JPS61182585A - Detecting display device of current due to accident - Google Patents

Abstract

PURPOSE:To make the titled device compact by arranging a current transformer, a control circuit and a magnetic inversion display device in a box case, fitting a cover to the box case to fix terminals and connecting the current transformer to both the terminals through a primary winding wound around the current transformer. CONSTITUTION:The current transformer 25 is stored in the box case 1, both the ends of the primary winding 26 wound around the transformer 25 are connected to a screw 30 through press-contact terminals 28, 29 for upper and lower terminal boards, 10, 11 and the transformer 25 is connected between both the terminal boards 10, 11. A control circuit substrate is engaged with the inside of the upper end part of a display body case 33 and fixed by a bonding agent. The magnetic inversion display device to be used as a display part is fixed on a control circuit substrate, the leading end part is arranged correspondingly to a display window 34 and a shielding agent is applied between the display window 34 and the display hole 32 to keep water-tightness. The transformer 25 and the case 33 are stored and arranged in the box case 1, and after applying the cover body 16 to the case 1, a filler 41 such as urethane resin is injected into the case K through an injection hole 22 of the cover body 16 to fill the case K with the filler 41. Consequently, weather resistance can be held in case of using the display device in both rooms and fields.

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) This invention relates to a detection indicator for detecting ground fault currents etc. that occur due to damage and deterioration of power distribution equipment such as power distribution equipment and power cables. It is.

(Prior art) Conventionally, a display device that displays a ground fault when a ground fault occurs, which occurs when the insulation of a distribution cable deteriorates when it is attached to a grounding wire, has been used to detect a current transformer that detects ground fault current. Since the display unit is also large in size, and an operating power source for the display unit that displays the ground fault is separately provided, there is a problem that the entire display unit is large and heavy. As a result, attaching the display to a cable or the like is troublesome and the structure is complicated.

Therefore, the present applicant has previously proposed a miniaturized fault current detection indicator ID in Japanese Patent Application No. 59-56788. As shown in FIGS. 17 and 18, this fault current indicator has a pair of terminals 62 and 63 arranged on the side of the frame 61,
A current transformer 64 whose primary side is connected to both terminals 62 and 63 is tied to the upper part of the frame 61 with a string 65, and a control circuit board 66 is fixed to the lower part of the frame 61 and a magnetic reversal display is attached. The device 67 is fixed, and the entire body is molded using a mold 69.

(Problems to be Solved by the Invention) However, the fault current detection indicator I configured as described above
D is a current transformer 64. Since the control circuit board 66, display device 67, etc. were integrally molded, it was necessary to fix these parts to the -H frame 61 during assembly. Also, the current transformer 64 is connected to the frame 61 by the string 6.
Terminal 62 to which the grounding wire is connected while fixing with a terminal 5 or the like.
Since 63 requires a frame 61, it is necessary to take into consideration the size of the product after molding and place it on the side of the frame 61, so it is placed on one side of the product as shown in Fig. When it was installed on the body, it could hardly be said that it had an excellent aesthetic shape.

Furthermore, once each of the parts is assembled to the frame 61, it is necessary to position the terminals 62 and 63 via the connecting pieces 68 made of insulating synthetic resin.
Assembling requires a large number of parts, and since the external shape of the product is molded, molds and the like are required, resulting in an increase in manufacturing costs.

This invention solves the problems of the previously proposed fault current detection indicator ID, and also solves the initial problems to quickly discover faults such as ground faults and short circuits in power distribution equipment. It is attached to the grounding wire or main circuit line to detect fault currents such as ground fault currents and overcurrents.It achieves the purpose of not requiring a separate operating power supply, and has a simple structure that makes it easy to assemble and display. An object of the present invention is to provide a fault current detection indicator which can be miniaturized, is easy to install, and can be used both indoors and outdoors.

