JP7621154B2 - Connection abnormality determination device and connection abnormality determination method - Google Patents

Description

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

Conventionally, there is a technology for detecting connection abnormalities such as partial disconnections and contact failures that occur in the conductors of a cable or in the lines of a circuit of a home appliance, for example, in Patent Document 1.

Patent document 1 discloses a device that includes a detection circuit that detects specific waveform distortions, an inrush voltage detection circuit that detects voltage changes due to load inrush currents from a rectified waveform, and a determination circuit that determines whether a cord short circuit has occurred.

JP 2015-089228 A

However, because electrical signals within a line are significantly affected by the connected equipment (load), conventional technology leaves room for improvement in the accuracy of determining connection anomalies within the line.

The present invention aims to provide a connection abnormality determination device and a connection abnormality determination method that can accurately determine connection abnormalities within a line.

In order to achieve the above object, the connection abnormality determination device of the present invention comprises:
An acquisition unit that acquires an electrical signal on the line;
an analysis unit that calculates a frequency spectrum, which is data on a frequency axis, using the electrical signal and performs an analysis to determine whether or not a connection abnormality has occurred in the line based on the frequency spectrum;
Equipped with
The analysis unit performs an analysis to determine whether or not a connection abnormality has occurred in the line, by utilizing periodic features on the frequency axis that appear in the frequency spectrum .

According to the above configuration, the electrical signal on the line is calculated into a frequency spectrum, and it is determined whether or not a connection abnormality has occurred based on the frequency spectrum. This makes it easier to distinguish the characteristics of the noise components caused by the connection abnormality from the effects of loads such as home appliances on the line, and makes it possible to accurately determine the connection abnormality.

The connection abnormality determination method of the present invention further comprises:
An acquisition step of acquiring an electrical signal on a line;
an analysis step of calculating a frequency spectrum, which is data on a frequency axis, using the electrical signal, and performing an analysis to determine whether or not a connection abnormality has occurred in the line based on the frequency spectrum;
having
In the analyzing step, an analysis is performed to determine whether or not a connection abnormality has occurred in the line by utilizing periodic features on the frequency axis that appear in the frequency spectrum .

According to the above method, the electrical signal on the line is calculated into a frequency spectrum, and whether or not a connection abnormality has occurred is determined based on the calculated frequency spectrum. This makes it easier to distinguish the effects of loads such as home appliances on the line and to capture the characteristics of the noise components caused by the connection abnormality, making it possible to accurately determine the connection abnormality.

The present invention provides a connection abnormality determination device and a connection abnormality determination method that can accurately determine connection abnormalities within a line.

1 is a block diagram showing a configuration of a connection abnormality determination device according to an embodiment of the present invention; 4 is a block diagram showing a configuration of an acquisition unit of the connection abnormality determination device; FIG. 1A is a diagram showing an example of a frequency spectrum when no connection abnormality occurs, and FIG. 1B is a diagram showing an example of a frequency spectrum when a connection abnormality occurs. 13A is a diagram showing another example of a frequency spectrum when no connection abnormality occurs, and FIG. 13B is a diagram showing another example of a frequency spectrum when a connection abnormality occurs. 13A is a diagram showing another example of a frequency spectrum when no connection abnormality occurs, and FIG. 13B is a diagram showing another example of a frequency spectrum when a connection abnormality occurs. FIG. 11 is a diagram illustrating an example of power consumption in one day.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a connection abnormality determination device and a connection abnormality determination method according to embodiments of the present invention will be described with reference to the drawings.
Fig. 1 is a block diagram showing the configuration of a connection abnormality determination device 1 according to 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 this embodiment, a single-phase three-wire system will be described as a power distribution system that supplies electricity to each home. The single-phase three-wire system has three core wires: a first voltage wire L1, a neutral wire N, and a second voltage wire L2. Commercial power with a power frequency of, for example, 50 Hz/60 Hz is supplied to a load P (such as a home appliance) via a line formed by the first voltage wire L1, the neutral wire N, and the second voltage wire L2. In this embodiment, the "line" is not limited to the line formed by the first voltage wire L1, the neutral wire N, and the second voltage wire L2, but also includes internal wiring (including electric wires and circuit patterns) of home appliances connected as a load.

