JP2022152724A - Device and method for determining connection abnormality - Google Patents

Abstract

To provide a device and method for determining connection abnormality, which enable accurate determination of connection abnormality within lines.SOLUTION: A connection abnormality determination device is provided, comprising: an acquisition unit 2 configured to acquire electrical signals on lines (first voltage line L1, neutral line N, and second voltage line L2); and an analysis unit 3 configured to compute a frequency spectrum representing data on a frequency axis using the electrical signals to perform an analysis for determining the presence or absence of connection abnormality within the lines on the basis of the frequency spectrum.SELECTED DRAWING: Figure 1

Description

The present invention relates to a connection abnormality determination device and a connection abnormality determination method.

2. Description of the Related Art Conventionally, for example, Patent Document 1 is known as a technique for detecting a connection abnormality such as a half disconnection or poor contact that occurs in a conductor in a cable or in a circuit line of a home appliance.

Patent Document 1 discloses a device that includes a detection circuit that detects a specific waveform distortion, a rush voltage detection circuit that detects a voltage change due to a rush current of a load from a rectified waveform, and a determination circuit that determines the occurrence of a cord short circuit. It is

JP 2015-089228 A

However, since the electrical signal in the line is greatly affected by the device (load) to which it is connected, the conventional technology has room for improvement in the accuracy of determining connection abnormality in the line.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a connection abnormality determination device and a connection abnormality determination method capable of accurately determining connection abnormality in a railway line.

In order to achieve the above object, the connection abnormality determination device of the present invention includes:
an acquisition unit that acquires an electrical signal on the track;
an analysis unit that calculates a frequency spectrum, which is data on the frequency axis, using the electrical signal, and performs analysis for determining whether or not a connection abnormality has occurred in the line based on the frequency spectrum;
Prepare.

According to the above configuration, the frequency spectrum of the electric signal on the line is calculated, and whether or not the connection abnormality has occurred is determined based on the frequency spectrum. For this reason, it becomes easier to grasp the characteristics of the noise component caused by the connection abnormality by distinguishing it from the effects of loads such as home appliances on the line, and it is possible to accurately determine the connection abnormality.

Further, the connection abnormality determination method of the present invention includes:
an acquisition step of acquiring an electrical signal on the track;
an analysis step of calculating a frequency spectrum, which is data on the frequency axis, using the electrical signal, and performing analysis for determining whether or not a connection abnormality has occurred in the line based on the frequency spectrum;
have

According to the above method, by calculating the frequency spectrum of the electrical signal on the line and determining whether or not a connection abnormality has occurred based on the calculated frequency spectrum, the influence of the load such as home appliances on the line can be determined. , and it is possible to easily grasp the characteristics of the noise component caused by the connection abnormality, so it is possible to accurately determine the connection abnormality.

ADVANTAGE OF THE INVENTION According to this invention, the connection abnormality determination apparatus and connection abnormality determination method which can determine the connection abnormality in a track with sufficient accuracy can be provided.

1 is a block diagram showing the configuration of a connection abnormality determination device according to an embodiment of the present invention; FIG. 3 is a block diagram showing the configuration of an acquisition unit of the connection abnormality determination device; FIG. (a) is a diagram showing an example of the frequency spectrum when no connection abnormality has occurred, and (b) is a diagram showing an example of the frequency spectrum when a connection abnormality has occurred. (a) is a diagram showing another example of the frequency spectrum when no connection failure occurs, and (b) is another example of the frequency spectrum when a connection failure occurs. (a) is a diagram showing another example of the frequency spectrum when no connection failure occurs, and (b) is another example of the frequency spectrum when a connection failure occurs. It is a figure which shows an example of the power consumption of one day.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a connection abnormality determination device and a connection abnormality determination method according to the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of a connection abnormality determination device 1 of this embodiment. As shown in FIG. 1 , the connection abnormality determination device 1 includes an acquisition unit 2 , an analysis unit 3 , a current measurement unit 4 and a setting unit 5 . The connection abnormality determination device 1 is incorporated in, for example, a distribution board D installed in each home.

