JP5746540B2 - Current detector - Google Patents

Description

  The present invention relates to a current detection device, and in particular, includes a housing in which a first through hole for passing an electric wire is formed, and a substrate that is accommodated in the housing and on which a current detection circuit using a Hall element is mounted. The present invention relates to a current detection device.

  In high-voltage distribution lines, there are cases where ground faults occur due to aged deterioration of distribution facilities (electric wires, switches, circuit breakers, etc.), leading to power outages. In order to detect such a sign leading to a ground fault, a ground fault current is monitored at a substation using a GDR (ground fault direction relay). The GDR detects a zero-phase current and a zero-phase voltage in a high-voltage distribution line, the levels of the zero-phase current and the zero-phase voltage are equal to or higher than a set level, and the phase difference between the zero-phase current and the zero-phase voltage is within a predetermined range. When it is inside, it becomes the structure which interrupts | blocks a circuit breaker.

  However, in the high-voltage distribution line, a short-circuit phenomenon occurs in which the duration of the ground-fault current is short and the circuit breaker is not cut off and a power failure accident does not occur. At this time, it is possible to confirm up to the bank (region) where the micro ground fault phenomenon has occurred in GDR, but it is not possible to identify the occurrence location. For this reason, it is considered to install a plurality of high-voltage current detectors on the line where a micro ground fault occurs, and to detect the micro ground fault from the current waveform obtained by the current detector and to determine the micro ground fault point. Has been.

  As the above-described current detection device, for example, the one shown in FIG. 8 is known (for example, Patent Document 1). As shown in the figure, a current detection device 2 includes a housing 5 in which a first through hole 4 for passing an overhead wire La as an electric wire is formed, and a current detection circuit that is accommodated in the housing 5 and uses a Hall IC. And a substrate 6 mounted thereon.

  The housing 5 is made of an elastic member such as rubber or silicone, and is provided with a cut portion 100 from the inner periphery of the first through hole 4 to the outer periphery of the housing 5. The cut portion 100 is expanded and the electric wire is passed through the first through hole 4. The substrate 6 is fixed to the inner wall of the housing 5 with screws.

  However, since the above-described conventional current detection device 2 has the substrate 6 directly screwed to the housing 5, the substrate 6 is inclined and the position of the Hall IC varies from product to product. However, there is a problem that the detection accuracy varies. There is also a problem that it is not desired to directly screw a metal screw on the substrate 6 itself.

JP 2006-119059 A

  Therefore, the present invention provides a current detection device that can prevent tilting of the substrate, reduce variation in detection accuracy for each product, and can be attached to a housing without directly screwing the substrate. Let it be an issue.

The invention according to claim 1 for solving the above-described problem includes a housing in which a first through-hole for passing an electric wire is formed, a substrate that is accommodated in the housing and on which a current detection circuit using a Hall element is mounted. In the current detecting device, the concave portion into which the substrate is fitted is provided on the inner wall of the housing, the concave portion is provided to be recessed toward the edge of the first through hole, and the concave portion is closed, A plate-shaped flat plate portion screwed to the inner wall of the housing, and a plurality of rod-shaped leg portions that protrude from the flat plate portion into the recess and press the substrate toward the bottom surface of the recess. The current detection device further includes a substrate pressing portion.

  The invention according to claim 2 further includes an adapter provided detachably in the first through-hole and having a second through-hole smaller than the first through-hole. It exists in the electric current detection apparatus as described in above.

  As described above, according to the invention described in claim 1, the substrate is prevented from being tilted by pressing the substrate toward the bottom surface of the concave portion by the leg portion of the substrate pressing portion, and variation in detection accuracy for each product is achieved. Can be reduced. Moreover, by screwing the flat plate portion of the substrate pressing portion to the housing, the substrate can be attached to the housing without being screwed directly.

