KR101625618B1 - Arc detecting apparatus, arc detecting method and power system - Google Patents

Abstract

An arc detecting apparatus according to the present invention comprises: a current sensor to sense a first current flowing through a first line of a system in which an influence of noise according to operating is detected in a first frequency band; a frequency data generation unit to digitally process a sensed value of the first current in a first temporal section and a second temporal section to generate first frequency data and second frequency data for the first frequency band; and an arc determination unit to determine whether an arc can be created in the system according to comparison data between the first frequency data and the second frequency data.

Description

TECHNICAL FIELD [0001] The present invention relates to an arc detection apparatus, an arc detection method,

The present invention relates to a technique for detecting an arc.

Arc is the flow of current between two electrodes that are either in contact with each other or in an unsecured contact.

Arcs can be largely classified into series arcs that occur in one conductor, parallel arcs that occur between two conductors, ground arcs that occur between one conductor and ground, and cross arcs that occur between other networks.

Such arcing in a power system can cause some devices to fail. In particular, when such an arc is left to be generated continuously, it is necessary to interrupt the corresponding electric power system so as to detect an arc at an early stage and prevent an arc from arising, since an electric fire may occur due to deterioration due to an arc discharge .

WO2002 / 39561 discloses a technology for detecting an arc and for interrupting a power system, but there is a problem in the technology.

In recent years, power systems often include a power conversion device. However, this technology has a problem in that it can not distinguish between noise and arc due to such a power conversion device. Accordingly, the arc may be erroneously detected according to the noise of the power conversion apparatus even in a normal operating state.

In this context, it is an object of the present invention to provide a technique for detecting an arc.

In another aspect, an object of the present invention is to provide a technique for distinguishing between noise and arc that arises in normal operation.

In another aspect, an object of the present invention is to provide a fast and accurate digital processing technique for arc detection.

In order to achieve the above-mentioned object, in one aspect, the present invention provides a semiconductor integrated circuit comprising: a current sensor for sensing a first current flowing in a first line of a system in which an influence of noise due to operation is detected in a first frequency band; A frequency data generation unit for digitally processing the sensing value for the first current in each of the first time interval and the second time interval to generate first frequency data and second frequency data for the first frequency band; And an arc determination unit for determining an arc occurrence possibility of the system according to comparison data between the first frequency data and the second frequency data.

In another aspect, the present invention provides a method comprising: sensing a first current flowing through a first line of a system in which an influence of noise due to operation is detected in a first frequency band; Digitally processing a sensing value for the first current in each of a first time interval and a second time interval to generate first frequency data and second frequency data for the first frequency band; And determining arc occurrence possibility of the system according to comparison data of the first frequency data and the second frequency data.

According to another aspect of the present invention, there is provided a current sensor comprising: a current sensor for sensing a first current flowing in a first line of a system in which a DC current is formed in a certain line or an entire line; An edge data generation unit generating digital current data by digitally converting a sensing value for the first current and generating current edge data through edge detection processing on the digital current data; A frequency data generation unit for comparing the current edge data with a first edge reference value to determine a first variation time point and digitally processing a sensing value for the first current after the first variation time point to generate frequency data; And an arc determination unit for determining an arc occurrence probability of the system according to the characteristics of the frequency data.

In another aspect, the present invention provides a method of driving a DC / DC converter comprising: sensing a first current flowing through a first line of a system in which a DC current is formed in some or all of the lines; Generating digital current data by digitally converting a sensing value for the first current and generating current edge data through edge detection processing on the digital current data; Comparing the current edge data with a first edge reference value to determine a first variation time and digitally processing the sensing value for the first current after the first variation time to generate frequency data; And determining an arc occurrence probability of the system according to the characteristics of the frequency data.

According to another aspect of the present invention, there is provided a method of generating digital current data by digitally converting a sensed value of a first current flowing in a first line of a system in which a DC current is formed in a certain line or an entire line; Storing the digital current data in a first buffer; Generating current edge data by edge detection processing on the digital current data; Storing the digital current data in a second buffer if the current edge data is greater than or equal to a first edge reference value; Generating first frequency data through Fourier transform processing on digital current data stored in the first buffer and generating second frequency data through Fourier transform processing on digital current data stored in the second buffer; And determining arc occurrence possibility of the system according to comparison data of the first frequency data and the second frequency data.

In another aspect, the present invention provides a power system in which a DC current is formed on a part of a line or an entire line, comprising: a power conversion device for converting power to a first switching frequency; A current sensor for sensing a first current flowing through the first line; A frequency data generation unit for digitally processing the sensing value for the first current in each of the first time interval and the second time interval to generate first frequency data and second frequency data for the first frequency band, Frequency or a harmonic of the first switching frequency corresponds to the first frequency band; And an arc determining unit determining an arc occurrence possibility of the system according to comparison data of the first frequency data and the second frequency data.

As described above, according to the present invention, an arc generated in the power system can be detected and the power system can be stably interrupted based on the detected arc. In addition, according to the present invention, there is an effect that the frequency of arc detection can be reduced by distinguishing noise and arc generated in normal operation. Further, according to the present invention, an arc can be detected quickly and accurately through a new digital processing technique.

