JP2007263663A - Electric leakage detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost leakage detector for identifying an electric leakage part in a single-phase two-wire or three-phase three-wire AC circuit. <P>SOLUTION: The electric leakage detector comprises a circular core surrounding the two or three wires of the single-phase two-wire type or the three-phase three-wire type, a coil winding wound around the core, and a fuse which is connected to the coil winding in series and which, when a difference current between the currents passing through the two or three wires occurs, is interrupted due to the fact that an induced current on the basis of the difference current passes through the coil winding. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a leakage detection device that detects a leakage in an AC circuit that constitutes, for example, an electrical wiring.

  A single-phase two-wire or three-phase three-wire AC circuit for supplying an AC current from a power source to a load is configured to include two or three AC wires connecting the power source and the load. is there. For example, electrical wiring in a building is configured by a combination of such a plurality of AC electric circuits. There is known a leakage detecting device for detecting a leakage when any of a plurality of loads in the electrical wiring has a leakage. Here, as a specific example, a so-called clamp-type ammeter is cited (for example, see Patent Document 1).

  As illustrated in FIG. 5, the clamp-type ammeter 910 includes a clamp unit 911 including a current transformer (CT) for detecting an alternating current, and a main body 912 that performs digital signal processing on the value of the detected alternating current, for example. It is a well-known ammeter comprised by providing. This figure is a block diagram showing an installation example of a leakage detection device in electrical wiring. In the illustration of the figure, the electrical wiring includes two AC electric wires 92 and 93 for supplying an AC current from an AC power source 91. The electrical wiring branches from the AC wires 92 and 93, and is connected to the load 94a. The two AC wires 92a and 93a (AC circuit 95a) are connected to the load 94b, and the two AC wires 92b are connected to the load 94b. , 93b (AC electric circuit 95b), two AC electric wires 92c, 93c (AC electric circuit 95c) connected to the load 94c, and the like. For example, in order to detect the presence or absence of electric leakage from the load 94a, the clamp-type ammeter 910 is installed such that the clamp portion 911 surrounds the two AC electric wires 92a and 93a.

  When there is no leakage in the load 94a, the magnetic fluxes formed in the inside of the clamp part 911 by the alternating currents that pass through the clamp part 911 in opposite directions through the two AC wires 92a and 93a cancel each other and become substantially zero. . On the other hand, when there is a leakage in the load 94a, this leakage causes the balance between the alternating currents flowing through the two alternating current wires 92a and 93a to be lost, and a differential current is generated. Since the differential current passing through the clamp portion 911 is an alternating current that changes with time, the clamp-type ammeter 910 can detect the differential current through a change in magnetic flux formed inside the clamp portion 911. The same applies to the load 94b and the load 94c illustrated in FIG. 5, and when there is a leakage, the clamp-type ammeter 910 installed in the vicinity of each detects a differential current. From the above, if there is a clamp-type ammeter 910 that has detected the differential current, it can be specified that leakage has occurred in the loads 94a, 94b, 94c in the vicinity of the clamp-type ammeter 910. Alternatively, in FIG. 5, it can be specified that a leakage has occurred in the AC wire and the load downstream of the clamp-type ammeter 910.

By the way, the electrical wiring may present a state of poor insulation temporarily and irregularly. As a result, electrical leakage due to poor insulation also occurs temporarily and irregularly. In such a case, for example, even if the operator temporarily installs the clamp-type ammeter 910 described above on the electrical wiring, the above-described differential current may not be detected with good timing. For this reason, the operator may overlook the electric leakage itself. Therefore, as illustrated in FIG. 5, normally, a number of clamp-type ammeters 910 corresponding to the number of loads 94a, 94b, 94c are installed in the electrical wiring, and the value of the differential current is recorded for each. A recording device 920 is connected to perform recording for a predetermined period. Thereby, even if the electric leakage in the electrical wiring is temporary and irregular, the value of the differential current generated by the electric leakage at a certain time in the predetermined period is recorded. Note that the clamp-type ammeter 910 itself may be equipped with the function of the recording device 920.
JP-A-64-38662