In addition, in this embodiment, a single-phase three-wire system will be described as a power distribution system for supplying electricity to each household. The single-phase three-wire system has a first voltage line L1, a neutral line N, and a second voltage line L2 as three core wires. For example, commercial power with a power supply frequency of 50 Hz/60 Hz is supplied to a load P (household appliances, etc.) via a line formed by a first voltage line L1, a neutral line N, and a second voltage line L2. be. In addition, in the present embodiment, the "line" is not limited to the line formed by the first voltage line L1, the neutral line N, and the second voltage line L2, and the internal wiring (including electric wires and circuit patterns), etc.

The acquisition unit 2 is connected to the first voltage line L1 in the distribution board D, the neutral line N, and the second voltage line L2. The acquisition unit 2 acquires electrical signals on lines (first voltage line L1, neutral line N, second voltage line L2, and load wiring). The acquisition unit 2 acquires, for example, an electrical signal on a line extending from the first voltage line L1 to the neutral line N and an electrical signal on the line extending from the second voltage line L2 to the neutral line N, These acquired electrical signals are transmitted to the analysis unit 3 . The "electrical signal" includes a load noise signal resulting from the driving of a home appliance or the like, a noise component signal resulting from a connection abnormality in a line, and the like. "Abnormal connections in the railroad tracks" include half-breaks due to repeated bending of cables, poor connections due to aged deterioration of railroad tracks on electric circuits, poor contact between outlets and plugs, and breaker B of distribution board D. Including poor contact of electric wires in A detailed configuration of the acquisition unit 2 will be described later with reference to FIG.

The analysis unit 3 is composed of at least one electronic control unit (MCU: Micro Control Unit). The electronic control unit includes a computer system (eg, SoC (System on a Chip), etc.) including one or more processors and memory, and an electronic circuit composed of active elements such as transistors and passive elements such as resistors. The analysis unit 3 includes a storage unit 31 , a comparison unit 32 and a determination unit 33 .

The analysis unit 3 frequency-analyzes the electric signal received from the acquisition unit 2 by Fast Fourier Transform, and calculates a frequency spectrum, which is data on the frequency axis. Based on the calculated frequency spectrum, the analysis unit 3 determines whether or not a connection abnormality has occurred in the lines (first voltage line L1 to neutral line N, second voltage line L2 to neutral line N). analysis for A determination as to whether or not there is a connection abnormality in the line is made while the load P (household appliance or the like) connected to the line is being driven.

In the storage unit 31, for example, data acquired under a test environment in which no connection abnormality occurs in the line (first voltage line L1 to neutral line N or second voltage line L2 to neutral line N), that is, A frequency spectrum for comparison calculated based on a test signal that does not contain noise components caused by abnormal connection is stored.

The comparison unit 32 compares, for example, the level of the first frequency spectrum calculated from the electric signal on the line extending from the first voltage line L1 to the neutral line N and the line extending from the second voltage line L2 to the neutral line N The level of the second frequency spectrum calculated from the electrical signal above is compared with a predetermined threshold. Also, the comparison unit 32 compares, for example, the level of the first frequency spectrum and the level of the second frequency spectrum. Also, the comparison unit 32 compares, for example, the level of the comparison frequency spectrum stored in the storage unit 31 with the level of the first frequency spectrum or the second frequency spectrum. Note that the "level" of the frequency spectrum means the strength of the electrical signal.

The determination unit 33 determines whether or not a connection abnormality has occurred in the line based on the comparison result of the comparison unit 32 . Further, the determination unit 33 determines whether or not to determine connection abnormality based on the current value measured by the current measurement unit 4 .

The current measurement unit 4 is a measurement unit for measuring the current flowing on the lines (first voltage line L1, second voltage line L2). The current flowing on the line means the consumption current consumed by the load P (household appliances, etc.).

The setting unit 5 is configured to be able to stepwise select and set a threshold to be compared with the level of the frequency spectrum calculated from the electric signal in the line. Further, the setting unit 5 is configured to be able to select and set a threshold value to be compared with the current consumption measured by the current measuring unit 4 step by step. The setting unit 5 is composed of, for example, a changeover switch capable of switching the threshold value.

