JPH0262827B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a device for detecting performance deterioration of a lightning arrester.
In particular, the present invention relates to a device for detecting performance deterioration of a lightning arrester in which a plurality of lightning arrester units using zinc oxide nonlinear resistors are stacked.

[Technical background of the invention]

In recent years, zinc oxide-based resistors with excellent non-linearity have been developed, and gear press type lightning arresters in which zinc oxide-based non-linear resistor elements are laminated have been developed and have already been put into practical use.

Such a zinc oxide-based nonlinear resistor element (hereinafter referred to as
For example, as shown in FIG. 1, a lightning arrester using a ZnO element (abbreviated as ZnO element) has an internal element 3 formed by stacking a plurality of cylindrical ZnO elements 2 inside a cylindrical insulator 1. The lower end opening and upper end opening of the insulator 1 are hermetically covered by a grounding frame 4 and a high pressure flange 5, respectively.
The high voltage flange 5 is connected to the high voltage side of the power system, and the grounding frame 4 is grounded to the earth.

In general, it is important for lightning arresters installed in power systems to maintain the same characteristics over a long period of time. In the above-mentioned lightning arrester, an increase in leakage current of the ZnO element is a major factor in deteriorating the characteristics. Therefore, the leakage current and temperature of the ZnO element of the lightning arrester are measured at regular intervals from when the lightning arrester was installed, and when the leakage current and temperature exceed the preset values, the lightning arrester is activated. We are currently carrying out inspections and repairs. In the lightning arrester shown in FIG. 1, the leakage current of the ZnO element 2 located at the bottom of the internal element 3 is measured, and if this leakage current value is below a preset limit value, the internal element 2 Since the leakage current value can be considered to be below the limit value throughout, it was determined that there would be no deterioration in the characteristics of the arrester as a whole.

[Problems with background technology]

However, the above-mentioned means for determining performance deterioration of a lightning arrester has the following problems. In other words, lightning arresters using ZnO elements include not only lightning arresters that are composed of one internal element 3 and one insulator tube 1 as shown in Fig. 1, but also lightning arresters that use the lightning arrester shown in Fig. 1 as one lightning arrester unit. Some lightning arresters are constructed by stacking multiple units.

FIG. 2 is a longitudinal sectional view of a lightning arrester using two lightning arrester units as described above. In other words, each of the vertically stacked lightning arrester units 6a, 6b has a plurality of lightning arresters in each of the same insulator tubes 1a, 1b.
It accommodates internal elements 3a and 3b of the same configuration consisting of ZnO elements 2a and 2b, the upper and lower end openings of the insulator tube 1a are closed by the high pressure flange 5a and the intermediate flange 7a, and the upper and lower end openings of the insulator tube 1b are closed by the intermediate flange 7b. and is closed by the grounding frame 4b.

The leakage current in a lightning arrester with such a configuration is as follows. Now, when a high voltage is applied to the high-voltage flange 5a, the leakage current flowing through the internal element 3a of the upper lightning arrester unit 6a is I _1a , the leakage current flowing through the outer surface of the insulator tube 1a is I _0a , and Let I _1b be the leakage current flowing through the internal element 3b of the unit 6b, and i _0b be the leakage current flowing through the outer surface of the insulator tube 1b. Immediately after installing the lightning arrester, each insulator tube 1a,
Since the outer surface of lightning arrester 1b is not contaminated and each lightning arrester unit 6a, 6b has the same configuration, the shared voltages of each lightning arrester unit 6a, 6b are equal to each other. Therefore, each of the above leakage currents I _1a , I _0a , I _1b ,
The following relationship holds true for I _1b .

I _1a = I _1b I _0a = I _0b I _1a + I _0a = I _1b + I _0b (1) However, after a certain amount of time has passed since the installation time, each insulator 1 of each lightning arrester unit 6a, 6b
If there is a difference between the degrees of contamination of the outer surfaces of tubes a and 1b, the shared voltage of the insulator tube with the greater degree of contamination will decrease. Therefore, since the shared voltage of each lightning arrester unit 6a, 6b is different, the relational expression of each leakage current described above changes from equation (1) to equation (2).