  However, in order to prepare the recording apparatus 920 described above for each of the plurality of clamp-type ammeters 910, there is a problem that the equipment cost increases. Even when data of differential current values is recorded while controlling a plurality of clamp-type ammeters 910 with one recording device 920, a cable is laid between each clamp-type ammeter 910 and the recording device 920. There is a problem that the maintenance cost increases. Furthermore, even when the clamp-type ammeter 910 is equipped with the function of the recording device 920, the clamp-type ammeter 910 itself is more expensive, and there is a possibility that the equipment cost will increase accordingly.

  In addition, the longer the recording period (predetermined period described above), the longer the period for occupying the clamp-type ammeter 910 and the recording device 920 for one electrical wiring. It becomes work.

  The present invention has been made in view of such problems, and an object thereof is to provide a low-cost leakage detection device for specifying a leakage point in a single-phase two-wire or three-phase three-wire AC circuit. There is to do.

  The invention for solving the above problems includes an annular core surrounding two or three electric wires of a single-phase two-wire system or a three-phase three-wire system, a coil winding wound around the core, and the coil A fuse that is connected in series to a winding and that is cut off when an induced current based on the differential current flows through the coil winding when a differential current of the current flowing through the two or three wires is generated. This is a leakage detection device.

  According to this leakage detection device, if a leakage current that generates a differential current that changes with time, for example, occurs in the core installation position in a single-phase two-wire or three-phase three-wire AC circuit, the differential current is This brings about a change in magnetic flux. Due to the change in the magnetic flux in the core, an induced current flows through the coil winding wound around the core. If the fuse is selected in advance so that it operates (breaks) with this induced current, whether or not a leakage has occurred from the location of the core in the AC circuit and its downstream based on whether or not this fuse is blocked Can be determined. Here, for example, the longer the distance from the power source in the AC circuit, the lower the downstream is defined. As described above, even if the leakage in the AC circuit is temporary and irregular, the leakage detection device of the present invention may be installed at a predetermined position and left for a predetermined period. For example, an operator finds a leakage detection device in which a fuse has been cut off due to a leakage occurring within a predetermined period, and easily identifies a leakage point in an AC circuit based on a predetermined position where the leakage detection device is installed. Can be identified. In addition, according to the leakage detection device of the present invention, the differential current itself generated due to the leakage plays the role of the power source of the device, so that the cost is low because there is no power supply. From the above, a low-cost leakage detection device for specifying a leakage point in a single-phase two-wire or three-phase three-wire AC circuit is provided.

In addition, the leakage detecting device further includes a capacitor that is connected in series to the coil winding to form a resonance circuit, and the inductance and resistance values of the coil winding and the capacitance value of the capacitor are commercial values. The Q value for the power supply frequency may be a value that is a predetermined value or more.
According to this leakage detection device, for example, the shape and size of the core, the length and number of turns of the coil winding, etc. (both of the coil winding) Can contribute to inductance and resistance) and the capacitance of the capacitor. Thereby, for example, even if a current having a frequency other than the commercial power supply frequency is generated in the vicinity of the core from the outside, the ratio of the current contributing to the induced current can be reduced. As a result, it is possible to reduce so-called false detection such that the fuse of the leakage detection device is interrupted by an external noise current.

In the leakage detection device, the core preferably includes a pair of rotating arms that open and close around a support shaft so as to surround the two or three electric wires.
According to this leakage detection device, the core can be easily installed at any position as long as there is enough space to open the core by installing two or three wires by opening and closing the rotating arm. it can. Thereby, the work efficiency of earth-leakage detection improves.

In the leakage detection device, it is preferable that the fuse has a characteristic of being interrupted when the induced current exceeds a predetermined value.
According to this leakage detection device, for example, by selecting a fuse that is cut off when the value of the differential current reaches a predetermined value, for example, an expensive circuit that digitally processes the value of the differential current is used. Without this, the detection sensitivity of leakage can be adjusted at low cost.