Specific analysis contents of the analysis unit 3 are as follows. For example, in the calculated frequency spectrum, the analysis unit 3 performs analysis for determining whether or not a connection abnormality has occurred in the line, based on the frequency spectrum within a predetermined frequency band. A "predetermined frequency band" is, for example, a frequency band in the range of 10 MHz or higher.

When the level of the frequency spectrum exceeds a predetermined threshold value T1 within a predetermined frequency band (10 MHz or higher), the analysis unit 3 determines that a connection abnormality has occurred in the line. The "predetermined threshold value T1" is, for example, 50 dBμV.

Further, for example, the analysis unit 3 utilizes periodic characteristics on the frequency axis due to noise components caused by the connection abnormality that appear in the frequency spectrum due to the occurrence of the connection abnormality, so that the connection abnormality occurs in the line. Analysis is performed to determine whether or not

When the level of the frequency spectrum exceeds a predetermined threshold value T1 multiple times at regular intervals on the frequency axis within a predetermined frequency band (10 MHz or higher), the analysis unit 3 determines that a connection abnormality has occurred in the line. I judge. The feature of "exceeding a predetermined threshold at regular intervals" is one of the periodic features. "Constant interval" is, for example, a value within the range of 2 MHz to 3 MHz. The "threshold T1" is 50 dBμV as above.

The analysis unit 3 calculates the first frequency spectrum calculated from the electrical signal on the line extending from the first voltage line L1 to the neutral line N, and the electrical signal on the line extending from the second voltage line L2 to the neutral line N. It is compared with the second frequency spectrum calculated from the signal, and when the difference value between the first frequency spectrum and the second frequency spectrum, which is the result of the comparison, exceeds a predetermined threshold value T3, it is determined that a connection abnormality has occurred. . The "predetermined threshold T3" is, for example, 20 (50-30) dBμV.

The analysis unit 3 compares the frequency spectrum for comparison calculated based on the test signal acquired under the test environment in which no connection abnormality occurs in the line, and the line extending from the first voltage line L1 to the neutral line N Compare the first frequency spectrum calculated from the above electric signal or the second frequency spectrum calculated from the electric signal on the line extending from the second voltage line L2 to the neutral line N, and both frequencies that are the comparison result If the spectrum difference value exceeds a predetermined threshold value T4, it is determined that a connection abnormality has occurred. The "predetermined threshold value T4" is, for example, 20 (50-30) dBμV.

When the difference value between both frequency spectra, which is the comparison result, does not exceed a predetermined threshold value T4, the analysis unit 3 determines whether or not the difference value exceeds a predetermined threshold value T5 (T5<T4). If the threshold T5 is exceeded, the frequency of occurrence of frequency spectra exceeding the threshold T5 is measured. The analysis unit 3 may determine that a connection abnormality has occurred when the frequency of occurrence exceeds a predetermined frequency.

The analysis unit 3 compares the maximum level of the frequency spectrum of the frequency band of 10 MHz or higher and the maximum level of the frequency spectrum of the frequency band of 10 MHz or lower in the frequency spectrum calculated from the electric signal in the line, and the comparison result is When the difference value between both frequency spectra exceeds a predetermined threshold value T6, it is determined that a connection abnormality has occurred in the line. The "predetermined threshold value T6" is, for example, 10 dBμV.

Further, for example, the analysis unit 3 receives the consumption current of the load P measured by the current measurement unit 4 from the current measurement unit 4, and analyzes the connection abnormality in the line according to the current value of the consumption current. Decide whether or not When the current consumption of the load P measured by the current measurement unit 4 is equal to or less than a predetermined threshold, the analysis unit 3 performs analysis to determine whether or not a connection abnormality has occurred in the line. Further, when the current consumption of the load P measured by the current measuring unit 4 is in an upward trend, the analysis unit 3 does not perform analysis for determining whether or not a connection abnormality has occurred in the line.

In addition, when the analysis unit 3 determines that a connection abnormality has occurred in the line as a result of the analysis, the analysis unit 3 sends a cutoff signal to the distribution board D to cut off the breaker (circuit breaker) B of the distribution board D In addition to the transmission, a notification signal for notifying that a connection abnormality has occurred is output to the outside.