Structure of the Invention (Means for Solving Problems) The fault current detection indicator of the present invention has a case composed of a box case and a lid, and terminals are fitted to both ends of the box case opening. the terminals are firmly fixed to the mounting grooves by closing the lid of the box case; a current transformer held by a primary winding, and a secondary winding of the current transformer, and when a fault current flows through the primary winding, the transformed current from the current transformer causes A control circuit that outputs a detection current and a magnetic reversal display device that performs a display operation using the detection current are installed therein, and one end of the case is provided with a display window through which display operations of the magnetic reversal display device can be visually confirmed. Its gist is that it was formed.

(Function) With the above configuration, a pair of terminals are fixed between both ends of the box case and the lid, and the current transformer is held within the case with the primary winding connected to both terminals, so the number of parts is reduced. In addition to being able to reduce the amount of time required, assembly and manufacturing can be performed easily.

(Embodiment) An embodiment in which the present invention is embodied in a ground fault indicator ID for indicating the passage of fault current in a power cable and power distribution equipment will be described below with reference to FIGS. 1 to 16.

In Fig. 1, a box case 1 of a ground fault indicator ID is made of synthetic resin, and has a stepped portion 2 formed on its upper part, and side pieces 3 protruding from both sides of the rear surface in a symmetrical manner. There is. A terminal mounting part 4 is provided upwardly projecting between the side pieces 3 at the center of the upper part of the box case 1, and a mounting groove 5 having a channel-shaped cross section extending in the vertical direction is provided on the rear surface of the terminal mounting part 4 and the step part 2. A low cylindrical mounting protrusion 6 with a screw hole in the center is formed on the rear surface of the terminal mounting portion 4 (see FIGS. 6 and 7). Note that the depth of the mounting groove 5 is formed to be the same as the thickness of the terminal plate 10, which will be described later.

Similarly, the side piece 3 is located at the center of the lower end of the box case 1.
A terminal mounting portion 7 is provided in between and protrudes downward.
A mounting groove 8 with a channel-shaped cross section extending in the vertical direction is formed on the rear surface, and a low cylindrical mounting projection 9 with a screw hole in the center is formed on the rear surface of the terminal mounting portion 7.

A pair of terminal plates 10.1 are provided in the grooves 5.8 with both claws.
1 are fitted respectively. The terminal plate 10.11 is positioned by fitting the mounting protrusions 6, 9 into fitting holes 12.13 provided at the center thereof.

6 and 7, locking step portions are provided on both inner sides of the box case 1 and extend in the vertical direction along the base ends of both side pieces 3, and are flush with the rear surface of the step portion 2. 14 is formed. A mounting step 1a is formed between both of the locking step portions 14 and the lower end side wall of the box case 1, and is located further inward than the locking step portion 14. Further, a locking hole 15 is transparently provided in the center of each side piece 3.

In FIGS. 8 and 9, a lid 16 covering the rear opening of the box case 1 is made of synthetic resin, and a bottom wall 16a
and a side wall 16b that goes around the periphery of the bottom wall 16a, and is formed into a box shape with a bottom, and is fitted into both side pieces 3 of the box case 1. In the lid body 16, upper and lower side walls 16b
At the center of the mounting protrusion 17 corresponding to the mounting groove 5.8 is provided.
．． 18 are respectively provided to protrude in the vertical direction.

Then, by tightening the screws 19 inserted from the rear side of the mounting protrusions 17 and 18, the top and left and right side walls 16b of the lid 16 come into contact with the rear surface of the step 2 of the box case 1 and the locking step 14. are attached in close contact. Moreover, the terminal plate 10
．． 11 is clamped and fixed between the mounting protrusion 17.18 and the corresponding terminal mounting portion 4.7, and the terminal plate 10.11 is positioned on the center line of the display case 1. The left and right sides are symmetrical and can be said to be beautiful.

In addition, in FIGS. 8 and 9, a pair of retaining protrusions 20 are formed at the center in the vertical direction of the left and right side walls 16b of the lid body 16, and the locking holes 15 in the left and right side pieces 3 of the box case 1 are formed.
The cover body 16 is locked when attached to the box case 1, so that the cover body 16 does not come off from the box case 1. Also, a pair of injection holes 22 are transparently provided in both the upper and lower parts of the bottom wall 16a of the lid body.
A pair of abutting protrusions 23 are provided on the outer surface of both sides of a.