  According to the second aspect of the present invention, even when it is desired to detect the current flowing through the electric wire having a diameter much smaller than the first through hole formed in the housing, the second through hole having a size matched to the electric wire diameter. Since the adapter provided with the hole can be installed in the first through-hole and the electric wire can be attached to the second through-hole, even if you want to attach to multiple types of electric wires with different wire diameters, The distance between the center and the Hall element can be kept unchanged. For this reason, even if it is a case where it was a case where it attached to a plurality of kinds of electric wires with different electric wire diameters, the inclination which is the output of the Hall element with respect to the current flowing through the electric wires can be made the same.

It is the schematic which shows the state which attached the fine ground fault detection apparatus incorporating the current detection apparatus of this invention to the overhead wire. It is a disassembled perspective view of the electric current detection apparatus shown in FIG. It is a cross-sectional perspective view of the electric current detection apparatus shown in FIG. It is a perspective view of the electric current detection apparatus shown in FIG. 2 of the state which attached the adapter. It is a perspective view of the adapter shown in FIG. It is an electrical block diagram of the fine ground fault detection apparatus shown in FIG. Detection of current flowing in the overhead wire when the current detection device with the adapter removed is attached to an overhead wire with a diameter of 32 mm, and when the current detection device with the adapter attached is attached to an overhead wire with a diameter of 15 mm It is a graph which shows the result of having measured a signal. It is the schematic which shows an example of the conventional electric current detection apparatus.

  Hereinafter, a fine ground fault detection apparatus incorporating a current detection apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing a state in which a fine ground fault detection device incorporating the current detection device of the present invention is attached to an overhead wire. FIG. 2 is an exploded perspective view of the current detection device shown in FIG. 3 is a cross-sectional perspective view of the current detection device shown in FIG. FIG. 4 is a perspective view of the current detection device shown in FIG. 2 with the adapter attached. FIG. 5 is a perspective view of the adapter shown in FIG. FIG. 6 is an electrical configuration diagram of the fine ground fault detection apparatus shown in FIG. 1.

  As shown in FIG. 1, the fine ground fault detection apparatus 1 according to the present embodiment detects a fine ground fault that occurs in an overhead wire La as three electric wires that are projected in the air by a concrete pillar P. In these three overhead lines La, three-phase alternating currents having phases different from each other by 120 ° flow.

  As shown in FIG. 1, the fine ground fault detection device 1 is attached to each of the three overhead lines La, and the three current detection devices 2 that detect the current flowing through the attached overhead lines La, and these are detected. And a detection unit 3 that detects a fine ground fault from the current.

  As shown in FIGS. 2 and 3, each of the current detection devices 2 includes a housing 5 having a first through hole 4 through which an overhead wire La is passed, and a current detection using a Hall IC 14 housed in the housing 5. A substrate 6 on which the circuit 13 (FIG. 6) is mounted, a substrate pressing portion 7 for fixing the substrate 6 to the inner wall of the housing 5, and a lid portion 8 that closes the opening of the housing 5 are provided.

  The housing 5 is made of a hard plastic having high insulation properties such as ABS, vinyl chloride, and the like. The lower housing 9 is positioned below the overhead line La, and the upper housing 10 is positioned above the overhead line La. It is equipped with. The lower housing 9 includes a box-shaped housing portion 91 for housing a substrate 6, a substrate pressing portion 7, a lid portion 8 and a battery (not shown), which will be described later, and the radial direction of the overhead wire La in the housing portion 91. A plate-like lower opening / closing operation part 92 projecting from the side surface on the Y1 side.

  The casing 91 is formed in a box shape whose upper side is closed and whose lower side is opened. As shown in FIG. 3, the side away from the lower opening / closing operation portion 92 of the upper wall portion 91a that covers the upper side of the housing portion 91 is formed thicker than the lower opening / closing operation portion 92 side. . A lower concave groove 91a-1 having a semicircular cross-section that accommodates the lower side of the overhead line La is provided on the upper surface of the portion of the upper wall portion 91a that is formed to be thick. A concave portion 91a-2 (FIG. 3) into which a substrate 6 to be described later is fitted is provided on the lower surface of the thick portion.