Next, with reference to FIG. 2, the configuration and functions of the acquisition unit 2 will be described.
As shown in FIG. 2, the acquisition unit 2 includes a coil H, a capacitor C, a resistor R, a low-pass filter circuit 21, an oscillator 22, a frequency coupling unit 23, a band-pass filter circuit 24, and an amplifier 25. , and an A/D conversion circuit 26 .

The acquisition unit 2 includes a circuit connected between the first voltage line L1 and the neutral line N, and a circuit connected between the second voltage line L2 and the neutral line N. One end of the coil H of the acquisition unit 2 is connected to the first voltage line L1 or the second voltage line L2. Also, one end of the resistor R is connected to the neutral line N. As shown in FIG. When measuring the noise component of the line (first voltage line L1, neutral line N, and second voltage line L2), if the impedance of the line is low, the amount of noise will be small, and conversely, if the impedance is high, the amount of noise will be measured a lot.

Therefore, after the electrical signal on the line extending from the voltage line L1 to the neutral line N and the electrical signal on the line extending from the voltage line L2 to the neutral line N are passed through the low-pass filter circuit 21, the electrical signal and the , and the oscillation frequency signal of the oscillator 22 are frequency-coupled by the frequency coupler 23 to reduce the noise frequency to an intermediate frequency (“electrical signal”−“oscillation frequency signal” frequency) that is easy to analyze. Then, by inputting the electric signal whose intermediate frequency has been lowered to the band-pass filter circuit 24, an electric signal in a predetermined frequency band (for example, 1 Hz to 10 MHz, 10 MHz to 20 MHz) is acquired.

At this time, since the band-pass filter circuit 24 is configured as a constant impedance circuit terminated with a resistor (50Ω), the impedance of the connection abnormality determination device 1 as viewed from the line side is fixed, and the noise contained in the electrical signal is reduced. It is possible to reduce the fluctuation width of the component. The electrical signal that has passed through the bandpass filter circuit 24 is amplified to a predetermined amplitude by the amplifier 25 , converted to a digital signal by the A/D conversion circuit 26 , and then input to the analysis section 3 .

Next, with reference to FIGS. 3 to 6, a specific analysis operation example by the connection abnormality determination device 1 will be described.

FIG. 3 is a frequency spectrum calculated using an electric signal as the load P when the toaster oven is driven. FIG. 3(a) is a frequency spectrum for comparison when no connection abnormality occurs in the line, and FIG. 3(b) is a frequency spectrum when connection abnormality occurs in the line. FIG. 4 is a frequency spectrum calculated using an electric signal when a vacuum cleaner is driven as the load P, and (a) is a frequency spectrum for comparison when no connection abnormality occurs in the line. , (b) are frequency spectra when a connection abnormality occurs in the line. FIG. 5 shows the frequency spectrum calculated using an electric signal when the shaved ice machine is driven as the load P. (a) is the frequency spectrum for comparison when no connection abnormality occurs in the line. , (b) are frequency spectra when a connection abnormality occurs in the line.

(First operation example)
The acquisition unit 2 of the connection abnormality determination device 1 acquires the electric signal on the line from the first voltage line L1 to the neutral line N in the distribution board D and the electric signal from the second voltage line L2 to the neutral line N. Acquire electrical signals on the track. It is assumed that the power switch of the home appliance connected as the load P is turned on.

The analysis unit 3 of the connection abnormality determination device 1 performs frequency analysis on the electric signal acquired by the acquisition unit 2 by fast Fourier transform to calculate a frequency spectrum.

As shown in FIGS. 3(a), 4(a), and 5(a), the frequency spectrum for comparison when no connection abnormality occurs shows that the noise level (load (load noise caused by driving home appliances) is 50 dBμV or less. Although the noise level differs depending on the type of load, it is 50 dBμV or less for any load. On the other hand, as shown in FIGS. 3(b), 4(b), and 5(b), the frequency spectrum when the connection abnormality occurs shows noise in the frequency band of 10 MHz to 20 MHz. The levels fluctuate greatly. The "noise level" means the intensity of an electrical signal, and the value on the vertical axis in the figure is shown.

