereof ) 是由 李宗睿 廖伟 熊梓丞 赵强 杨亚军 于 2020-06-10 设计创作，主要内容包括：本发明的实施例提供一种智能用电插排及其故障电弧的检测方法,智能用电插排包括：母线；与所述母线电连接的第一分支电路；与所述母线电连接的变压器,与所述变压器电连接的电源模块；与所述母线电连接的至少一个第二分支电路；与所述电源模块、第一分支电路和所述至少一个第二分支电路电连接的主控制器,所述主控制器根据所述第一分支电路的采样信号确定母线存在故障电弧时,控制所述母线断开；和/或,根据所述第二分支电路的采样信号确定第二分支电路存在故障电弧时,控制所述第二分支电路断开。本发明的方案可以提升故障电弧的检测精度,避免误判现象的产生。(The embodiment of the invention provides an intelligent power strip and a method for detecting a fault arc thereof, wherein the intelligent power strip comprises the following components: a bus bar; a first branch circuit electrically connected to the bus bar; the transformer is electrically connected with the bus, and the power supply module is electrically connected with the transformer; at least one second branch circuit electrically connected to the bus bar; the main controller is electrically connected with the power supply module, the first branch circuit and the at least one second branch circuit and controls the bus to be disconnected when the main controller determines that fault electric arcs exist in the bus according to sampling signals of the first branch circuit; and/or controlling the second branch circuit to be disconnected when the fault arc of the second branch circuit is determined to exist according to the sampling signal of the second branch circuit. The scheme of the invention can improve the detection precision of the fault arc and avoid the occurrence of the erroneous judgment phenomenon.)

1. The utility model provides an intelligent power strip which characterized in that includes:

a bus bar;

a first branch circuit electrically connected to the bus bar;

the transformer is electrically connected with the bus, and the power supply module is electrically connected with the transformer;

at least one second branch circuit electrically connected to the bus bar;

the main controller is electrically connected with the power supply module, the first branch circuit and the at least one second branch circuit and controls the bus to be disconnected when the main controller determines that fault electric arcs exist in the bus according to sampling signals of the first branch circuit; and/or controlling the second branch circuit to be disconnected when the fault arc of the second branch circuit is determined to exist according to the sampling signal of the second branch circuit.

2. The intelligent power strip of claim 1, wherein the first branch circuit comprises: the bus comprises a voltage type current transformer connected with the bus, and a first signal conditioning module connected with the voltage type current transformer, wherein the first signal conditioning module is also electrically connected with the transformer;

the transformer converts the voltage on the bus into a first path of output voltage to the first signal conditioning module, and the transformer converts the voltage on the bus into a second path of output voltage to the power supply module;

the voltage type current transformer outputs the collected current signal to the first signal conditioning module;

and the first signal conditioning module is used for filtering and shaping the current signal and the first output voltage.

3. The intelligent power strip of claim 2, wherein the first branch circuit further comprises: the first relay is connected to the bus and connected with the main controller;

and the main controller outputs a control signal to control the first relay to be switched off when determining that the fault arc exists in the bus according to the signal output by the first signal conditioning module.

4. The intelligent power strip of claim 3, wherein the first signal conditioning module comprises a rectifier circuit and a filter circuit connected to the rectifier circuit.

5. The intelligent power strip of claim 1, wherein the second branch circuit comprises:

the voltage and current acquisition module is connected with the bus, and the second signal conditioning module is electrically connected with the voltage and current acquisition module and the main controller;

the voltage and current acquisition module outputs the acquired current signal to the second signal conditioning module;

and the second signal conditioning module carries out filtering and shaping on the voltage and current signals acquired by the voltage and current acquisition module and outputs the voltage and current signals to the main controller.

6. The intelligent power strip of claim 5, wherein the second branch circuit further comprises:

the driving module is connected with the main controller;

a second relay electrically connected to the driving module;

and when the main controller determines that the second branch circuit has fault electric arc according to the signal output by the second signal conditioning module, the main controller outputs a control signal to the second relay through the driving module to control the second relay to be switched off.

7. The intelligent power strip of claim 6, wherein the second signal conditioning module comprises a rectifier circuit and a filter circuit connected to the rectifier circuit.

8. The intelligent power strip according to any one of claims 1 to 7, further comprising: with the WIFI module that main control unit electricity is connected and/or be used for reminding the pilot lamp that has the trouble electric arc.

9. A method for detecting a fault arc in an intelligent power strip, the method being applied to the intelligent power strip according to any one of claims 1 to 8, the method comprising:

acquiring an acquisition signal of a first branch circuit;

when the fact that fault arcs exist in the bus is determined according to sampling signals of the first branch circuit, the bus is controlled to be disconnected;

if the bus has no fault arc, acquiring a sampling signal of a second branch circuit;

and controlling the second branch circuit to be disconnected when the second branch circuit is determined to have the fault arc according to the sampling signal of the second branch circuit.

10. The method for detecting according to claim 9, wherein determining that the fault arc exists on the bus according to the sampling signal of the first branch circuit comprises:

acquiring a first output voltage after voltage conversion on the bus of the transformer and a current signal to be acquired by the voltage type current transformer;

performing zero-crossing detection on the first output voltage, and outputting the first output voltage and the current signal to the first signal conditioning module for analog-to-digital conversion if the first output voltage crosses zero;

carrying out time domain waveform analysis on the converted voltage signals of the plurality of half cycles to obtain a plurality of groups of time domain data, and carrying out frequency domain waveform analysis on the current signals of the plurality of half cycles to obtain a plurality of groups of frequency domain data;

if the time domain data abnormal value is larger than a first preset threshold value and/or the frequency domain data abnormal value is larger than a second preset threshold value, determining that the bus has a fault arc according to a judgment result value, wherein the judgment result value is 1 multiplied by a weighted value (time domain data abnormal value) + 2 multiplied by a weighted value (frequency domain data abnormal value); and if the judgment result value exceeds a target threshold value, determining that the fault arc exists in the bus.