The acquisition unit 2 is connected to the first voltage line L1, neutral line N, and second voltage line L2 in the distribution board D. The acquisition unit 2 acquires electrical signals on the lines (first voltage line L1, neutral line N, second voltage line L2, and load line). The acquisition unit 2 acquires, for example, an electrical signal on the line continuing from the first voltage line L1 to the neutral line N and an electrical signal on the line continuing from the second voltage line L2 to the neutral line N, and transmits these acquired electrical signals to the analysis unit 3. The "electrical signal" includes a load noise signal caused by the operation of a home appliance or the like, and a noise component signal caused by a connection abnormality in the line. The "connection abnormality in the line" includes a partial disconnection caused by repeated bending of the cable, a connection failure caused by aging of the line on the electric circuit, a contact failure between the outlet and the plug, and a contact failure of the electric wire in the breaker B of the distribution board D. The detailed configuration of the acquisition unit 2 will be described later with reference to FIG. 2.

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 (e.g., a SoC (System on a Chip)) equipped with one or more processors and memories, and an electronic circuit composed of active elements such as transistors and passive elements such as resistors. The analysis unit 3 includes a memory unit 31, a comparison unit 32, and a determination unit 33.

The analysis unit 3 performs frequency analysis of the electrical signal received from the acquisition unit 2 using a Fast Fourier Transform to calculate a frequency spectrum, which is data on the frequency axis. Based on the calculated frequency spectrum, the analysis unit 3 performs an analysis to determine whether or not a connection abnormality has occurred in the line (first voltage line L1 to neutral line N, second voltage line L2 to neutral line N). The determination of whether or not a connection abnormality has occurred in the line is performed while a load P (such as a home appliance) connected to the line is operating.

The memory unit 31 stores a comparison frequency spectrum that is calculated based on a test signal obtained in a test environment where no connection abnormalities occur within the line (first voltage line L1 to neutral line N or second voltage line L2 to neutral line N), i.e., a test signal that does not contain noise components caused by connection abnormalities.

The comparison unit 32, for example, compares the level of a first frequency spectrum calculated from an electrical signal on a line extending from the first voltage line L1 to the neutral line N and the level of a second frequency spectrum calculated from an electrical signal on a line extending from the second voltage line L2 to the neutral line N with a predetermined threshold value. The comparison unit 32 also compares, for example, the level of the first frequency spectrum with the level of the second frequency spectrum. The comparison unit 32 also compares, for example, the level of a comparison frequency spectrum stored in the memory unit 31 with the level of the first frequency spectrum or the second frequency spectrum. The "level" of a frequency spectrum means the intensity of an electrical signal.

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

The current measuring unit 4 is a measuring unit for measuring the current flowing on the line (first voltage line L1, second voltage line L2). The current flowing on the line refers to the current consumed by the load P (such as a home appliance).

The setting unit 5 is configured to be able to select and set in a stepwise manner a threshold value to be compared with the level of the frequency spectrum calculated from the electrical signal in the line. The setting unit 5 is also configured to be able to select and set in a stepwise manner a threshold value to be compared with the current consumption measured by the current measuring unit 4. The setting unit 5 is configured, for example, with a changeover switch that can change the threshold value.

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

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

In addition, for example, the analysis unit 3 performs an analysis to determine whether or not a connection abnormality has occurred in the line by utilizing periodic characteristics on the frequency axis due to noise components caused by a connection abnormality that appear in the frequency spectrum when a connection abnormality occurs.

The analysis unit 3 determines that a connection abnormality has occurred in the line when the level of the frequency spectrum exceeds a predetermined threshold T1 multiple times at regular intervals on the frequency axis within a predetermined frequency band (10 MHz or more). The characteristic of "exceeding a predetermined threshold at regular intervals" is one of the periodic characteristics mentioned above. The "regular intervals" 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 compares a first frequency spectrum calculated from an electrical signal on the line extending from the first voltage line L1 to the neutral line N with a second frequency spectrum calculated from an electrical signal on the line extending from the second voltage line L2 to the neutral line N, and determines that a connection abnormality has occurred if the difference between the first and second frequency spectra, which is the comparison result, exceeds a predetermined threshold value T3. The "predetermined threshold value T3" is, for example, 20 (50-30) dBμV.

The analysis unit 3 compares a comparison frequency spectrum calculated based on a test signal acquired in a test environment where no connection abnormality occurs in the line with a first frequency spectrum calculated from an electrical signal on the line extending from the first voltage line L1 to the neutral line N or a second frequency spectrum calculated from an electrical signal on the line extending from the second voltage line L2 to the neutral line N, and determines that a connection abnormality has occurred if the difference between the two frequency spectra resulting from the comparison exceeds a predetermined threshold value T4. The "predetermined threshold value T4" is, for example, 20 (50-30) dBμV.

