JP5914940B2 - Power shut-off device that can cut off power supply by sensing various arcs and overloads - Google Patents

Description

  The present invention relates to a power shut-off device, and more particularly to a power shut-off device capable of sensing various arcs and overloads that can occur in an electric line and shutting off power supply.

  When using each electrical device for home or industrial use, each abnormal situation caused by power line failure, grounding failure, load failure, user error, etc. is caused by short circuit, load overcurrent, Appears in various forms such as arc.

  Each power shut-off device, commonly referred to as an outlet (power outlet or socket) or multi-tap (multi-strip or power board), has no function to detect an abnormal situation, or even if it has such a function. Only a single function that cuts off the power supply when detecting a limited abnormal situation, for example, a leakage, is provided. In most buildings and houses, the earth leakage breaker installed on the power line can detect only the earth leakage. As described above, in each normal power shut-off device, there are many cases where it is not possible to detect an abnormal situation other than leakage, and there is a limit in preventing an electrical disaster.

  On the other hand, leakage is usually known as a cause of fire, but even if the leakage is likely to cause a waste of power or an electric shock accident, the possibility of a fire due to a leakage phenomenon is not great. Therefore, when the power shut-off device has only a function of detecting power leakage and shutting off the power, it is difficult to exert the effect of preventing fire.

  Rather, an electric fire occurs because the surrounding ignitable material is ignited by an arc spark due to an abnormality in an electric line or electrical equipment, or due to overheating caused by an overcurrent caused by a large amount of current flowing through the load. However, even if it is not an overcurrent of the load itself, when the terminal power source line connected to the load causes a short circuit, the line is often caused by overheating generated while acting as a kind of load having a small capacity.

  However, even if the arc is likely to cause a fire, the arc is a phenomenon that is easily observed when the power switch is turned on, plugged in, and unplugged. If the power is turned off unconditionally, the electrical equipment cannot be used normally. Therefore, it has a function to detect overload, and it is possible to distinguish between short arcs that can occur when the user turns on and off the power and continuous arcs that can cause a fire, and to shut off the power supply appropriately. A circuit and power shut-off device are required.

  The problem to be solved by the present invention is to provide a power shut-off device that can detect a continuous voltage-type fine arc and a large-current-type arc that can cause a fire and thereby shut off the power. It is in.

  Another problem to be solved by the present invention is that the power supply can be shut off not only when a fine arc and a large arc are generated, but also when the line is overheated due to overload or when an instantaneous voltage drop occurs due to a line abnormality. The object is to provide a power shut-off device.

  A power shutoff device according to one aspect of the present invention conducts a first switching element based on a voltage induced in a high frequency choke coil by a high frequency pulse current caused by a fine arc on a power line, and the first switching element is The second switching element conducts based on the fluctuation of the magnetic field that occurs in the coil inserted on the power line due to the large current arc on the power line and the fine arc detector that outputs the fine arc detection current while conducting A high-current arc detection unit that outputs a high-current arc detection current in between, and the delay capacitor is cumulatively charged with a predetermined time constant with the fine arc detection current or the high-current arc detection current, and the voltage of the delay capacitor is predetermined When the operating voltage is applied, a delay unit that outputs an arc detection signal when the level reaches the load level and the power line are electrically connected It may include a power cutoff unit that can cross, and a first switch for connecting the operating voltage to the power-off portion by the arc detection signal.

According to an embodiment, the micro arc detector includes an inductor inserted into the power line and forming a closed circuit with the high frequency choke coil, and the closed circuit is between the inductor and a terminal 1 of the high frequency choke coil. A second capacitor is connected in series, a first diode and a first capacitor are connected in series between the inductor and the terminal 2 of the high-frequency choke coil, and the terminal 2 of the high-frequency choke coil and the other A fourth diode is connected to the power line, and one end of the high-frequency choke coil is commonly connected to the control terminal of the first switching element and the second capacitor via a high-frequency rectifier diode. and the other end an input terminal of said first switching element, anode of the anode and the fourth diode of the first diode It may be linked to.

  According to one embodiment, the high current arc detector may be a current transformer when a magnetic field variation occurs in a coil inserted on the power line due to a current variation caused by a large current arc on the power line. Based on the induced voltage, the second switching element is turned on, and a high-current arc detection current can be output so as to flow through the second switching element while the second switching element is turned on. .

  According to an embodiment, the second switching element of the high-current arc detector is a reed switch, and a magnetic field generated in a coil inserted on the power line due to a current fluctuation caused by a large-current arc on the power line. While the reed switch is turned on due to fluctuations, a high-current arc detection current can be output to flow through the reed switch.

  According to an embodiment, the delay unit includes a delay resistor that discharges the charge charged in the delay capacitor by at least a part of the fine arc detection current and the large current arc detection current, and cumulatively charges the delay capacitor. A constant voltage element that conducts when the applied voltage reaches a predetermined level, and a third switching element that conducts when the constant voltage element is conducted and outputs the arc detection signal.

  According to an exemplary embodiment, the first switch may include a coupling element that electrically connects a power line and the power cutoff unit when the arc detection signal is received at a control terminal.

  According to one embodiment, the power shut-off unit is electrically insulated from the load side when the first switch is energized by the arc detection signal and the operating voltage is connected, and the arc detection signal disappears. It is possible to include a magnetic sustaining relay that is maintained in an electrically insulated state from the load side later.

  According to an embodiment, the magnetic sustaining relay includes a driving coil that is magnetized when the operating voltage is connected by energization of the first switch or a voltage is applied from a power line, and the magnetization of the driving coil. A three-terminal switch that can be switched from a position that magnetically connects the power line and the load side to a position that connects the power line and the drive coil.

  According to one embodiment, the power shut-off unit further includes a manual return switch inserted between the three-terminal switch and the drive coil, and when the manual return switch is opened during operation of the drive coil, The connection between the drive coil and the power line is cut off, and the three-terminal switch can be switched to a position that connects the power line and the load side.

  According to one embodiment, the power cut-off device outputs an overload detection signal when a DC voltage obtained by rectifying an AC voltage induced in a current transformer due to a current fluctuation due to an overload or a short circuit exceeds a predetermined level. A detection unit may be further included.

  The power cut-off device may further include a second switch that connects the operating voltage to the power cut-off unit according to the overload detection signal.

  According to one embodiment, the power shut-off device charges a rectified voltage in a capacitor connected between the power line and another power line, and provides the charged voltage as the operating voltage. May further include a portion.

  According to one embodiment, the power cut-off device may be configured such that the second reed switch is turned on by a magnetic field variation caused by a second coil inserted on the power line due to a current variation due to an overload or short circuit on the power line. And an overload detector that operates to connect the operating voltage to the power shut-off unit through the second reed switch.