11. The method of claim 9, wherein determining that a fault arc exists in the second branch circuit based on the sampled signal from the second branch circuit comprises:

carrying out zero-crossing detection on a voltage signal acquired by a voltage and current acquisition module connected with the bus, and if the voltage signal crosses a zero point;

the second signal conditioning module performs analog-to-digital conversion on the voltage signal acquired by the voltage and current acquisition module and performs analog-to-digital conversion on the current signal;

carrying out time domain waveform analysis on the converted voltage signals of the plurality of half cycles to obtain a plurality of groups of time domain data, and carrying out frequency domain waveform analysis on the current signals of the plurality of half cycles to obtain a plurality of groups of frequency domain data;

if the time domain data abnormal value is larger than a third preset threshold value and/or the frequency domain data abnormal value is larger than a fourth preset threshold value, determining that the second branch circuit has a fault arc according to a judgment result value, wherein the judgment result value is 1 multiplied by a weighted value (time domain data abnormal value) + 2 multiplied by a weighted value (frequency domain data abnormal value); and if the judgment result value exceeds a target threshold value, determining that the second branch circuit has the fault arc.

12. The detection method according to claim 10 or 11, wherein the time domain data outliers are obtained by:

an arithmetic root mean square value Rms of the time domain data for each half cycle is obtained,

wherein, Va_iThe voltage collected in one half period is 0,1,2 … N1-1;

the sum of squared deviations SSRms for Rms0, Rms1, Rms2, Rms3, … …, RmsN-1 was determined as:

setting SS_RmsHas a standard threshold value of SS_Rms0；

Voltage effective value abnormal value ERRV ═ SS_Rms-SS_Rms0|；

Respectively sequencing multiple groups of time domain data, judging whether the time domain data have the condition that more than L continuous values are similar, if so, recording ERRarc as 1, otherwise, recording ERRarc as 0;

for the results after the sorting of multiple groups, the maximum P points are taken to calculate the average values and are respectively recorded as Vmax0, Vmax1, Vmax2, Vmax3, … and Vmaxp-1, the minimum P points are taken to calculate the average values and are respectively recorded as Vmin0, Vmin1, Vmin2, Vmin3, … and Vmin P-1, the difference value between the maximum value and the minimum value in each half period, namely the difference value between the maximum value and the minimum value in each half period is respectively calculated, namely the difference value is calculated

Vdiff0 is Vmax0-Vmin0, and is sequentially represented as Vdiff0, Vdiff1, Vdiff2, Vdiff3, …, and Vdiff p-1, and the above formula of the sum of squared deviations is used to obtain the product

The value can describe the difference degree of the peak-to-valley difference values of N half cycles, and the standard threshold value of SSdiff is set to be SS_diff0Then the peak-to-valley difference outlier is defined herein as ERRdiff ═ SSdiff-SSdiff0 |;

after the time domain waveform analysis is completed, three parameters representing the abnormal degree of the time domain data, namely ERRV, ERRarc and ERRdiff, are obtained, and the abnormal value Kt of the time domain data is represented as ERRarc (ERRV + ERRdiff).

13. The detection method according to claim 10 or 11, wherein the frequency domain data outliers are obtained by:

a group of current signals are decomposed into a low-frequency sequence La, a high-frequency sequence Ha1, a high-frequency sequence Ha2 and a high-frequency sequence Ha3, all sequence wavelet coefficients are extracted to form a characteristic vector Ca, and wavelet coefficient sequences Ca, Cb, Cc, Cd and Ce of each group of data are respectively obtained; the five groups of wavelet coefficient sequences are utilized to construct a Hankel matrix Aa, Ab, Ac, Ad and Ae,

the Hankel matrix (Hankel) a is constructed as follows:

wherein N is more than 1 and less than N, m is N-N +1, and the dimension of the characteristic matrix A needs to satisfy the following conditions: when N is even number, the row number m is N/2+1, and the column number N is N/2; when N is an odd number, the number of rows is equal to the number of columns, and N is equal to m and N + 1/2;

the data sampling length is 2000, the generated wavelet coefficient length is 2020, and then the row number m is 1011, and the column number n is 1010 according to the arrangement rule of the hankel matrix;

thereafter, Aa, Ab, Ac, Ad, Ae are subjected to singular value decomposition SVD using the following formula,

wherein the column vector of U is composed of the feature vectors of AAT, the row vector of VT is composed of the feature vectors of ATA,Σ_r＝diag(α₁,α₂,α₃,...α_r) Is a diagonal matrix, i is the singular value of matrix A, and α₁≥α₂≥α₃≥...≥α_rThe number of the non-zero singular values is equal to the rank of the matrix when the number is more than 0;

obtaining five groups of low-dimensional singular value vectors alpha of the essential characteristics of the reaction matrix through singular value decomposition_a＝(α_a1，α_a2...α_ar)，α_b＝(α_b1，α_b2...α_br)，α_c＝(α_c1，α_c2...α_cr)，α_d＝(α_d1，α_d2...α_dr)，α_e＝(α_e1，α_e2...α_er) (ii) a Singular value alpha in each group of vectors₁，α₂，...α_rThe characteristic value is used for representing the current signal;

analyzing the eigenvalues of the five half-period current signals, taking a vector a as an example, and calculating the average value ha1, the root mean square ha2 and the standard deviation ha3 of the eigenvalue analysis parameters; similarly, the same analysis is carried out on other four groups, and the characteristic value analysis parameters hb1, hb2, hb3, hc1, hc2, hc3, hd1, hd2, hd3, he1, he2 and he3 of each group can be respectively obtained;

setting the threshold values of the current signal characteristic values ha1, ha2 and ha3 as h1, h2 and h3 respectively, the current signal abnormal degree parameter can be expressed as h1, h2 and h3 on the frequency domain

ERRf1＝|ha1-h1|，ERRf2＝|ha2–h2|，ERRf3＝|ha3–h3|；

The current signal abnormal value Kf in the frequency domain is represented as ERRf1+ ERRf2+ ERRf 3.