1 is a configuration diagram of a power system according to an embodiment of the present invention.
2 is a block diagram of an arc detection apparatus 110 according to an embodiment of the present invention.
3 is a diagram showing a first frequency band waveform of a first current when an arc occurs.
4 is a diagram showing a switching noise waveform of the power converter detected at the first current.
5 is a diagram showing a reference frequency waveform and a comparison frequency waveform.
6 is a diagram showing the first time period and the second time period in the waveform of the first current.
FIG. 7 is a chart showing the quantization of the probability similarity by frequency.
8 is a diagram for explaining an example of determining the first time period and the second time period from the inflection point.
9 is a block diagram of an arc detection apparatus further including an edge data generation unit.
10 is a diagram showing an example in which edge detection processing is applied.
11 is a diagram for explaining the differential convolution process.
12 is a block diagram of an arc detection apparatus according to another embodiment of the present invention.
13 is a flowchart of an arc detection method according to another embodiment of the present invention.
14 is a diagram illustrating an example of a power system to which an arc detection apparatus according to an embodiment of the present invention can be applied.
15 is a block diagram of a test apparatus for testing an arc generator according to an embodiment of the present invention.
16 is an actual external view of the test apparatus.
17 is a waveform diagram of a test current when an arc is generated.
18 is a waveform diagram of the first frequency data generated in the first time period.
19 is a waveform diagram of the second frequency data generated in the second time slot.
FIG. 20 is a diagram showing a value serving as a reference of arc generation and a waveform at the time of arc generation.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference numerals whenever possible, even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected to or connected to the other component, It should be understood that an element may be "connected," "coupled," or "connected."

1 is a configuration diagram of a power system according to an embodiment of the present invention.

Referring to FIG. 1, a power system 100 includes a plurality of devices 110, 120, 130, and 140, and these devices 110, 120, 130, and 140 may be connected by lines. One line 154 is provided between the first device 120 and the second device 130 and another line 152 is provided between the second device 130 and the third device 140 have. For convenience of explanation, the latter is referred to as a first line 152 and the former is referred to as a second line 154. [

Arcs may occur in these lines 152 and 154 of the power system 100. [ In FIG. 1, an arc is generated in the second line 154, but an arc may be generated in another position.

The power system 100 includes an arc detection device 110 for sensing the first current i1 of the first line 152 to detect such an arc and analyzing the sensed value to determine whether the arc is arc.

The arc detecting apparatus 110 can detect an arc generated in the second line 154 by analyzing the first current i1 flowing through the first line 152. [ 1, the first line 152 and the second line 154 are shown at different positions, but the first line 152 and the second line 154 may be the same line. In other words, the arc detection device 110 can detect the arc generated in the first line 152 by analyzing the first current i1 flowing through the first line 152. [

Although not shown in FIG. 1, the arc detecting apparatus 110 analyzes the first current i1 flowing through the first line 152 and outputs the first current i1 to the other line or the first device 120, the second device 130, 3 device 140 can also be detected.

2 is a block diagram of an arc detection apparatus 110 according to an embodiment of the present invention.

2, the arc detection apparatus 110 may include a current sensor 210, a frequency data generation unit 220, an arc determination unit 230, and the like. Although not shown in FIG. 2, the arc detection apparatus 110 may further include an additional configuration according to an embodiment.

The current sensor 210 can sense the current flowing in one line of the power system (100 in Fig. 1). According to the embodiment shown in Fig. 1, the current sensor 210 can sense the first current i1 flowing through the first line 152 shown in Fig.

The frequency data generating unit 220 may digitally process the sensed value of the current sensor 210 to generate frequency data.

The arc determining unit 230 may analyze the frequency data generated by the frequency data generating unit 220 to determine the possibility of arcing of the power system 100 in FIG.

Reference is made to FIGS. 3 to 8 to describe additional embodiments of the frequency data generator 220 and the arc determiner 230.

3 is a diagram showing a first frequency band waveform of a first current when an arc occurs.

Referring to FIG. 3, it can be seen that the waveform 310 of the first current i1 rises in the first frequency band FB1. It has been confirmed by a number of experiments that the waveform of a specific frequency band (the frequency band corresponding to FB1 in Fig. 3) is raised when an arc is generated.

Based on this fact, the frequency data generating unit 220 may generate frequency data including the first frequency band FB1 information for the first current i1. The arc determining unit 230 may analyze the first frequency band FB1 included in the frequency data to determine the possibility of arcing.

For example, the frequency data generator 220 may generate the frequency data to include frequency-dependent size information of the first frequency band FB1 with respect to the first current i1. The arc determining unit 230 may compare the magnitude of the frequency of the first frequency band FB1 included in the frequency data with the first arc reference value 320 to determine the possibility of arcing. Specifically, the arc determining unit 230 compares the magnitude of the frequency of the first frequency band FB1 with the first arc reference value 320, and outputs the frequency band of frequencies larger than the first arc reference value 320 to the first frequency band (FB1) is larger than the first reference ratio, it can be judged that the possibility of arcing is high.

Here, the first arc reference value 320, which serves as a reference for arc determination, may have different values for different frequencies. The first arc reference value 320 may have a different value depending on the setting. For example, depending on the characteristics of the power system 100 including the arc detection device 110, the first arc reference value 320 may have a different value, such that the first arc reference value 320 is measured off-line It can be set differently according to the input of the user.