  According to an embodiment, the power shut-off device further includes an operating voltage generator that charges a rectified voltage to a capacitor connected between two power lines, and provides the charged voltage as the operating voltage. it can.

  According to the power cut-off device of the present invention, sparks, arcs, overloads, voltage drops and overheats that can occur due to abnormal conditions such as electric wires and electric appliances, that is, poor connection, short circuit, overload, line overheating, line resistance change, etc. Disasters such as fires can be prevented by using a single power cut-off device.

  In particular, the power shutoff device can sense and cope with fine arcs and large current arcs that can occur inside the appliance.

  Furthermore, the power shut-off device does not require a ground line and can be easily applied to a single-phase AC power line, and can be used as an original power shut-off device, or can be used for existing household and industrial power shut-off devices. It can be used widely by additionally mounting.

1 is a block diagram illustrating a power shut-off device according to an embodiment of the present invention. 1 is a circuit diagram specifically illustrating a power shut-off device according to an embodiment of the present invention. It is the circuit diagram which illustrated the fine arc detection part of the power interruption device concerning one example of the present invention. It is the circuit diagram which illustrated the large current arc detection part of the power interruption device concerning one example of the present invention. It is the circuit diagram which illustrated the overload detection part of the power interruption device concerning one example of the present invention. It is the circuit diagram which illustrated the power cutoff part of the power cutoff device concerning one example of the present invention. It is the block diagram which illustrated the power shut-off device concerning other examples of the present invention. FIG. 6 is a circuit diagram specifically illustrating a power shut-off device according to another embodiment of the present invention. It is the circuit diagram which illustrated the large current arc detection part of the power interruption device concerning other examples of the present invention. It is the circuit diagram which illustrated the overload detection part and power interruption part of the power interruption device concerning other examples of the present invention.

  For each embodiment of the invention disclosed herein, the specific structural and functional description is merely illustrative for the purpose of describing the embodiment of the invention, and each embodiment of the invention is described. Can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals are used for the same constituent elements in the drawings, and a duplicate description of the same constituent elements is omitted.

  FIG. 1 is a block diagram illustrating a power shut-off device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram illustrating a power shut-off device according to an embodiment of the present invention.

  Referring to both FIG. 1 and FIG. 2, the power shut-off device 10 is usually installed on the wall of a building, for example, an input power terminal on the system power input side such as an input plug to be inserted into an outlet (power outlet). 18, for example, an output power supply terminal 19 such as a socket into which a plug of a load device is inserted, a fine arc detection unit 11 connected between the input power supply terminal 18 and the output power supply terminal 19, and a large current arc detection unit 12. In addition, the delay unit 13, the overload detection unit 14, the operating voltage generation unit 15, and the power cutoff unit 16 can be included, and a filtering unit 17 can be further included.

  First, each component will be briefly described as follows.

  The fine arc detector 11 delays the fine arc detection current corresponding to the strength of the fine arc detected each time a fine arc is detected using the voltage sensor 111 connected to the power line AC1, for example, the inductor T3. Applied to the unit 13.

  For example, when a voltage-type fine arc with little current is generated in the load device or the power supply line, the fine arc detection unit 11 is a voltage induced in the inductor T3 by a high-frequency pulse due to the fine arc propagated along the power supply line. Each time such a high-frequency pulse is detected, a fine arc detection current can be output to the delay unit 13 in the form of a pulse corresponding to the size and width of the detected high-frequency pulse.

  The large current arc detector 12 detects a large arc with a large current using a current sensor 121 using a coil that can induce a change in magnetic field by the large current arc, for example, a current transformer (CT). Each time, a large-current arc detection current corresponding to the strength of the detected large arc is applied to the delay unit 13.

  In addition, when a medium- and large-sized current type arc that can cause a fire even if generated once or twice occurs in the electric load device, the large-current arc detector 12 generates an induced AC voltage that appears on the power line due to the large-current arc and The high frequency pulse current can be detected based on the voltage induced in the current transformer CT. When the detected induced AC voltage and the high-frequency pulse current are equal to or larger than a predetermined size, the large current arc detecting unit 12 delays the large current arc detected current in the form of a pulse corresponding to the size and appearance time of the induced AC voltage. Apply to.

  The delay unit 13 can be implemented to include an integrator capable of accumulating a fine arc detection current or a high current arc detection current. Such an integrator can be implemented using a delay capacitor 131 and a delay resistor 132, for example. Can do. At this time, the delay capacitor 131 is charged by the fine arc detection current or the large current arc detection current, and the charge charged in the delay capacitor 131 can be discharged by the delay resistor 132 with a predetermined time constant.

  When a fine arc or a large current arc continuously or strongly occurs above a predetermined level and the delay capacitor 131 is charged above a predetermined voltage, the delay unit 13 generates an arc detection signal to Output to the first switch 161.

  For example, when the voltage type fine arc detected by the fine arc detector 11 is a continuous fine arc that may cause a fire, or the current type large arc detected by the high current arc detector 12 is When the arc is strong and persistent enough to induce a fire, the voltage at both ends of the delay capacitor 131 is set to a predetermined reference while charge is accumulated in the delay capacitor 131 by a continuous fine arc detection current or a large current arc detection current. Beyond the voltage level, this can generate an arc detection signal.

  On the other hand, if the detected fine arc or high-current arc is temporary and instantaneous, the electric charge accumulated in the delay capacitor 131 is discharged by the delay resistor 132, and the accumulated detection signal is determined as time elapses. Disappears with. Therefore, there is no risk of fire and the power supply is not shut off by a momentary arc.

  In the embodiment of FIG. 2, the delay unit 13 is designed to be shared, but according to the embodiment, the fine arc detection unit 11 and the large current arc detection unit 12 have separate delay circuits for each. May be designed. In this case, each delay circuit outputs a respective arc detection signal, and each arc detection signal can be connected to activate each switch in the power shut-off unit 16.

  Next, when the current suddenly increases or the voltage drops in the power line due to overload or short circuit, the overload detection unit 14 generates an overload detection signal and outputs it to the second switch 162 of the power cutoff unit 16. To do.

  For example, the overload detection unit 14 uses the current sensor 141, for example, the current transformer CT, to increase the alternating current rapidly due to an overload of the power line AC2, or to increase the alternating current due to an abnormal voltage drop. And an overload detection signal can be generated.

  According to the embodiment, the current sensor 121 of the large current arc detection unit 12 and the current sensor 141 of the overload detection unit 14 may be implemented by separate current transformer elements, and share one current transformer element. You can also.

  At this time, when the overload detection unit 14 senses a sudden increase in alternating current due to a voltage drop, the power cutoff unit 16 may not operate reliably because the voltage of the power line AC1 is low. The operating voltage generation unit 15 is charged when the second switch 162 is closed while the overload detection unit 14 outputs an overload detection signal together with a voltage drop in a state where the operation voltage generation unit 15 is normally charged with an appropriate operation voltage. The operating voltage can be provided to the relay 163 as a driving voltage necessary for the relay 163 to operate through the second switch 162.