Technical Field

The invention relates to the technical field, in particular to an intelligent power strip and a fault arc detection method thereof.

Background

Some of the fires caused by electrical reasons are caused by electric arcs, some equipment can generate sparks and electric arcs during normal work, for example, electric arcs are generated during the operation of switch electrical pulling and closing operation, electric furnaces, incandescent lamps, electric welding machines and the like, because the short circuit of circuits or equipment, long-term overload work or poor contact and other conditions exist, the insulation layer of the electric wire is damaged or aged, sparks and electric arcs are generated during the operation, surrounding things are easy to ignite, if the electric arcs burn continuously, the temperature of the electric arcs can reach thousands of DEG C in the burning process, the insulation is damaged to endanger the safety of the circuits and the equipment, and a power supply system loses stability and has large-area power failure; the fire disaster is caused, the hard imaginable consequences such as the serious burning of the electrical equipment are caused, even the personal safety is hurt, the casualty accident is caused, and the huge loss is caused to the economic property of the human society. Therefore, it is necessary to detect the power consumption and ensure the power consumption safety of the user. The nature of fault arc detection is identified by certain algorithms based on the characteristics of the detected object. At present, three methods are mainly used for detecting fault arcs, wherein the first method is to judge according to an arc model; the second is to judge according to the physical phenomenon generated when the electric arc occurs; the third is to make a judgment based on the characteristics of arc voltage and current.

WIFI is a technology capable of wirelessly connecting terminals such as personal computers and handheld devices (e.g., PDAs and mobile phones) to each other. WiFi is a brand of wireless network communication technology, held by the Wi-Fi Alliance (Wi-Fi Alliance). The object is to improve the interoperability between wireless network products based on the IEEE 802.11 standard. A local area network using IEEE 802.11 series protocols becomes Wi-Fi.

The intelligent home is embodied in an internet of things manner under the influence of the internet. The intelligent home is connected with various devices in the home through the Internet of things technology, and provides multiple functions and means such as household appliance control, lighting control, telephone remote control, indoor and outdoor remote control, anti-theft alarm, environment monitoring, heating and ventilation control, infrared forwarding and programmable timing control. Compared with the common home, the intelligent home has the traditional living function, integrates the functions of building, network communication, information household appliance and equipment automation, provides an all-around information interaction function, and even saves funds for various energy expenses.

In the prior art, the arc detection has the problems of inaccurate detection effect and easy occurrence of misjudgment. Meanwhile, the WIFI networking module is not provided, the interconnection function of the smart home cannot be realized, and the intelligent characteristic is lacked.

In addition, the arc detection in the prior art has no universality, and both the socket and the load are required to support the required communication protocol, so that the arc detection has limitations.

Disclosure of Invention

The invention aims to provide an intelligent power strip and a method for detecting a fault arc thereof, which improve the detection precision and avoid the occurrence of misjudgment.

In order to solve the technical problems, the technical scheme of the invention is as follows:

an intelligent power strip comprising:

a bus bar;

a first branch circuit electrically connected to the bus bar;

the transformer is electrically connected with the bus, and the power supply module is electrically connected with the transformer;

at least one second branch circuit electrically connected to the bus bar;

the main controller is electrically connected with the power supply module, the first branch circuit and the at least one second branch circuit, and controls the bus to be disconnected when the main controller determines that fault arc exists in the bus according to the sampling signal of the first branch circuit; and/or controlling the second branch circuit to be disconnected when the fault arc of the second branch circuit is determined to exist according to the sampling signal of the second branch circuit.

Optionally, the first branch circuit includes: the bus comprises a voltage type current transformer connected with the bus, and a first signal conditioning module connected with the voltage type current transformer, wherein the first signal conditioning module is also electrically connected with the transformer;

the transformer converts the voltage on the bus into a first path of output voltage to the first signal conditioning module, and the transformer converts the voltage on the bus into a second path of output voltage to the power supply module;

the voltage type current transformer outputs the collected current signal to the first signal conditioning module;

and the first signal conditioning module is used for filtering and shaping the current signal and the first output voltage.

Optionally, the first branch circuit further includes: the first relay is connected to the bus and connected with the main controller;

and the main controller outputs a control signal to control the first relay to be switched off when determining that the fault arc exists in the bus according to the signal output by the first signal conditioning module.

Optionally, the first signal conditioning module includes a rectifying circuit and a filtering circuit connected to the rectifying circuit.

Optionally, the second branch circuit includes:

the voltage and current acquisition module is connected with the bus, and the second signal conditioning module is electrically connected with the voltage and current acquisition module and the main controller;

the voltage and current acquisition module outputs the acquired current signal to the second signal conditioning module;

and the second signal conditioning module carries out filtering and shaping on the voltage and current signals acquired by the voltage and current acquisition module and outputs the voltage and current signals to the main controller.

Optionally, the second branch circuit further includes:

the driving module is connected with the main controller;

a second relay electrically connected to the driving module;

and when the main controller determines that the second branch circuit has fault electric arc according to the signal output by the second signal conditioning module, the main controller outputs a control signal to the second relay through the driving module to control the second relay to be switched off.