If the difference value between the two frequency spectra resulting from the comparison does not exceed a predetermined threshold T4, the analysis unit 3 determines whether or not the difference value exceeds a predetermined threshold T5 (T5<T4). If the difference value exceeds the threshold T5, the analysis unit 3 measures the frequency at which a frequency spectrum exceeding the threshold T5 occurs. If the frequency at which the frequency occurs exceeds the predetermined frequency, the analysis unit 3 may determine that a connection abnormality has occurred.

The analysis unit 3 compares the maximum level of the frequency spectrum in a frequency band of 10 MHz or more with the maximum level of the frequency spectrum in a frequency band of 10 MHz or less in the frequency spectrum calculated from the electrical signal in the line, and if the difference value between the two frequency spectra resulting from the comparison exceeds a predetermined threshold value T6, it determines that a connection abnormality has occurred in the line. The "predetermined threshold value T6" is, for example, 10 dBμV.

For example, 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 determines whether or not to analyze a connection abnormality in the line depending on the current value of the current consumption. When the current consumption of the load P measured by the current measurement unit 4 is equal to or lower than a predetermined threshold, the analysis unit 3 performs an analysis to determine whether or not a connection abnormality has occurred in the line. When the current consumption of the load P measured by the current measurement unit 4 is on an upward trend, the analysis unit 3 does not perform an analysis to determine whether or not a connection abnormality has occurred in the line.

If the analysis unit 3 determines that a connection abnormality has occurred in the line as a result of the analysis, it sends a shutoff signal to the distribution board D to shut off the breaker (circuit breaker) B of the distribution board D, and outputs an alarm signal to the outside to notify the user that a connection abnormality has occurred.

Next, the configuration and functions of the acquisition unit 2 will be described with reference to FIG.
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, an amplifier 25, and an A/D conversion circuit 26.

The acquisition unit 2 has 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. In the acquisition unit 2, one end of the coil H 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. When measuring the noise components of the lines (the first voltage line L1, the neutral line N, and the second voltage line L2), if the impedance of the lines is low, the amount of noise measured is small, and conversely, if the impedance is high, the amount of noise measured is large.

The electrical signal on the line extending from voltage line L1 to neutral line N and the electrical signal on the line extending from voltage line L2 to neutral line N are passed through a low-pass filter circuit 21, and then the electrical signal and the oscillation frequency signal of the oscillator 22 are frequency-combined in a frequency combining unit 23 to reduce the noise frequency to an intermediate frequency (the frequency of the "electrical signal" - "oscillating frequency signal") that is easy to analyze. The electrical signal that has been reduced to the intermediate frequency is then input to a band-pass filter circuit 24 to obtain an electrical signal in a specified frequency band (for example, 1 Hz to 10 MHz, 10 MHz to 20 MHz).

At this time, since the bandpass filter circuit 24 is configured as a constant impedance circuit terminated with a resistor (50 Ω), the impedance of the connection abnormality determination device 1 as seen from the line side is fixed, and the fluctuation range of the noise components contained in the electrical signal can be reduced. 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 unit 3.

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

Figure 3 shows a frequency spectrum calculated using an electrical signal when a toaster oven is operated as the load P. Figure 3(a) shows a comparison frequency spectrum when no connection abnormality occurs in the line, and Figure 3(b) shows a frequency spectrum when a connection abnormality occurs in the line. Figure 4 shows a frequency spectrum calculated using an electrical signal when a vacuum cleaner is operated as the load P, where (a) shows a comparison frequency spectrum when no connection abnormality occurs in the line, and (b) shows a frequency spectrum when a connection abnormality occurs in the line. Figure 5 shows a frequency spectrum calculated using an electrical signal when a shaved ice machine is operated as the load P, where (a) shows a comparison frequency spectrum when no connection abnormality occurs in the line, and (b) shows a frequency spectrum when a connection abnormality occurs in the line.

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

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

As shown in Figures 3(a), 4(a), and 5(a), the comparison frequency spectrum when no connection abnormality occurs has a noise level (load noise caused by driving a home appliance as a load) of 50 dBμV or less in the frequency band from 10 MHz to 20 MHz. The noise level differs depending on the type of load, but it is 50 dBμV or less for all loads. In contrast, as shown in Figures 3(b), 4(b), and 5(b), the frequency spectrum when a connection abnormality occurs has a noise level that fluctuates greatly in the frequency band from 10 MHz to 20 MHz. Note that "noise level" refers to the strength of the electrical signal, and is shown as the value on the vertical axis in the figures.