On the left and right side pieces 3 of the box case 1 corresponding to the abutting protrusions 23, there are protrusions 24, which together with the abutting protrusions 23 constitute legs, in the same manner as the protrusions a of the abutting protrusions 23. It is installed protrudingly. The concave portion formed by the protrusions 23 and 24 makes it possible to more stably attach heavy equipment onto the circumferential surface of the utility pole P, for example (see FIG. 3).

A case K is constituted by the box case 1 and the lid 16.

A current transformer 25 is housed within the box case 1 . Both ends of the primary winding 26 wound around the current transformer 25 are connected to crimp terminals 28 to the upper and lower terminal plates 10.11.
．． 29 with screws 30, both terminal plates io and i
A current transformer 25 is installed between the two. Therefore, unlike the fault current detection indicator proposed earlier, it does not require a frame or the like, and since both terminal plates 10 and 11 are positioned and fixed to the case K, twisting of the external ground wire etc. This does not affect the transformer 25 and internal parts.

In the box case 1, a display storage chamber 31 is formed obliquely in the front part of the lower end wall through a diagonal locking step 1b, and a display hole 32 is formed in the center of the slanted surface. (See Figures 4, 6, and 7). The display case 31 houses a square box-shaped transparent display case 33.

As shown in FIG. 4, the display case 33 has a display window 3 in the center of the lower surface that is fixed to the slanted inner wall surface of the display storage chamber 31.
4 is bulged. The display window 34 is the display hole 3
2 so that its distal end surface protrudes to the outside, and its distal end surface is formed into a convex lens shape in cross section. Note that a shielding agent is applied between the display window 34 and the display hole 32 to maintain watertightness.

Further, the display case 33 has a locking flange 35 formed on the outer periphery of the upper end thereof, so that the locking step 1 of the display storage chamber 31 can be closed.
A pair of mounting pieces 36 corresponding to the mounting steps 1a of the box case 1 are provided at the upper portions of both sides of the rear side wall. In FIG. 5, the mounting piece 36
The display case 33 is firmly fixed by tightening the screws 36a to the stepped portion 1a through the screws 36a.

In addition, at the center of the upper part of the rear side wall of the display case 33, there is a regulating protrusion 38 provided with a regulating groove 37 extending in the vertical direction.
is provided, and the regulating groove 37 fits into the inner end portion of the terminal plate 11 to regulate the movement of the terminal plate 11 in the left-right direction (in FIG. 5).

In FIG. 10, a control circuit board 39 is fitted into the upper end of the display case 33 and fixed with an adhesive. Note that a shielding agent is applied to the upper surface of the control circuit board 39. A secondary winding 27 of the current transformer 25 is connected to the control circuit board 39 . A magnetic reversal display device as a display section 40 (to be described later) is fixedly installed on the control circuit board 39, and its tip is arranged corresponding to the display window 34.

As described above, the current transformer 25 and the display case 33 are housed and arranged, and with the lid 16 attached to the case case 1, urethane resin is injected into the case through the injection hole 22 of the lid 16. A filler material 41 such as the like is injected and filled,
It can be used indoors or outdoors, has excellent weather resistance, and improves equipment reliability. A pair of bearing portions 42 are provided on both sides of the front surface of the box case 1 immediately above the display storage chamber 31 in a vertical direction, and a return lever 43 is rotatable between the central portions of the bearing portions 42. It is pivotably supported on a shaft 43a.

The return lever 43 is driven by a biasing spring 4 wound around a shaft 43a.
4, it is always biased to be in the state shown by the solid line in FIG.

A magnet 45 is attached to the back surface of the return lever 43. Further, a regulating protrusion 46 extending in the left-right direction (in FIG. 1) is formed in the front of the box case 1 at a position above the bearing part 42, and a regulating protrusion 46 is formed between the regulating protrusion 46 and the bearing part 42. Attach the mounting band 4 to the front of the body case 1.
7 and this display ID is attached to a telephone pole P (see Fig. 16) or the like.