Therefore, the analysis unit 3 determines whether or not the noise level of the frequency spectrum exceeds the threshold value T1 of 50 dBμV in the frequency band of 10 MHz to 20 MHz. When the noise level of the frequency spectrum exceeds 50 dBμV in the frequency band of 10 MHz to 20 MHz, the analysis unit 3 determines that a connection abnormality has occurred in the line. When the analysis unit 3 determines that a connection abnormality has occurred, the analysis unit 3 outputs a cutoff signal and a notification signal. The breaker B is cut off based on the cut-off signal, and an alarm sound, for example, is output based on the notification signal.

(Second operation example)
As in the first operation example described above, the acquisition unit 2 acquires an electrical signal in the track. Further, the analysis unit 3 performs fast Fourier transform on the acquired electrical signal to calculate a frequency spectrum.

As shown in FIGS. 3(b), 4(b), and 5(b), the frequency spectrum when the connection abnormality occurs shows that the noise level is It fluctuates greatly at constant intervals (constant intervals within the range of 2 MHz to 3 MHz).

Specifically, in FIG. 3(b), the noise level of the frequency spectrum fluctuates significantly around 14 MHz, around 17 MHz, and around 20 MHz indicated by broken lines. The maximum fluctuation reaches 50 dBμV or more. These 14 MHz, 17 MHz, and 20 MHz are periodic at approximately 3 MHz intervals on the frequency axis.

Therefore, in the frequency band of 10 Hz to 20 MHz, the analysis unit 3 determines whether the noise level of the frequency spectrum exceeds the threshold T1 of 50 dBμV multiple times at regular intervals within the range of 2 MHz to 3 MHz, If the constant interval is exceeded multiple times, it is determined that a connection abnormality has occurred in the line. When the analysis unit 3 determines that a connection abnormality has occurred, the analysis unit 3 outputs a cutoff signal and a notification signal.

(Third operation example)
As in the first operation example described above, the acquisition unit 2 acquires an electrical signal in the track. Further, the analysis unit 3 performs fast Fourier transform on the acquired electrical signal to calculate a frequency spectrum.

As shown in FIGS. 3(b), 4(b) and 5(b), when a connection abnormality occurs, the level of the frequency spectrum in the frequency band of 1 Hz to 10 MHz and the level of 10 MHz to 20 MHz Comparing the level of the frequency spectrum in the frequency band, the level of the frequency spectrum in the frequency band of 10 MHz to 20 MHz is higher.

Therefore, in the calculated frequency spectrum, the analysis unit 3 determines that the level of the frequency spectrum in the frequency band of 10 MHz to 20 MHz is higher than the level of the frequency spectrum in the frequency band of 10 MHz or less, and the difference value between the maximum values of both frequency spectra exceeds the threshold value T6 of 10 dBμV, it is determined that a connection abnormality has occurred in the line. When the analysis unit 3 determines that a connection abnormality has occurred, the analysis unit 3 outputs a cutoff signal and a notification signal.

(Fourth operation example)
When the home appliance connected as the load P is in operation, noise with a frequency peculiar to the home appliance is generated. Therefore, the electrical signal obtained from the line may contain load noise generated from the home appliance. Therefore, in order to suppress the influence of noise generated from the load P (home appliance) when determining whether or not a connection abnormality has occurred in the line, the analysis unit 3 of the connection abnormality determination device 1 performs the following: perform such an analysis.

FIG. 6 is a diagram showing an example of daily power consumption of a four-person household. As shown in FIG. 6, power consumption is high around breakfast when people start their activities and around dinner when people return home from outside and have meals, and during the daytime when many people go out. , Electricity consumption tends to be low in the late-night hours when people go to bed.

Therefore, the analysis unit 3 receives the current consumption of the load P measured by the current measurement unit 4 from the current measurement unit 4, and the power consumption calculated from the current consumption is 0.4 KWh or less, which is the threshold value T2. In this case, analysis is performed to determine whether or not a connection abnormality has occurred in the track.

The method of determining whether or not a connection abnormality has occurred is the same as in the first to third operation examples.

