JPH0314921Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a ground fault indicator for electrical equipment that detects and displays the occurrence of a ground fault in electrical equipment such as insulators or columnar transformers used on utility poles. It is related to.

The purpose is to provide a ground fault indicator for electrical equipment that can be used, for example, to collect data for determining the effectiveness of current limiting elements installed in large numbers on power distribution lines.

In other words, even if a large number of current limiting elements are installed on the distribution line,
It is impossible to determine which parts were effective and which parts were meaningless because lightning strikes are instantaneous and current limiting elements recover. Therefore, the present inventor attempts to provide a simple ground fault indicator for electrical equipment that has a highly reliable and inexpensive operating body so that the effectiveness of the current limiting element can be easily determined on site. It is something.

The structure is such that when an abnormally high voltage is applied to the electrical equipment on the pole, a voltage non-linear current limiting element 13 is used to ground the application part for a short period of time to protect the electrical equipment. A search coil 28 is attached to the ground side of the current limiting element for detecting a discharge current for a minute time due to the application of abnormal high voltage passing through the current limiting element. a display body 43 that is always biased in the direction of display in order to display an operation during a ground fault; an operating body 65 that operates the display body in the event of a ground fault; In the ground fault indicator for electrical equipment, which is equipped with a switching element 42 for closing the power supply circuit and supplying power to the operating body 65, the operating body 65 is connected between the power source 29 and the switching element 42. the carbon resistor 66 and the display body 4 which is biased in the direction of display.
3 and a retaining piece 68 for retaining the housing part 26, and one end of the retaining piece 68 is connected to the carbon resistor 66 with a material that is easily melted by heat, so that the ground When the carbon resistor 66 is energized and generates heat in the event of a circuit accident, one end of the stopper piece 68 separates from the carbon resistor 66 to allow the display body 43 to protrude.

The drawings showing the embodiments of the present application will be described below. In FIGS. 1 to 7, reference numeral 1 denotes an arm of a utility pole, which is grounded to the earth via a grounding wire, as is well known. 2 is a high-voltage pin insulator (for example, a No. 10 solid high-voltage pin insulator), one end of which is fixed to the cross arm 1 with a support bolt 3 and a nut 4, and the other end is connected to a high-voltage distribution line 5 as is well known. is also fixed with a binding wire 6. The high voltage distribution line 5 is an insulated wire.

Next, the current limiting device 7 will be explained. Reference numeral 8 denotes a support piece, which is fixed to the insulator metal fitting 2a of the high-voltage pin insulator 2 by a fixture 9. This support piece 8 is formed of a metal material. Reference numeral 10 denotes an insulating container, in which a current limiting element 13, auxiliary electrode fittings 14, 15, etc. are provided. The insulating container 10 is made of an insulating material such as epoxy resin or porcelain, and has multiple flanges formed on its outer peripheral surface to increase the creeping distance between the upper and lower terminals. Also, insulating container 1
0 is closed by a seal plug 11 via an O-ring 12. The above-mentioned insulating container 10, etc., includes the electrode fitting 1
It is fixed to the tip of the support piece 8 by a lower terminal 16 connected to the support piece 8 and a nut 17. The current limiting element 13 is a sintered body containing zinc oxide as a main component, and has excellent nonlinearity (voltage nonlinearity). Reference numeral 19 denotes an arcing horn, which is fixed via a support piece 20 to the upper terminal 18 attached to the auxiliary electrode fitting 15. This arcing horn 19 is formed in an annular shape from a material with a low electrical resistance value such as copper or brass, and has a slight air gap on the outer peripheral surface of the high voltage pin insulator 2 between the high voltage distribution line 5 and the cross arm 1. They are placed separately.

Next, reference numeral 21 indicates a ground fault indicator, which is attached to the lower terminal 16 with a support fitting 22 and a nut 23. In this ground fault indicator 21, 24 is a case exemplified as a base body, which is formed of an insulating material (for example, synthetic resin) into the shape shown in the figure, and has a circuit element storage section 25 and a display body storage section inside. 26 are formed. In the circuit element storage section 25, 27 is a board, and a search coil 28, a battery 29, an electronic circuit 30, holders 31, 32, etc. are attached to this board. The search coil 28 has an air-core structure with several turns, and is arranged to interlink with the support piece 8. For example, as the battery 29,
Two 1.5V dry batteries are used.