The power system 100 shown in FIG. 1 may include a power conversion device 130. The switching noise generated in the power conversion device 130 may be applied to the first frequency band FB1 shown in FIG. . ≪ / RTI >

4 is a diagram showing a switching noise waveform of the power converter detected at the first current.

Referring to FIG. 4, the switching frequency fsw of the power inverter 130 corresponds to the first frequency band FB1. Accordingly, the switching noise of the power converter 130 appears in the first frequency band FB1 waveform 410 of the first current i1. The switching noise of the power converter 130 may vary depending on the load. In a specific load condition, the first frequency band FB1 of the first current i1 due to the influence of the switching noise 410 may exceed the first arc reference value 320.

Accordingly, when the arc determining unit 230 compares the first arc reference value 320 with the first frequency band FB1 waveform 410 of the first current i1 to determine the possibility of arcing, In case of not operating (normal operating condition), it can be detected that an arc has occurred.

In order to solve the problem of false detection, the frequency data generator 220 may generate a variable value without fixing the first arc reference value 320, which is a reference of comparison, to one value. For example, the frequency data generating unit 220 may generate frequency data in a state where the power system 100 operates normally and generate the frequency data as reference frequency data. The reference frequency data is a substitute for the first arc reference value 320. The arc determination unit 230 may compare the reference frequency data with the comparison frequency data generated at each time point to determine the possibility of arcing.

More specifically, the reference frequency data generated by the frequency data generation unit 220 may include switching noise generated in a normal operating state. The arc determination unit 230 can solve the problem of the arc error due to the influence of the switching noise by comparing the reference frequency data with the comparison frequency data generated at each time point.

5 is a diagram showing a reference frequency waveform and a comparison frequency waveform.

Referring to FIG. 5, reference frequency waveform 510 and comparison frequency waveform 520 are shown. The reference frequency waveform 510 is a first frequency band FB1 waveform of the first current i1 measured in the normal operating state of the power system 100 and the comparison frequency waveform 520 is a waveform 1 < / RTI > current i1.

The arc determination unit 230 compares the reference frequency data including the reference frequency waveform 510 and the comparison frequency waveform 520 including the comparison frequency waveform 520 measured at each point in time By comparing the data, it is possible to determine the possibility of arcing irrespective of the influence of the switching noise.

In the foregoing description, it has been described that the switching noise may affect the first frequency band FB1 when the switching frequency fsw of the power conversion apparatus 130 is located in the first frequency band FB1. However, The harmonics of the frequency fsw may correspond to the first frequency band FB1.

In addition to the switching noise of the power conversion device 130, the power system 100 may have other sources of noise sources, such that noise from the noise source sources also affects the first frequency band FB1, It can cause the same problem.

The switching noise of the power inverter 130 may vary in size depending on the load. For example, when the conduction noise is largely generated in the power conversion apparatus 130, the switching noise can be reduced when the load is reduced. Accordingly, when the load is reduced, the influence of the switching noise detected in the first frequency band FB1 can also be reduced.

On the other hand, the frequency data generator 220 generates reference frequency data using the first current i1 sensed in the first time period, and generates the reference frequency data using the first current i1 sensed in the second time period, Data can be generated. The arc determining unit 230 may determine the possibility of arcing of the power system 100 according to the comparison data of the reference frequency data and the comparison frequency data.

6 is a diagram showing the first time period and the second time period in the waveform of the first current.

When an arc occurs in the power system 100, a constant inflection point may occur in the current waveform. The arc detection apparatus 110 can distinguish the first time interval TI1 and the second time interval TI2 based on the inflection point.

Referring to Fig. 6, an inflection point occurs at the first point P1 in the waveform of the first current i1. Accordingly, the arc detecting apparatus 110 can set the first time interval TI1 in the section before the inflection point P1 and the second time interval TI2 in the section after the inflection point P1. The end point of the first time period TI1 or the start point of the second time period TI2 may be located within a predetermined time from the point of time when the inflection point P1 appears. Such an inflection point may be caused by the occurrence of an arc, but may occur as the load is reduced or increased to a certain size or more.

On the other hand, the frequency data generator 220 can generate the first frequency data in the first time period TI1, and the first frequency data can be used as the reference frequency data described above. Then, the frequency data generator 220 can generate the second frequency data in the second time period TI2, and the second frequency data can be used as the above-described comparison frequency data.

The first time interval TI1 may be further divided into detailed time periods. Referring to FIG. 6, the first time interval TI1 is a time interval between the first time period TI11, the first time period TI12, the first time period TI13, (TI14) and the 1-5th time zone (TI15). The frequency data generator 220 may generate the sub data of the first frequency data in these subdivided time periods. For example, the frequency data generation unit 220 may generate the first sub data of the first frequency data in the first-time interval TI11. In the same manner, the frequency data generation unit 220 may also generate the 1-2 th to the 1-5 th sub data. The frequency data generation unit 220 may generate the first frequency data using the 1-1 to 1-5 sub data. When frequency data is generated by using such sub data, the frequency data generator 220 may generate probability distribution data such as a variance of frequency-dependent magnitudes as well as an average of frequency-dependent magnitudes.