Optionally, the second signal conditioning module includes a rectifying circuit and a filtering circuit connected to the rectifying circuit.

Optionally, the intelligent power strip further comprises: with the WIFI module that main control unit electricity is connected and/or be used for reminding the pilot lamp that has the trouble electric arc.

The embodiment of the invention also provides a method for detecting the fault arc of the intelligent power strip, which comprises the following steps:

acquiring an acquisition signal of a first branch circuit;

when the fact that fault electric arcs exist in the bus is determined according to sampling signals of the first branch circuit, the bus is controlled to be disconnected;

if the bus has no fault arc, acquiring a sampling signal of a second branch circuit;

and controlling the second branch circuit to be disconnected when the second branch circuit is determined to have the fault arc according to the sampling signal of the second branch circuit.

Optionally, determining that the fault arc exists in the bus according to the sampling signal of the first branch circuit includes:

acquiring a first output voltage after voltage conversion on the bus of the transformer and a current signal to be acquired by the voltage type current transformer;

performing zero-crossing detection on the first output voltage, and outputting the first output voltage and the current signal to the first signal conditioning module for analog-to-digital conversion if the first output voltage crosses zero;

carrying out time domain waveform analysis on the converted voltage signals of the plurality of half cycles to obtain a plurality of groups of time domain data, and carrying out frequency domain waveform analysis on the current signals of the plurality of half cycles to obtain a plurality of groups of frequency domain data;

if the time domain data abnormal value is larger than a first preset threshold value and/or the frequency domain data abnormal value is larger than a second preset threshold value, determining that the bus has the fault arc according to a judgment result value, wherein the judgment result value is 1 multiplied by a weighted value (time domain data abnormal value) + 2 multiplied by a weighted value (frequency domain data abnormal value); and if the judgment result value exceeds a target threshold value, determining that the fault arc exists in the bus.

Optionally, determining that the second branch circuit has the fault arc according to the sampling signal of the second branch circuit includes:

carrying out zero-crossing detection on a voltage signal acquired by a voltage and current acquisition module connected with the bus, and if the voltage signal crosses a zero point;

the second signal conditioning module performs analog-to-digital conversion on the voltage signal acquired by the voltage and current acquisition module and performs analog-to-digital conversion on the current signal;

carrying out time domain waveform analysis on the converted voltage signals of the plurality of half cycles to obtain a plurality of groups of time domain data, and carrying out frequency domain waveform analysis on the current signals of the plurality of half cycles to obtain a plurality of groups of frequency domain data;

if the time domain data abnormal value is larger than a third preset threshold value and/or the frequency domain data abnormal value is larger than a fourth preset threshold value, determining that the second branch circuit has a fault arc according to a judgment result value, wherein the judgment result value is 1 multiplied by a weighted value (time domain data abnormal value) + 2 multiplied by a weighted value (frequency domain data abnormal value); and if the judgment result value exceeds a target threshold value, determining that the second branch circuit has the fault arc.

Optionally, the time domain data outlier is obtained through the following process:

an arithmetic root mean square value Rms of the time domain data for each half cycle is obtained,

wherein, Va_iThe voltage collected in one half period is 0,1,2 … N1-1;

the sum of squared deviations SSRms for Rms0, Rms1, Rms2, Rms3, … …, RmsN-1 was determined as:

setting SS_RmsHas a standard threshold value of SS_Rms0；

Voltage effective value abnormal value ERRV ═ SS_Rms-SS_Rms0|；

And respectively sequencing multiple groups of time domain data, judging whether the time domain data have the condition that more than L continuous values are close, if so, recording ERRarc as 1, and otherwise, recording ERRarc as 0.

For the results after the multiple groups of sorting, the maximum P points are taken to calculate the average values which are respectively recorded as Vmax0, Vmax1, Vmax2, Vmax3, … and Vmaxp-1, the minimum P points are taken to calculate the average values which are respectively recorded as Vmin0, Vmin1, Vmin2, Vmin3, … and Vmin P-1, the difference value between the maximum value and the minimum value in each half period, namely the difference value between the maximum value and the minimum value in each half period is calculated respectively, namely the difference value is calculated

Vdiff0 is Vmax0-Vmin0, and is sequentially represented as Vdiff0, Vdiff1, Vdiff2, Vdiff3, …, and Vdiff p-1, and the above formula of the sum of squared deviations is used to obtain the product

The value can describe the difference degree of the peak-to-valley difference values of N half cycles, and the standard threshold value of SSdiff is set to be SS_diff0Then the peak-to-valley difference outlier is defined herein as ERRdiff ═ SSdiff-SSdiff0 |;

after the time domain waveform analysis is completed, three parameters representing the abnormal degree of the time domain data, namely ERRV, ERRarc and ERRdiff, are obtained, and the abnormal value Kt of the time domain data is represented as ERRarc (ERRV + ERRdiff).

Optionally, the frequency domain data outlier is obtained by the following process:

a group of current signals are decomposed into a low-frequency sequence La, a high-frequency sequence Ha1, a high-frequency sequence Ha2 and a high-frequency sequence Ha3, all sequence wavelet coefficients are extracted to form a characteristic vector Ca, and wavelet coefficient sequences Ca, Cb, Cc, Cd and Ce of each group of data are respectively obtained; constructing Hankel matrix Aa, Ab, Ac, Ad and Ae by using the five groups of wavelet coefficient sequences,

the Hankel matrix (Hankel) a is constructed as follows:

where 1< N, m ═ N-N +1, the dimension of the feature matrix a needs to satisfy the following condition: when N is even number, the row number m is N/2+1, and the column number N is N/2; when N is an odd number, the number of rows is equal to the number of columns, and N is equal to m and N + 1/2;

the data sample length is 2000, the generated wavelet coefficient length is 2020, and the row number m is 1011 and the column number n is 1010 according to the arrangement rule of the hank matrix.