Moreover, it is preferable that the leakage detection device further includes a fuse case for attaching the fuse to a predetermined position of the core.
According to this leakage detection device, for example, when a fuse can be electrically and mechanically attached to and detached from the fuse case, even if the fuse is cut off as a result of a certain leakage detection, the cut-off fuse is replaced with a new fuse. By exchanging, the leakage detection device can be applied again to other leakage detection. Further, only the fuse can be selected as the predetermined one while the core and the coil winding remain the same, depending on the degree of leakage detected.

In the leakage detection device, the fuse case is preferably made of an insulating material.
According to this leakage detection device, since the fuse case made of an insulating material can be directly fixed to the core, the coil winding or the like, the leakage detection device itself is miniaturized, thereby improving the work efficiency of leakage detection.

  A low-cost leakage detection device for specifying a leakage point in a single-phase two-wire or three-phase three-wire AC circuit is provided.

=== Electrical leakage detector ===
<<< Without frequency selection function >>>
With reference to FIG. 1, a leakage detection device 10 of the present embodiment will be described. FIG. 1A is a plan view showing a configuration example of a leakage detection device 10 of the present embodiment. FIG.1 (b) is a circuit diagram which shows an example of the equivalent circuit of the leak detection apparatus 10 of this Embodiment.

  As illustrated in FIG. 1A, the leakage detection device 10 of the present embodiment includes an annular core 100, an electric wire 110 wound around the core 100, and the electric wire 110 connected in series. And a fuse portion 120 forming a closed circuit.

  The core 100 has a ring shape that can surround the AC electric circuit so as to intersect with the AC circuit. For example, the core 100 includes a pair of permeable arms 100 a and 100 b that are semicircular. In the pair of rotating arms 100a and 100b in which both ends are in contact with each other, the other ends are connected to each other via a support shaft 100c so that the one ends can be separated from each other. Thereby, the pair of rotating arms 100a and 100b can be opened and closed with the support shaft 100c as a hinge.

  The electric wire 110 is, for example, an insulation-coated copper wire wound around the rotating arms 100a and 100b, and is an electric wire (coil winding) wound around the rotating arms 100a and 100b in a predetermined direction. 110b, an electric wire 110a forming one end of the electric wire 110b and connected to one side of the fuse portion 120, and an electric wire 110c forming the other end of the electric wire 110b and connected to the other side of the fuse portion 120. It is configured. In the present embodiment, the electric wire 110b is wound from the separable end portion of the rotating arm 100a to the separable end portion of the rotating arm 100b via the support shaft 100c. The electric wire 110a electrically connects the electric wire 110b at the end of the rotating arm 100a to the fuse portion 120 near the support shaft 100c. The electric wire 110c electrically connects the electric wire 110b at the end of the rotating arm 100b to the fuse portion 120 near the support shaft 100c.

  The electric wire 110b may be fixed to the core 100 with, for example, resin, or the electric wire 110a and the electric wire 110c may be fixed to a plurality of locations on the outer circumference of the core 100 by predetermined fixing means, for example. Good. However, in the electric wire 110b, the winding is loose in the vicinity of the support shaft 100c so that the rotating arms 100a and 100b are not subjected to tensile stress when the rotation arms 100a and 100b are opened through the support shaft 100c. Then, it is assumed that the fixing process is not performed.

  In the illustration of FIG. 1A, the fuse portion 120 is attached on a rotating arm 100a (or the rotating arm 100b) around which the electric wire 110b is wound, and is connected to the electric wire 110b via the electric wires 110a and 110c. They are connected in series. In addition to the fuse 120b, the fuse portion 120 of the present embodiment includes, for example, a pair of terminals 120a for the fuse 120b and an insulating fuse case 120c that accommodates the pair of terminals 120a. The The electric wires 110a and 110c described above are connected to the pair of terminals 120a, respectively. The fuse 120b is selected in advance according to the value of the induced current that is expected to flow through the electric wire 110 due to leakage in the AC circuit.

