JPH0476435B2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) This invention relates to a detection indicator that detects 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. Moreover, since the display section for displaying ground faults was provided with a separate operating power source, the entire display became 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 previously proposed a miniaturized fault current detection indicator ID in Japanese Patent Application No. 56788/1983. As shown in FIGS. 17 and 18, this fault current indicator has a pair of terminals 62 and 63 arranged on the side of a frame 61, and a primary side connected to both terminals 62 and 63 on the upper part of the frame 61. A current transformer 64 to be connected is tied with a string 65, a control circuit board 66 is fixed to the lower part of the frame 61, a magnetic reversal display device 67 is fixed, and the whole is molded into a mold 69.

(Problems to be Solved by the Invention) However, in the fault current detection indicator ID configured as described above, the current transformer 64, control circuit board 66, display device 67, etc. are integrally molded. During the assembly process, it was necessary to temporarily fix the parts to the frame 61. In addition, since the current transformer 64 is fixed to the frame 61 with a string 65 or the like, and the terminals 62 and 63 for connecting the ground wire require the frame 61, the size of the product after molding is taken into consideration. frame 61
As shown in Fig. 18, the product had to be placed on one side of the product, and could not be said to have an excellent aesthetic shape when attached to a utility pole or the like.

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 piece 68 made of insulating synthetic resin, which increases the number of parts to be assembled. However, since the external shape of the product was molded, molds and the like were required, resulting in an increase in manufacturing costs.

This invention is based on the previously proposed fault current detection indicator.
In order to solve the problem of ID, as well as to solve the initial problem and quickly discover fault points such as ground faults and short circuits in power distribution equipment, it is installed on grounding wires and main circuit lines to detect ground fault current. This device detects fault currents such as overcurrents and overcurrents, and achieves the purpose of not requiring a separate operating power source.The structure is simple, easy to assemble, and the display device can be made compact.As a result, The object of the present invention is to provide a fault current detection indicator that 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 with a connected primary winding and electrically connected to a secondary winding of the current transformer, when a fault current flows through the primary winding;
A control circuit that outputs a detection current using a transformed current from the current transformer and a magnetic reversal display device that performs a display operation using the detection current are installed, and one end of the case is provided with a magnetic reversal display device. The gist is to form a display window through which display operations can be visually confirmed.

(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. The number of parts can be reduced and manufacturing can be easily performed.

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

In Figure 1, earth fault indicator ID box case 1
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. A terminal mounting portion 4 is provided upwardly protruding 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 portion 4 and the step portion 2. is formed, and a low cylindrical mounting protrusion 6 with a screw hole in the center is formed on the rear surface of the terminal mounting part 4.
is formed (see Figures 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, at the center of the lower end of the box case 1, a terminal mounting portion 7 is provided between the side pieces 3 to protrude downward;
A mounting groove 8 with a channel-shaped cross section extending in the vertical direction is formed on the rear surface of the terminal mounting portion 7, and a low cylindrical mounting protrusion 9 with a screw hole in the center is formed on the rear surface of the terminal mounting portion 7. It is formed.

A pair of terminal plates 10 and 11 are fitted into both the mounting grooves 5 and 8, respectively. The terminal plates 10 and 11 have a fitting hole 1 provided in the center thereof.
The mounting protrusions 6 and 9 are fitted together at 2 and 13 for positioning.

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, the lid 16 covering the rear opening of the box case 1 is made of synthetic resin, and has a bottomed box-like shape consisting of a bottom wall 16a and a side wall 16b surrounding the periphery of the bottom wall 16a. and is fitted into both side pieces 3 of the box case 1. In the lid body 16, mounting protrusions 17 and 18 corresponding to the mounting grooves 5 and 8 are provided at the center of the upper and lower side walls 16b.
are provided to protrude in the vertical direction, respectively.

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. Further, the terminal plates 10 and 11 are clamped and fixed between the terminal mounting parts 4 and 7 corresponding to the mounting protrusions 17 and 18, so that the overall shape of the display ID is on the center line of the box case 1. 10 and 11 are positioned symmetrically, which 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 are inserted into the locking holes 15 of the left and right side pieces 3 of the box case 1. On the other hand, it is locked when attached, so that the lid body 16 does not come off from the box case 1. Further, a pair of injection holes 22 are provided in both the upper and lower parts of the bottom wall 16a of the lid body, and a pair of contact protrusions 23 are provided on the outer surface of both sides of the bottom wall 16a.

On the right and left side pieces 3 of the box case 1 corresponding to the abutting protrusions 23, protrusions 24 which together with the abutting protrusions 23 constitute legs are provided with the same protrusion amount as the abutting protrusions 23. It is installed protrudingly. This protrusion 23,2
The concave portion formed at 4 makes it more stable to mount the device on the circumferential surface of the telephone pole P, for example (see FIG. 3).

The case K is formed by the box case 1 and the lid 16.
is configured.