Thereafter, Aa, Ab, Ac, Ad, Ae are subjected to singular value decomposition SVD using the following formula,

wherein the column vector of U is composed of the feature vectors of AAT, the row vector of VT is composed of the feature vectors of ATA,∑_r＝diag(α₁,α₂,α₃,...α_r) Is a diagonal matrix, i is the singular value of matrix A, and α₁≥α₂≥α₃≥...≥α_r>0, non-zero oddsThe number of the different values is equal to the rank of the matrix;

obtaining five groups of low-dimensional singular value vectors alpha of the essential characteristics of the reaction matrix through singular value decomposition_a＝(α_a1,α_a2...α_ar)，α_b＝(α_b1,α_b2...α_br)，α_c＝(α_c1,α_c2...α_cr)，α_d＝(α_d1,α_d2...α_dr)， α_e＝(α_e1,α_e2...α_er) (ii) a Singular value alpha in each group of vectors₁,α₂,...α_rIt is used to characterize the characteristic value of the current signal.

Analyzing the eigenvalues of the five half-period current signals, taking a vector a as an example, and calculating the average value ha1, the root mean square ha2 and the standard deviation ha3 of the eigenvalue analysis parameters; similarly, the same analysis is performed on other four groups, and the characteristic value analysis parameters hb1, hb2, hb3, hc1, hc2, hc3, hd1, hd2, hd3, he1, he2 and he3 of each group can be obtained respectively.

Setting the threshold values of the current signal characteristic values ha1, ha2 and ha3 as h1, h2 and h3 respectively, the current signal abnormal degree parameter can be expressed as

ERRf1＝|ha1-h1|，ERRf2＝|ha2–h2|，ERRf3＝|ha3–h3|；

The current signal abnormal value Kf in the frequency domain is represented as ERRf1+ ERRf2+ ERRf 3.

The scheme of the invention at least comprises the following beneficial effects:

according to the scheme, the hardware architecture of the intelligent power socket product with the fault arc detection function innovatively provides an alternating current fault arc detection algorithm for increasing the judgment precision by combining wavelet transformation singular value decomposition and detection on a time domain waveform and a frequency domain, so that the detection precision is improved, and the occurrence of the erroneous judgment phenomenon is avoided.

Drawings

FIG. 1 is a schematic diagram of a hardware architecture of an intelligent power strip of the present invention;

FIG. 2 is a schematic diagram of a power module of the intelligent power strip of the present invention;

FIG. 3 is a schematic diagram of the circuit configuration of the signal conditioning module of the intelligent power strip of the present invention;

FIG. 4 is a schematic flow chart of a method for detecting a fault arc in an intelligent power strip of the present invention;

FIG. 5 is a schematic diagram of the overall detection flow of the method for detecting a fault arc of the intelligent power strip of the present invention;

fig. 6 is a schematic diagram of a specific detection flow of the method for detecting a fault arc in an intelligent power strip according to the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

As shown in fig. 1, an embodiment of the present invention provides an intelligent power strip, including:

a bus bar; the bus comprises a live wire L and a zero wire N; a first branch circuit electrically connected to the bus bar; the transformer is electrically connected with the bus, and the power supply module is electrically connected with the transformer; at least one second branch circuit electrically connected to the bus bar; the main controller is electrically connected with the power supply module, the first branch circuit and the at least one second branch circuit and controls the bus to be disconnected when the main controller determines that fault electric arcs exist in the bus according to sampling signals of the first branch circuit; and/or controlling the second branch circuit to be disconnected when the fault arc of the second branch circuit is determined to exist according to the sampling signal of the second branch circuit.

In an optional embodiment of the invention, the first branch circuit comprises: the bus comprises a voltage type current transformer connected with the bus, and a first signal conditioning module connected with the voltage type current transformer, wherein the first signal conditioning module is also electrically connected with the transformer;

the transformer converts the voltage on the bus into a first path of output voltage to the first signal conditioning module, and the transformer converts the voltage on the bus into a second path of output voltage to the power supply module;

the voltage type current transformer outputs the collected current signal to the first signal conditioning module;

and the first signal conditioning module is used for filtering and shaping the current signal and the first output voltage.

In an optional embodiment of the present invention, the first branch circuit further includes: the first relay is connected to the bus and connected with the main controller;

and the main controller outputs a control signal to control the first relay to be switched off when determining that the fault arc exists in the bus according to the signal output by the first signal conditioning module.

In an optional embodiment of the present invention, the first signal conditioning module includes a rectifying circuit and a filtering circuit connected to the rectifying circuit.

In an optional embodiment of the present invention, the second branch circuit comprises: the voltage and current acquisition module is connected with the bus, and the second signal conditioning module is electrically connected with the voltage and current acquisition module and the main controller;

the voltage and current acquisition module outputs the acquired current signal to the second signal conditioning module;

and the second signal conditioning module carries out filtering and shaping on the voltage and current signals acquired by the voltage and current acquisition module and outputs the voltage and current signals to the main controller.

In an optional embodiment of the present invention, the second branch circuit further includes: the driving module is connected with the main controller; a second relay electrically connected to the driving module;

and when the main controller determines that the second branch circuit has fault electric arc according to the signal output by the second signal conditioning module, the main controller outputs a control signal to the second relay through the driving module to control the second relay to be switched off.

In an optional embodiment of the present invention, the second signal conditioning module includes a rectifying circuit and a filtering circuit connected to the rectifying circuit.