  In the present embodiment, as an example of attaching the fuse portion 120 to the core 100, the electric wire 110b is wound and the adhesive is raised on the uneven core 100 surface, and the bottom of the fuse case 120c is attached to the raised adhesive. It is glued.

  In the present embodiment, the fuse 120b can be electrically and mechanically attached to and detached from the pair of terminals 120a. As a result, even if the fuse 120b is cut off as a result of a certain leakage detection, the leakage detection device 10 can be applied again to other leakage detection by replacing the blocked fuse 120b with a new fuse 120b. . Further, depending on the degree of electric leakage to be detected, only the fuse 120b can be selected as a predetermined one while the core 100 and the electric wire 110 remain the same.

  Further, although the above-described fuse case 120c has an insulating property (insulating material), it is not limited to this. For example, if the surface of the core 100 around which the electric wire 110b is wound is covered with an insulating material, a fuse case 120c made of a conductive material such as metal may be directly attached thereto.

  As illustrated in FIG. 1B, the leakage detecting device 10 of the present embodiment is configured such that an inductance L, a resistor R, and a fuse 120b are connected in series to form a closed circuit. L corresponds mainly to the electric wire 110 (particularly, the electric wire 110b), and R corresponds to the electric wire 110, the terminal 120a, and the fuse 120b. At the time of leakage detection, an induced current flows in the closed circuit by a magnetic flux that changes with time acting on L due to a differential current described later.

<<< With frequency selection function >>>
With reference to FIG. 2, the leakage detection device 10 ′ of the present embodiment will be described. FIG. 2A is a plan view showing a configuration example of the leakage detection apparatus 10 ′ of the present embodiment. FIG. 2B is a circuit diagram showing an example of an equivalent circuit of the leakage detection device 10 ′ of the present embodiment. In FIG. 2, members that are substantially the same as the members illustrated in FIG.

  As illustrated in FIG. 2A, the leakage detection device 10 ′ of the present embodiment includes an annular core 100, an electric wire 110 wound around the core 100, a fuse portion 120, an electric wire 110 and a fuse. And a capacitor 130 that is connected in series with the unit 120 to form a closed circuit. Hereinafter, description of the same components (core 100 and fuse portion 120) as those illustrated in FIG.

  The configuration of the electric wire 110 differs from the configuration of the electric wire 110 illustrated in FIG. 1A only in the connection of the electric wire 110a and the electric wire 110d, and is otherwise the same. The electric wire 110a forms one end of the electric wire 110b and is connected to one side of the capacitor 130. Further, the electric wire 110d connects the other side of the capacitor 130 and one side of the fuse portion 120.

  As illustrated in FIG. 2B, the leakage detecting device 10 ′ of the present embodiment includes an inductance L, a capacitance C, a resistor R, and a fuse 120b connected in series to form a closed circuit. Is. L corresponds mainly to the electric wire 110 (particularly the electric wire 110b), C corresponds mainly to the capacitor 130, and R corresponds to the electric wire 110, the terminal 120a, and the fuse 120b. It is. At the time of leakage detection, an induced current flows through the closed circuit by a magnetic flux that changes over time due to a differential current described later.

  When the differential current is an alternating current having a commercial power supply frequency, the induced current is also an alternating current having the same frequency as the differential current, and the closed circuit is a so-called LC circuit (resonant circuit). On the other hand, the Q value with respect to the oscillation frequency of the LC circuit is determined by the values of L, C, and R. In the present embodiment, the shape and size of the core 100, and the length and the number of turns of the electric wire 110b (so that the Q value of the leakage detection device 10 ′ for a predetermined frequency (for example, 60 Hz) is equal to or greater than the predetermined value). As described above, it is assumed that the contribution of L and R), the capacitance of the capacitor 130 (contribution to C), and the like are set in advance. As a result, even if a differential current having a frequency other than 60 Hz, for example, is generated, this is regarded as noise for the leakage detection device 10 '. That is, the leakage detection device 10 'according to the present embodiment has a frequency selection function.