  The lower concave groove 91 a-1 forms the lower side of the first through hole 4. As shown in FIG. 3, the concave portion 91a-2 is fitted into the substrate 6 so that the upper side of the substrate 6 is in contact with the bottom surface of the concave portion 91a-2 and the side surface of the substrate 6 is in contact with the inner side surface of the concave portion 91a-2. The substrate 6 is provided in such a shape that it can be positioned.

  Further, a pair of lower shaft support portions 91a-3 (FIG. 4) projecting from the upper housing 10 described later is provided on the upper surface of the thin portion of the upper wall portion 91a. The pair of lower shaft support portions 91 a-3 is provided between the lower groove 91 a-1 and the lower opening / closing operation portion 92. Further, as shown in FIG. 4, the pair of lower shaft support portions 91a-3 are provided at both ends in the longitudinal direction Y2 of the overhead line La of the upper wall portion 91a. Further, the pair of lower shaft support portions 91a-3 are arranged side by side in the longitudinal direction Y2.

  Each of the pair of lower shaft support portions 91a-3 is composed of a pair of lower shaft support walls 91a-4 and 91a-5 provided at an interval in the longitudinal direction Y2. Each of the pair of lower shaft support walls 91a-4 and 91a-5 is formed with a bearing portion 91a-6 penetrating in the longitudinal direction Y2. On the lower surface of the lower opening / closing operation unit 92, as shown in FIGS. 2 and 3, etc., a plurality of irregularities along the longitudinal direction Y2 are provided side by side in the radial direction Y1.

  As shown in FIGS. 2 and 3, the upper housing 10 includes a clamp portion 11 positioned above the overhead line La, a plate-like upper opening / closing operation portion 12 positioned above the lower opening / closing operation portion 92, Are provided continuously in the radial direction Y1. On the lower surface of the clamp portion 11, an upper concave groove 11 a having a semicircular cross section for accommodating the upper side of the overhead wire La is provided. The upper concave groove 11 a forms the upper side of the first through hole 4.

  The upper opening / closing operation part 12 has a pair of upper shaft support parts 12a projecting downward on the clamp part 11 side. The pair of upper shaft support portions 12a are provided at both ends in the longitudinal direction Y2 of the upper opening / closing operation portion 12, respectively. Further, the pair of upper shaft support portions 12a are arranged side by side in the longitudinal direction Y2. On the upper shaft support portion 12a, convex portions (not shown) that are convex toward both sides in the longitudinal direction Y2 are formed.

  Then, as shown in FIG. 4, when the upper shaft support portion 12a is inserted between the pair of lower shaft support walls 91a-4 and 91a-5, and a convex portion (not shown) is inserted into the bearing portion 91a-6, The upper housing 10 is supported by the lower housing 9 so as to be rotatable about an axis passing through the bearing portion 91a-6 and extending along the longitudinal direction Y2. Further, as shown in FIGS. 2 and 3 and the like, a plurality of irregularities along the longitudinal direction Y2 are arranged in the radial direction Y1 on the upper surface of the upper opening / closing operation unit 12.

  A torsion coil spring (not shown) is formed by winding a wire or the like, and includes a coil part wound in a coil shape and a pair of arm parts extending linearly from both ends of the coil part. This coil part is arrange | positioned along the center axis | shaft of the lower side pivot support part 91a-3 and the upper side pivot support part 12a. One of the pair of arm portions is in contact with the lower surface of the upper opening / closing operation portion 12, and the other of the pair of arm portions is in contact with the upper surface of the lower opening / closing operation portion 92.

  Therefore, when the lower opening / closing operation part 92 and the upper opening / closing operation part 12 are brought close to each other using a jig or the like, the upper housing 10 rotates around the central axes of the upper shaft support part 12a and the lower shaft support part 91a-3, The side away from the upper opening / closing operation part 12 of the upper housing 10 and the side away from the lower opening / closing operation part 92 of the lower housing 9 are opened apart from each other, and the overhead line La is routed from the opening to the upper concave groove 11a, It can be inserted and accommodated in the lower concave groove 91a-1 (that is, in the first through hole 4).