Next, the reference numeral 61 shown in FIG. 2 is a display storage case, which is formed into a cylindrical shape using a synthetic resin material. 62 indicates a groove formed in a part thereof. This case 61 houses a display body 43, a biasing spring 64, a cutting body 65, and the like. In the cutting body 65, 66 indicates a main body, 67 indicates an upper lead wire, and 68 indicates a stopper piece. The main body 66
A carbon resistor of several ohms to several tens of ohms and a small wattage is used, and one of the lead wires is removed and a stopper piece 6 is installed in its place.
The cutting body 65 is constructed by attaching the cutting member 8 by a means that is easy to melt and cut, such as by soldering. A flexible covered electric wire is used for the above-mentioned retaining piece 68, and this is connected to the display body 43 as shown in FIG.
It is connected to a switching element as shown in FIG. 5 through the groove 63 provided in the groove 63 and the groove 62 described above.

In the case of the above structure, under normal conditions, when the bottom of the groove of the display body 43 is pulled by the stopper piece 68, the display body 43 is located inside the case 61 as shown in FIGS. 2 and 3.

In the case of the above structure, if an abnormally high voltage is applied due to a lightning strike or other cause to the high voltage distribution line 5 where the insulation coating has been damaged near the insulator 2 for some reason, the above-mentioned voltage distribution line 5 An arc is generated from the damaged part of the coating toward the arm 1 or the insulator metal fitting 2a that is grounded. In this case, since the arcing horn 19 is present between the high-voltage power distribution line 5 and the cross arm 1, electric discharge is started between the damaged part of the coating and the arcing horn 19. The discharge current is arcing horn 19, support piece 2
0, upper terminal 18, auxiliary electrode fitting 15, current limiting element 13, electrode fitting 14, lower terminal 16, support piece 8,
It flows to the ground through the fixture 9, the insulator metal fitting 2a, the cross arm 1, the grounding wire, etc., that is, through the protective grounding circuit. In this case, since the current limiting element 13 has excellent voltage nonlinearity, the response to the abnormal high voltage is fast.
The discharge current based on the discharge is discharged on the order of several tens of microseconds. Therefore, even if an arc occurs due to the abnormally high voltage mentioned above, only the abnormally high voltage is discharged and then 50 or 60 cycles are generated.
The commercial frequency of the cycle does not overlap, and the follow-on current is blocked. In the above case, due to the presence of the arcing horn 19, the arc does not lick the surface of the high voltage pin insulator 2, and damage to the high voltage pin insulator 2 is prevented.

When a ground fault current flows through the support piece 8 due to the discharge as described above, the ground fault indicator 21 detects the ground fault current and performs an indicating operation. Next, its operation will be explained. When the ground fault current flows, the current is first detected by the search coil 28, and the search coil 28 produces an output current. This output current is rectified by a rectifier 41 and connected to the switching element 4.
Added to gate 2. The switching element 42 then becomes conductive. As a result, current flows through the cutting body 65. Then, the main body 66 generates heat, and the connecting portion between the main body 66 and the stopper piece 68 is fused and separated. Then, the display body 43 projects downward from the case 24 as shown in FIG. 4 by the force of the biasing spring 64. This makes it possible to indicate that a ground fault current has flowed. It is preferable that the display body 43 is provided with a nighttime reflective tape or reflective paint so that its protruding state can be easily detected even from a distance.

Next, FIGS. 8 to 12 show different embodiments. In the figure, the support fitting 22g includes tongue pieces 71, 71 that are designed to sandwich the support piece 8g, and a tongue piece 7 that can be bent and engaged with the end portion 8g' of the support piece.
2. Board 27g is insulation collar 7
3, 74, bolts 75, and nuts 76 to fix it to the case 24g. Also search coil 2
8g is wound around the outer periphery of the battery 29g which is fixed to the substrate 27g with a binding wire 77. A carbon resistor similar to that in the previous embodiment is used as the operating body 78, and its upper lead wire 7
8a is connected to a switching element, and a lower lead wire 78b is connected to a positive terminal of a battery 29g. The display body 43g is constructed using a light thin plate made of synthetic resin, etc., and has a long hole 79 in its center.
is formed so that its vertical movement is guided by the insulating collar 74. Also, display body 43
A hooking portion 80 is formed at the lower part of
The other end of a retaining piece 68g connected by low alloy metal (solder) is connected to the base of the plate.