  When the first switch 161 is closed by the arc detection signal or the second switch 162 is closed by the overload detection signal, the power cutoff unit 16 is connected to the output power terminal 19 by the relay 163. The power supply can be cut off by electrically disconnecting the path AC1.

  Depending on the embodiment, the first switch 161 or the second switch 162 may electrically connect the relay 163 to an AC power supply voltage or a DC operating voltage according to signals output from the delay unit 13 and the overload detection unit 14, Alternatively, it may be realized by an element such as a two-terminal switch, a photo-coupler, or a two-terminal relay that can cut off the electrical connection.

  On the other hand, the relay 163 of the power shut-off unit 16 includes a three-terminal switch 164 inserted in a conductive wire between the input power terminal 18 and the output power terminal 19, and the relay 163 is operated by the operations of the first and second switches 161 and 162. By driving the terminal switch 164 to be connected to one of the output power supply terminal 19 and the drive coil 165, the power supply to the load can be connected or cut off.

  For example, in the relay 163, when the second switch 162 is closed, the solenoid driving coil 165 is operated by the DC voltage charged in the operating voltage generation unit 15, and the connecting contact of the three-terminal switch 164 is operated by the solenoid driving coil 165. Moving from the terminal 2 to the terminal 3, the electrical connection between the input power supply terminal 18 and the output power supply terminal 19 is broken. At this time, the relay 163 can be realized not only as a relay element but also as an electric element such as a switch capable of performing an operation similar to the relay.

  Once the power cut-off unit 16 cuts off the power supply to the load, such a cut-off state can be continued as long as external power is supplied from the input power supply terminal 18 to the power cut-off unit 16. Furthermore, the power shut-off unit 16 may further include a manual return switch 166 that can manually resume power supply after the power is shut off due to an arc or overload. When the input power terminal 18 is disconnected from the wall outlet or the power supply to the power shut-off unit 16 is interrupted by operating the manual return switch 166, the power shut-off unit 16 is brought into a connected state before the shut-off operation. Return. When the manual return switch 166 is closed, the power cut-off state is maintained. When the manual return switch 166 is opened by the user, the relay 163 returns to the original connection state, whereby the power supply path is connected again, and the power supply is turned on. It can be supplied again.

  Hereinafter, the configuration and operation of the fine arc detector 11 will be described in more detail with reference to FIGS. 1, 2, and 3. FIG. 3 is a specific circuit diagram for the fine arc detector of the power shut-off device according to one embodiment of the present invention.

  Briefly, the fine arc detector 11 detects a high-frequency pulse due to a fine arc in the power line by the inductor T3 and the choke coil inductor L1 as the voltage sensor 111 connected between the power lines AC1 and AC2 on both sides. The first switching element Q1 is turned on by detecting such a high frequency pulse, and each fine arc detection current is output to the delay capacitor 131 having a predetermined time constant while the first switching element Q1 is turned on. Is charged cumulatively.

  Fine arcs can occur momentarily when plugging and unplugging, turning on and off the power switch, and fine sparks can occur continuously within a few seconds due to electrical load and line abnormalities. Should not be turned off or need to be turned off, but in the latter case there is a risk of fire and should be turned off.

  A fine arc generated in a load or a line is generally expressed in the form of a pulse current having a frequency component from several kHz to several GHz. Such a high-frequency pulse current is blocked by the filtering unit 17 while being propagated along the AC power supply line, and can be detected by the fine arc detection unit 11. The fine arc detector 11 outputs a fine arc detection current each time a high frequency pulse is detected.

  First, the filtering unit 17 inserted in the power supply line allows a low-frequency AC component of a normal commercial power supply to pass through, but prevents a high-frequency pulse due to a fine arc generated on the load side from propagating to the system side. The high frequency pulse by the fine arc can be assisted so that the operation of the fine arc detector 11 can be triggered.

  For this purpose, the filtering unit 17 may include two inductors T1 and T2 inserted in series in the AC power supply lines AC1 and AC2, respectively. The first inductor T1 and the second inductor T2 are high-frequency inductors, and can prevent the passage of high frequencies above a certain frequency.

  Specifically, the high frequency inductors T1 and T2 inserted at both ends of the AC power supply lines AC1 and AC2 on the input side or both ends of the load side transmit the high frequency pulse generated on the load side to the system (grid) on the input power supply terminal 18 side. In addition, it is possible to prevent the power shut-off device 10 from being damaged by preventing external high-frequency surge that can be propagated from the input power terminal 18 side.

  On the other hand, the filtering unit 17 is a kind of TNR (non-linear variable resistor (NVR)) connected in parallel to the power line on the input power terminal 18 side so as to absorb a surge transmitted from the outside. And TNR is a trade name).

  In a normal state, a high-frequency voltage that can trigger the operation of the fine arc detector 11 does not appear in the power line in which the filtering unit 17 is inserted. However, when a high-frequency pulse current is generated by a fine arc, the high-frequency pulse current cannot pass through the first and second inductors T1 and T2, and a high-frequency pulse voltage is induced in the third inductor T3.

  Since the high-frequency choke coil element has a high impedance with respect to the high-frequency AC signal, a voltage difference is generated between both ends when a high-frequency pulse voltage by an arc pulse is applied. In a normal state, the high frequency choke inductor L1 passes the low frequency AC voltage as it is, and no voltage difference is formed between both ends.

  The high frequency pulse voltage induced in the third inductor T3 is applied to the high frequency choke inductor L1 by a closed circuit formed by the first capacitor C1, the second capacitor C2, the first diode D1, and the high frequency choke inductor L1. While the high frequency choke inductor L1 is saturated by the high frequency pulse, a small voltage is induced at both ends (between the terminal 1 and the terminal 2).

  The high frequency choke inductor L1 is connected to the input terminal 2 of the first switching element Q1 by the second diode D2 whose terminal 1 is a high frequency rectifier diode, and the terminal 2 is connected to the input terminal 1 of the first switching element Q1. The Therefore, the voltage induced across the high-frequency choke inductor L1 forms a voltage difference between the input terminal 1 and the input terminal 2 on both sides of the first switching element Q1 while being rectified by the second diode D2. The first switching element Q1 is made conductive.

  When the first switching element Q1 is turned on, a current flows from the terminal 3 to the terminal 1. However, when the fine arc disappears, the voltage induced in the high frequency choke inductor L1 also disappears, and the first switching element Q1 is turned off. Since the current path between the terminal 3 and the terminal 1 is closed by the activation, the fine arc detection current flowing in the delay capacitor C4 also disappears.