  The predetermined value of the Q value will be specifically described. For example, a current having a frequency other than 60 Hz may be generated from an external noise source having a frequency higher or lower than 60 Hz to form an alternating current inside the core 100 ring. The predetermined value of Q means a Q value such that an induced current having a frequency f different from 60 Hz does not reach a current value enough to cut off the fuse 120b. In the leakage detection device 10 ′ of the present embodiment, the Q value for 60 Hz is set to a predetermined value or more, thereby reducing the contribution of the induced current of the frequency f generated by the alternating current of the frequency f different from 60 Hz. It is possible to prevent the fuse 120b from being interrupted by such external noise.

=== Leakage detection method ===
A leakage detection method using the leakage detection devices 10 and 10 'having the above-described configuration will be described with reference to FIGS. FIG. 3 is a block diagram showing an installation example of the leakage detection devices 10 and 10 ′ of the present embodiment in the electrical wiring. FIG. 4 is a flowchart illustrating an example of an operation procedure of the leakage detection device 10 or 10 ′ according to the present embodiment.

  The electrical wiring illustrated in FIG. 3 includes two AC wires 2 and 3 for supplying an AC current from the AC power source 1. In addition, this electric wiring is branched from the AC electric wires 2 and 3 respectively, and is connected to the load 4a, two AC electric wires 2a and 3a (AC electric circuit 5a), and the two AC electric wires 2b connected to the load 4b. 3b (AC electric circuit 5b), two AC electric wires 2c, 3c (AC electric circuit 5c) connected to the load 4c, and the like.

  In addition, AC electric circuit 5a, 5b, 5c of this Embodiment consists of two AC electric wires of a single-phase two-wire system, respectively. However, the present invention is not limited to this, and the two AC wires may be any two AC wires used as a single phase of, for example, three three-phase three-wire AC wires. Good. In this case, in FIG. 3, a third AC wire that is not used is omitted for convenience of illustration. Alternatively, as will be described later, the leakage detection device 10, 10 ′ of the present embodiment can also be applied to an AC electric circuit composed of, for example, three AC wires of a three-phase three-wire system.

In the leakage detection method of the present embodiment, first, it is detected which of the plurality of loads 4a, 4b, 4c in the electrical wiring is leaking.
In order to detect the presence or absence of a leakage from the load 4a, the leakage detection device 10, 10 ′ of the present embodiment is installed such that the core 100 surrounds the AC circuit 5a in the vicinity of the load 4a.

  In the illustration of FIG. 3, only one leakage detection device 10, 10 ′ is installed in the AC circuit 5 a, but the present invention is not limited to this. For example, in the AC circuit 5 a, the AC wire 2 A plurality of leakage detecting devices 10, 10 ′ may be installed from 3 to the load 4a. In general, in the AC circuit 5a, a leakage occurring on the downstream side with the installation position of the leakage detection device 10, 10 'as a boundary is detected by the leakage detection device 10, 10'. Here, in the AC electric circuit 5a, the longer the distance from the AC power source 1, the more downstream it is defined. Therefore, by installing the leakage detection devices 10 and 10 'at a plurality of positions in the AC circuit 5a, not only the presence or absence of leakage of the load 4a is determined, but also in which range the leakage points in the AC wires 2a and 3a are located. Can be narrowed down.

  Similarly, in order to detect the presence / absence of leakage from the loads 4b and 4c, the leakage detection devices 10 and 10 ′ of the present embodiment have the core 100 surrounding the AC circuits 5b and 5c near the loads 4b and 4c, respectively. Installed.

  An operator leaves the leakage detection devices 10 and 10 'in the AC electric circuits 5a, 5b, and 5c near the loads 4a, 4b, and 4c to be subjected to a leakage check and leaves them for a predetermined period. In the present embodiment, it is assumed that the loads 4a, 4b, and 4c are operating during the predetermined period. As described above, since electric leakage may occur irregularly, the predetermined period is set to a period sufficient to cover this irregularity. Hereinafter, for the sake of explanation, it is assumed that, for example, a leakage due to an insulation failure occurs in the load 4a.