The analysis unit 3 then determines whether 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. If 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. If the analysis unit 3 determines that a connection abnormality has occurred, it outputs a shutoff signal and a notification signal. Breaker B is shut off based on the shutoff signal, and, for example, an alarm sound is output based on the notification signal.

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

As shown in Figures 3(b), 4(b), and 5(b), when a connection abnormality occurs, the frequency spectrum shows that the noise level fluctuates significantly at regular intervals on the frequency axis (regular intervals within the range of 2 MHz to 3 MHz) in the frequency band of 10 MHz to 20 MHz.

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

The analysis unit 3 then 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 in the frequency band of 10 Hz to 20 MHz, and if it does exceed the threshold T1 multiple times at the regular intervals, it determines that a connection abnormality has occurred in the line. If the analysis unit 3 determines that a connection abnormality has occurred, it outputs a disconnection signal and a notification signal.

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

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

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

(Fourth operation example)
When a home appliance connected as the load P is in operation, noise with a frequency specific to the home appliance is generated. Therefore, the load noise generated from the home appliance may be included in the electrical signal acquired from the line. Therefore, 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 analysis in order to suppress the influence of the noise generated from the load P (home appliance).

Figure 6 shows an example of the daily power consumption of a four-person household. As shown in Figure 6, power consumption is high around breakfast time when people start to become active, and around dinner time when people return home from outside and eat, and power consumption tends to be low during the day when many people are out and about, and late at night when people go to bed.

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 if the power consumption calculated from the current consumption is equal to or less than the threshold value T2 of 0.4 kWh, performs an analysis to determine whether or not a connection abnormality has occurred in the line.

The method for determining whether a connection abnormality has occurred is the same as in the first to third operation examples above.

(Fifth operation example)
Depending on the type of home appliance connected as the load P, for example, when an inductive load or an inverter load is connected, high noise may be generated from the home appliance. Therefore, when the home appliance is driven, the noise generated from the home appliance is likely to affect the determination of whether or not a connection abnormality has occurred in the line. Therefore, in order to prevent erroneous determination of the occurrence of a connection abnormality due to the noise generated from the home appliance, the analysis unit 3 of the connection abnormality determination device 1 performs the following analysis.

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 measures the state of the received current consumption. The analysis unit 3 also calculates a frequency spectrum based on the electrical signal acquired by the acquisition unit 2. If the analysis unit 3 determines that the noise level of the frequency spectrum exceeds the threshold T1 (50 dBμV), it determines whether the current consumption of the load P is on an upward trend. If the analysis unit 3 determines that the current consumption of the load P is on an upward trend, it compares the timing at which the noise level of the frequency spectrum exceeded the threshold T1 (50 dBμV) with the timing of the upward trend of the current consumption of the load P. If the two timings match, the analysis unit 3 determines that the increase in the noise level is due to the influence of the load P, and does not perform an analysis to determine whether a connection abnormality has occurred in the line.

(Sixth operation example)
In order to prevent erroneous determination of the occurrence of a connection abnormality, the analysis unit 3 may perform the following analysis.

When the analysis unit 3 determines that a connection abnormality has occurred in the line, it measures whether or not the current consumption of the load P measured by the current measurement unit 4 has increased at the time of the determination. When the current consumption of the load P is increasing at the time of the determination, the analysis unit 3 temporarily stores the determination as a "provisional determination" associated with the increase in current consumption. After that, when it is determined that a connection abnormality has occurred in the line in association with the increase in the current consumption of the load P, it determines whether or not the determination frequency exceeds a predetermined threshold (for example, 5 times in 10 minutes). If the determination frequency exceeds the predetermined threshold, the analysis unit 3 determines that these determinations were erroneous determinations associated with the increase in the current consumption of the load P. Therefore, the analysis unit 3 outputs a notification signal to change the threshold T of the frequency spectrum level at which it is determined that a connection abnormality has occurred in the line from the currently set threshold T. In this case, for example, based on the notification signal, an announcement may be made from a speaker saying, "If you plan to continue using this load (home appliance) for a long period of time, please operate the setting unit to increase the determination threshold."