The arc determining unit 230 may determine the possibility of arcing according to the comparison data of the first frequency data and the second frequency data, and the comparison data may indicate the probability similarity with respect to the first frequency data of the second frequency data. Lt; / RTI >

For example, the first frequency data and the second frequency data may comprise frequency-specific magnitudes, and the first frequency data may include an average, variance, and standard deviation of frequency-specific magnitudes using the detailed time- And the like. Accordingly, the arc determining unit 230 can check whether the frequency of the second frequency data is within the standard deviation of N (N is a positive real number) times the average of the frequency-dependent sizes of the first frequency data , The probability similarity can be calculated according to the N value. The arc determination unit 230 may generate the comparison data by calculating the probability similarity for each frequency. If the degree of similarity is high and the probability of occurrence of arc is low and the degree of similarity is low, it can be judged that the possibility of arcing is high.

More specifically, the arc determination unit 230 may generate comparison data by quantizing the probability similarities between the first frequency data and the second frequency data for each frequency. For example, the arc determination unit 230 determines whether the frequency-dependent size of the second frequency data falls within the standard deviation range of N (N is a positive real number) times the average of the frequency-dependent sizes of the first frequency data by 1 Or 0 to generate comparison data. Here, N may be a fixed value.

FIG. 7 is a chart showing the quantization of the probability similarity by frequency.

Referring to FIG. 7, the arc determination unit 230 divides the first frequency band FB1 into frequency intervals (1 KHz) of a predetermined size, compares the first frequency data with the second frequency data for each frequency, Whether or not the frequency-dependent size of the data corresponds to the N-fold standard deviation of the frequency-dependent size of the first frequency data can be expressed as a probability similarity of 1 or 0.

Here, the frequency-dependent magnitude can represent the magnitude of each frequency by the Fourier-transformed value. For example, the frequency data generating unit 220 generates first frequency data and second frequency data according to digital processing including Fourier transform, wherein the frequency-dependent magnitudes included in the first frequency data and the second frequency data are May be a frequency-dependent magnitude obtained by Fourier transforming the sensing value of the first current i1.

7, the arc determination unit 230 generates comparison data and calculates the sum of the probabilistic similarities. If the sum of the probabilistic similarities exceeds the first reference value or exceeds the first reference value, Lt; RTI ID = 0.0 > arc < / RTI > If the first arc variable is equal to or greater than the second reference value or exceeds the second reference value, the arc determining unit 230 may determine that an arc has occurred in the power system 100. [

In order to increase the first arc parameter, the arc determination unit 230 repeats the process of generating the comparison data of the first frequency data and the second frequency data. 6, the frequency data generation unit 220 generates sub data by subdividing the second time period TI2, and the arc determination unit 230 generates comparison data for each of the sub data Can be generated to determine the possibility of arcing. For example, referring again to FIG. 6, the second time period TI2 is subdivided into the second-first time period TI21 and the second-second time period TI22. The frequency data generator 220 may generate frequency-specific size data for the first frequency band FB1 in the 2-1th time interval TI21 and the 2-2 hour time interval TI22, respectively. The arc determining unit 230 then outputs frequency-dependent magnitude data for the first frequency band FB1 generated in the second-time period TI21 and the second-time period TI22 to the first frequency data FB1, The comparison data can be generated.

On the other hand, there may be various embodiments for determining the start time and the end time of the first time interval TI1 and the second time interval TI2.

8 is a diagram for explaining an example of determining the first time period and the second time period from the inflection point.

Referring to FIG. 8, the end point t3 of the first time period TI1 may be located a certain time before the point of time t1 when the inflection point P1 appears. The start time t2 of the second time period TI2 may be located after a certain time from the time point t1 when the inflection point P1 appears.

Although not shown in FIG. 8, the start time of the first time slot TI1 may be equal to the normal operating start time of the power system 100. [

On the other hand, the first time interval TI1 may not be constituted by a continuous time period but may be composed of a combination of several time points. For example, if it is determined that an arc has not occurred at the end of the second time period TI2, the first time period TI1 may be restarted from the end time point of the second time period TI2 or after a certain time from the end time point You can extend it. Since the first time interval TI1 can correspond to the time periods normally operated by the power system 100, all the time periods other than the second time period TI2, except for the time periods to be excluded, May be included in the liver TI1.

In order to distinguish the first time period TI1 from the second time period TI2, it is important to set an inflection point P1 that distinguishes the first time period TI1 from the second time period TI2. An embodiment for setting such an inflection point P1 will be further described.

9 is a block diagram of an arc detection apparatus further including an edge data generation unit.

9, the arc detection apparatus 910 includes an arc detection unit 210, a frequency data generation unit 220, and an arc determination unit 230, which are included in the arc detection apparatus 110 described with reference to FIG. And may further include a data generation unit 940.

The edge data generation unit 940 generates digital current data by digitizing the sensed value for the first current i1 and generates current edge data through edge detection processing on the digital current data have. The first time period TI1 and the second time period TI2 described above can be determined according to such current edge data.

The edge detection process is a process of finding a discontinuity point of a specific value. The edge detection process is a process of finding a discontinuity at specific values representing successive data under normal circumstances.

10 is a diagram showing an example in which edge detection processing is applied.