  When the jig is removed, the lower opening / closing operation portion 92 and the upper opening / closing operation portion 12 are urged away from each other by the torsion coil spring, so that the upper housing 10 has the upper shaft support portion 12a and the lower shaft support portion 91a-3. The side away from the upper opening / closing operation part 12 of the upper housing 10 and the side away from the lower opening / closing operation part 92 of the lower housing 9 approach each other, and the opening is closed. As a result, the overhead wire La is clamped between the upper housing 10 and the lower housing 9.

  As shown in FIG. 2, the substrate 6 is provided in a square shape in plan view. Further, as shown in FIG. 6, the substrate 6 is equipped with a current detection circuit 13 for detecting a current flowing through the overhead line La. The current detection circuit 13 is mounted with a power supply circuit (not shown), a Hall IC 14 as a mounting type Hall element, and an amplification circuit 15 that amplifies the output of the Hall IC 14. A power supply circuit (not shown) generates a power supply voltage for the Hall IC 14 and the amplifier circuit 15 from a battery voltage supplied from a battery (not shown) accommodated in each current detection device 2.

  The Hall IC 14 is, for example, a surface-mount type, and outputs a detection signal corresponding to magnetism generated when a current flows through the overhead wire La as a current value flowing through the overhead wire L. The amplifier circuit 15 amplifies the detection signal output from the Hall IC 14.

  Similar to the housing 5, the substrate pressing portion 7 is made of a hard plastic having high insulation properties such as ABS and vinyl chloride. As shown in FIGS. 2 and 3, the substrate pressing portion 7 is provided with a flat plate portion 71 that covers the concave portion 91 a-2 and four rod-like leg portions 72 that protrude from the flat plate portion 71. The flat plate portion 71 is provided larger than the concave portion 91a-2, and is attached to the upper wall portion 91a of the lower housing 9 by screws. The four leg portions 72 are inserted into the recess 91a-2, support the lower surface of the substrate 6, and press the substrate 6 toward the bottom surface of the recess 91a-2. The four leg portions 72 hold the four corners of the substrate 6.

  The lid portion 8 is provided so as to close the lower opening of the housing portion 91. The lid portion 8 is provided with packing or the like to prevent water from entering the inside of the housing portion 91, and is further accommodated in the housing portion 91. The lid portion 8 is provided with a connector mounting hole 81. A connector (not shown) provided at one end of an electric wire (not shown) that transmits the detection signal amplified by the amplifier circuit 15 is attached to the connector attachment hole 81. A connector provided at one end of an electric wire L1 (FIG. 1) for connecting the current detection device 2 and the detection unit 3 is connected to the connector (not shown). A detection signal from the circuit 13 can be supplied.

  The detection unit 3 includes a housing (not shown) and a substrate housed in the housing (none of which are shown). As shown in FIG. 6, an addition circuit 31 that adds a detection signal supplied from a current detection circuit 13 built in each current detection device 2 and an addition circuit 31 add to the substrate in the detection unit 3. And a micro ground fault current detection unit 32 such as an oscilloscope for displaying the waveform of the added value.

  Next, the procedure of the fine ground fault detection method using the fine ground fault detection apparatus 1 described above will be described. First, the worker attaches the above-described current detection device 2 to each of the three overhead wires La. As a result, the current detection circuit 13 incorporated in each current detection device 2 detects each of the currents flowing through the three overhead wires La and supplies the detection signals to the detection unit 3. In the detection unit 3, the addition circuit 31 adds the detection signals supplied from the three current detection circuits 13, and the fine ground fault current detection unit 32 displays the waveform of the added value on the display unit (not shown).