  Thus, every time a fine arc is generated, the fine arc detection unit 11 and the delay unit 13 cause the third diode D3, the fourth resistor R4, the delay capacitors 131 and C4, the sixth diode D6, A path through which a fine arc detection current can flow through the fifth resistor R5 to the power supply line AC2 through the terminals 3 and 1 of the first switching element Q1 and the fourth diode D4 is temporarily formed.

  The fine arc detection current is generated in the form of a pulse by temporary conduction between the terminal 1 and the terminal 3 of the first switching element Q1 every time a fine arc is generated.

  On the other hand, the first LED LED1 is a signal lamp that informs the power shut-off device 10 that power is being applied. The first resistor R1 is for discharging the voltage applied to the second capacitor C2 when normal power is supplied. The first LED R1 is driven by a fine current flowing through the first resistor R1 to emit light. By doing so, it can be displayed that power is being applied.

  Due to temporary conduction between the terminal 1 and the terminal 3 of the first switching element Q1, the third diode D3, the second LED LED2, the third resistor R3, and the terminal 3 and the terminal of the first switching element Q1. 1. A current path connected to the first and fourth diodes D4 is also formed. This makes it possible to blink the second LED LED2 each time a fine arc is detected.

  On the other hand, when the high-frequency pulse current of the fine arc passes through the first and second diodes D1 and D2, the low-frequency band cannot pass through the first and second capacitors C1 and C2, and only the high-frequency band passes. However, when this pulse current passes through the first and second capacitors C1 and C2, only a high frequency component of several tens of MHz or more remains. As a result, a noise component of several kHz to several thousand kHz that can occur even during normal use of the load is eliminated from the arc detection, and the malfunction of the power shutoff device 10 can be minimized.

  The fine arc detection current generated by the fine arc detection unit 11 charges the delay capacitor 131 in the delay unit 13. In the delay unit 13, the voltage level of the delay capacitor 131 that is charged while each fine arc detection current by continuous arc is applied exceeds a predetermined reference voltage, for example, the breakdown voltage of the constant voltage element 133 such as the Zener diode ZD 1. Then, an arc detection signal that can make the first switch 161 conductive is generated.

  At this time, if a short arc occurs once or twice, the delay unit 13 cannot exceed the voltage level charged in the delay capacitor 131 beyond a predetermined reference voltage, for example, the breakdown voltage of the Zener diode ZD1. The arc detection signal cannot be generated.

  Further, when no further arc is generated, the delay capacitor 131 is discharged immediately with the lapse of time by the delay resistor 132 connected to the delay capacitor 131.

  In this way, the fine arc detector 11 accurately ignores continuous fine arcs that actually have a high risk of fire, while ignoring one or two instantaneous or artificial arcs that are not at great risk. Can be detected.

  Specifically, referring to FIG. 3, the fine arc detection current output from the first switching element Q1 of the fine arc detector 11 is substantially in the form of a fine arc pulse each time a fine arc pulse is detected. When generated with a similar waveform and applied to the delay unit 13, the fourth capacitor C4 in the delay unit 13 is charged. The charging speed of the fourth capacitor C4 can be adjusted by the current driving capability of the first switching element Q1, the value of the fourth resistor R4 or the fifth resistor R5.

  When there is no sufficiently continuous or dangerous arc pulse, the fine arc detection current does not flow any more while the first switching element Q1 is turned off, and the fourth capacitor C4 has been charged until then. The charge can be discharged by the variable delay resistor R6. The discharge speed of the fourth capacitor C4 can be adjusted by the variable resistance value of the variable delay resistor R6.

  When the arc detection current is continuously generated due to the presence of a sufficiently continuous arc pulse, a voltage sufficiently higher than a predetermined reference voltage is induced across the fourth capacitor C4, whereby an arc detection signal can be generated. .

  For example, when the arc detection current flows continuously, the fourth capacitor C4 is continuously charged, and the voltage across the fourth capacitor C4 is, for example, the breakdown voltage of the constant voltage diode ZD1 that can be implemented by a Zener diode. In this case, the AC power line AC1 is connected to the input terminal 2 of the third switching element Q3 while the constant voltage diode ZD1 is conducting, and the terminal 3 and the terminal are connected while the third switching element Q3 is conducting. A current path is formed between the current and 1. The current flowing from the terminal 3 to the terminal 1 of the third switching element Q3 can activate the first photocoupler PTC1 constituting the first switch 161 while serving as an arc detection signal.

  In addition, the fourth resistor R4, the sixth diode D6, and the fifth resistor R5 provide an appropriate voltage drop to the delay unit 13 in consideration of a high AC voltage level between the power supply lines, and reverse current flow. Is to appropriately determine the charging speed of the fourth capacitor C4.

  On the other hand, the second resistor R2 and the third capacitor C3 are circuit elements that are connected to each other in order to protect the first switching element Q1 and facilitate the conduction operation.

  Hereinafter, the configuration and operation of the high-current arc detector 12 will be described in more detail with reference to FIGS. 1, 2, and 4. FIG. 4 is a circuit diagram illustrating a high-current arc detector of the power shutoff device according to one embodiment of the present invention.

  A current sensor 121 that can detect a sudden change in alternating current is attached to the alternating current power supply line AC2. When a pulse current flows from the output power supply terminal 19 to the input power supply terminal 18 side while a large current arc is generated, for example, a predetermined voltage is induced across the current sensor 121 such as the current transformer CT. The voltage induced in the current transformer CT charges the detection capacitor C6 connected in parallel to both ends of the current transformer CT. When the charging voltage of the detection capacitor C6 is equal to or higher than a predetermined voltage level, a large current arc detection unit 12 can generate a high-current arc detection current.

  Specifically, referring to FIG. 4, first, the input terminal 1 of the second switching element Q2 is connected to the power line AC2 via the fifth diode D5, and the second switching element Q2 is connected. The potentials of the input terminals 1 and 2 are usually substantially the same or have a difference that does not cause conduction of the second switching element Q2.

  When a large current arc is generated, the voltage rectified by the tenth high-frequency diode D10 is induced in the both ends of the current transformer CT, and the seventh capacitor C7 is charged through the ninth resistor R9. While the charging voltage of C7 rises rapidly, the voltage charged in the seventh capacitor C7 begins to be discharged by the eighth resistor R8, and the potential of the input terminal 2 of the second switching element Q2 increases while the second switching element Q2 increases. Q2 conducts.

  Due to the conduction of the second switching element Q2, a third diode D3, a fourth resistor R4, a delay capacitor C4, a seventh diode D7, a seventh resistor R7, and a second switching are provided between the power supply lines AC1 and AC2. A current path connected to the terminals 3 and 1 of the element Q2 and the fifth diode D5 is formed, a large current arc detection current flows through this current path, and the delay capacitor C4 is charged.