An image 1010 on the left side in FIG. 10 is an image obtained by a video device such as a camera. Since the objects (clouds, sky, trees, and mountains) shown in the image 1010 each have a continuous surface, the image data of the inner surface of each object has continuous or relatively similar data values. On the other hand, each object has different image data, so that a discontinuity point of the image data appears at the boundary of each object. This discontinuity point is an image 1020 on the right side of FIG. When the discontinuity point of the specific image 1010 is displayed in this manner, it is possible to acquire the image 1020 in which only the boundary is displayed as shown in the right image 1020 in FIG.

On the other hand, when an arc is generated in the power system 100, a discontinuity point as described above appears in the current measurement value. The arc detection apparatus 910 according to the embodiment of the present invention can recognize such a discontinuity point and distinguish the first time interval TI1 and the second time interval TI2 before and after the discontinuity point.

The edge detection processing may use a Laplacian filter processing for differentiating data, and a difference convolution processing for calculating a difference of data may be used.

11 is a diagram for explaining the differential convolution process.

Referring to FIG. 11, the time-dependent measurements of the first current i1 may be stored in the first array 1110. In FIG. 11, the first graph 1112 shown on the right side of the first array 1110 is a graph in which the first array 1110 is represented by a time axis and a size axis. Referring to the first graph 1112, it can be seen that the first current i1 varies discontinuously or largely at the inflection point P2.

11, the second arrangement 1120 is an arrangement in which differential convolution is performed by multiplying three consecutive values in the first array 1110 by {-1, 0, 1}. As can be seen from the second arrangement 1120, the data of the specific portion (the fourth data in the second array) is higher than the data of the other portions, which can be the inflection point P2. In FIG. 11, the second graph 1122 shown on the right side of the second array 1120 is a graph showing the second array 1120 in terms of time and magnitude axes. Referring to the second graph 1120, it is confirmed that the inflection point P2 at the first current i1 occurs at time t4.

The values of the first array 1110 described with reference to FIG. 11 are examples of the digital current data described above, and the second array 1120 may be an example of current edge data.

The frequency data generation unit 220 may determine the change time point by comparing the current edge data with the first edge reference value and determine the first time period TI1 and the second time period TI2 based on the change time point .

11, the frequency data generator 220 compares the current edge data stored in the second array 1120 with a first edge reference value (a value corresponding to 1130 in FIG. 11) If it is larger than the edge reference value (the value corresponding to 1130 in FIG. 11), the time corresponding to the current edge data can be determined as the change time point t4.

On the other hand, the frequency data generation unit 220 may determine the change time point using only the negative (-) value of the current edge data, or may determine the change time point using only the positive (+) value. For example, if the frequency data generation unit 220 only recognizes the change time point in a situation where the first current i1 is sharply reduced, the change time point can be determined using only the negative value, and the first current i1 ), The change point may be determined using only a positive value if the change point is to be recognized.

In the case of a parallel arc, the current rapidly increases. Therefore, a positive (+) value of the current edge data is used, May be used to determine the point of change.

Meanwhile, the frequency data generator 220 generates a first edge reference value according to the average and standard deviation of the current edge data when determining the variation time point using the current edge data. Based on the first edge reference value, You can decide. At this time, when the frequency data generation unit 220 determines the change time point only by using a negative value, the current edge data of the current edge data obtained in the specific time period (the third time interval) The mean and standard deviation can be calculated using only data. Here, the first edge reference value can be determined by adding the standard deviation of M (M is a real number) times to the previously calculated average. On the other hand, the frequency data generation unit 220 may determine the variation time point or generate the first edge reference value based on the absolute value of the current edge data.

The average and standard deviation of the current edge data may be continuously updated, for example, if the absolute value of the current edge data is less than or equal to the first edge reference value, or is less than the first edge reference value, The mean and standard deviation for the current edge data can be updated.

Since the edge detection process may be sensitive to the noise of the data, the edge data generation unit 940 may generate the edge current data by using the Gaussian convolution such as Gaussian convolution in the process of digitizing the sensing value for the first current i1. Filter processing can be applied.

Hereinafter, another embodiment of the present invention will be described. The techniques of one embodiment may be applied to the other embodiments described below as long as no technical conflict with the above-described one embodiment occurs. Likewise, the techniques of the other embodiments described below can be combined with the configurations of the above-described one embodiment as long as they do not technically conflict with the above-described one embodiment.

12 is a block diagram of an arc detection apparatus according to another embodiment of the present invention.

The arc detection apparatus 1200 described with reference to FIG. 12 can be applied in place of the arc detection apparatus 110 according to an embodiment in the power system 100 shown in FIG.

The arc detection apparatus 1200 of FIG. 12 may be considered to operate in conjunction with the first apparatus 120, the second apparatus 130, and the third apparatus 140 shown in FIG. 1 have.

12, the arc detecting apparatus 1200 may include a current sensor 210, a frequency data generating unit 1220, an arc determining unit 1230, and an edge data generating unit 1240.

The current sensor 210 can sense the first current i1 flowing through the first line 152 shown in Fig.

The edge data generator 1240 may generate digital current data by digitizing the sensed value of the first current i1 and generate current edge data through edge detection processing on the digital current data.