(Fifth operation example)
Depending on the type of home appliance connected as the load P, for example, when a dielectric load or an inverter load is connected, these home appliances may generate high noise. Therefore, when these home appliances are driven, there is a high possibility that the noise generated from the home appliances will affect the determination of whether or not there is a connection abnormality in the line. Therefore, in order to prevent erroneous determination of occurrence of connection abnormality due to noise generated from these home appliances, the analysis unit 3 of the connection abnormality determination device 1 performs the following analysis.

The analysis unit 3 receives the consumption current of the load P measured by the current measurement unit 4 from the current measurement unit 4 and measures the state of the received current consumption. Also, the analysis unit 3 calculates a frequency spectrum based on the electrical signal acquired by the acquisition unit 2 . When it is determined that the noise level of the frequency spectrum has exceeded the threshold value T1 (50 dBμV), the analysis unit 3 determines whether the current consumption of the load P is on an upward trend. When it is determined that the current consumption of the load P is in an upward trend, the analysis unit 3 determines the timing when the noise level of the frequency spectrum exceeds the threshold value T1 (50 dBμV) and the timing of the upward trend of the current consumption of the load P. compare. If the timings of the two match, the analysis unit 3 determines that the increase in the noise level is due to the influence of the load P, and determines whether a connection abnormality has occurred in the line. No analysis is performed to determine

(Sixth example of operation)
The analysis unit 3 may perform the following analysis in order to suppress erroneous determination of occurrence of connection abnormality.

When determining that a connection abnormality has occurred in the line, the analysis unit 3 measures whether or not the consumption current of the load P measured by the current measurement unit 4 has increased at the time of determination. If the current consumption of the load P is increasing at the time of determination, the analysis unit 3 temporarily stores the determination as a "provisional determination" accompanying the increase in current consumption. After that, when it is determined that a connection abnormality has occurred in the line as the current consumption of the load P similarly increases, the determination frequency exceeds a predetermined threshold (for example, 5 times in 10 minutes). or not. Then, when the determination frequency exceeds a predetermined threshold value, the analysis unit 3 determines that these determinations were erroneous determinations due to an increase in current consumption of the load P. Therefore, the analysis unit 3 outputs a notification signal to change the threshold value T of the level of the frequency spectrum for determining that a connection abnormality has occurred in the line from the currently set threshold value T. FIG. In this case, based on the notification signal, for example, even if the speaker announces, "If this load (home appliance) is to be used for a long period of time, please operate the setting unit to increase the determination threshold." good.

As described above, according to the connection abnormality determination device 1, the electric signal in the line continuing from the first voltage line L1 to the neutral line N and the electric signal in the line continuing from the second voltage line L2 to the neutral line N are acquired, the frequency spectrum of these electrical signals is calculated, and whether or not a connection abnormality has occurred is determined based on the frequency spectrum. As a result, it becomes easier to distinguish environmental factors that have a low direct relationship to connection abnormalities that occur on the line (for example, load noise caused by loads (home appliances)) from electrical signals. Easier to catch features. This makes it possible to determine the connection abnormality with high accuracy.

Further, according to the connection abnormality determination device 1, an electric signal obtained from inside the line is frequency-analyzed by fast Fourier transform to calculate a frequency spectrum, and occurrence of connection abnormality is determined based on the calculated frequency spectrum. Therefore, it is possible to capture the noise characteristics in the initial stage of the connection abnormality, and to detect the connection abnormality at an earlier stage.

Further, according to the connection abnormality determination device 1, it is determined whether or not a connection abnormality has occurred in the line by using a periodic feature on the frequency axis that appears in the frequency spectrum. In this way, it is possible to accurately determine the occurrence of a connection abnormality by capturing the periodic feature on the frequency axis appearing in the frequency spectrum as a feature of the noise component caused by the connection abnormality.

By the way, when a judgment line is generated in a railway line, the generated spark noise is a sharp pulse wave with an extremely short noise width and rise time, although there are some differences depending on the type of home appliance connected as a load. There are many things. Such steep spark noise tends to appear in the harmonic band of the frequency spectrum. Therefore, it is presumed that the noise generated in the decision line has a high noise level in the harmonic region.