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 the upper and lower terminal plates 10, 1.
1 with a screw 30 via crimp terminals 28 and 29, and a current transformer 2 is connected between both terminal plates 10 and 11.
5 is installed. Therefore, unlike the previously proposed fault current detection indicator, it does not require a frame or the like, and since both terminal boards 10 and 11 are positioned and fixed to the case K, there is no possibility of twisting of the external grounding wire, etc. This does not affect the current transformer 25 and internal components.

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 storage chamber 31 houses a square box-shaped transparent display case 33.

As shown in FIG. 4, the display case 33 has a display window 34 bulging in the center of its lower surface which is engaged with the oblique inner wall surface of the display storage chamber 31. The display window 34 is fitted into the display hole 32 so that its front end surface protrudes to the outside, and the front 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 its upper end, and is locked to the oblique locking step 1b of the display storage chamber 31. Mounting step 1a of case 1
A pair of mounting pieces 36 corresponding to the above are provided. In FIG. 5, the display case 33 is firmly fixed by tightening the screw 36a to the mounting step 1a via the mounting piece 36.

A regulating protrusion 38 having a regulating groove 37 extending in the vertical direction is provided at the center of the upper part of the rear side wall of the display case 33, and the regulating groove 37 fits into the inner end of the terminal plate 11 to prevent terminals. Movement of the plate 11 in the left-right direction (in FIG. 5) is restricted.

In FIG. 10, a control circuit board 39 is fitted into the upper end of the display case 33 and fixed with an adhesive. In addition, the control circuit board 39
A shielding agent is applied to the top surface. The control circuit board 39 includes the secondary winding 2 of the current transformer 25.
7 are connected and arranged. 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 with the lid 16 attached to the box case 1, urethane resin is injected into the case K through the injection hole 22 of the lid 16. The filler 41 is injected and filled, and it can be used both indoors and outdoors, has excellent weather resistance, and improves the reliability of the device. A pair of bearing portions 42 are provided on both sides of the box case 1 protruding in the vertical direction immediately above the display storage chamber 31, and a return lever 43 is rotatable between the center portions of the bearing portions 42. It is pivotably supported on a shaft 43a. The return lever 43 is a shaft 43a
It is always biased by a biasing spring 44 wound around the body so as to be in the state shown by the solid line in FIG.

A magnet 4 is attached to the back surface of the return lever 43.
5 is attached. Further, a regulating protrusion 46 extending in the left-right direction (in FIG. 1) is formed on the front surface of the box case 1 at a position above the bearing part 42, and the regulating protrusion 46 is located between the regulating protrusion 46 and the bearing part 42. Hang the mounting band 47 on the front of the case 1,
This display ID is attached to a telephone pole P (see Fig. 16), etc.

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

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

The primary winding of the current transformer 25 is connected in series to a grounding wire 49 of a power cable or power distribution equipment (switch 48 in this embodiment) via both terminal plates 10 and 11. A full-wave rectifier 50 is connected to both terminals of the secondary winding of the current transformer 25 via a chiyoke coil L.
is connected. 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 SCR has an anode connected to the display section 40 and a cathode connected to the negative terminal of the full-wave rectifier 50.

A capacitor C for charge storage is connected between the positive and negative terminals of the full-wave rectifier 50, as well as 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 gate terminal of the thyristor SCR is connected to the positive terminal of the resistor R2.

The Zener diode ZD is designed not to conduct unless a Zener voltage or higher is applied, and the Zener voltage is applied to the thyristor.
The SCR is set so that even when the temperature is low, a sufficient gate voltage is applied to the gate terminal to turn it on, and the resistors R1 and R2 divide the voltage of the capacitor C and resistor R when the Zener diode ZD conducts.
2 is supplied to the thyristor SCR, and its resistance value is set so that the gate voltage is equal to or higher than the gate trigger voltage required at low temperatures.

To explain the display section 40, this display section 4
0 is a magnetic reversal display device, and in FIG. 14, a disk 5 whose both ends are magnetized to N and S poles.
1 is rotatably supported around a rotation shaft 52,
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.

A magnetic pole portion 5 is provided between the magnetic pole portions 54a and 54b.
4a and 54b are attached to the disk 51 in the state shown in FIG.
A display drive coil 57 connected between the plus terminal 55 and the minus terminal 56 of the display section is wound so as to be magnetized with the same polarity as the magnetic poles at both ends of the display section. Furthermore, 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. has been done.

Display 59a and back surface 59b of the disk 51
Labels of different colors (in this embodiment, the front side 59a is black and the back side 59b is red) are displayed on the .

Then, when a detection current flows through the display driving coil 57, the magnetic pole portion 54a as shown in FIG.
is magnetized as an S pole, and the magnetic pole portion 54b is magnetized as an N pole, and the disk 51 has its N pole as a magnetic pole portion 54a (S pole).
The S pole is reversely rotated so as to face the magnetic pole portion 54b (N pole), and a label attached to the back surface 59b of the disk 51 is displayed to the outside.

Furthermore, when the return lever 43 is rotated to the position shown by the chain line in FIG. 2, the display unit 40 easily reverses the disk 51 by the magnet 45 attached to the return lever 43, and the normal position shown in FIG. It is now possible to return to the display state.

