Wire break detection device, outlet device, and wire break detection method

Abstract

The present invention provides a circuit break detection device, an outlet device, and a circuit break detection method that can detect a circuit break even if a spark occurs once due to a circuit break. [Solution] The outlet device 1 includes a wire break detection device 2, a circuit breaker 3, an alarm circuit 4, and an electrical circuit L, and supplies AC current from a power source 1 to a load 5. The wire break detection device 2 includes a phase detection unit 11, a noise detection unit 12, and a determination unit 13. When the noise detection unit 12 detects noise caused by a break in the electrical circuit L, if the relationship between the duration of the noise and the voltage phase detected by the phase detection unit 11 satisfies predetermined conditions, it transmits a signal to the circuit breaker 3 and the alarm circuit 4, indicating that a break in the electrical circuit L has occurred.

Description

Technical Field

[0001] The present invention relates to an open - circuit detection device for detecting an open - circuit of an electric circuit, a socket device provided with the open - circuit detection device, and an open - circuit detection method using the open - circuit detection device.

Background Art

[0002] Conventionally, as described in Patent Document 1, there is known an open - circuit detection device that detects an open - circuit of an electric circuit by detecting the current waveform of an intermittent current from the spark generated when the electric circuit is open - circuited.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the above - mentioned conventional open - circuit detection method is configured to detect an open - circuit by detecting the current waveform of an intermittent current from continuous sparks, it is necessary to judge from at least two cycles of the intermittent current, and there is a problem that an open - circuit cannot be detected when a spark due to an open - circuit occurs only once.

[0005] Therefore, an object of the present invention is to provide an open - circuit detection device, a socket device, and an open - circuit detection method capable of detecting an open - circuit of an electric circuit even when a spark due to an open - circuit of the electric circuit occurs only once.

Means for Solving the Problems

[0006] To achieve the above objective, the invention described in claim 1 is a circuit break detection device for determining whether or not there is a break in a circuit through which alternating current supplied from an AC power source to a load flows, comprising: a phase detection unit for detecting the voltage phase with respect to the alternating current flowing through the circuit; a noise detection unit for detecting a noise voltage with a frequency higher than the alternating current flowing through the circuit; and a determination unit for determining whether or not there is a break in the circuit based on the data detected by the phase detection unit and the noise detection unit, wherein when the noise detection unit detects a noise voltage exceeding a predetermined noise threshold, the determination unit determines that a break has occurred in the circuit if the relationship between the voltage phase when the noise voltage exceeds the noise threshold and the duration for which the noise voltage exceeding the noise threshold was detected satisfies predetermined conditions. Furthermore, the invention described in claim 2 is characterized in that, in the invention described in claim 1, when the voltage phase when the noise voltage exceeds the noise threshold is θv[°] and the noise duration is tn[ms], the following relational expression (1) is satisfied, and a predetermined condition is met. -0.042 × θv + 6.1 <tn<-0.042×θv+7.3··(1)

[0007] Furthermore, the invention described in claim 3 is an outlet device comprising an outlet for plugging an electrical device, an electrical circuit through which alternating current supplied from an AC power source to a load flows, a circuit breaker for interrupting the circuit and / or an alarm circuit for issuing an alarm, and a wire break detection device described in claim 1 or 2, characterized in that the wire break detection device activates the circuit breaker and / or alarm circuit when it detects the occurrence of a wire break in the circuit. Furthermore, the invention described in claim 4 is a method for detecting a break in an electrical circuit through which alternating current supplied from an AC power source to a load flows, comprising: a phase detection unit for detecting the voltage phase with respect to the alternating current flowing through the circuit; a noise detection unit for detecting a noise voltage with a frequency higher than the alternating current flowing through the circuit; and a determination unit for determining whether or not a break has occurred in the circuit based on the data detected by the phase detection unit and the noise detection unit, wherein when the noise detection unit detects a noise voltage exceeding a predetermined noise threshold, the determination unit determines that a break has occurred in the circuit if the relationship between the voltage phase when the noise voltage exceeds the noise threshold and the duration for which the noise voltage exceeding the noise threshold was detected satisfies predetermined conditions. [Effects of the Invention]