I _1a ≠I _1b I _0a ≠I _0b I _1a + I _0a = I _1b + I _0b ...(2) Therefore, for example, the lower lightning arrester unit 6
If the outer surface of the insulator tube 1b in b is contaminated and the shared voltage of the upper lightning arrester unit 6a increases as a result, I _1b < I _1a (3), and the internal elements of the lower lightning arrester unit 6b become larger. 3b
The leakage current I _1b flowing through the pipe is reduced compared to when it is installed.

Therefore, the lowest part of the internal element 6b
Conventionally, the leakage current of the ZnO element 2b was measured, this leakage current was taken as the leakage current I _1b of the internal element 6b, and the performance deterioration of the entire lightning arrester was determined based on the value of this leakage current I _1b . In the case of the means described above, the performance deterioration of the internal element 3b in the lower lightning arrester unit 6b is detected, but the deterioration in the performance of the internal element 3b in the lower lightning arrester unit 6b is detected.
There was a risk that the performance deterioration of the internal element 3a would not be detected.

Therefore, the development of a lightning arrester performance deterioration detection device that can accurately detect not only the performance deterioration of the internal element 3b of the lower stage lightning arrester unit 6b but also the performance deterioration of the internal element 3a of the upper stage lightning arrester unit 6a has been awaited. .

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its purpose is to provide a simple structure and to prevent performance deterioration of each lightning arrester unit, even if the arrester is composed of a plurality of lightning arrester units. It is an object of the present invention to provide a performance deterioration detection device for a lightning arrester that can perform accurate detection and improve the reliability of the entire lightning arrester.

[Summary of the invention]

In order to achieve the above object, the performance deterioration detection device of the present invention also includes an element that measures the leakage current of the zinc oxide nonlinear resistor element (ZnO element) located at the lowest end of the lowermost lightning arrester unit. A leakage current measuring device is installed, and a surface leakage current measuring device is also installed to measure the leakage current on the outer surface of the insulator tube in the lowermost lightning arrester unit. If the current value measured by the element leakage current measuring device is greater than or equal to a predetermined upper limit value, and if this current value is less than or equal to a predetermined lower limit value and the current value measured by the surface leakage current measuring device is An alarm is issued when the measured current value exceeds a predetermined set value.

With this configuration, when the element leakage current value exceeds the upper limit value, performance deterioration of the lowermost lightning arrester unit is detected, and when the element leakage current value falls below the lower limit value, The present invention is also characterized in that performance deterioration of the lightning arrester units other than the lowest one can be detected when the surface leakage current value exceeds a set value.

[Embodiments of the invention]

FIG. 3 is a block diagram showing a schematic configuration of a lightning arrester performance deterioration detection device according to an embodiment of the present invention, and this performance deterioration detection device is attached to the lightning arrester shown in FIG. Therefore, since the same parts as in FIG. 2 are given the same reference numerals, the explanation of the overlapping parts will be omitted.

In this embodiment, ZnO at the lowest end of the internal element 3b in the lower lightning arrester unit 6b of the lightning arrester is used.
One end of the measurement line 11 for detecting the leakage current of this ZnO element 2b, that is, the leakage current _I1b flowing through the internal element 3b, is attached to the element 2b.
An element leakage current measuring device 12 is connected to the other end of the device. Further, a conductive tape 13 is attached to the outer peripheral surface of the insulator tube 1b of the lower lightning arrester unit 6b near the lower end for detecting the leakage current _I0b flowing on the outer surface of the insulator tube 1b.
The conductive tape 13 is connected to a surface leakage current measuring device 15 via a measuring wire 14.
The respective outputs of the element leakage current measuring device 12 and the surface leakage current measuring device 15 are input to a determination device 16. An alarm device 17 is connected to the output end of this determination device 16.