In an optional embodiment of the present invention, the intelligent power strip further includes: and the WIFI module is electrically connected with the main controller and/or an indicator lamp is used for reminding that a fault electric arc exists.

Specifically, this row's hardware circuit is inserted to intelligence has included sampling module, signal conditioning module, power module, relay module, drive module and main control unit module and pilot lamp and WIFI module.

The main controller module adopts i.MX280 SOC of NXP, and the chip integrates an ARM9 inner core, an external 128MB DDR2 memory chip and a 128MB NAND FLASH chip. An AD7689 chip of ADI company is externally arranged, the chip is a 16-bit 8-channel chip, the sampling rate is 250kSPS, and the PulSAR framework is adopted. The main chip and the ADC chip communicate through an SPI interface. The main controller runs a Linux system, and performs synchronous sampling analog-to-digital conversion on voltage and current signals collected on an alternating current bus and voltage and current signals collected by a sampling module of each branch on the socket through an external ADC chip, and then performs operation analysis, so as to judge whether fault arcs exist in each loop.

The power module is shown in fig. 2, and converts 220V commercial power into two paths of 5V and 12V output through a transformer. The 5V output is used for zero-crossing comparison and voltage signal sampling, and the 12V output is used as a driving power supply of the relay. And then, a DC-DC chip is selected to reduce 12V into 5V for output, the power is supplied to the SOC module of the main controller, and meanwhile, a high-precision LDO is selected to convert 5V into 3.3V for supplying power to the ADC chip. In addition, the 5V is converted into 3.3V through the isolated DC-DC chip, and then the converted voltage is used as an analog power supply of the system to supply power to the integrated operational amplifier in the signal conditioning module.

The relay module adopts 1 AC bus high-power relay and 3 branch relays, and controls the opening and closing of the branches by using a G5LE-E relay control bus and a G6DN-1A-SL relay of ohm dragon company respectively.

The driving module is used for amplifying the control signal output by the main controller, controlling the relay and simultaneously playing a role in protecting the main control chip.

The sampling module is used for collecting and converting voltage and current of a 220V alternating-current bus and voltage and current of each branch circuit of the power strip into weak current signals with voltages within a certain range and capable of being subjected to operation processing, wherein the sampling on the bus uses a voltage type current transformer and a transformer with double-tap output, and after 220V voltage is converted into 12V by one tap, the main controller module, the WIFI module and the driving circuit are powered by the power module; and the other tap outputs an alternating current signal with a peak value of 5V, and subsequent zero crossing point detection and bus voltage signal sampling are carried out. The sampling on the branch circuit respectively uses the Hall sensor to sample alternating voltage and current, and then the alternating voltage and the current enter the signal conditioning module to be filtered and shaped.

As shown in fig. 3, the signal conditioning module is divided into a rectifying circuit part and a filter circuit, and the circuit thereof is as shown in fig. three, after positive and negative alternating signals output by a 220V alternating current bus transformer and a current transformer are rectified by a diode, a negative half-cycle signal becomes a positive value, then, a zero crossing point is detected on a voltage signal, and at the same time, the rectified voltage and current signals are added with a certain direct current bias and then enter an active filter circuit, and after passing through a designed band-pass filter, the filtered signals enter a main control ADC and are converted into digital signals for processing by a main control chip SOC.

The WIFI module uses ESP8266 module, and the terminal provides internet access ability and is connected with main control unit through the UART interface, transmits the detection result of each return circuit running state and fault arc to the cloud platform, and the user of being convenient for observes the power consumption state in real time.

As shown in fig. 4, after the zero crossing of the voltage signal is detected and determined by the zero crossing point, the ADC chip is triggered to perform analog-to-digital conversion on the voltage and current sampling signals, and the analog signals are converted into digital signals and then sent to the main control SOC through the SPI interface for operation processing. The master control SOC analyzes signals in a frequency domain and a time domain respectively, when an abnormal result exceeding a set threshold value occurs, the occurrence of fault electric arc is judged, a relay is controlled to disconnect a corresponding passage through a switch signal, meanwhile, a corresponding indicator lamp is controlled to give an alarm on site through an output switch signal, and the running state, the electricity utilization data and the alarm prompt of the passage are uploaded in real time through the WIFI module.

After the normal operation of electrification, the zero crossing point of each voltage signal triggers the ADC to sample the voltage and current signals, the voltage and current signals are sent to the main control SOC for analysis and judgment, once the generation of a fault arc is detected, the corresponding path is cut off rapidly, and the on net cloud platform is reported in time.

The embodiment of the invention also provides a method for detecting the fault arc of the intelligent power strip, which comprises the following steps:

step 41, acquiring an acquisition signal of the first branch circuit;

step 42, controlling the bus to be disconnected when the fault arc of the bus is determined to exist according to the sampling signal of the first branch circuit; optionally, the relay connected with the bus can be controlled to be disconnected;

step 43, if the bus has no fault arc, acquiring a sampling signal of a second branch circuit;

and step 44, when it is determined that the fault arc exists in the second branch circuit according to the sampling signal of the second branch circuit, controlling the second branch circuit to be disconnected, and optionally, disconnecting a relay in the second branch circuit.

In an optional embodiment of the present invention, determining that a fault arc exists in the bus according to the sampling signal of the first branch circuit includes:

acquiring a first output voltage after voltage conversion on the bus of the transformer and a current signal to be acquired by the voltage type current transformer;

performing zero-crossing detection on the first output voltage, and outputting the first output voltage and the current signal to the first signal conditioning module for analog-to-digital conversion if the first output voltage crosses zero;

carrying out time domain waveform analysis on the converted voltage signals of the plurality of half cycles to obtain a plurality of groups of time domain data, and carrying out frequency domain waveform analysis on the current signals of the plurality of half cycles to obtain a plurality of groups of frequency domain data;

if the time domain data abnormal value is larger than a first preset threshold value and/or the frequency domain data abnormal value is larger than a second preset threshold value, determining that the bus has a fault arc according to a judgment result value, wherein the judgment result value is weighted value 1 (time domain data abnormal value) + weighted value 2 (frequency domain data abnormal value); and if the result value exceeds a target threshold value, determining that the fault arc exists in the bus.