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

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

Now, the display ID is attached to the utility pole P using the mounting band 47, and the terminal plate 1 is attached to the grounding wire 49 provided on the power cable and power distribution equipment.
Connect 0 and 11.

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 increases, and becomes higher than the zener voltage of the zener diode ZD, and the zener diode ZD becomes conductive, the capacitor C voltage is divided by the resistors R1 and R2, and the voltage is increased by the resistor R2.
A voltage across the thyristor SCR is applied between the gate and cathode of the thyristor SCR.

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

When current flows through the display drive 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, disk 51
A sign attached to the back side 59b of is displayed externally,
Displays ground fault accident. Note that at this time, the display section 40
The disk 51 is located in the display window section 3 of the display case 33.
4 has a convex lens shape, so it 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, in order to restore the display ID, the return lever 43 must be moved from the state shown in FIG. 2 to the state shown by the chain line against the biasing spring 44. Rotate. 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 due to the urging force of the urging spring 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 steady display state, the external magnetic field φ1 may be applied to the stator 5 for some reason.
3, an electromotive force is generated in the short-circuited series circuit of the protective coil 58 and the resistor R2 due to electromagnetic induction accompanying 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,
This prevents display malfunctions caused by the external magnetic field φ1 of the disk 51.

Furthermore, in general, a thyristor turns on with a low gate voltage when the temperature rises, and turns on with a high gate voltage when the temperature drops, so its 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 the Zener voltage. No voltage is applied, so thyristor SCR does not turn on. When the voltage across the Zener diode ZD reaches a predetermined voltage and becomes conductive, the thyristor SCR
The gate voltage is applied to the thyristor.
SCR becomes conductive.

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

In this embodiment, the thyristor SCR can operate stably even when the temperature changes as described above.

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

Furthermore, 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 can be 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 thyristor
The SCR gate circuit is usually a Zener diode.
Since it is blocked by the ZD, the thyristor SCR will not malfunction due to radio waves, and it can reliably respond to only the fault current and display the fault.

The ground fault indicator ID configured as described above can detect ground fault current and does not require a separate operating power supply, so the structure can be simplified and the indicator
ID can be made smaller. Therefore, the indicator
The weight of the entire ID is reduced, the installation work becomes easier, and the efficiency of the installation work can be improved.

Furthermore, in this embodiment, the current transformer 25, which takes up a relatively large space, is disposed in the upper part of the case K, and the display case 33 is disposed in the lower part of the case K.
There is nothing obstructing visibility below the display window 34, and since the display window 34 is a circular convex lens, the viewing angle is large regardless of its installation status (vertically or horizontally), and the display status can be clearly observed. .

Furthermore, when assembling this display, the current transformer 25, which is relatively large compared to other components, is housed in the case K, and later the current transformer 25 is fixed by simply injecting the filler 41 into the case K. This allows for easy assembly.

Note that this invention is not limited to the above embodiments, but can be embodied in arrester deterioration indicators, etc.
Any changes may be made without departing from the spirit of the invention.

Effects of the Invention As detailed above, the present invention includes a current transformer in a case, a control circuit that outputs the current detected by the current transformer, and a magnetic field that indicates an accident based on the detected current from the control circuit. The inverting display device is placed, the terminals are fixed by attaching the lid to the box case, and the current transformer is installed with the primary winding that electrically connects both terminals. In addition to being easy to install, it can be designed very compactly as it does not require a separate operating power supply.As a result, it is easy to assemble and can be used indoors and outdoors, making it an excellent choice for industrial use. It is an invention.

[Brief explanation of the drawing]

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 longitudinal 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 a rear view, Figure 8 is a bottom view of the lid, Figure 9 is a rear view, and Figure 10 is a display unit. A sectional view of the 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 an electric circuit diagram of this display, and FIG. The figure is a perspective view of a magnetic reversal display device, FIG. 15 is a perspective view showing the same operation, and FIG.
The figure is a side view of the display with this indicator attached, FIG. 17 is a perspective view of the entire conventional fault current detection indicator excluding the molded part, and FIG. 18 is a front view of the conventional fault current detection indicator. 1...Box case, 10, 11...Terminal board, 1
6... Lid body, 25... Current transformer, 39... Control circuit board, 43... Return lever, 45... Magnet,
49...Grounding wire, 50...Full wave rectifier, 51...
Disc, 52... Rotating shaft, 53... Stator,
57...Display drive coil, ID...Display device,
SCR...Thyristor, R0, R1, R2...Resistor, C...Capacitor, ZD...Zener diode, K...Case.

Claims (1)

[Scope of 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 body of the box case and a current transformer held within the box case with a primary winding electrically connected to both the terminals. a control circuit that is electrically connected to the secondary winding of the current transformer and outputs a detected current based on the transformed current from the current transformer when a fault current flows to the primary winding; A fault current detection display characterized in that a magnetic reversal display device that performs a display operation using electric current is installed inside the case, and a display window is formed at one end of the case so that the display operation of the magnetic reversal display device can be visually recognized. vessel. 2. The fault current detection indicator according to claim 1, wherein the case composed of the box case and the lid is filled with a filler.