  As described above, the three overhead lines La have three-phase alternating currents having different phases by 120 °. For this reason, when the detection signal corresponding to the current flowing through the overhead line La is added by the adding circuit 31, the three-phase AC component becomes 0, and the added value becomes a value corresponding to the minute ground fault current. The worker looks at the added value waveform displayed by the fine ground fault current detector 32, that is, the fine ground fault current waveform, and determines whether or not a fine ground fault has occurred.

  According to the current detection device 2 described above, the substrate 6 is pressed toward the bottom surface of the recess 91a-2 by the leg portion 72 of the substrate pressing portion 7, thereby preventing the substrate 6 from being tilted and improving the detection accuracy for each product. Variations can be reduced. In addition, by screwing the flat plate portion 71 of the substrate pressing portion 7 to the lower housing 9, the substrate 6 can be attached to the lower housing 9 without being screwed directly.

  Further, as shown in FIG. 4, the current detection device 2 can detachably attach an adapter 17 in which a second through hole 16 smaller than the first through hole 4 is formed in the first through hole 4. . The second through hole 16 of the adapter 17 is provided to be coaxial with the first through hole 4 when the adapter 17 is attached to the first through hole 4.

  As shown in FIG. 5 and the like, the adapter 17 includes a lower adapter 18 attached to the lower housing 9 and an upper adapter 19 attached to the upper housing 10. A screw hole 93 (FIG. 2) for attaching the lower adapter 18 is formed on the outer surface of the lower housing 9. Further, a screw hole 11 b (FIG. 2) for attaching the upper adapter 19 is formed on the outer surface of the upper housing 10.

  The lower adapter 18 includes a main body portion 18a formed in a semi-cylindrical shape obtained by dividing a cylinder in half, and a pair of flange portions 18b provided at both ends in the longitudinal direction Y2 of the main body portion 18a. The inner peripheral surface of the semi-cylindrical main body 18 a forms the lower side of the second through hole 16. Then, the outer peripheral side of the semi-cylindrical main body 18 a is fitted toward the lower concave groove 91 a-1 of the lower housing 9.

  Each of the pair of flange portions 18b is formed with a screw hole 18c for attachment to the lower housing 9. The pair of flange portions 18b sandwich the side surfaces of both sides of the lower housing 9 in the longitudinal direction Y2 when the main body portion 18a is fitted into the lower concave groove 91a-1 of the lower housing 9. Thereby, the screw hole 93 provided in the lower housing 9 and the screw hole 18c provided in the flange portion 18b of the lower adapter 18 overlap. The lower adapter 19 can be attached to the lower housing 9 by screwing the screw holes 93 and 18c that overlap each other with screws.

  The upper adapter 19 includes a main body portion 19a formed in a semi-cylindrical shape obtained by dividing a cylinder in half, and a pair of flange portions 19b provided at both ends in the longitudinal direction Y2 of the main body portion 19a. The inner peripheral surface of the semi-cylindrical main body portion 19 a forms the upper side of the second through hole 16. Then, the outer peripheral side of the semi-cylindrical main body 19 a is fitted into the upper concave groove 11 a of the upper housing 10. Each of the pair of flange portions 19b is formed with a screw hole 19c for attachment to the upper housing 10.

  When the body portion 19a is fitted into the upper concave groove 11a of the upper housing 10, the pair of flange portions 19b sandwich the side surfaces on both sides in the longitudinal direction Y2 of the upper housing 10 between each other. As a result, the screw hole 11 b provided in the upper housing 10 and the screw hole 19 c provided in the flange portion 19 b of the upper adapter 19 overlap. The lower adapter 19 can be attached to the lower housing 9 by screwing the screw holes 11b and 19c overlapping each other with screws.