[0008] According to the present invention, the device includes a phase detection unit that detects the voltage phase with respect to the alternating current flowing through the circuit, a noise detection unit that detects noise voltages with a frequency higher than the alternating current flowing through the circuit, and a determination unit that determines whether or not there is a break in the circuit based on the data detected by the phase detection unit and the noise detection unit. When a noise voltage exceeding a predetermined noise threshold is detected, the determination unit determines that a break in the circuit has occurred if the relationship between the duration for which the noise voltage exceeding the noise threshold was detected and the voltage phase when the noise voltage exceeded the noise threshold satisfies predetermined conditions.

[0009] Therefore, even if a spark occurs once due to a break in the electrical circuit, it is possible to detect the break in the circuit by measuring the noise caused by the spark. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram of an electrical outlet device according to the present invention. [Figure 2] This graph shows the correlation between voltage phase and noise duration. [Figure 3] This is a correlation table showing the predetermined conditions created from Figure 2. [Figure 4] A graph showing the noise voltage when an electrical circuit is broken. [Figure 5] A graph showing the noise voltage when plugging and unplugging a device. [Figure 6] A graph showing the voltage phase in Figure 4. [Figure 7] A graph showing the voltage phase in Figure 5. [Modes for carrying out the invention]

[0011] Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a block diagram showing the outlet device 100 according to the present invention.

[0012] As shown in Figure 1, the outlet device 100 includes a wire break detection device 2, a circuit breaker 3, an alarm circuit 4, and an electrical circuit L, and is a device that supplies alternating current from a power source 1 to a load 5 via the electrical circuit L. The outlet device 100 is connected to the load 5 via a plug (not shown). In this embodiment, the case in which the power source 1 is an AC power source with a frequency of 60 Hz will be used as an example for explanation. The wire break detection device 2 includes a phase detection unit 11, a noise detection unit 12, and a determination unit 13, and measures the alternating current flowing through the electrical circuit L. When it detects noise caused by sparks generated by a break in the electrical circuit L in the measured alternating current data, it determines that the electrical circuit L is broken and sends a signal to the circuit breaker circuit 3 and the alarm circuit 4. The circuit breaker circuit 3 receives the signal when the wire break detection device 2 detects a break in the electrical circuit L and opens the switching contact part 3a provided on the electrical circuit L to shut off the electrical circuit L. The alarm circuit 4 receives a signal from the wire break detection device 2 when it detects a break in the electrical circuit L, and uses an LED, speaker, or the like (not shown) to notify the system of the break in the electrical circuit L. The load 5 is an electrical appliance or other device that is connected to the outlet device 100 and receives AC power from the power supply 1.

[0013] The phase detection unit 11 is connected to each of the two circuits L and detects the phase of the voltage relative to the alternating current flowing through the circuits L. The noise detection unit 12 is a device for detecting noise caused by sparks generated by a break in the circuit L, and includes a current detection transformer 21, a high-pass filter 22, an operational amplifier 23, and a frequency conversion circuit 24. The determination unit 13 has a memory area and operators (not shown) and determines whether or not the circuit L is broken based on the data measured by the phase detection unit 11 and the noise detection unit 12. The determination unit 13 is also connected to the cutoff circuit 3 and the alarm circuit 4, and when it determines that the circuit L is broken, it sends a signal to the cutoff circuit 3 and the alarm circuit 4 to activate them.

[0014] The current detection transformer 21 is a high-frequency compatible transformer connected to one of the two circuits L, and measures the AC current over time. The high-pass filter 22 filters the AC current detected by the current detection transformer 21 by attenuating the frequency band below the cutoff frequency in order to extract high-frequency noise caused by a break in the circuit L. In this embodiment, the cutoff frequency is 500 kHz. The operational amplifier 23 amplifies the AC current filtered by the high-pass filter 22. The frequency conversion circuit 24 is composed of an RF detection path / CR circuit, etc., and converts the AC current amplified by the operational amplifier 23 into a DC voltage and outputs it as noise voltage data. It also measures the converted noise voltage data along with the time and stores it in the memory area of ​​the determination unit 13.