  When the high-current arc disappears, the charge charged in the seventh capacitor C7 is immediately discharged, and the second switching element Q2 is deactivated again, so that the current path is closed.

  The voltage charged to the delay capacitor C4 during the formation of the current path does not reach the breakdown voltage of the Zener diode ZD1, or since there is no subsequent large current arc, the voltage charged to the delay capacitor C4 again becomes the Zener diode. If the breakdown voltage of the diode ZD1 is not reached, the third switching element Q3 does not conduct, and no arc detection signal is generated.

  Therefore, only when there is a harmful large current arc that may cause a fire, the third switching element Q3 is made to conduct by the delay unit 13 even when a single arc is generated, and an arc detection signal can be generated. Simple arcs that can occur during use, or slow arcs that can be caused by fluorescent lights and flashers can be ignored.

  On the other hand, the fifteenth resistor R15 and the fifth capacitor C5 are circuit elements connected to each other in order to protect the third switching element Q3 and facilitate the conduction operation.

  As described above, according to the operations of the fine arc detection unit 11 and the large current arc detection unit 12, the delay unit 13 includes the delay capacitor 131 that is charged with at least a part of the fine arc detection current and the large current arc detection current, and the delay capacitor. A constant voltage element 133 such as a Zener diode ZD1, for example, including a delay resistor 132 that discharges the charge charged in 131, and conducting when the voltage charged in the delay capacitor reaches a predetermined level; A third switching element Q3 that conducts when the constant voltage element 133 is conducted and outputs an arc detection signal can be included.

  Hereinafter, the configuration and operation of the overload detection unit 14 of the power shutoff device 10 will be described with reference to FIGS. 1, 2, and 5. FIG. 5 is a circuit diagram illustrating an overload detector of the power shutoff device according to an embodiment of the present invention.

  A current sensor 141 of the overload detection unit 14 that can detect a sudden change in the alternating current is attached to the alternating current power line AC2. Depending on the embodiment, the current sensor 141 may be mounted only for the overload detection unit 14, but the current sensor 121 of the large current arc detection unit 12 may be shared.

  When an overload or a short circuit occurs on the load side, a sudden current change occurs in the AC power supply line AC2, and since such a current change has a frequency band and energy different from that of the large current arc, the large current arc detection unit 12 is not detected.

  Due to such a current change, a predetermined AC voltage induced at both ends of the current sensor 141 such as the current transformer CT is converted into a predetermined DC voltage via the bridge diode D11 and the ninth diode C9. The converted DC voltage is passed through the tenth resistor R10 for current control and the eleventh resistor R11 for circuit protection to the second photocoupler PCT2 serving as the second switch 162 as an overload detection signal. Can be applied.

  The circuit protection Zener diode DS and the circuit protection capacitor CS are circuits for preparing for sudden voltage fluctuation that may occur in the current transformer CT.

  Hereinafter, the configuration and operation of the power shut-off unit 16 of the power shut-off device 10 will be described with reference to FIGS. 1, 2, and 6. FIG. 6 is a circuit diagram illustrating a power cutoff unit of a power cutoff device according to an embodiment of the present invention.

  The power cutoff unit 16 is activated by the first switch 161 that is activated by the arc detection signal output from the delay unit 13 and controls the relay 163, and the overload detection signal output from the overload detection unit 14. And a second switch 162 that controls the relay 163, and is driven when connected to the power supply voltage or the operating voltage of the operating voltage generation unit 15, and can include a relay 163 that switches the connection state of the power supply.

  Depending on the embodiment, the second switch 162 may also apply a power supply voltage to the relay 163. However, normally, when an overload or short circuit occurs, the impedance of the line itself acts as a load, and the line is suddenly overheated, which can easily lead to a fire. Switches are slow and have large errors.

  Therefore, in preparation for this, a circuit for preparing an operating voltage in advance is required. Such a circuit is the operating voltage generator 15. The operating voltage generator 15 normally stores an appropriate amount of electrical energy, and can drive the relay 163 by transmitting the stored electrical energy to the relay 163 when necessary.

  The operating voltage generation unit 15 is a DC voltage charging circuit including an eighth diode D8, a thirteenth resistor R13, an eighth capacitor C8, and a ninth diode D9 between two AC power supply lines AC1 and AC2. . The direct current rectified using the eighth diode D8 and the ninth diode D9 flows to the thirteenth resistor R13 and the eighth capacitor C8, and the eighth capacitor C8 is charged. Once the eighth capacitor C8 is fully charged, there is no later discharge path, so power consumption by the operating voltage generator 15 is not a major problem.

  When the arc detection signal is generated, the first switch 161 is closed and connected to the power supply line AC1, and the power supply voltage is applied from the power supply line AC1 to the solenoid drive coil 165 of the relay 163.

  When the overload detection signal is generated, the second switch 162 is closed and the drive coil 165 of the relay 163 is supplied with the power supply voltage, or preferably the operation voltage of the predetermined level charged in the operation voltage generator 15. Apply.

  On the other hand, the first and second switches 161 and 162 may be implemented by photocoupler switches PTC1 and PTC2 or ordinary relays. In this case, when the arc detection signal or the overload detection signal is activated, the light emitting diodes in the photocoupler switches PTC1 and PTC2 emit light, and the light receiving diode is energized while receiving light. When the first and second switches 161 and 162 are implemented as relays, energization is performed while the relays are closed when the fine arc detection signal or the overload detection signal is activated. Due to the characteristics of the photocoupler and the relay, both ends are electrically insulated, and no signal is transmitted in the opposite direction. Therefore, the generation or disappearance of each detection signal is not affected by the operation of the relay 163.

  The relay 163 maintains the switching conductor of the three-terminal switch 164 at the position of the terminal 2 in a normal state, but when the power supply voltage or the predetermined operating voltage is applied, the switching conductor is connected to the terminal 3 by the magnetic force generated by the magnetization of the drive coil 165. The three-terminal switch 164 can be switched by moving to the position. When the magnetic field of the drive coil 165 disappears, the switching conductor is restored to the position of the terminal 2 by a restoring force such as a spring.

  Such a relay 163 can be implemented as a magnetic sustaining relay. In this case, unlike a normal relay that returns to its original position when the operation signal disappears, the magnetic maintenance type relay is applied with an operation signal and switched to a specific terminal position, and then the operation signal disappears. The position of the switched terminal can be maintained by itself.

  For example, the three-terminal switch 164 inserted into the power supply line AC1 electrically connects the input power supply terminal 18 side and the output power supply terminal 19 side at the position of the terminal 2 in a normal state, but once the drive coil 165 forms a magnetic field. Then, the switching conductor is switched to the position of the terminal 3, and the input power supply terminal 11 side (or the operating voltage generation unit 15 side) and the drive coil 165 are electrically connected.