In addition, in FIG. 16, 48 is a switch attached to the armrest Pa of the utility pole P.

Next, the control circuit provided on the control circuit board 39 will be explained according to FIG.

Electric power cable or power distribution equipment (in this example, switch 48
) The primary winding of the current transformer 25 is connected in series with the grounding wire 49 of the terminal board 10.11. A full-wave rectifier 50 is connected to both terminals of the secondary winding of the current transformer 25 via a choke coil L. Note that Z is a surge absorber connected between both terminals on the secondary side of the current transformer 25. A display section 40 and a thyristor SCR as a switching element are connected in series to both the positive and negative terminals of the full-wave rectifier 50. This thyristor S
The CR has an anode connected to the display section 40 and a full-wave rectifier 5.
The cathode is connected to the negative terminal of o.

A charge storage capacitor C is connected between the positive and negative terminals of the full-wave rectifier 50, and a capacitor discharge resistor RO, a Zener diode ZD as a thyristor temperature compensation element, and a gate voltage application resistor. A series circuit of resistors R1 and R2 is connected. The thyristor S is connected to the positive terminal of the resistor R2.
The gate terminal of CR is connected.

The Zener diode ZD is configured not to conduct unless a voltage higher than the Zener voltage is applied, and the Zener voltage is set so that a sufficient gate voltage is applied to the gate terminal of the thyristor SCR even when the temperature is low, and the Zener diode ZD is turned on. When the Zener diode ZD becomes conductive, the resistors R1 and R2 divide the voltage of the capacitor C and supply the voltage across the resistor R2 to the thyristor SCR so that the gate voltage is higher than the gate trigger voltage required at low temperatures. Its resistance value is set.

To explain the display unit 40, the display unit 40 is a magnetic reversal display device, and as shown in FIG. Further, the round bar-shaped stator 53 is formed to have a magnetic pole portion 54a corresponding to the S pole of the disk 51 and a magnetic pole portion 54b corresponding to the N pole of the disk 51. Note that the stator 53 is preferably formed of a material with low coercive force.

Between the two magnetic pole portions 54a, 54b, the same magnetic pole portions 54a, 5
The positive terminal 5 of the display section is connected so that the terminal 4b is magnetized with the same polarity as the magnetic poles at both ends of the disk 51 in the state shown in FIG.
5. A display driving coil 57 connected between the negative terminals 56 is wound. Roughly speaking, a series circuit of a resistor R3 and a protective coil 58 is connected to the positive terminal 55 of the display section 40, and the protective coil 58 is wound around the stator 53 in the same direction as the winding direction of the display driving coil 57. equipped.

The front side 59a and the back side 59b of the disk 51 are marked with different colors (in this embodiment, the front side 59a is black;
The back side 59b is displayed in red.

When a detection current flows through the display driving coil 57, the magnetic pole part 54a is magnetized to the S pole and the magnetic pole part 54b is magnetized to the N pole, as shown in FIG. (S pole), and the S pole is the magnetic pole part 54b (
The disc 51 is rotated in the opposite direction so as to face the N pole, and a mark attached to the back surface 59b of the disc 51 is displayed to the outside.

Further, this display section 40 shows the return lever 43 when the return lever 43 is rotated to the position shown by the chain line in FIG.
The disk 51 can be easily reversed by a magnet 45 attached to the disk 51 to return to the normal display state shown in FIG.

In the display device of this embodiment, initially, as shown in FIG. 14, the mark on the surface 59a of the disk 51 faces outward to indicate a steady state.

The operation of the display ID configured as above will be explained.

Now, the display ID is attached to the mounting band 47 on the utility pole P.
The terminal board 10° 11 is connected to the grounding wire 49 provided on the power cable and power distribution equipment.

When a ground fault current flows through the grounding wire 49 due to deterioration of the power cable (not shown) in this installed state, a transformed current is outputted by the current transformer 25, and the transformed current is rectified by the full-wave rectifier 50. , charges capacitor C.