Therefore, the connection abnormality determination device 1 determines that a connection abnormality has occurred in the line when the level of the frequency spectrum exceeds the threshold T1 (50 dBμV) in the frequency spectrum within the range of 10 MHz to 20 MHz. did. This makes it possible to distinguish the influence of load noise on the load P, which is represented by home electric appliances, from the electric signal on the line, making it easier to grasp the characteristics of the noise component caused by the abnormal connection.

Furthermore, according to the connection abnormality determination device 1, in the frequency spectrum within the range of 10 MHz to 20 MHz, when the level of the frequency spectrum exceeds the threshold value T1 (50 dBμV) at a constant interval of 2 MHz to 3 MHz on the frequency axis Then, it is determined that a connection abnormality has occurred in the line. This makes it possible to distinguish the influence of noise from the load P, which is typified by home appliances, from the electric signal on the line, making it easier to understand the characteristics of the noise component caused by the connection abnormality.

Further, according to the connection abnormality determination device 1, the first frequency spectrum calculated from the electric signal in the line continuing from the first voltage line L1 to the neutral line N, and the second voltage line L2 to the neutral line N and the second frequency spectrum calculated from the electrical signal in the following line, and when the difference value between both frequency spectra exceeds the threshold value T3 of 20 (50-30) dBμV, it is determined that a connection abnormality has occurred. judge. In the case of a single-phase three-wire system, when connection abnormalities occur simultaneously in both the line extending from the first voltage line L1 to the neutral line N and the line extending from the second voltage line L2 to the neutral line N. are relatively few. For this reason, by making a judgment based on the difference between both frequency spectra as described above, environmental factors that have a low direct relationship to connection abnormalities that occur in the line (for example, load noise caused by loads (home appliances)) ) can be excluded from the electrical signal to determine whether there is an abnormality in the connection.

Further, according to the connection abnormality determination device 1, the frequency spectrum for comparison calculated based on the test signal acquired under the test environment in which no connection abnormality occurs in the line, and the neutral spectrum from the first voltage line L1 Compare the frequency spectrum calculated from the electrical signal in the line leading to the line N or the frequency spectrum calculated from the electrical signal in the line leading from the second voltage line L2 to the neutral line N, and both frequency spectra If the difference value exceeds 20 (50-30) dBμV, which is the threshold value T4, it is determined that a connection abnormality has occurred. In this way, by comparing the level of the frequency spectrum for comparison under the test environment where there is no connection abnormality in the line with the level of the frequency spectrum obtained during the actual operation, it is possible to detect the connection abnormality that occurs in the line. It is possible to determine whether or not there is a connection abnormality by excluding environmental factors (for example, load noise caused by a load (household appliance)) that have a low direct relationship with the electrical signal.

Further, according to the connection abnormality determination device 1, the level of the frequency spectrum in the frequency band of 10 MHz to 20 MHz is higher than the level of the frequency spectrum in the frequency band of 10 MHz or less, and the difference value between the two frequency spectrums is the threshold value T6. If it exceeds 10 dBμV, it is determined that a connection abnormality has occurred in the line. As a result, it is possible to distinguish the load noise of the load P, which is represented by a home electric appliance, from the electric signal on the line, making it easier to grasp the characteristics of the noise component caused by the connection abnormality.

Further, according to the connection abnormality determination device 1, when the power consumption calculated from the current consumption of the load P measured by the current measuring unit 4 is 0.4 KWh or less, which is the threshold value T2, the connection abnormality is detected in the line. is occurring. As a result, it is possible to reduce erroneous determination of the occurrence of a connection abnormality due to the influence of load noise of a load represented by home electric appliances and the like.

Further, according to the connection abnormality determination device 1, when the consumption current of the load P measured by the current measuring unit 4 is in an upward trend, it is not determined whether or not a connection abnormality has occurred in the line. As a result, it is possible to reduce erroneous determination of the occurrence of a connection abnormality due to the influence of load noise of a load represented by home electric appliances and the like.