  The driving coil 165 of the relay 163 has a terminal 1 connected to the power supply line AC1 through the first switch 161, and is connected to the eighth capacitor C8 of the operating voltage generator 15 through the second switch 162. Is connected to the power line AC2.

  When the first switch 161 is turned on with the three-terminal switch 164 connected to the terminal 2, a current flows from the power line AC1 to the drive coil 165 through the first switch 161, and the drive coil 165 is magnetized. The three-terminal switch 164 inserted into AC1 is switched from terminal 2 to terminal 3 by magnetic force to cut off the power supply to the output power supply terminal 19 side. At the same time, the drive coil 165 is connected from the terminal 3 to the power supply line AC1, and the current flows. It continues to flow through the drive coil 165.

  Similarly, when the second switch 162 is turned on with the three-terminal switch 164 connected to the terminal 2, a current flows from the operating voltage generator 15 to the drive coil 165 through the second switch 162, and the drive coil 165 is magnetized. However, the three-terminal switch 164 inserted into the power supply line AC1 is switched from the terminal 2 to the terminal 3 by magnetic force to cut off the power supply to the output power supply terminal 19 side, and at the same time, the drive coil 165 from the terminal 3 to the power supply line AC1. As a result, the current continues to flow through the drive coil 165.

  As a result, once the magnetic sustaining relay 163 is driven, the arc detection signal or the overload detection signal may be deactivated later as long as the power source is connected to the input power supply terminal 18, that is, the first Even if the first switch 161 and the second switch 162 are opened again, the drive coil 165 of the magnetic sustaining relay 163 can cut off the power supply to the load side while continuously operating.

  The manual return switch 166 is, for example, a push button switch, which is normally closed, but is opened when the user presses the switch, and when the manual return switch 166 is opened, the magnetic sustaining relay 163 is driven. In this state, the electrical connection between the terminal 3 of the three-terminal switch 164 and the drive coil 165 is cut off. Therefore, when the manual return switch 166 is turned off, the current flowing through the drive coil 165 is cut off, the operation of the magnetic sustaining relay 163 is interrupted, and the magnetic force of the drive coil 165 switches to the terminal 3 3 The terminal switch 164 is switched from the terminal 3 to the terminal 2 again with the disappearance of the magnetic force, and the power supply to the load side can be resumed.

  FIG. 7 is a block diagram illustrating a power shut-off device according to another embodiment of the present invention, and FIG. 8 is a circuit diagram specifically illustrating a power shut-off device according to another embodiment of the present invention.

  Referring to FIGS. 7 and 8 together, the power shut-off device 70 includes an input power terminal 78 on the system power input side, an output power terminal 79, and a fine connected between the input power terminal 78 and the output power terminal 79. An arc detection unit 71, a large current arc detection unit 72, a delay unit 73, an overload detection unit 74, an operating voltage generation unit 75, and a power cutoff unit 76 can be included, and a filtering unit 77 is further included. be able to.

  7 is substantially similar to the power shut-off device 10 in FIG. 1, and the fine arc detecting unit 71, the delay unit 73, the operating voltage generating unit 75, and the power shut-off unit of the power shut-off device 70 in FIG. 76 is substantially the same as the fine arc detection unit 11, the delay unit 13, the operating voltage generation unit 15, and the power cut-off unit 16 of the power cut-off device 10 of FIG.

  The fine arc detector 71 delays the fine arc detection current corresponding to the strength of the fine arc detected each time a fine arc is detected using the voltage sensor 711 connected to the power line AC1, for example, the inductor T3. Applied to the unit 73.

  For example, when a voltage-type fine arc with little current is generated in the load device or the power supply line, the fine arc detection unit 71 generates a voltage induced in the inductor T3 by a high-frequency pulse due to the fine arc propagated along the power supply line. Each time such a high-frequency pulse is detected, a fine arc detection current can be output to the delay unit 73 in the form of a pulse corresponding to the size and width of the detected high-frequency pulse.

  The large current arc detector 72 can detect a large current arc by a reed relay 721 using a coil capable of inducing a change in magnetic field by the large current arc, and each time a large arc with a large current is detected, the large current arc is detected. A detection current is applied to the delay unit 73.

  The reed relay is an element in which a coil is wound around a reed switch including two magnetic alloys separated from each other in a vacuum tube. Reed switches are fast and very reliable.

  The operation of the reed relay 721 will be described. When an AC power supply current flows through the coil in a normal state, the two magnetic alloys forming the reed switch do not contact each other. However, when a large current arc flows through the coil, the magnetic field generated in the coil is reduced. While strengthening, the two magnetic alloys of the reed switch are magnetized with different polarities and eventually come into contact with each other, energizing the reed switch.

  The role of the reed relay 721 of the large current arc detector 72 can correspond to the roles of the current sensor 121 and the second switching element Q2 of the large current arc detector 12 of FIG. The large current arc detector 72 is similar to the large current arc detector 12 of FIG. 1 in that when there is a large current arc on the basis of a coil, a large change in the magnetic field occurs in the coil, and such a change in the magnetic field. Cause switching that forms a current path. The difference between the large current arc detector 72 and the large current arc detector 12 shown in FIG. 1 is that, in the large current arc detector 12 shown in FIG. On the other hand, the large-current arc detector 72 uses a magnetic material that is more strongly magnetized by a change in the magnetic field of the coil.

  When a large arc with a large current flows through the power supply line AC2, a strong magnetic field is generated while the large current arc flows through the coil of the reed relay 721, and the reed switch is energized. A large arc detection current can flow through the energized reed switch. The operation of the large current arc detector 72 will be described in detail with reference to FIG.

  The delay unit 73 can be implemented to include an integrator capable of accumulating the fine arc detection current, and is substantially the same as the delay unit 13 of FIG.

  In the embodiment of FIG. 8, the delay unit 73 is designed to be shared by the fine arc detection unit 71 and the large current arc detection unit 72, but the fine arc detection unit 71 and the large current arc detection unit 72 are designed according to the embodiment. May be designed to have a separate delay circuit for each of them, or only the fine arc detector 71 may be designed to have a delay circuit. In this case, each delay circuit outputs a respective arc detection signal, and each arc detection signal may be connected to activate each switch at the power shut-off unit 76.

  Next, when the current suddenly increases or the voltage drops due to an overload or short circuit, the electric energy accumulated in the operating voltage generation unit 75 while the overload detection unit 74 is energized is supplied to the power supply cutoff unit 76. The relay 763 is supplied to activate the relay 763.

  Similar to the large current arc detection unit 72, the overload detection unit 74 uses the second reed relay 741 to cause an alternating current to suddenly increase due to an overload of the power line AC2, or to cause an abnormal voltage drop. It can be energized by sensing the sudden increase in alternating current.