The above configuration is normally shown in Figures 9 and 10.
It is in the state shown in the figure. On the other hand, when a ground fault current flows and current flows through the operating body 78 in the same manner as described above, the operating body generates heat and the stopper piece 68g separates from the operating body 78. As a result, the display body 43g falls and protrudes downward from the case 24g, as shown in FIG. 12, and enters the display state. The circuit in this embodiment has the same structure as that shown in FIG. 5 above.

It should be noted that parts that are functionally the same or equivalent to those in the previous figure are given the same reference numerals as those in the previous figure with the letter g, and redundant explanations are omitted.

Next, FIGS. 13 and 14 show a further different embodiment, and show an example in which differential search coils 81, 81 are used as the search coils in the previous embodiment. When such differential search coils 81, 81 are used, even if a ground fault current (discharge current) flows in an adjacent utility pole, electromagnetic induction due to the current will not be detected, and the indicator will not be attached. This method detects only when a ground fault current flows through the supporting piece of a utility pole. Therefore, when a ground fault current flows in an adjacent utility pole, the indicator attached to the utility pole is prevented from erroneously detecting it and entering a display state.

As described above, in the present invention, the current limiting element 1
3 has the practical effect of increasing the possibility of protecting electrical equipment (insulators, pole transformers, etc.) from abnormally high voltages. By attaching a ground fault indicator 43 for electrical equipment to each current-limiting element 13, it is possible to tell which current-limiting element 13 will operate during a lightning strike and which current-limiting element 13 will operate. It also has the effect of collecting useful data such as non-operating data. Of course, the above case has the advantage that even if the current flowing through the current limiting element 13 lasts for an extremely short period of several tens of microseconds, it can be displayed without malfunction.

Moreover, the operating body 65 utilizes a carbon resistor 66 connected between the power source 29 and the switching element 42, and when the search coil 28 detects a discharge current, the operating body 65 immediately causes the carbon resistor 66 to generate heat to close the stopper piece 68. Since it is configured to be separated, there is an effect that the reliability of the operation of the display body 43 is increased. That is, the reliability of the heat generation of the carbon resistor 66 when energized is extremely high, and the carbon resistor 66 does not deteriorate over time, can maintain the above reliability for a long time, and is inexpensive. By connecting one end of the retaining piece 68 to the resistor 66 using a thermally fused material, the feature is utilized for retaining the display body 43, and as a result, the operating body 65 is miniaturized. Many practical effects have resulted, such as the case 24 becoming smaller and more compact.

This type of reliability of operation is unprecedented in conventional examples.
The excellent features of simple configuration and low cost are important for planning the deployment of current limiting devices in other districts and prefectures, as well as for knowing the quality of current limiting devices in the field. It can be said that this is a practical and excellent idea.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, in which Fig. 1 is a partially cutaway front view, Figs. 2 to 4 are longitudinal sectional views, Fig. 5 is an electric circuit diagram, and Figs. 6 and 7 are longitudinal sectional views. 8 is a front view, 9 and 10 are longitudinal sectional views, 11 is a horizontal sectional view, 12 is a front view,
FIGS. 13 and 14 are partially cutaway views. 9... Current limiting device (grounding circuit), 24... Case (base body), 28... Search coil (detection circuit), 3
3...Rupture disconnection body (display mechanism), 43...Display body (display mechanism).

Claims (1)

[Scope of utility model registration request] The electrical equipment on the pole is equipped with a current-limiting element 1 with voltage non-linearity to protect the electrical equipment by grounding the application part for a short period of time when an abnormally high voltage is applied to the electrical equipment.
3 is attached to the ground side of the current limiting element, and a search coil 28 is attached to the ground side of the current limiting element for detecting a discharge current for a minute time due to the application of abnormally high voltage passing through the current limiting element. A display body 43 that is always biased in the direction of display to display the operation in the event of an accident;
Operating body 65 for operating the display body in the event of a ground fault accident
and a switching element 42 for receiving a signal from the search coil 28 in the event of a ground fault to close the power circuit and energize the operating body 65. The operating body 65 is composed of a carbon resistor 66 connected between the power source 29 and the switching element 42, and a retaining piece 68 for retaining the display body 43, which is biased in the above-mentioned direction, in the storage portion 26. One end of the stopper piece 68 is connected to the carbon resistor 66 using a material that easily melts due to heat, so that when the carbon resistor 66 is energized and generates heat in the event of a ground fault, the trigger A ground fault indicator for electrical equipment, characterized in that one end of the stopper piece 68 is separated from the carbon resistor 66 to allow the indicator 43 to protrude.