The frequency data generator 1220 determines the first variation time point by comparing the current edge data with the first edge reference value, digitizes the sensing value for the first current i1 after the first variation time, Data can be generated.

The arc determination unit 1230 can determine the possibility of arcing of the power system (see 100 in FIG. 1) according to the characteristics of the frequency data.

Specifically, the edge data generator 1240 may apply Gaussian convolution in the process of digitizing the sensing value for the first current i1.

The edge detection process for the digital current data may be a Laplacian filter process or a difference convolution process.

The frequency data generation unit 1220 can determine the first change time point using only the negative (-) value of the current edge data.

In addition, the frequency data generator 1220 may generate the first edge reference value according to the average and standard deviation of the current edge data obtained in the specific time period. Here, only negative (-) current edge data obtained in the above-mentioned specific time period can be used to generate the average and standard deviation. The frequency data generator 1220 can update the average and standard deviation of the current edge data obtained in the specific time period using the current edge data whose absolute value is less than or equal to the first edge reference value have.

13 is a flowchart of an arc detection method according to another embodiment of the present invention.

The arc detection method of FIG. 13 may be performed by the above-described arc detection device, but not limited thereto, and may be performed by other types of hardware.

Referring to FIG. 13, a sensing value of a current flowing in a line, such as the example of the first line 152 in FIG. 1, is digitally converted to generate digital current data (S1302).

Current edge data is generated by the edge detection processing on the digital current data (S1304).

The current edge data is compared with the first edge reference value (S1306). If the current edge data is smaller than the first edge reference value, the digital current data is stored in the first buffer (S1308). Conversely, if the current edge data is equal to or greater than the first edge reference value or exceeds the first edge reference value, the digital current data is stored in the second buffer (S1310).

The digital current data stored in the first buffer is converted into the first frequency data through the Fourier transform process, and the digital current data stored in the second buffer is converted into the second frequency data through the Fourier transform process (S1312).

Then, the possibility of arcing the system is determined based on the comparison data of the first frequency data and the second frequency data (S1314).

On the other hand, in the step of generating current edge data (S1304), the digital current data is subjected to a Gaussian filter process and then stored in the third buffer and subjected to edge detection processing on the data stored in the third buffer Data can be generated.

Here, the third buffer may be a first in first out (FIFO) buffer in which three pieces of digital current data are stored. In the step of generating current edge data (S1304), current edge data may be generated by multiplying a third buffer storing three digital current data by a differential convolution vector.

The first buffer and the second buffer may also be first in first out (FIFO) buffers.

14 is a diagram illustrating an example of a power system to which an arc detection apparatus according to an embodiment of the present invention can be applied.

The arc detection apparatus 1410 according to an embodiment of the present invention may be applied to a power system 1400 in which a DC current is formed in some or all of the lines.

The power system 1400 may include a power source 1420, which may be a solar power panel or a large capacity battery that outputs a DC current. In some cases, the power system 1400 in which the solar power generation panel is used as the power source 1420 may be referred to as a solar power generation system. The power system 1400 in which the large capacity battery is used as the power source 1420 may be referred to as a large capacity battery energy storage system.

The power system 1400 may include a power converter 1430 that converts power to a first switching frequency. A load device 1440 may be connected to the power conversion device 1430.

The magnitude of the noise related to the first switching frequency may be changed according to the load of the power converter 1430. Also, the power inverter 1430 can be controlled at a variable frequency, where the first switching frequency can be varied.

The power system 1400 may include a current sensor 1412 that senses line current flowing through a line of the power system 1400.

The power system 1400 digitally processes the sensing value for the first current in each of the first time interval and the second time interval to generate first frequency data and second frequency data for the first frequency band, And a generating unit 1414. At this time, the switching noise caused by the power converter 1430 may affect the first frequency data and the second frequency data. Depending on the load, the first switching frequency component represented by the first frequency data or the second frequency data, .

The power system 1400 may include an arc determination unit 1416 that determines the likelihood of an arc of the power system 1400 in accordance with the comparison data of the first frequency data and the second frequency data.

The power system 1400 further includes an edge data generator 1418 for generating digital current data by digitally converting the sensing value for the first current and generating current edge data through edge detection processing on the digital current data . At this time, the first time interval and the second time interval may be determined according to the current edge data. The arc determination unit 1416 can determine whether the characteristic change of the current edge data is due to a load change or an arc occurrence according to comparison data between the first frequency data and the second frequency data.

The current sensor 1412, the frequency data generation unit 1414, the arc determination unit 1416, and the edge data generation unit 1418 may be included in the arc detection apparatus 1410.

15 to 21 are diagrams showing an apparatus for testing an arc generator according to an embodiment of the present invention and experimental waveforms thereof.

15 is a block diagram of a test apparatus for testing an arc generator according to an embodiment of the present invention.

15, a test apparatus 1500 may include a DC 380V power supply 1520, a DC / DC power inverter 1530, a load 1540 and an arc detection apparatus 1510 for outputting DC power . The DC380V power supply 1520 and the DC / DC power inverter 1530 may be connected to a test line 1502 where an arc is generated and the arc detecting device 1510 may be connected to a test The current can be sensed.

16 is an actual external view of the test apparatus.