When the capacitor C is charged and the voltage rises and becomes higher than the Zener voltage of the Zener diode ZD and the Zener diode ZD becomes conductive, the capacitor C voltage is transferred to the resistor R1,
The voltage is divided by R2, and the voltage across the resistor R2 is applied to the thyristor SC.
It is applied between the gate and cathode of R.

When a sufficient gate voltage is applied to thyristor SCH, thyristor SCR is turned on and conductive. Then,
The charged capacitor C is discharged and current flows to the display section 40.

When a current flows through the display driving coil 57 of the display section 40, the magnetic pole part 54a is magnetized to the S pole and the magnetic pole part 54b is magnetized to the N pole, as shown in FIG. 54a (S pole), it is reversely rotated so that the S pole faces the magnetic pole portion 54b (N pole). By this,
A sign attached to the back surface 59b of the disk 51 is displayed externally to indicate a ground fault accident. Note that at this time, the display section 40
Since the distal end surface of the display window portion 34 of the display case 33 has a convex lens shape, the disk 51 is magnified and visually recognized.

By viewing the mark on the back surface 59b from below, it can be determined that a ground fault has occurred in the grounding wire 49.

After the ground fault point has been discovered as described above,
To restore the display ID, the return lever 43 is rotated against the biasing spring 44 from the state shown in FIG. 2 to the state shown by the chain line. Then, the disk 51 is reversed by the magnetic force of the magnet 45 of the return lever 43, returns to its original state, and stands by ready to respond to the next ground fault. Note that, when the operating force is released, the return lever 43 returns to its original state by the urging force of the urging member 44.

In addition, in the display section 40, a protective coil 58 with both ends short-circuited is arranged around the stator 53, so that in the ground fault display state or the steady display state, the external magnetic field φ1 is applied to the stator for some reason. 53, the protective coil 58. An electromotive force is generated in the short-circuited series circuit of the resistor R2 due to the induction of the electric current 1a caused by the external magnetic field φ1, and a current I is generated in a direction that obstructs the external magnetic field φ1. As a result, a magnetic field φ2 in the opposite direction to the external magnetic field φ1 is induced, thereby weakening the external magnetic field φ1. Therefore,
Display malfunctions due to the external magnetic field φ1 of the disk 51 are prevented.

Also, in general, when the temperature is high, the thyristor turns ON at a low gate voltage, and when the temperature drops, it turns ON at a high gate voltage.
Therefore, the operation is unstable depending on the temperature. However, since the Zener voltage of the Zener diode ZD is set to a predetermined voltage, even if a ground fault current flows in a state where the ambient temperature is high, the gate has sufficient voltage until the Zener diode ZD reaches that Zener voltage. No voltage is applied and therefore thyristor SCR is not ONL. Then, when the voltage across the Zener diode 20 reaches a predetermined voltage and becomes conductive, the gate voltage is applied to the thyristor SCR, and the thyristor SCR becomes conductive.

Furthermore, when a ground fault current flows at a low temperature, the thyristor SCR becomes conductive because a sufficient gate voltage is applied to its gate only when the voltage across the Zener diode 20 reaches the Zener voltage, similar to the case at a high temperature. .

Even with such temperature changes, the thyristor SCR can operate stably in this embodiment.

Further, since this display device uses a current transformer, it hardly affects the grounding resistance value of the grounding wire 49.

In addition, in the past, this type of display used a relay coil in the control circuit for driving the display, which required the use of a large current transformer, but in this embodiment, the control circuit uses a large current transformer. Since no relay coil is used, the output energy of the current transformer 25 is small and the current transformer 25 can be made smaller. Thereby, the entire display ID can be made compact.

Furthermore, in the control circuit of this embodiment, the gate circuit of the thyristor SCR is normally cut off by the Zener diode 2D, so the thyristor SCR will not malfunction due to radio waves, and will reliably respond only to the fault current and display the fault display. It can be carried out.