It should be noted that the present invention is not limited to the above-described embodiments, and can be modified, improved, etc. as appropriate. In addition, the material, shape, size, numerical value, form, number, location, etc. of each component in the above-described embodiment are arbitrary and not limited as long as the present invention can be achieved.

For example, in the above embodiment, the case where the power distribution system is the single-phase three-wire system has been described, but the system is not limited to this system. For example, it may be a single-phase two-wire system or a three-phase three-wire system.

Further, in the above-described embodiment, the case where the connection abnormality determination device is incorporated in the distribution board has been described, but the present invention is not limited to this form. For example, the connection abnormality determination device may be a device installed outside the distribution board, or may be a device for inspection that is separated from the distribution board and is portable.

Further, in the above-described embodiment, a case where the connection abnormality determination device is incorporated in a distribution board installed in a general household has been described, but the present invention is not limited to this form. For example, the connection abnormality determination device may be installed in a distribution board installed in an office, company, factory, commercial facility, or the like.

1: connection abnormality determination device, 2: acquisition unit, 3: analysis unit, 4: current measurement unit, 5: setting unit, 21: low-pass filter circuit, 22: oscillator, 23: frequency coupling unit, 24: band-pass filter circuit , 25: amplifier, 26: A/D conversion circuit, 31: storage unit, 32: comparison unit, 33: determination unit, B: breaker (breaker), D: distribution board, L1: first voltage line, L2 : Second voltage line, N: Sex line, P: Load (household appliances, etc.)

Claims (9)

an acquisition unit that acquires an electrical signal on the track;
an analysis unit that calculates a frequency spectrum, which is data on the frequency axis, using the electrical signal, and performs analysis for determining whether or not a connection abnormality has occurred in the line based on the frequency spectrum;
comprising
Connection abnormality determination device. The analysis unit uses periodic features on the frequency axis that appear in the frequency spectrum to perform analysis for determining whether a connection abnormality has occurred in the line.
2. The connection abnormality determination device according to claim 1. The analysis unit performs analysis to determine whether a connection abnormality has occurred in the line based on the frequency spectrum of a frequency band of 10 MHz or higher.
3. The connection abnormality determination device according to claim 1 or 2. The analysis unit is
a storage unit that stores a frequency spectrum for comparison calculated based on a test signal acquired under a test environment in which no connection abnormality occurs in the line;
a comparison unit that compares the level of the frequency spectrum for comparison with the level of the frequency spectrum acquired by the acquisition unit;
a determination unit that determines whether or not a connection abnormality has occurred in the line based on the comparison result compared by the comparison unit;
having
The connection abnormality determination device according to any one of claims 1 to 3. The line has a first voltage line, a neutral line, and a second voltage line,
The analysis unit calculates a first frequency spectrum calculated from an electric signal between the first voltage line and the neutral line, and an electric signal between the second voltage line and the neutral line. comparing with the calculated second frequency spectrum, and determining that a connection abnormality has occurred in the line when the difference value as a result of the comparison exceeds a predetermined threshold;
The connection abnormality determination device according to any one of claims 1 to 4. moreover,
Equipped with an ammeter side part that measures the current consumption flowing on the line,
The analysis unit performs analysis to determine whether a connection abnormality has occurred in the line when the current consumption is equal to or less than a predetermined threshold.
The connection abnormality determination device according to any one of claims 1 to 5. moreover,
Equipped with an ammeter side part that measures the current consumption flowing on the line,
The analysis unit does not perform analysis for determining whether or not a connection abnormality has occurred in the line when the current consumption is in an upward trend.
The connection abnormality determination device according to any one of claims 1 to 6. The analysis unit is
The level of the frequency spectrum in the frequency band of 10 MHz or more is compared with the level of the frequency spectrum in the frequency band of 10 MHz or less, and if the difference value as a comparison result exceeds a predetermined threshold, there is an abnormality in the connection in the line. determine that has occurred,
The connection abnormality determination device according to any one of claims 1 to 7. an acquisition step of acquiring an electrical signal on the track;
an analysis step of calculating a frequency spectrum, which is data on the frequency axis, using the electrical signal, and performing analysis for determining whether or not a connection abnormality has occurred in the line based on the frequency spectrum;
having
Connection error determination method.

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