JPH07220851A - Deterioration detecting device for lighting arrester - Google Patents

Abstract

PURPOSE:To prevent the total thermal breakdown of a lightning element by detecting the infiltration of a large thunder surge capable of causing a thermal breakdown into part of unit lightning elements constituting the lightning element of a lightning arrester. CONSTITUTION:This deterioration detecting device 9 is constituted of a detecting element 90 connected in series to a lightning element 2, a neon lamp 94 serving as a light emitting element and connected in parallel with the detecting element 90, an optical fiber 95 transmitting the light emitted by the neon lamp 94, and a light detecting device 96 receiving the light transmitted by the optical fiber 95, converting it into an electric signal, and judging the presence of light via the process by an electronic circuit. The detecting element 90 is constituted of a lightning element 91 having a withstand current slightly smaller than that of the lightning element 2 and electrodes 92, 93 pinching it. When a thunder surge infiltrates to cause the thermal breakdown of the detecting element 90, the light emitting element 94 emits no light. When it is detected, the infiltration of a large thunder surge near the withstand current into a lightning arrester 100 can be judged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects that a lightning arrester for protecting electric equipment installed in a power system from a lightning surge is partially destroyed by thermal damage due to a large lightning surge and is deteriorated. The present invention relates to a lightning arrestor deterioration detection device for preventing thermal destruction.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view of a conventional lightning arrester. In this figure, a lightning arrester 100 has a lightning arrester element 2 in which a plurality of elements are stacked in an insulating cylinder 1 made of an insulator.
It is sandwiched between 32 and stored. The lightning arrester element 2 is formed by stacking unit lightning arrester elements 20 in series. In the figure, the number of unit lightning arresters 20 is 15. The spring 33 applies a predetermined pressure stably without being affected by the temperature change. Insulation cylinder 1 containing the lightning protection element 2
The interior of the lightning protection element 2 is filled with dry air or dry nitrogen so that the lightning protection element 2 does not deteriorate in characteristics due to moisture absorption. In order to make the inside of the insulating cylinder 1 airtight, a pressure release plate 5 covers the upper opening of the insulating cylinder 1. By the way, the total height of the arrester 100 is about 1 m.

A metal lid 4 is provided on the upper part of the insulating cylinder 1 and is attached to the insulating cylinder 1 with bolts 7. A packing (not shown) is provided on the surface of the lid 4 that comes into contact with the insulating cylinder to maintain airtightness. Further, the pressure relief plate 5 is attached to the outside of the lid 4 by a mounting plate which is not attached to the bolt 51, and the contact surface between the lid 4 and the pressure relief plate 5 is also provided with a packing (not shown) to provide an airtight seal. Is held. The pressure release plate 5 is constructed by coating a thin copper plate of about 0.1 mm with epoxy resin on one surface.

The lid 4 is provided with through-holes on both sides of the central portion of the drawing, and the pressure relief plate 5 directly contacts the dry gas in the insulating cylinder 1 at that portion. The upper portion of the spring 33 is supported by the cap 34, and the rectangular cross section above the cap 34 is a part of the lid 4. The upper electrode 31 and the lower electrode 32 of the lightning protection element 2 are connected by four insulating bolts (not shown). The insulating bolts support the lightning protection element 2 so as not to collapse even if the tightening force is insufficient. Has been done.

The terminal 80 on the high voltage side is connected to the high voltage wiring by a lead (not shown), and is connected to the electrode 31 from the terminal 80 through a copper plate (not shown) provided in parallel with the cover 6, the bolt 7, the lid 4 and the spring 33. High voltage is being applied. Further, in the lower part, the ground lead 83 is mounted by being sandwiched between the terminal 81 and the terminal plate 82, and the terminal 81 is electrically connected to the electrode 32 via the mounting metal fitting 35. In this way, the lightning arrester element 2 is sandwiched between the high voltage side electrode 31 and the ground side electrode 32 and a high voltage is applied.