16, the test apparatus 1500 may include a DC 380V power supply 1520, a DC / DC power inverter 1530, a load 1540 and an arc detection apparatus 1510, The load 1540 does not appear on the screen.

17 is a waveform diagram of a test current when an arc is generated.

Referring to FIG. 17, a discontinuity point of current appears at the first point 1702 together with an arc occurrence, and a discontinuity point of current at the second point 1704 appears again after a short time. The arc detecting apparatus 1510 recognizes the first point 1702 and can distinguish the first time period T11 from the second time period TI2 and the first frequency data at this first time period TI1 And generate the second frequency data in the second time slot TI2.

18 is a waveform diagram of the first frequency data generated in the first time period.

The arc detection device 1510 can subdivide the first time interval TI1 into subdivisions and obtain a frequency waveform through a Fourier transform on the sensed value of the test current in each subdivision, Are the frequency waveforms obtained through the Fourier transforms in these sub-sections, respectively.

Referring to FIG. 18, it can be seen that the frequency waveform is formed to be low because it is a normal operating state. However, it can be seen that the value between 10 KHz and 20 KHz is somewhat higher due to the influence of the DC / DC power inverter 1530.

19 is a waveform diagram of the second frequency data generated in the second time slot.

The arc detection apparatus 1510 may subdivide the second time period TI2 into subdivisions and obtain a frequency waveform through a Fourier transform on the sensed value of the test current in each subdivision, Are the frequency waveforms obtained through the Fourier transforms in these sub-sections, respectively.

Referring to FIG. 19, it can be seen that the waveform of the frequency band from 10 KHz to 70 KHz is formed higher than the waveform of FIG. This fact can be used to detect the occurrence of an arc in the test apparatus 1500.

FIG. 20 is a diagram showing a value serving as a reference of arc generation and a waveform at the time of arc generation.

The arc detection apparatus 1510 may generate a reference value for determining an arc occurrence based on the first frequency data. In FIG. 20, the lowermost waveform 2010 is an average value waveform of frequency-specific magnitudes in a normal operating state calculated through the first frequency data. The waveform 2020 located at the middle in FIG. 20 is a waveform obtained by adding the standard deviation value of three times to the average value of the frequency-dependent magnitudes in the normal operating state calculated through the first frequency data.

The arc detection apparatus 1510 may set the average value waveform of the frequency-dependent magnitude in the normal operating state as the reference waveform or the waveform in which the average value of the frequency-dependent magnitude plus three times the standard deviation value may be set as the reference waveform. The arc detector 1510 may compare the reference waveform with the waveform 2030 generated through the second frequency data to determine whether an arc has occurred in the test apparatus 1500.

If the arc detecting apparatus 1510 determines that the arc is determined, the arc detecting apparatus 1510 may generate a signal such that the system is turned off.

As described above, according to the present invention, an arc generated in the power system can be detected and the power system can be stably interrupted based on the detected arc. In addition, according to the present invention, there is an effect that the frequency of arc detection can be reduced by distinguishing noise and arc generated in normal operation. Further, according to the present invention, an arc can be detected quickly and accurately through a new digital processing technique.

It is to be understood that the terms "comprises", "comprising", or "having" as used in the foregoing description mean that the constituent element can be implanted unless specifically stated to the contrary, But should be construed as further including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (29)