As illustrated in FIG. 4, when leakage occurs in the load 4a (S100: YES), a differential current is generated in the AC circuit 5a connected to the load 4a (S101).
The AC differential current is a current that changes with time. Therefore, the magnetic flux inside the core 100 of the leakage detection device 10, 10 ′ installed in the AC circuit 5a also changes with time (S102).
When the magnetic flux inside the core 100 changes with time, an electromotive force is generated in the electric wire 110 wound around the core 100 based on the electromagnetic induction phenomenon, and as a result, an induced current flows (S103).
When an induced current 110 of a predetermined value or more flows through the electric wire 110, the fuse 120b in the fuse portion 120 is cut off (S104).

  The operator checks the fuse part 120 of each leakage detection device 10, 10 'after the predetermined period described above, and determines whether or not the fuse 120b is cut off. Whether or not the fuse 120b is cut off may be determined by the presence or absence of conduction between the two terminals 120a of the fuse 120b. If the fuse 120b is sealed in a glass tube, it is determined visually. Also good. If a leakage occurs in the load 4a, the operator finds that the fuse 120b of the leakage detection device 10, 10 'installed in the AC circuit 5a is cut off.

=== Low-Cost Earth Leakage Detection Device for Identifying the Location of Electric Leakage ===
According to the leakage detection devices 10 and 10 ′ of the present embodiment, when a leakage that generates a differential current that changes with time occurs at the installation position of the core 100 in the AC circuits 5a, 5b, and 5c, the differential current Causes a change in magnetic flux inside the core 100. An induced current flows through the electric wire 110 wound around the core 100 due to a change in the magnetic flux inside the core 100. If the fuse 120b is preliminarily selected so as to operate (cut off) by this induced current, the installation position of the core 100 in the AC circuits 5a, 5b, and 5c and its position are determined based on whether or not the fuse 120b is cut off. It is possible to determine whether or not a leakage has occurred from the downstream. As described above, even if the leakage in the AC circuits 5a, 5b, and 5c is temporary and irregular, the leakage detectors 10 and 10 'of the present invention are installed at predetermined positions in the AC circuits 5a, 5b, and 5c. It can be left for a predetermined period. For example, the worker finds the leakage detection device 10 or 10 'in which the fuse 120b is cut off due to the leakage that has occurred within a predetermined period, and based on the predetermined position where the leakage detection device 10 or 10' is installed. , It is possible to easily identify the leakage point in the AC circuits 5a, 5b, and 5c.

  In addition, according to the leakage detection devices 10 and 10 ′ of the present embodiment, the differential current itself generated due to the leakage plays the role of the power source of the device, so that the cost is low because there is no power supply.

  Furthermore, according to the leakage detection device 10, 10 ′ of the present embodiment, for example, by selecting the fuse 120b that is cut off when the value of the differential current reaches a predetermined value, for example, the value of the differential current Without using an expensive circuit for processing a digital signal, the detection sensitivity of leakage can be adjusted at a low cost.

  From the above, it can be said that the leakage detection devices 10 and 10 ′ of the present embodiment are low-cost devices for specifying the leakage point in the AC circuits 5 a, 5 b, and 5 c.

  The above-described AC electric circuits 5a, 5b, and 5c are either two single-phase two-wire AC wires or two of three-phase three-wire AC wires used as a single phase. However, the present invention is not limited to this.

  The leakage detection devices 10 and 10 ′ of the present embodiment can be applied to, for example, an AC electric circuit including three AC wires of a three-phase three-wire system. In this case, the leakage detectors 10 and 10 'may be installed so that the core 100 surrounds the three AC lines. The three alternating currents flowing through the three-phase three-wire AC wires have a phase difference of 120 °. If there is no leakage in the load connected to the AC circuit, the three AC currents are kept in balance and the instantaneous value given by adding them is zero. Therefore, a differential current is generated between the three AC currents. do not do. Therefore, the fuse 120b of the leakage detection device 10, 10 'is not cut off. On the other hand, if there is a leakage in the load, the balance is broken and the instantaneous value is not zero, so that a differential current is generated between the three alternating currents. Therefore, the fuse 120b of the leakage detection device 10, 10 'is cut off.