As described above, the connection abnormality determination device 1 acquires an electrical signal in the line extending from the first voltage line L1 to the neutral line N and an electrical signal in the line extending from the second voltage line L2 to the neutral line N, calculates a frequency spectrum for these electrical signals, and determines whether or not a connection abnormality has occurred based on the frequency spectrum. This makes it easier to distinguish environmental factors (e.g., load noise due to a load (home appliance)) that have a low direct relationship to a connection abnormality occurring in the line from the electrical signal, making it easier to capture the characteristics of the noise components caused by the connection abnormality. This makes it possible to accurately determine a connection abnormality.

In addition, the connection abnormality determination device 1 performs frequency analysis on electrical signals acquired from within the line using a fast Fourier transform to calculate a frequency spectrum, and determines the occurrence of a connection abnormality based on the calculated frequency spectrum. This makes it possible to capture noise characteristics in the early stages of a connection abnormality, making it possible to detect a connection abnormality at an earlier stage.

In addition, the connection abnormality determination device 1 uses periodic features on the frequency axis that appear in the frequency spectrum to determine whether or not a connection abnormality has occurred in the line. In this way, by capturing periodic features on the frequency axis that appear in the frequency spectrum as features of noise components caused by a connection abnormality, it becomes possible to accurately determine the occurrence of a connection abnormality.

When a judgment line occurs within a line, the spark noise that is generated is often a steep 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. Furthermore, this type of steep spark noise tends to appear in the harmonic band of the frequency spectrum. For this reason, it is assumed that the noise generated by the judgment line will have a high noise level in the harmonic region.

Therefore, in the present connection abnormality determination device 1, when the level of the frequency spectrum in the range of 10 MHz to 20 MHz exceeds the threshold value T1 (50 dBμV), it is determined that a connection abnormality has occurred in the line. This makes it possible to distinguish the effect of load noise of the load P, such as home appliances, from the electrical signal on the line, making it easier to grasp the characteristics of the noise components caused by the connection abnormality.

Furthermore, according to the connection abnormality determination device 1, when the level of a frequency spectrum in the range of 10 MHz to 20 MHz exceeds the threshold value T1 (50 dBμV) at a certain interval on the frequency axis, for example, from 2 MHz to 3 MHz, it is determined that a connection abnormality has occurred in the line. This makes it possible to distinguish the influence of noise from a load P, such as a home appliance, from the electrical signal on the line, making it easier to capture the characteristics of the noise components caused by the connection abnormality.

In addition, according to the connection abnormality determination device 1, a first frequency spectrum calculated from an electrical signal in a line extending from the first voltage line L1 to the neutral line N is compared with a second frequency spectrum calculated from an electrical signal in a line extending from the second voltage line L2 to the neutral line N, and if the difference between the two frequency spectra exceeds the threshold value T3 of 20 (50-30) dBμV, it is determined that a connection abnormality has occurred. In the case of a single-phase three-wire system, there are relatively few cases in which a connection abnormality occurs 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. Therefore, by making a determination based on the difference between the two frequency spectra as described above, it is possible to determine the presence or absence of a connection abnormality by excluding from the electrical signal environmental factors (e.g., load noise due to a load (household appliance)) that are less directly related to a connection abnormality occurring in the line.

In addition, according to the connection abnormality determination device 1, a comparison frequency spectrum calculated based on a test signal acquired in a test environment in which no connection abnormality occurs in the line is compared with a frequency spectrum calculated from an electrical signal in the line extending from the first voltage line L1 to the neutral line N or a frequency spectrum calculated from an electrical signal in the line extending from the second voltage line L2 to the neutral line N, and it is determined that a connection abnormality has occurred if the difference between the two frequency spectra exceeds the threshold value T4 of 20 (50-30) dBμV. In this way, by comparing the level of the comparison frequency spectrum in a test environment in which no connection abnormality occurs in the line with the level of the frequency spectrum acquired during actual operation, it is possible to determine the presence or absence of a connection abnormality by excluding from the electrical signal environmental factors (e.g., load noise due to a load (home appliance)) that are less directly related to the connection abnormality occurring in the line.

In addition, according to the connection abnormality determination device 1, if the level of the frequency spectrum in the 10 MHz to 20 MHz frequency band is greater than the level of the frequency spectrum in the frequency band below 10 MHz, and the difference between the two frequency spectra exceeds the threshold value T6 of 10 dBμV, it is determined that a connection abnormality has occurred in the line. This makes it possible to distinguish the load noise of the load P, such as a home appliance, from the electrical signal on the line, making it easier to capture the characteristics of the noise components caused by the connection abnormality.