In an optional embodiment of the present invention, determining that the fault arc exists in the second branch circuit according to the sampling signal of the second branch circuit includes:

carrying out zero-crossing detection on a voltage signal acquired by a voltage and current acquisition module connected with the bus, and if the voltage signal crosses a zero point;

the second signal conditioning module performs analog-to-digital conversion on the voltage signal acquired by the voltage and current acquisition module and performs analog-to-digital conversion on the current signal;

carrying out time domain waveform analysis on the converted voltage signals of the plurality of half cycles to obtain a plurality of groups of time domain data, and carrying out frequency domain waveform analysis on the current signals of the plurality of half cycles to obtain a plurality of groups of frequency domain data;

if the time domain data abnormal value is larger than a third preset threshold value and/or the frequency domain data abnormal value is larger than a fourth preset threshold value, determining that the second branch circuit has a fault arc according to a judgment result value; the discrimination result value is 1 (time domain data abnormal value) + 2 (frequency domain data abnormal value); and if the result value exceeds a target threshold value, determining that the fault arc exists in the bus.

The specific detection flow is shown in fig. 4. After the zero crossing point of the voltage signal is detected and judged by the zero crossing point, the ADC chip is triggered to carry out analog-to-digital conversion on the voltage and current sampling signals, and the analog signals are converted into digital signals and then are sent to the main control SOC through the SPI to carry out operation processing. The master control SOC analyzes signals in a frequency domain and a time domain respectively, when an abnormal result exceeding a set threshold value occurs, the occurrence of fault electric arc is judged, a relay is controlled to disconnect a corresponding passage through a switch signal, meanwhile, a corresponding indicator lamp is controlled to give an on-site alarm through an output switch signal, and the running state, the electricity utilization data and the alarm prompt of the passage are uploaded in real time through a WIFI module.

As shown in fig. 5, after normal operation of power-on, the zero-crossing point of the voltage signal triggers the ADC to sample the voltage and current signals each time, and the voltage and current signals are sent to the main control SOC for analysis and judgment, and once the generation of the fault arc is detected, the corresponding path is cut off rapidly, and the fault arc is reported to the Onenet cloud platform in time.

Optionally, the time domain data outlier is obtained through the following process:

an arithmetic root mean square value Rms of the time domain data for each half cycle is obtained,

wherein, Va_iThe voltage collected in one half period is 0,1,2 … N1-1;

the sum of squared deviations SSRms for Rms0, Rms1, Rms2, Rms3, … …, RmsN-1 was determined as:

setting SS_RmsStandard threshold ofIs SS_Rms0；

Voltage effective value abnormal value ERRV ═ SS_Rms-SS_Rms0|；

And respectively sequencing multiple groups of time domain data, judging whether the time domain data have the condition that more than L continuous values are close, if so, recording ERRarc as 1, and otherwise, recording ERRarc as 0.

For the results after the multiple groups of sorting, the maximum P points are taken to calculate the average values which are respectively recorded as Vmax0, Vmax1, Vmax2, Vmax3, … and Vmaxp-1, the minimum P points are taken to calculate the average values which are respectively recorded as Vmin0, Vmin1, Vmin2, Vmin3, … and Vmin P-1, the difference value between the maximum value and the minimum value in each half period, namely the difference value between the maximum value and the minimum value in each half period is calculated respectively, namely the difference value is calculated

Vdiff0 is Vmax0-Vmin0, and is sequentially represented as Vdiff0, Vdiff1, Vdiff2, Vdiff3, …, and Vdiff p-1, and the above formula of the sum of squared deviations is used to obtain the product

The value can describe the difference degree of the peak-to-valley difference values of N half cycles, and the standard threshold value of SSdiff is set to be SS_diff0Then the peak-to-valley difference outlier is defined herein as ERRdiff | SSdiff-SSdiff0 |.

After the time domain waveform analysis is completed, three parameters representing the abnormal degree of the time domain data, namely ERRV, ERRarc and ERRdiff, are obtained, and the abnormal value Kt of the time domain data is represented as ERRarc (ERRV + ERRdiff).

In a specific implementation example, as shown in fig. 6, after the voltage signal is collected, the zero-crossing detection circuit performs judgment, and once a zero-crossing point is detected, the main controller SOC enables the ADC chip to perform analog-to-digital conversion on the collected voltage and current signals. The ADC chip runs at a sampling rate of 120kSPS, collecting approximately 2000 points of voltage data and 2000 points of current data every half cycle. After storing 5 half cycles of data (Va0, Va1, Va2 … Va1999), (Vb0, Vb1, Vb2 … Vb1999), (Vc0, Vc1, Vc2, Vc3 … Vc1999), (Vd0, Vd1, Vd2 … Vd1999), (Ve0, Ve1, Ve2 … Ve1999) and (Ia0, Ia1, Ia2 … Ia1999), (Ib0, Ib1, Ib2 … Ib1999), (Ic0, Ic1, Ic2, Ic3 … Ic1999), (Id0, Id1, Id 2 … Id1999), (Ie0, Ie1, Ie2 … Ie1999), the data is operated in both time and frequency domains by the controller.