When the applied voltage is a steady voltage, the lightning arrester element 2 has a high resistance and only a small leakage current flows, and the value is the capacitance between the electrodes 31 and 32 when the lightning arrester is sound. It is usually much smaller than the charging current of the component. On the other hand, when a lightning surge enters the high-voltage wiring and the voltage exceeds the limit voltage determined by the characteristics of this arrester, the resistance value drastically decreases and a large current flows, limiting the rise in the voltage of the system and installing it in the vicinity. Protects electrical equipment such as existing transformers and circuit breakers from lightning surges.

The pressure release plate 5 is provided on the upper and lower electrodes.
This is to prevent the insulation cylinder 1 from being broken due to a pressure increase inside the insulation cylinder 1 when dielectric breakdown occurs between the electrode 31 and the electrode 32 for some reason and a continuous arc is generated. The arc is generated when the lightning arrester element 2 is destroyed and the arc is developed when the debt exceeding the protection capability of the lightning arrester is given.
The pressure rise due to the generation of such an arc destroys the pressure relief plate 5 and the high pressure gas generated by the arc causes the cover 6 to
Among these, the pressure rise in the insulating cylinder 1 is restricted by being released to the outside through the pressure release hole 61 provided on the left side of the cover 6 in the figure. An arc horn 62 is provided at a position where high-pressure gas is released, and the high-pressure gas containing ions generated by the internal arc facilitates dielectric breakdown between the arc horn and ground, resulting in an insulating cylinder. The arc generated inside 1 moves between the arc horn 62 and the ground, and has a function of stopping the pressure increase in the insulating cylinder 1.

The above-mentioned debt exceeding the protection capability of the lightning arrester is specifically that the energy value obtained by time-integrating the product of current and voltage is so large that the lightning protection element cannot withstand, and as a result, the lightning protection element 2 is heated. Although it is destroyed, if the lightning arrester element 2 is replaced, it can be used again as a lightning arrester.

[0009]

By the way, there is a case in which all of the unit lightning arrester elements 20 are not destroyed by heat but only a part thereof is destroyed by heat and the others are sound. In such a case, the lightning arrester will be in a normal state after the lightning surge disappears. That is, the lightning protection element 2 as a whole maintains a sufficiently large resistance value with respect to a steady voltage.

Generally, the deterioration of the lightning arrester element 2 of the lightning arrester is detected by measuring the leakage current. However, even if the partial thermal destruction of the lightning arrestor as described above occurs, the leakage current does not immediately increase. There is. This is because the increase of the leakage current due to the deterioration of the lightning arrester element 2 becomes so large that it is detected only when the deterioration of the entire lightning arrester element 20 is accumulated over a considerably long period.

Due to the above-mentioned reasons, there is a problem that even if a part of the unit lightning arrester element 20 is thermally destroyed, it cannot be detected by the conventional technique. An object of the present invention is to solve such a problem and detect that a part of the unit lightning arrester 20 is provided with a debt enough to cause thermal destruction, so that the lightning arrester of the lightning arrester can operate in a system due to total thermal destruction. An object of the present invention is to provide a deterioration detection device for a lightning arrester that does not hinder normal operation.

[0012]

According to the present invention, in order to solve the above-mentioned problems, a lightning arrester, in which a plurality of unit lightning arresters are connected in series and sandwiched by both electrodes on the high voltage side and the ground side, is an insulating cylinder. A deterioration detecting device for detecting deterioration of a lightning arrester housed therein, a detection element connected in series to the lightning arrester element of the lightning arrester,
It consists of a light emitting element connected in parallel to this detection element and a photodetector for detecting the presence or absence of light emission of this light emitting element, and the detection element is a current of a predetermined value smaller than the lightning arrester element of the lightning arrester, with both sides sandwiched by electrodes. It shall consist of a lightning arrester having a predetermined voltage sharing ratio with respect to the withstand capability and the lightning arrester of the lightning arrester. Further, it is assumed that the light emitting element is a neon lamp or a light emitting diode.