=== Other Embodiments ===
The above-described embodiment is intended to facilitate understanding of the present invention, and is not intended to limit the present invention. The present invention is changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

  In the embodiment described above, the core 100 has a circular ring shape, but is not limited thereto. In short, a polygonal shape may be used as long as the AC electric paths 5a, 5b, and 5c can be enclosed inside the ring.

  In the above-described embodiment, the electric wire 110 is wound around the entire core 100, but the present invention is not limited to this. In short, as long as the electromotive force is generated by a change in the magnetic flux inside the core 100, the core 100 may be wound around a part of the core 100, for example.

  In the above-described embodiment, the core 100 can be opened and closed using the support shaft 100c as a hinge, but is not limited to this. For example, the core 100 may have a ring shape in a normally closed state that is previously installed in the AC electric paths 5a, 5b, and 5c. For example, the above-described configuration can be achieved by using two AC wires in which one or more cores 100 are inserted in advance during the construction work of electrical wiring. Thereby, for example, the operator can keep the leakage detection devices 10 and 10 ′ always in a detection state while replacing only the fuse 120 b.

(A) is a top view which shows the structural example of the leak detection apparatus of this Embodiment, (b) is a circuit diagram which shows an example of the equivalent circuit of the leak detection apparatus of this Embodiment. (A) is another top view which shows the example of a structure of the leak detection apparatus of this Embodiment, (b) is another circuit which shows an example of the equivalent circuit of the leak detection apparatus of this Embodiment FIG. It is a block diagram which shows the example of installation of the leak detection apparatus of this Embodiment in an electrical wiring. It is a flowchart which shows an example of the operation | movement procedure of the leak detection apparatus of this Embodiment. It is a block diagram which shows the example of installation of the leakage detection apparatus in an electrical wiring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,91 AC power source 10, 10 'Leakage detection apparatus 2, 2a, 2b, 2c AC electric wire 3, 3a, 3b, 3c AC electric wire 4a, 4b, 4c Load 5a, 5b, 5c AC electric circuit 92, 92a, 92b, 92c AC electric wires 93, 93a, 93b, 93c AC electric wires 94a, 94b, 94c Loads 95a, 95b, 95c AC electric circuit 100 Core 100a, 100b Rotating arm 100c Spindle 120 Fuse portion 110, 110a, 110b, 110c, 110d Electric wire 120a Terminal 120b Fuse 120c Fuse case 130 Capacitor 910 Clamp-type ammeter 911 Clamp part 912 Main body 920 Recording device

Claims (6)

An annular core that surrounds two or three wires of a single-phase two-wire system or a three-phase three-wire system;
A coil winding wound around the core;
A fuse that is connected in series to the coil winding and generates a differential current of the current flowing through the wire, and that is blocked by flowing an induced current based on the differential current through the coil winding;
A leakage detection device comprising: A capacitor that is connected in series to the coil winding to form a resonance circuit;
The inductance and resistance values of the coil winding and the capacitance value of the capacitor are values that make the Q value with respect to the commercial power frequency a predetermined value or more.
The leakage detection device according to claim 1. The core is composed of a pair of rotating arms that open and close around a support shaft to surround the electric wire.
The leakage detecting apparatus according to claim 1 or 2, wherein The fuse has a characteristic of being interrupted when the induced current exceeds a predetermined value.
The leakage detecting device according to any one of claims 1 to 3, wherein A fuse case for attaching the fuse to a predetermined position of the core;
The leakage detecting device according to claim 1, further comprising: The fuse case is made of an insulating material.
A leakage detection device characterized by that.

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