[0015] The following describes a method for detecting a break in the electrical circuit L using the break detection device 2. Figure 2 is a graph showing the correlation between voltage phase and noise duration measured experimentally. Figure 3 is a correlation table between voltage phase and noise duration created from Figure 2.

[0016] When the noise voltage detected by the noise detection unit 12 exceeds a predetermined noise threshold, the determination unit 13 acquires the voltage phase from the phase detection unit 11 when the noise voltage exceeds the noise threshold, and measures the duration of the noise voltage exceeding the noise threshold (hereinafter referred to as the noise duration). The noise threshold is determined based on the peak value of the noise voltage when noise due to disconnection occurs. Specifically, 30%, 50%, 70%, etc. of the peak value of the noise voltage are considered, and in the embodiment, the noise threshold is 0.3V. Then, when the voltage phase when the noise voltage exceeds the noise threshold and the noise duration satisfy a predetermined condition, the determination unit 13 determines that the circuit L is disconnected and transmits a signal to the cutoff circuit 3 and the alarm circuit 4. The predetermined condition is created from the correlation between the voltage phase and the noise duration measured in advance by experiments or the like. In the embodiment, the determination unit 13 determines that disconnection has occurred when the voltage phase θv [°] when the noise voltage exceeds the noise threshold and the noise duration tn [ms] satisfy the following relational expression (1). -0.042×θv+6.1<tn<-0.042×θv+7.3··(1) Expression (1) is created from the graph of the correlation between the voltage phase and the noise duration shown in FIG. 2 and the correlation table between the voltage phase and the noise duration shown in FIG. 3 measured by experiments. The straight lines a and b shown in FIG. 2 are for showing the range of Expression (1).

[0017] Subsequently, the operation of determining the presence or absence of disconnection of the circuit L will be described with reference to the table showing the predetermined conditions in FIG. 3, with specific examples. FIGS. 4 and 5 are graphs showing the noise voltage output by the noise detection unit 12 and the elapsed time. FIG. 4 is a graph showing the noise voltage when the circuit L is disconnected, and FIG. 5 is a graph showing the noise voltage when the plug is inserted and removed for comparison. FIG. 6 is a graph showing the voltage phase in FIG. 4, and FIG. 7 is a graph showing the voltage phase in FIG. 5. In FIGS. 6 and 7, the voltage phase does not represent one cycle as 0 to 360°, but is represented as 0 to 180° for the positive voltage cycle and 0 to 180° for the negative voltage cycle with the first zero crossing as 0°.

[0018] When the circuit L is disconnected and a spark occurs once, as shown in FIG. 4, a noise voltage that continuously exceeds the noise threshold of 0.3 V is output. Reading FIG. 4, the noise duration is about 3 ms (elapsed time 4.3 ms to 7.3 ms). Also, when referring to FIG. 6 at the time (elapsed time 4.3 ms) when the noise voltage exceeds the noise threshold, the voltage phase is about 90°. Therefore, for the voltage phase θv = 90 [°], the noise duration tn = 3 [ms]. Since this satisfies Equation (1), the determination unit 13 determines that a disconnection of the circuit L has occurred and transmits a signal to the cutoff circuit 3 and the alarm circuit 4. Thus, even if a spark occurs only once, it is possible to determine whether the cause of the noise is a disconnection based on the noise duration and the voltage phase when the noise voltage exceeds the noise threshold.

[0019] On the other hand, as shown in FIG. 5, when the plug is inserted and removed, a noise voltage is detected such that the noise voltage intermittently exceeds the noise threshold of 0.3 V. Reading FIG. 5, the noise duration is 1 ms or less. Also, when referring to FIG. 7 at the time (elapsed time 19.4 ms) when the noise voltage first exceeds the noise threshold, the voltage phase is about 90°. For the voltage phase θv = 90 [°], the noise duration tn ≤ 1 [ms], and since Equation (1) is not satisfied, the determination unit 13 determines that the circuit L is not disconnected.