[0013]

In the structure of the present invention, when the detecting element composed of the lightning arrester is connected in series to the arrester and the light emitting element is connected in parallel to this detecting element, when the detecting element is normal, the capacitor between the arrester and the detecting element is separated. A voltage is generated between the terminals of the detection element based on the voltage division ratio based on the pressure, the light emitting element emits light, and when the detection element is thermally destroyed, the light emitting element becomes conductive, so that the light emitting element does not emit light. Therefore, the presence or absence of thermal destruction of the detection element can be detected by detecting this light with the light detection device. By setting the current withstanding capability of the detection element to a value smaller than the current withstanding capability of the lightning arrester, even if the detection element is thermally destroyed, the lightning arrester element of the lightning arrester is not totally thermally destroyed. By setting the current resistance of the detection element to a value that is as large as possible under the above conditions, when the detection element is thermally destroyed, some of the multiple lightning arresters that compose the lightning arrester of the lightning arrester cause thermal destruction. It can be determined that there is a possibility. As the light emitting element, a neon lamp, a light emitting diode, or the like can be used as an element that emits light by a current flowing through the lightning arrester when a voltage is constantly applied.

[0014]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a schematic diagram of a lightning arrester and a deterioration detecting apparatus therefor according to an embodiment of the present invention. The same components as those of the lightning arrester 100 shown in FIG. See also FIG.
Then, illustration of components not directly related to the present invention is omitted. In FIG. 1, the deterioration detection device 9 transmits a detection element 90 electrically connected in series to the lightning arrester 100 via the electrode 32 on the low voltage side, a neon lamp 94 and light emitted from the neon lamp 94 in parallel to the detection element 90. The optical fiber 95 and the photodetector 96 provided at the monitoring station for receiving the light transmitted by the optical fiber 95 and determining the presence or absence of the light.

The detection element 90 is a lightning protection element 91 and electrodes sandwiching it.
The lightning protection element 91 is made of the same material as that of the lightning protection element 2, and its cross-sectional area is set to be slightly smaller than that of the lightning protection element 2. The thickness of the lightning protection element 91 is set so that the neon lamp 94 is lit during normal operation and a voltage of about 100 V that can detect it by the photodetector 96 is generated between the electrodes 92, 93. The voltage sharing ratio between the arrester 100 and the deterioration detection device pressure 9 is determined by their respective impedances. Since the impedance of the lightning arrester 100 has almost the capacitance between the electrodes 31 and 32, the resistance value of the lightning arrester element 2 can be ignored as long as this is normal. The impedance of the deterioration detecting device 9 is determined by the capacitance between the electrodes 92 and 93 of the detecting element 90 and the impedance of the neon lamp 94. The thickness of the lightning protection element 90 is set in consideration of these impedances.

The cross-sectional area of the lightning arrester element 91 is made smaller than that of the lightning arrester element 2 when the surge of large energy close to the current withstanding capacity of the lightning arrester 100 enters, the lightning arrester element 2 does not cause total thermal destruction and the detection element 90 Is to cause thermal destruction. If the cross-sectional area of the lightning arrester 91 is set smaller than that of the lightning arrester 2, the lightning arrester 100 is given a debt close to the current withstanding capability when the lightning arrester 100 is in a normal state and the lightning arrester 100 is normal. Therefore, it can be considered that there is a possibility that a part of the plurality of unit lightning protection devices 20 has caused thermal destruction.

When the detection element 90 is thermally destroyed, the electrodes 92, 93
Since the impedance between them becomes substantially zero, the detection element
The voltage between 90 becomes zero and the neon lamp 94 does not emit light. Therefore, it is determined that the photodetection device 96 has detected this and the detection element 90 has caused thermal destruction. If such a decision is made, remove the arrester 100 and check if it is really defective. When a voltage application test is performed to apply a voltage up to the limit voltage of the lightning arrester 100, if some of the unit lightning arrester elements 20 are damaged by heat, they operate at a voltage lower than the normal limit voltage and the limit voltage drops. It is easy to see that the product is defective. Of course, when the limiting voltage is not lowered, the lightning protection device is normal and can be reused.

The lightning protection element 91 is practically made of the same material as the lightning protection element 2. At this time, the cross-sectional area of the lightning protection element 91 is determined in consideration of variations in the characteristics of the unit lightning protection element 20. . If the cross-sectional area of the lightning arrester element 91 is too small, the probability of judging that the lightning arrester 100 is defective is high even though the lightning arrester 100 is normal, and the frequency of tests for determining the quality of the lightning arrester 100 as described above increases. As a result, various problems such as an increase in test cost occur. On the other hand, if the cross-sectional area is too large, there is a problem that the probability that the lightning arrester 100 itself will be totally destroyed by heat will decrease the effect of providing the deterioration detection device 9. Therefore, in determining the cross-sectional area of the lightning protection element 91, an optimum value must be set in consideration of various factors.