  When the rapidly increasing AC current flows through the power line AC2, a strong magnetic field is generated while a large current flows through the coil of the second reed relay 741, and the reed switch is energized. An overload detection signal can flow through a reed switch energized by the voltage charged in the operating voltage generator 75.

  Hereinafter, the detailed operation of the overload detection unit 74 will be described with reference to FIG.

  The operating voltage generator 75 normally stores an appropriate amount of electrical energy, and can drive the relay 763 by transmitting the stored electrical energy to the relay 763 when necessary.

  The operating voltage generation unit 75 is a DC voltage charging circuit including an eighth diode D8, a thirteenth resistor R13, an eighth capacitor C8, and a ninth diode D9 between two AC power supply lines AC1 and AC2. . The direct current rectified using the eighth diode D8 and the ninth diode D9 flows to the thirteenth resistor R13 and the eighth capacitor C8, and the eighth capacitor C8 is charged. Once the eighth capacitor C8 is fully charged, there is no later discharge path, so power consumption by the operating voltage generator 75 is not a major problem.

  When the first switch 761 is closed by the arc detection signal or the second reed relay 741 of the overload detection unit 74 is closed by the arc detection signal, the power cutoff unit 76 is connected to the output power terminal 79 by the relay 763. The power supply path AC1 is electrically disconnected, whereby the power supply can be cut off.

  Depending on the embodiment, the first switch 761 may electrically connect the relay 763 to an AC power supply voltage or a DC operating voltage according to a signal output from the delay unit 73 and the overload detection unit 74, or the electrical connection. For example, an element such as a two-terminal switch, a photocoupler, or a two-terminal relay can be realized.

  On the other hand, the relay 763 of the power shut-off unit 76 includes a three-terminal switch 764 inserted in a conductive wire between the input power terminal 78 and the output power terminal 79, and the operations of the first switch 761 and the second reed relay 741. By driving the three-terminal switch 764 to be connected to one of the output power supply terminal 79 and the drive coil 765, the power supply to the load can be connected or cut off.

  For example, in the relay 763, when the second reed relay 741 is closed, the solenoid driving coil 765 is operated by the DC voltage charged in the operating voltage generation unit 75, and the connecting contact of the three-terminal switch 764 is operated by the solenoid driving coil 765. Moves from the terminal 2 to the terminal 3, and the electrical connection between the input power supply terminal 78 and the output power supply terminal 79 is disconnected. At this time, the relay 763 can be embodied not only as a relay element but also as an electric element such as a switch capable of performing an operation similar to the relay.

  Once the power cut-off unit 76 cuts off the power supply to the load, such a cut-off state can be continued as long as external power is supplied from the input power supply terminal 78 to the power cut-off unit 76. Further, the power shut-off unit 76 may further include a manual return switch 766 that can manually resume power supply after the power is shut off due to an arc or overload. When the input power terminal 78 is separated from the wall outlet or the manual return switch 766 is turned off to interrupt the power supply to the relay 763 of the power shut-off unit 76, the power shut-off unit 76 is connected before the shut-off operation. Return to. When the manual return switch 766 is closed, the power-off state is maintained. When the manual return switch 766 is opened by the user, the solenoid driving coil 765 of the relay 763 loses the magnetic field, and the switching conductor of the three-terminal switch 764 is switched. By returning to the original connection state, that is, the terminal 2, the power supply path is connected again, and the power can be supplied again.

  FIG. 9 is a circuit diagram illustrating a high-current arc detector of a power shutoff device according to another embodiment of the present invention.

  Referring to FIGS. 7, 8, and 9, when a normal AC power supply current flows through the power supply line AC <b> 2 in a normal state, the coil of the first reed relay 721 generates a weak magnetic field, and the two magnets of the reed switch The alloy cannot be fully magnetized. Therefore, the reed switch maintains the opened state.

  When a large current arc occurs, first, a large current due to the arc flows through the coil of the first reed relay 721, and the strength of the magnetic field formed in the coil increases rapidly. Magnetize. When the strongly magnetized magnetic alloys come into contact with each other, the reed switch is closed, the power supply line AC1 to the third diode D3, the fourth resistor R4, the fourth capacitor C4 of the delay unit 73, and the first reed relay 721. A current path to the closed reed switch, the first switch resistor RS1, the fourth diode D4, and the power supply line AC2 is formed, and a large current arc detection current flows along this current path.

  When the voltage of the terminal 1 of the third switching element Q3 of the delay unit 73 becomes sufficiently lower than the voltage of the terminal 2 while the fourth capacitor C4 is charged by the large current arc detection current, the third switching element Q3 A current path is formed between the terminal 3 and the terminal 1 while conducting. The current flowing from the terminal 3 to the terminal 1 of the third switching element Q3 can activate the first photocoupler PTC1 constituting the first switch 761 while serving as an arc detection signal.

  On the other hand, the resistor connected in parallel to the coil by the first reed relay 721 functions as a current detour path when a large current arc is generated, and consumes the energy accumulated in the coil after the arc is detected to generate a magnetic field. It is possible to function as an element for reopening the reed switch by removing.

  FIG. 10 is a circuit diagram illustrating an overload detection unit 74 and a power cut-off unit 76 of a power cut-off device according to another embodiment of the present invention.

  Referring to FIGS. 7, 8, and 10, when a normal AC power supply current flows through the power supply line AC2 in a normal state, the coil of the second reed relay 741 generates a weak magnetic field, and the two magnetic alloys of the reed switch. Cannot be sufficiently magnetized. Therefore, the reed switch remains open.

  When the current suddenly increases due to overload, first, an excessive current flows through the coil of the second reed relay 741, and the two magnetic alloys of the reed switch are magnetized with different polarities while the strength of the magnetic field formed in the coil increases rapidly. Let When the strongly magnetized magnetic alloy comes into contact, the reed switch is closed, and the electric energy charged in the eighth capacitor C8 of the operating voltage generating unit 75 passes through the closed reed switch of the second reed relay 741 to turn off the power shutoff unit 76. The relay 763 is applied.

  Next, the configuration and operation of the power cutoff unit 76 of the power cutoff device 70 will be described.

  The power cutoff unit 76 is activated by the first switch 761 energized by the arc detection signal output from the delay unit 73 and the overload detection signal output from the overload detection unit 74, and generates a power supply voltage or an operating voltage. And a relay 763 that is driven when connected to the operating voltage of the unit 75 and switches a connection state of the power source.

  When an arc occurs, the first switch 761 is closed while an arc detection signal is generated, the power supply line AC1 and the relay 763 are connected, and the power supply voltage is applied from the power supply line AC1 to the solenoid drive coil 765 of the relay 763. .