A current sensor for sensing a first current flowing through a first line of the system in which an influence of noise due to operation is detected in a first frequency band;
A frequency data generation unit for digitally processing the sensing value for the first current in each of the first time interval and the second time interval to generate first frequency data and second frequency data for the first frequency band; And
And an arc determination unit for determining an arc occurrence possibility of the system according to comparison data of the first frequency data and the second frequency data,
Wherein the first frequency data and the second frequency data include frequency-specific sizes,
The arc determining unit may determine,
And generates the comparison data for the frequency-dependent magnitude. The method according to claim 1,
Wherein the system comprises a power conversion device and switching noise generated in the power conversion device affects the first frequency band. 3. The method of claim 2,
Wherein the switching frequency of the power inverter corresponds to the first frequency band or the harmonic of the switching frequency corresponds to the first frequency band. 3. The method of claim 2,
And the influence of the switching noise detected in the first frequency band varies depending on the load. 5. The method of claim 4,
And the influence of the switching noise detected in the first frequency band is reduced when the load is reduced. 6. The method of claim 5,
Wherein the first time interval is a time interval before the inflection point and the second time interval is a time interval after the inflection point based on an inflection point at which the load is reduced to a predetermined size or more. The method according to claim 6,
And a start point of the second time point is located within a predetermined time from the inflection point. The method according to claim 1,
Wherein the first frequency data includes probability distribution data,
Wherein the comparison data is data indicating a probability similarity of the second frequency data with respect to the first frequency data. delete The method according to claim 1,
Wherein the first frequency data includes an average and a standard deviation of frequency-specific sizes,
The arc determining unit may determine,
Whether the size of the second frequency data is within a standard deviation of N (N is a positive real number) times the average of the frequency-dependent sizes of the first frequency data is represented as 1 or 0 as a probability similarity, And generates comparison data. 11. The method of claim 10,
The arc determining unit may determine,
And increases the first arc parameter for the arc probability of the system if the sum of the probabilistic similarities included in the comparison data is equal to or greater than a first reference value or exceeds the first reference value. 12. The method of claim 11,
The arc determining unit may determine,
Wherein the arc determining unit determines that an arc has occurred in the system when the first arc parameter is equal to or greater than a second reference value or exceeds the second reference value. The method according to claim 1,
Wherein the frequency data generator comprises:
And generates the first frequency data and the second frequency data through a Fourier transform. The method according to claim 1,
Further comprising an edge data generation unit for generating digital current data by digitally converting a sensing value for the first current and generating current edge data through edge detection processing on the digital current data,
Wherein the first time period and the second time period are determined according to the current edge data. 15. The method of claim 14,
Wherein the frequency data generator comprises:
Wherein the current edge data is compared with a first edge reference value to determine a first variation time point, and the first time period and the second time period are determined based on the first variation time point. 16. The method of claim 15,
Wherein the frequency data generator comprises:
Wherein the first change point is determined using only a negative value of the current edge data. 16. The method of claim 15,
Wherein the first edge reference value is generated according to an average and a standard deviation of the current edge data obtained in the third time interval. 18. The method of claim 17,
Wherein only negative (-) current edge data obtained in the third time period is used for generating the average and the standard deviation. 18. The method of claim 17,
Wherein the frequency data generator comprises:
And updating the average and standard deviation for the current edge data obtained in the third time period by using the current edge data whose absolute value is equal to or less than the first edge reference value or less than the first edge reference value. Device. 15. The method of claim 14,
Wherein the edge data generation unit comprises:
Wherein a Gaussian convolution is applied in a process of digitally converting a sensing value for the first current. The method according to claim 1,
Further comprising an edge data generator for generating digital current data by digitally converting a sensed value of the first current and generating current edge data through Laplacian filter processing on the digital current data,
Wherein the first time period and the second time period are determined according to the current edge data. The method according to claim 1,
Further comprising an edge data generation unit for generating digital current data by digitally converting a sensing value for the first current and generating current edge data through a difference convolution process on the digital current data,
Wherein the first time period and the second time period are determined according to the current edge data. Sensing a first current flowing through a first line of the system in which the influence of noise due to operation is detected in a first frequency band;
Digitally processing a sensing value for the first current in each of a first time interval and a second time interval to generate first frequency data and second frequency data for the first frequency band; And
And determining an arc occurrence possibility of the system according to comparison data of the first frequency data and the second frequency data,
Wherein the first frequency data and the second frequency data include frequency-specific sizes,
In the step of determining the possibility of arc occurrence,
Wherein the comparison data is generated for the frequency-specific magnitude. In a power system in which DC current is formed in some or all of the lines,
A power converter for converting power to a first switching frequency;
A current sensor for sensing a first current flowing through the first line;
A frequency data generation unit for digitally processing the sensing value for the first current in each of the first time interval and the second time interval to generate first frequency data and second frequency data for the first frequency band, Frequency or a harmonic of the first switching frequency corresponds to the first frequency band; And
And an arc determination unit for determining an arc occurrence possibility of the system according to comparison data of the first frequency data and the second frequency data,
Wherein the first frequency data and the second frequency data include frequency-specific sizes,
The arc determining unit may determine,
And generate the comparison data for the frequency-specific magnitude. 25. The method of claim 24,
The power conversion device performs variable frequency control,
And the magnitude of the first switching frequency component appearing in the first frequency data or the second frequency data varies depending on the load. 25. The method of claim 24,
Further comprising an edge data generation unit for generating digital current data by digitally converting a sensing value for the first current and generating current edge data through edge detection processing on the digital current data,
Wherein the first time period and the second time period are determined according to the current edge data. 27. The method of claim 26,
The arc determining unit may determine,
And determines whether the characteristic change of the current edge data is due to a load change or an arc occurrence according to comparison data between the first frequency data and the second frequency data. In a photovoltaic power generation system in which a DC current is formed in some or all of the lines,
A power converter for converting power to a first switching frequency;
A current sensor for sensing a first current flowing through the first line;
A frequency data generation unit for digitally processing the sensing value for the first current in each of the first time interval and the second time interval to generate first frequency data and second frequency data for the first frequency band, Frequency or a harmonic of the first switching frequency corresponds to the first frequency band; And
And an arc determination unit for determining an arc occurrence possibility of the system according to comparison data of the first frequency data and the second frequency data,
Wherein the first frequency data and the second frequency data include frequency-specific sizes,
The arc determining unit may determine,
And generates the comparison data for the frequency-specific size. In a high capacity battery energy storage system in which DC current is formed in some or all of the lines,
A power converter for converting power to a first switching frequency;
A current sensor for sensing a first current flowing through the first line;
A frequency data generation unit for digitally processing the sensing value for the first current in each of the first time interval and the second time interval to generate first frequency data and second frequency data for the first frequency band, Frequency or a harmonic of the first switching frequency corresponds to the first frequency band; And
And an arc determination unit for determining an arc occurrence possibility of the system according to comparison data of the first frequency data and the second frequency data,
Wherein the first frequency data and the second frequency data include frequency-specific sizes,
The arc determining unit may determine,
And generate the comparison data for the frequency-specific magnitude.

Images