When the cross-sectional area of the lightning arrester element 91 is determined, the actual lightning arrester element 91 is easily manufactured by cutting out the same material as the unit lightning arrester element 20 with a predetermined thickness and cutting out a part of the cross section. It is possible to manufacture the lightning protection device 91 that satisfies the specifications. Of course, the arrester as the lightning arrester element 91
It is not necessary to use the same material as the lightning protection element 2 of 100, and it is also possible to use the material of the lightning protection element having a different diameter as long as a desired function can be obtained.

The position where the detection element 90 is provided can be provided immediately above the electrode 32. It is also possible to use the space where the mounting bracket 35 is provided. When such a detecting element 90 is provided in the insulating cylinder 1, the neon lamp 94 may be similarly provided in the insulating cylinder 1 and the optical fiber 95 may be pulled out from the inside. When installing the deterioration detector 9 on the existing lightning arrester 100, the detector element 9
Both the 0 and neon lamps 94 can be provided at appropriate positions outside the insulating cylinder 1.

The neon lamp 95 informs whether the detection element 90 is normal or has caused thermal destruction by the presence or absence of light emission. Therefore, the neon lamp 95 is not limited as long as it has the same function. For example, a light emitting diode which is frequently used as a light emitting element may be used. However, since the light emitting diode has a small impedance when emitting light, it is necessary to adopt an appropriate circuit configuration such as connecting a series resistor.
Further, the optical fiber 95 and the photodetector 96 are for performing optical transmission and converting the transmitted light into an electric signal and then performing necessary processing by an electronic circuit, but such an apparatus has been used in many fields in the past. However, the optimum one can be easily configured within the range of the related art.

[0022]

As described above, according to the present invention, by providing the detecting element connected in series to the lightning arrester element of the lightning arrester and the light emitting element connected in parallel to the lightning arrester element, the light emitting element emits light under normal conditions, and a lightning surge is introduced. When the lightning protection element that constitutes the detection element is thermally destroyed due to excessive debt, the voltage between the terminals of the detection element becomes zero and the light emitting element does not emit light. It is possible to detect the presence or absence of thermal destruction of the detection element, and the thermal destruction of the detection element 90 indicates that the surge arrester was given a large debt close to the current withstand capability. By investigating whether or not a failure has actually occurred by performing it, it is possible to prevent the lightning arrester from being thermally destroyed and hindering the normal operation of the system. It is obtained.

A neon lamp or a light emitting diode is adopted as the light emitting element to obtain the above effects.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a lightning arrester and its deterioration detecting device showing an embodiment of the present invention.

[Fig. 2] Cross section of lightning arrester

[Explanation of symbols]

100 Lightning arrester 1 Insulation tube 2 Lightning arrester 31, 32 Electrode 9 Deterioration detector 90 Detector 91 Lightning arrester 92, 93 Electrode 94 Neon lamp (light emitting element) 95 Optical fiber 96 Photodetector

Claims (3)

[Claims] 1. A deterioration detecting device for detecting deterioration of a lightning arrester, comprising a plurality of unit lightning arresters connected in series, and a lightning arrester sandwiched between electrodes on a high voltage side and a ground side being housed in an insulating cylinder. It is composed of a detection element connected in series to the lightning protection element, a light emitting element connected in parallel to this detection element, and a photodetection device for detecting the presence or absence of light emission of this light emitting element. The detection element is sandwiched by electrodes on both sides of the lightning arrester. Of the lightning arrester having a current withstand value of a predetermined value smaller than that of the lightning arrester and a predetermined voltage sharing ratio to the lightning arrester of the lightning arrester. 2. The deterioration detecting device for a lightning arrester according to claim 1, wherein the light emitting element is a neon lamp. 3. The lightning arrester deterioration detection device according to claim 1, wherein the light emitting element is a light emitting diode.