  By providing the adapter 17 described above, for example, the first through hole 4 is provided with a diameter slightly larger than the diameter of 32 mm so as to pass the overhead wire La having a diameter of 32 mm, and the second through hole 16 is passed through the overhead wire La having a diameter of 15 mm. The diameter is slightly larger than 15 mm. As shown in FIG. 2, when the overhead wire La having a diameter of 32 mm is passed through the first through hole 4 with the adapter 17 removed, the center of the overhead wire La is positioned at the center of the first through hole 4. On the other hand, as shown in FIG. 4, when the overhead wire La having a diameter of 15 mm is passed through the second through hole 16 with the adapter 17 attached, the center of the overhead wire La is positioned at the center of the second through hole 16. Therefore, even if the wire diameter of the overhead wire La is different, the distance between the center of the overhead wire La and the Hall IC 14 (that is, the substrate 6) can be made the same.

  That is, even when it is desired to detect the current flowing through the overhead wire La having a diameter much smaller than the first through hole 4 formed in the housing 5, the second penetration having a size corresponding to the wire diameter of the overhead wire La. Since the adapter 17 provided with the hole 16 can be attached in the first through hole 4 and attached to the second through hole 16 through the overhead wire La, there are cases where it is desired to attach to a plurality of types of overhead wires La having different wire diameters. It is possible to prevent the distance between the center of the overhead line La and the Hall IC 14 from changing by simply attaching and detaching the adapter 17. For this reason, even if it is a case where it attaches to multiple types of overhead wire La from which an electric wire diameter differs, the inclination which is the output of Hall IC14 with respect to the electric current which flows in overhead wire La can be made the same.

  Next, the inventors attached the current detection device 2 shown in FIG. 2 or the like without the adapter 17 attached to the overhead wire La having a diameter of 32 mm, and measured the output of the Hall IC 14 with respect to the current flowing through the overhead wire La. 4 was attached to the overhead wire La having a diameter of 15 mm, and the output of the Hall IC 14 with respect to the current flowing through the overhead wire La was measured to confirm the effect of the present invention. . The results are shown in FIG. As shown in FIG. 7, even when the wires are attached to a plurality of types of overhead wires La having different wire diameters, the inclination that is the output of the Hall IC 14 with respect to the current flowing through the overhead wires La can be made the same.

  According to the above-described embodiment, the housing 5 is divided into the lower housing 9 and the upper housing 10, and the first through hole 4 is also divided. However, the present invention is not limited to this. The housing 5 may be any housing as long as the first through-hole 4 is formed and can pass the overhead wire La through the first through-hole 4. For example, the conventional housing shown in FIG. 8 may be used. .

  Moreover, according to embodiment mentioned above, although the adapter 17 was provided, this invention is not limited to this. The adapter 17 may not be provided.

  Moreover, according to embodiment mentioned above, although the four leg parts 72 were provided in the board | substrate holding | suppressing part 7, this invention is not limited to this. The leg part 72 should just be at least 2 or more.

  Moreover, according to embodiment mentioned above, although the electric current detection apparatus 2 of this invention was incorporated in the fine ground fault detection apparatus 1, this invention is not limited to this. The current detection device 2 may only detect the current flowing through the overhead line La and display the waveform, and may not be incorporated in the fine ground fault detection device 1.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

2 Current detection device 4 First through hole 5 Housing 6 Substrate 7 Substrate pressing portion 16 Second through hole 17 Adapter 71 Flat plate portion 72 Leg portion 91a-2 Recessed portion 14 Hall IC (Hall element)
15 Current detection circuit La Overhead wire (electric wire)

Claims (2)

In a current detection device comprising: a housing in which a first through hole for passing an electric wire is formed; and a substrate mounted in the housing and mounting a current detection circuit using a Hall element.
A recess into which the substrate is fitted is provided on the inner wall of the housing;
The recess is provided to be recessed in a direction approaching an edge of the first through hole,
A plate-shaped flat plate portion that closes the concave portion and is screwed to the inner wall of the housing, and a plurality of bar-shaped legs that protrude from the flat plate portion into the concave portion and press the substrate toward the bottom surface of the concave portion. And a substrate pressing part constituted by a current detecting device. The current detection device according to claim 1, further comprising: an adapter that is detachably provided in the first through hole and has a second through hole that is smaller than the first through hole.

Images