  The first switch 761 can be implemented by a photocoupler switch PTC1 or a normal relay. In this case, when the arc detection signal is activated, the light emitting diode inside the photocoupler switch PTC1 emits light, and the light receiving diode is energized while receiving light. When the first switch 761 is implemented as a relay, the energization is performed while the relay is closed when the fine arc detection signal is activated. Due to the characteristics of the photocoupler and the relay, both ends are electrically insulated, and no signal is transmitted in the opposite direction. Therefore, the generation or disappearance of the detection signal is not affected by the operation of the relay 763.

  When an overload occurs, the second reed relay 741 of the overload detector 74 is closed, and a predetermined level of operating voltage charged by the operating voltage generator 75 is applied to the drive coil 765 of the relay 763. . While the electric power is normally supplied to the load, predetermined electric energy is stored in the operating voltage generation unit 75, but when the overload is detected and the overload detection unit 74 is energized, it is stored in the operating voltage generation unit 75. The electrical energy thus transmitted is transmitted to the solenoid drive coil 765 of the power cutoff unit 76. The relay 763 can be driven based on the transmitted electrical energy.

  The relay 763 keeps the switching conductor of the three-terminal switch 764 at the position of the terminal 2 in normal times, but when the power supply voltage or the predetermined operating voltage is applied, the switching conductor is moved to the position of the terminal 3 by the magnetic force by the magnetization of the driving coil 765. The three-terminal switch 764 can be switched. When the magnetic field of the drive coil 765 disappears, the switching conductor is restored to the position of the terminal 2 by a restoring force such as a spring.

  Similar to the relay 163 of FIG. 2, the relay 763 can be realized as a magnetic sustaining relay.

  As described above, the present invention has been described based on the limited embodiments and drawings. However, the present invention is not limited to the above-described embodiments, and has ordinary knowledge in the field to which the present invention belongs. Those skilled in the art can make various modifications and variations from such description. Therefore, the idea of the present invention should be grasped only by the claims described below, and any equivalent or equivalent modification can be said to belong to the category of the idea of the present invention. .

  The power cut-off device capable of cutting off the power supply by detecting various arcs and overloads according to the present invention is a spark, arc, overload, voltage drop, fire due to overheating, etc. that may occur due to abnormal conditions such as electric wires and electric appliances, etc. Disaster can be prevented, and by making fine arc sensing and large current arc sensing possible, it can be widely used in existing household and industrial power shut-off devices.

Claims (14)

The first switching element is turned on based on the voltage induced in the high-frequency choke coil by the high-frequency pulse current caused by the fine arc on the power line, and the fine arc detection current is output while the first switching element is turned on. An arc detector;
A high-current arc detection unit that outputs a high-current arc detection current while the second switching element is conducting based on a magnetic field variation caused in a coil inserted on the power supply line due to a high-current arc on the power supply line When,
A delay unit that cumulatively charges the delay capacitor with a predetermined time constant with the fine arc detection current or the large current arc detection current, and outputs an arc detection signal when the voltage of the delay capacitor reaches a predetermined level;
When an operating voltage is applied, a power cutoff unit that can electrically cut off the load side and the power line, and
And a first switch that couples the operating voltage to the power cut-off unit according to the arc detection signal. The fine arc detector is
Including an inductor inserted into the power line and forming a closed circuit with the high-frequency choke coil;
In the closed circuit, a second capacitor is connected in series between the inductor and the terminal 1 of the high-frequency choke coil, and a first diode and a first capacitor are connected between the inductor and the terminal 2 of the high-frequency choke coil. Are connected in series,
A fourth diode is connected between the terminal 2 of the high-frequency choke coil and another power line;
One end of the high-frequency choke coil is commonly connected to the control terminal of the first switching element and the second capacitor via a high-frequency rectifying diode, and the other end is an input terminal of the first switching element, The power shut-off device according to claim 1, wherein the power shut-off device is connected to an anode of the first diode and an anode of the fourth diode. The large current arc detector is
When a magnetic field change occurs in a coil inserted on the power supply line due to a current change caused by a large current arc on the power supply line, the second switching element is based on a voltage induced in the current transformer by the magnetic field change. 3. The power shutoff device according to claim 1, wherein a high-current arc detection current is output so as to flow through the second switching element while the second switching element is conductive. The second switching element of the large current arc detector is a reed switch,
A large current arc detection current flows through the reed switch while the reed switch is conducting due to a magnetic field variation caused by a coil inserted on the power line due to a current variation due to a large current arc on the power line. The power shut-off device according to any one of claims 1 to 3, which outputs the power. The delay unit is
A delay resistor for discharging the charge charged in the delay capacitor by at least a part of the fine arc detection current and the large current arc detection current;
A constant voltage element that conducts when the voltage charged to the delay capacitor reaches a predetermined level; and
5. The power shut-off device according to claim 1, further comprising a third switching element that conducts when the constant voltage element is conducted and outputs the arc detection signal. 6.   6. The first switch according to claim 1, wherein the first switch includes a coupling element that electrically connects a power line and the power shut-off unit when the arc detection signal is received at a control terminal. The power shut-off device described in 1. The power shut-off unit is
When the first switch is energized by the arc detection signal and the operating voltage is connected, it is electrically insulated from the load side, and is electrically insulated from the load side even after the arc detection signal disappears The power shut-off device according to claim 1, comprising a magnetic sustaining relay in which the current is maintained. The magnetic maintenance type relay is
A drive coil that is magnetized when the operating voltage is connected by energization of the first switch or when a voltage is applied from a power line;
The three-terminal switch which is switched from a position where the power line and the load side are magnetically coupled by magnetization of the drive coil to a position where the power line and the drive coil are coupled. Power shut-off device. The power shut-off unit is
A manual return switch inserted between the three-terminal switch and the drive coil;
When the manual return switch is opened during operation of the drive coil, the connection between the drive coil and the power line is cut off, and the three-terminal switch is in a position to connect the power line and the load side. The power shut-off device according to claim 8, which is switched.   10. An overload detection unit that outputs an overload detection signal when a DC voltage obtained by rectifying an AC voltage induced in a current transformer due to a current fluctuation due to an overload or a short circuit exceeds a predetermined level. The power shut-off device according to any one of the above.   11. The power shut-off device according to claim 10, further comprising a second switch that couples the operating voltage to the power shut-off unit according to the overload detection signal.   The operation voltage generator according to claim 11, further comprising an operation voltage generator configured to charge a rectified voltage to a capacitor connected between the power supply line and another power supply line, and to provide the charged voltage as the operation voltage. Power shut-off device.   While the second reed switch is turned on by a magnetic field variation caused by a second coil inserted on the power line due to a current variation due to overload or short circuit on the power line, the operating voltage is changed to the second reed switch. 10. The power shut-off device according to claim 1, further comprising an overload detection unit that operates to be connected to the power shut-off unit via a power source.   The power shut-off device according to claim 13, further comprising an operating voltage generator that charges a rectified voltage in a capacitor connected between two power lines, and provides the charged voltage as the operating voltage.

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