In time domain data, firstly, respectively obtaining arithmetic root mean square values Rms0, Rms1, Rms2, Rms3 and Rms4 of each half period by using the following formula;

then, the sum of squared deviations SSRms of Rms0, Rms1, Rms2, Rms3, Rms4 is determined, namely:

this value can describe the degree of difference between the effective values of the voltage over five half-cycles, the greater the SSRms, the more likely it is for a fault arc to occur. When the standard threshold value of SSRms is set to SSRms0, the voltage virtual value abnormal value is defined as ERRV | SSRms-SSRms0 |.

And then, sorting the five groups of data respectively, judging whether the situation that more than 10 continuous numerical values are close exists, if so, recording ERRarc as 1, otherwise, recording ERRarc as 0. And this value is used as a necessary condition for the generation of a fault arc.

For the results after five groups of sorting, the maximum 50 points are taken to calculate the average values and are respectively recorded as Vmax0, Vmax1, Vmax2, Vmax3 and Vmax4, the minimum 50 points are taken to calculate the average values and are respectively recorded as Vmin0, Vmin1, Vmin2, Vmin3 and Vmin4, the difference value between the maximum value and the minimum value in each half period, namely the difference value between the maximum value and the minimum value in each half period is respectively calculated, namely the difference value is calculated

Vdiff0 is Vmax0-Vmin0, and is sequentially designated as Vdiff0, Vdiff1, Vdiff2, Vdiff3, and Vdiff 4. Then, the above formula of the sum of squared deviations is used to obtain

This value can describe the degree of difference in peak-to-valley difference over five half cycles, with the greater the SSdiff, the more likely a fault arc will occur. Setting the standard threshold for SSdiff to SSdiff0, the peak-to-valley difference outlier is defined herein as ERRdiff | SSdiff-SSdiff0 |.

After the time domain waveform analysis is completed, three parameters representing the abnormal degree of the time domain data, namely ERRV, ERRarc and ERRdiff, are obtained. Representing the time domain data outlier Kt as ERRarc (ERRV + ERRdiff)

Optionally, the frequency domain data outlier is obtained by the following process:

a group of current signals are decomposed into a low-frequency sequence La, a high-frequency sequence Ha1, a high-frequency sequence Ha2 and a high-frequency sequence Ha3, all sequence wavelet coefficients are extracted to form a characteristic vector Ca, and wavelet coefficient sequences Ca, Cb, Cc, Cd and Ce of each group of data are respectively obtained; constructing Hankel matrix Aa, Ab, Ac, Ad and Ae by using the five groups of wavelet coefficient sequences,

the Hankel matrix (Hankel) a is constructed as follows:

where 1< N, m ═ N-N +1, the dimension of the feature matrix a needs to satisfy the following condition: when N is even number, the row number m is N/2+1, and the column number N is N/2; when N is an odd number, the number of rows is equal to the number of columns, and N is equal to m and N + 1/2;

the data sample length is 2000, the generated wavelet coefficient length is 2020, and the row number m is 1011 and the column number n is 1010 according to the arrangement rule of the hank matrix.

Thereafter, Aa, Ab, Ac, Ad, Ae are subjected to singular value decomposition SVD using the following formula,

wherein the column vector of U is composed of the feature vectors of AAT, the row vector of VT is composed of the feature vectors of ATA,∑_r＝diag(α₁,α₂,α₃,...α_r) Is a diagonal matrix, i is the singular value of matrix A, and α₁≥α₂≥α₃≥...≥α_r>0, the number of the non-zero singular values is equal to the rank of the matrix;

obtaining five groups of low-dimensional singular value vectors alpha of the essential characteristics of the reaction matrix through singular value decomposition_a＝(α_a1,α_a2...α_ar)，α_b＝(α_b1,α_b2...α_br)，α_c＝(α_c1,α_c2...α_cr)，α_d＝(α_d1,α_d2...α_dr)， α_e＝(α_e1,α_e2...α_er) (ii) a Singular value alpha in each group of vectors₁,α₂,...α_rIt is used to characterize the characteristic value of the current signal.

Analyzing the eigenvalues of the five half-period current signals, taking a vector a as an example, and calculating the average value ha1, the root mean square ha2 and the standard deviation ha3 of the eigenvalue analysis parameters; similarly, the same analysis is performed on other four groups, and the characteristic value analysis parameters hb1, hb2, hb3, hc1, hc2, hc3, hd1, hd2, hd3, he1, he2 and he3 of each group can be obtained respectively.

Setting the threshold values of the current signal characteristic values ha1, ha2 and ha3 as h1, h2 and h3 respectively, the current signal abnormality degree parameter can be expressed as ERRf1 ═ ha1-h1|, ERRf2 ═ ha 2-h 2|, and ERRf3 ═ ha 3-h 3|, in the frequency domain.

The current signal abnormal value Kf in the frequency domain is represented as ERRf1+ ERRf2+ ERRf 3.

By integrating the time domain data abnormal value and the frequency domain data abnormal value, the discrimination result can be expressed as:

K_arc＝K_T·K_f

a normal range of Karc values can be determined through a number of experiments, and the occurrence of a faulty arc can be determined when Karc exceeds a set normal threshold.

According to the embodiment of the invention, the fault arc is judged by performing weighting calculation through the combined analysis of the time domain data and the frequency domain data, so that the detection precision is improved, and the occurrence of a misjudgment phenomenon is avoided. The realization inserts row product with intelligence and inserts thing networking cloud platform, masters power consumption data and rear end consumer power consumption condition in real time to can carry out the warning in high in the clouds immediately when the hidden danger appears. The intelligent socket with the fault arc detection function can be used in the field of industrial production, and the power utilization safety is effectively guaranteed.

The foregoing is a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should be construed as the protection scope of the present invention.