In addition, 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 measurement unit 4 is equal to or less than the threshold value T2 of 0.4 KWh, it is determined whether or not a connection abnormality has occurred in the line. This makes it possible to reduce erroneous determinations of the occurrence of a connection abnormality caused by the influence of load noise from loads such as home appliances.

In addition, according to the connection abnormality determination device 1, if the current consumption of the load P measured by the current measurement unit 4 is on an upward trend, it is not determined whether or not a connection abnormality has occurred in the line. This makes it possible to reduce erroneous determinations of the occurrence of a connection abnormality caused by the influence of load noise from loads such as home appliances.

The present invention is not limited to the above-described embodiment, and can be modified, improved, etc. as appropriate. In addition, the material, shape, dimensions, values, form, number, location, etc. of each component in the above-described embodiment are arbitrary and not limited as long as they can achieve the present invention.

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

In the above embodiment, the connection abnormality determination device is described as being incorporated in the distribution board, but this is not limited to the above embodiment. For example, the connection abnormality determination device may be a device that is installed outside the distribution board, or may be a portable inspection device that is separate from the distribution board.

In the above embodiment, the connection abnormality determination device is described as being incorporated into a distribution board installed in a typical home, but the present invention is not limited to this form. For example, the connection abnormality determination device may be incorporated into a distribution board installed in an office, company, factory, commercial facility, etc.

1: Connection anomaly 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: Memory unit, 32: Comparison unit, 33: Determination unit, B: Breaker, D: Distribution board, L1: First voltage line, L2: Second voltage line, N: Power line, P: Load (household appliances, etc.)

Claims (8)

An acquisition unit that acquires an electrical signal on the line;
an analysis unit that calculates a frequency spectrum, which is data on a frequency axis, using the electrical signal and performs an analysis to determine whether or not a connection abnormality has occurred in the line based on the frequency spectrum;
Equipped with
the analysis unit performs an analysis to determine whether or not a connection anomaly has occurred in the line by utilizing a periodic feature on a frequency axis that appears in the frequency spectrum.
Connection abnormality determination device. The analysis unit performs an analysis to determine whether or not a connection abnormality has occurred in the line based on the frequency spectrum in a frequency band of 10 MHz or more.
The connection abnormality determination device according to claim 1 . The analysis unit is
a storage unit that stores a comparison frequency spectrum calculated based on a test signal acquired in a test environment in which no connection abnormality occurs in the line;
a comparison unit that compares a level of the comparison frequency spectrum with a 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 a comparison result obtained by the comparison unit;
having
The connection abnormality determination device according to claim 1 or 2 . The line includes a first voltage line, a neutral line, and a second voltage line;
the analysis unit compares a first frequency spectrum calculated from an electrical signal between the first voltage line and the neutral conductor with a second frequency spectrum calculated from an electrical signal between the second voltage line and the neutral conductor, and determines that a connection anomaly has occurred in the line when a difference value that is a comparison result exceeds a predetermined threshold value.
The connection abnormality determination device according to any one of claims 1 to 3 . moreover,
The device is provided with an ammeter section for measuring a current consumption flowing on a line,
the analysis unit performs an analysis to determine whether or not a connection abnormality has occurred in a line when the current consumption is equal to or less than a predetermined threshold value.
The connection abnormality determination device according to claim 1 . moreover,
The device is provided with an ammeter section for measuring a current consumption flowing on a line,
the analysis unit does not perform an analysis to determine whether or not a connection abnormality has occurred in a line when the consumption current is on an upward trend.
The connection abnormality determination device according to claim 1 . The analysis unit is
a level of the frequency spectrum in a frequency band of 10 MHz or more is compared with a level of the frequency spectrum in a frequency band of 10 MHz or less, and when a difference value that is a comparison result exceeds a predetermined threshold value, it is determined that a connection abnormality has occurred in the line.
The connection abnormality determination device according to claim 1 . An acquisition step of acquiring an electrical signal on a line;
an analysis step of calculating a frequency spectrum, which is data on a frequency axis, using the electrical signal, and performing an analysis to determine whether or not a connection abnormality has occurred in the line based on the frequency spectrum;
having
In the analyzing step, an analysis is performed to determine whether or not a connection abnormality has occurred in the line by utilizing periodic features on a frequency axis that appear in the frequency spectrum.
A method for determining a connection abnormality.

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