[0020] According to the disconnection detection device 2 and the outlet device 100 having the disconnection detection device 2 described above, there are a phase detection unit 11 that detects the voltage phase with respect to the alternating current flowing through the circuit L, a noise detection unit 12 that detects a noise voltage having a higher frequency than the alternating current flowing through the circuit L, and a determination unit 13 that determines the presence or absence of a disconnection of the circuit L based on the data detected by the phase detection unit 11 and the noise detection unit 12. When a noise voltage exceeding a predetermined noise threshold is detected, the determination unit 13 determines that a disconnection of the circuit L has occurred when the relationship between the duration during which the noise voltage exceeding the noise threshold is detected and the voltage phase when the noise voltage exceeds the noise threshold satisfies a predetermined condition, and transmits a signal to the cutoff circuit 3 and the alarm circuit 4 to operate them.

[0021] Therefore, even if a spark occurs once due to a break in the electrical circuit L, it is possible to detect the break in the electrical circuit L by measuring the noise caused by the spark. Furthermore, if sparks occur two or more times, it is possible to detect the break in the electrical circuit L by performing the above-mentioned determination for each individual spark.

[0022] Furthermore, the wire break detection device, outlet device, and wire break detection method according to the present invention are not limited in any way to the embodiments described above, and the overall configuration of the wire break detection device, as well as the configuration of the noise detection unit, can be modified as needed.

[0023] For example, in the embodiment, the presence or absence of a break in the circuit L is determined based on the duration for which the noise voltage exceeds the noise threshold, but the determination may also be made based on the integrated value of the noise voltage. [Explanation of symbols]

[0024] 1. Power supply, 2. Disconnection detection device, 3. Cutoff circuit, 4. Alarm circuit, 5. Load, 11. Phase detection unit, 12. Noise detection unit, 13. Judgment unit, 21. Current detection transformer, 22. High-pass filter, 23. Operational amplifier, 24. Frequency conversion circuit, 100. Outlet device, L. Circuit.

Claims

1. A circuit break detection device that determines whether or not there is a break in an electrical circuit through which alternating current supplied from an AC power source to a load flows, The system includes a phase detection unit that detects the voltage phase relative to the alternating current flowing through the circuit, a noise detection unit that detects a noise voltage with a frequency higher than the alternating current flowing through the circuit, and a determination unit that determines whether or not there is a break in the circuit based on the data detected by the phase detection unit and the noise detection unit. A circuit break detection device characterized in that, when the noise detection unit detects a noise voltage that exceeds a predetermined noise threshold, the determination unit determines that a circuit break has occurred if the relationship between the voltage phase when the noise voltage exceeds the noise threshold and the duration for which the noise voltage exceeding the noise threshold was detected satisfies predetermined conditions.

2. The wire break detection device according to claim 1, characterized in that the predetermined conditions are met when the voltage phase when the noise voltage exceeds the noise threshold is θv [°] and the noise duration is tn [ms], and the following relational expression (1) is satisfied. -0.042×θv+6.1<tn<-0.042×θv+7.3...(1)

3. An outlet device comprising an outlet for plugging in an electrical device, an electrical circuit through which alternating current supplied from an AC power source to a load flows, a circuit breaker for interrupting the circuit and / or an alarm circuit for issuing an alarm, and a wire break detection device according to claim 1 or 2, An outlet device characterized in that, when the wire break detection device detects the occurrence of a wire break in the electrical circuit, it activates the circuit breaker circuit and / or the alarm circuit.

4. A method for detecting a break in an electrical circuit through which alternating current is supplied from an AC power source to a load, wherein the presence or absence of a break in the circuit is determined. The system includes a phase detection unit that detects the voltage phase relative to the alternating current flowing through the circuit, a noise detection unit that detects a noise voltage with a frequency higher than the alternating current flowing through the circuit, and a determination unit that determines whether or not there is a break in the circuit based on the data detected by the phase detection unit and the noise detection unit. A method for detecting a circuit break, characterized in that when the noise detection unit detects a noise voltage that exceeds a predetermined noise threshold, the determination unit determines that a circuit break has occurred if the relationship between the voltage phase when the noise voltage exceeds the noise threshold and the duration for which the noise voltage exceeding the noise threshold was detected satisfies a predetermined condition.

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