The earth fault indicator IO configured as described above can detect the earth fault current and does not require a separate operating power supply, so the structure can be simplified and the indicator IQ can be downsized. Therefore, the overall weight of the display device ID is reduced, and the installation work becomes simple, making it possible to improve the efficiency of the installation work.

Furthermore, in this embodiment, the current transformer 25, which takes up a relatively large space, is placed in the upper part of the case, and the display case 33 is placed in the lower part of the case, so there is nothing below the display window 34 that obstructs visibility. Furthermore, since the display window 34 is a circular convex lens, the viewing angle is large regardless of its mounting state (vertically or horizontally), and the display state can be clearly observed.

Also, when assembling this display, the current transformer 25, which is relatively large compared to other components, is housed in the case, and later the current transformer 25 can be installed simply by injecting the filler 41 into the case. Since it can be fixed, assembly can be easily performed.

Note that this invention is not limited to the above embodiments (
It is also possible to make arbitrary changes without departing from the spirit of the invention, such as by implementing it into an arrester deterioration indicator.

Effects of the Invention As detailed above, the present invention includes a current transformer in the case,
A control circuit that outputs the current detected by this current transformer and a magnetic reversal display device that displays an accident using the detected current from this control circuit are arranged, and the terminal is fixed by attaching the lid to the box case and both ends It is easy to assemble by simply installing the current transformer with the primary winding that electrically connects the transformers, and since no separate operating power source is required, it can be designed very compactly. It is easy to install and can be used indoors and outdoors, making it an excellent invention for industrial use.

[Brief explanation of drawings]

Fig. 1 is a front view of a display device of an embodiment embodying the present invention, Fig. 2 is a side view, Fig. 3 is a bottom view, Fig. 4 is a vertical sectional view, and Fig. 5 is a similar one. Partially cutaway rear view, Figure 6 is a central sectional view of the box case, Figure 7 is also a rear view, Figure 8 is a bottom view of the lid, Figure 9 is also a rear view,
Fig. 10 is a sectional view of the display case, Fig. 11 is a right side view of the display case, Fig. 12 is a sectional view taken along line A-A of the display case in Fig. 10, and Fig. 13 is a cross-sectional view of the display case. Electrical circuit diagram, Fig. 14 is a perspective view of the magnetic reversal display, Fig. 15 is a perspective view showing the same operation, Fig. 16 is a side view of the display with the display installed, and Fig. 17 is a conventional fault current diagram. FIG. 18 is a perspective view of the entire detection display excluding the molded portion, and is also a front view. 1... Box case, 10.11... Terminal board, 16.
... Lid body, 25 ... Current transformer, 39 ... Control circuit board, 43 ... Return lever, 45 ... Magnet, 49.
...Grounding wire, 50...Full wave rectifier, 51...Disk, 52...Rotating shaft, 53...Stator, 57...
・Display drive coil, ID...Display device, SCR...
Thyristor, RO, R1゜R2...Resistor, C...Capacitor, ZD...Zener diode, K...Case. Patent applicant: Takamatsu Electric Manufacturing Co., Ltd.
Person Patent Attorney On 1) Hironobu Figure 10 Figure 19 Figure 11 Figure 14 Figure 15

Claims (1)

[Claims] 1. A case is constituted by a box case and a lid body, mounting grooves into which terminals can be fitted are formed at both ends of the box case opening, and the lid of the box case Both terminals are firmly fixed to the mounting groove by closing the body, and a current transformer held within the box case with a primary winding electrically connected to both terminals; A control circuit that is electrically connected to a secondary winding of a current transformer and outputs a detected current based on a transformed current from the current transformer when a fault current flows to the primary winding, and an indication based on the detected current. What is claimed is: 1. A fault current detection indicator, characterized in that an operating magnetic reversal display device is housed therein, and a display window is formed at one end of the box case through which the display operation of the magnetic reversal display device can be visually confirmed. 2. Claim 1, characterized in that the case composed of the box case and the lid is filled with a filler.
Fault current detection indicator described in section.