JPS59150352A - Ground-fault current detection and display for power cable and power distribution equipment - Google Patents

Abstract

PURPOSE:To keep the ground wire from being opened even when an ground- fault current flows by connecting the primary winding of a saturation type transformer in series to the ground wire while a display element is connected to the secondary winding thereof. CONSTITUTION:When an ground-fault current flows through a ground wire 1 due to a lightning surge and other accidents to saturate a core magnetic flux of a transformer 2, a peak voltage instantaneously generated in the secondary winding 4 is applied to a display element 5. Consequently, a spark generated between both terminals of a resistor 12, explodes a igniting agent 14 to break a display cylinder 13 and then, an insulation cylinder 6 is blacked by a combustion gas thereby checking the ground-fault current flowing through the ground wire 1. Even when the section is opened between both electrodes 10 and 11, the ground wire 1 is always closed, any surge generated continuously won't break a power distribution equipment.

Description

TECHNICAL FIELD AND OBJECTS The present invention relates to a power cable for high-voltage power distribution lines and a ground fault current detection indicator for power distribution equipment.

The ground fault current detection indicator is connected to the ground wire of the power cable, and when a ground fault occurs in the power cable, a ground fault current flows through this ground wire, and the ground fault current indicates a fault in the power cable. It looks like this. This display is characterized by a structure that does not open the ground wire even if a ground fault current flows and operates. That is, since the grounding wire is closed, there is no risk of induced voltage being generated on the cable surface and the power distribution equipment even in overcurrent conditions as well as lightning surges.

The purpose of this invention is to detect and display the ground fault current flowing in the ground wire, to reduce the labor and time required to search and discover a faulty cape, and to replace the display element without changing the ground resistance. An object of the present invention is to provide a ground fault current detection indicator that can be used repeatedly.

Embodiment An embodiment embodying the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a grounding wire of a power cable and power distribution equipment (not shown), and a primary winding 3 of a saturation transformer (CP) 2. are connected in series. When a ground fault current flows through the ground wire 1, the magnetic flux induced in the transformer 2 is saturated. 4 is a secondary winding of the transformer 2,
Display elements 5 are connected in series to both ends thereof. Then, at the moment when the ground fault current flows through the negative secondary winding 3 and the magnetic flux induced in the iron core is saturated, a peak voltage generated between the lines of the secondary winding 4 is applied to the display element 5. It looks like this.

Next, an example of the display element 5 will be explained according to FIG. 2. Reference numeral 6 is an insulating tube made of heat-resistant transparent synthetic resin such as polycarbonate, and support members 7 made of synthetic resin are attached to both ends of the insulating tube. It is fitted. A protective cover 8 is fitted around the outer periphery of both ends of the insulating tube 6, and a sealing material 9 is filled between the covers and the insulating tube 6 to seal the insulating tube 6. Reference numerals 10 and 11 denote electrodes that pass through the protective cover 8 and the support member 7 from outside the insulating cylinder 6 and project into the insulating m6, and a resistor 12 is placed between the two electrodes 10 and 11 within the insulating cylinder 6. is connected.

Reference numeral 13 denotes a display tube that covers the resistor 12, and electrodes 1o and ii are fitted to both ends to seal the resistor.The outer peripheral surface is colored with a highly visible color so that it can be seen from outside the insulating tube 6. It is possible. 14 is an incendiary agent placed around the resistor 12. The display element 5 configured as described above is connected to the secondary winding 4 of the transformer 2.

Next, the operation of the earth fault current detection indicator configured as described above will be explained.

Now, when a ground fault current flows through the ground wire 1 due to a lightning surge or other accident, and the iron core magnetic flux of the transformer 2 becomes saturated, the peak voltage generated in the secondary to winding 4 at that moment is applied to the display element 5. applied. Then, a spark is generated between both terminals of the resistor 12, the pyrotechnic agent 14 explodes, and the display cylinder 13 is destroyed. When the display tube 13 is destroyed, the insulating tube 6 is colored black by the combustion gas.

Therefore, by visually confirming that the display tube 13 has been destroyed and the color inside the insulating tube 6 has changed from the color of the display tube 13 to black, it can be confirmed that a ground fault current has flowed through the grounding wire 1. . Then, the resistor 12 is destroyed and both electrodes 10.1
Since the grounding line 1 is always closed even if the line 1 is opened, the power distribution equipment will not be destroyed even if a subsequent lightning surge occurs. Further, this display device can be used repeatedly by replacing the broken display element 5, and the replacement is also easy. Further, as the display element 5, in addition to the above-mentioned embodiments, it is also possible to use a needle type meter, a flash lamp, or other device capable of detecting and displaying the flow of current.

Effects As detailed above, this invention connects the primary winding 3 of a saturation transformer 2 in series to the grounding wire 1 of the power distribution equipment of a lightning cable, and connects the display element to the secondary winding 4 of the transformer 2. By connecting 5 in series, the grounding wire 1 can always be kept closed even after the grounding current flowing through the grounding wire 1 of the power distribution equipment of the power cable is detected and displayed, so that subsequent lightning surges, etc. This has an excellent effect of preventing damage to power distribution equipment even in the event of such occurrence.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a ground fault current detection indicator embodying the invention, and FIG. 2 is a sectional view showing the display element thereof. Grounding wire 1, saturation transformer 2, negative winding 3, secondary winding 4,
Display element 5°

Claims (1)

[Claims] 1. Connect the negative winding (3) of the saturation transformer (2) in series to the grounding wire (1) of the power distribution equipment of the power cable, and connect the secondary winding (4) of the transformer (2) A ground fault current detection indicator for power cables and power distribution equipment, characterized in that a display element (5) is connected in series to the power cable.