The determination device 16 and alarm device 17 are provided with the following functions as a means for determining and displaying the performance deterioration of the lightning arrester based on the above leakage currents I _1b and I _0b . That is, as shown in FIG. 4, when the leakage current I _1b of the internal element b input from the element leakage current measuring device 12 exceeds the predetermined upper limit value I ₁ max, or the above also occurs. When the leakage current I _1b becomes less than the predetermined lower limit I ₁ min, the leakage current I _0b flowing through the outer surface of the insulating tube 16 inputted from the surface leakage current measuring device 15 is determined in advance and set at a predetermined value. When the value exceeds I _0s , an alarm signal is sent from the determination device 16 to the alarm device 17. Then, the warning device 17 displays the performance deterioration of the lightning arrester.

Above upper limit value I ₁ max, lower limit value I ₁ min and set value
I _0s is determined as follows. That is, when the leakage current I _1b flowing through each ZnO element 2b of the internal element 3b increases, each ZnO element 2b generates heat,
Although the performance of each ZnO element 2b deteriorates, various experiments have been conducted to find out to what extent the leakage current I _1b described above deteriorates in performance of the lightning arrester, and this critical current value is the upper limit of the above-mentioned upper limit. The value is I ₁ max. Therefore, if the leakage current I _1b exceeds the upper limit value I ₁ max, the performance of the lightning arrester may deteriorate.

Next, when the outer surface of the insulator tube 1b of the lower lightning arrester unit 6b becomes contaminated, the leakage current I _1a of the internal element 3a increases as described above, and the leakage current I _1b of the internal element 3b increases.
decreases. And the leakage current of the internal element 3a
As with the above upper limit value I ₁ max, many experiments have been conducted to determine to what extent the leakage current _{I 1b of} the internal element 3b decreases when I 1a exceeds the above upper limit value I ₁ max. This limit current value is the lower limit value I ₁ min. However, this lower limit value I ₁ min changes depending on the degree of contamination of the outer surface of the insulator tube 1b of the lower lightning arrester unit 6b, so for example, if the degree of contamination of the outer surface of the insulator tube 1b becomes extremely large, the lower limit value I ₁ min becomes even more. There is a possibility that it will decrease.
Therefore, determining performance deterioration only when the leakage current I _1b of the internal element 3b becomes equal to or less than the lower limit value I ₁ min may lead to an erroneous determination. Therefore, in this embodiment, only the leakage current _I1b corresponding to the shared voltage flows through the internal register element 3b.
When the leakage current I _1a of the internal element 3a exceeds the upper limit value I ₁ max, there is a high possibility that most of this leakage current I _1a flows through the outer surface of the lower porcelain tube 1b. Therefore, it can be determined that the performance of the upper lightning arrester unit 6a has deteriorated when the leakage current I _0b flowing through the outer surface of the insulator tube 1b of the lower lightning arrester unit 6b exceeds a certain set value I _0s . For example, the above set value I _0s may be set to the upper limit value I ₁ max in the internal elements 3a, 3b.

As described above, when the leakage current I _1b of the internal element 3b becomes less than the lower limit value I ₁ min and the leakage current I _0b of the insulator tube 1b becomes more than the set value I _0s , the upper lightning arrester unit 6a If it is determined that the performance has deteriorated, this judgment can be said to be a fairly accurate judgment.

FIG. 4 is a diagram showing the determination circuit 16 using an OR gate and an AND gate. As shown in the figure, when the leakage current I _1b becomes more than the upper limit value I _1nax , an alarm signal is sent to the alarm device 17 via the OR gate, and when the leakage current _1b becomes less than the lower limit value I _1b and leakage on the outer surface occurs. When the current I _0b exceeds the set value I _0s , an alarm signal is sent to the alarm device 17 via the AND gate and the OR gate.

In this way, in this embodiment, when performance deterioration occurs in the lower lightning arrester unit, the leakage current I _1b of the internal element 3b exceeds the upper limit value I ₁ max and is displayed on the alarm device 17. . On the other hand, if performance deterioration occurs in the upper lightning arrester unit, the above leakage current
As I _1b becomes less than the lower limit value I ₁ min, the leakage current I _0b on the outer surface of the insulator tube 1b becomes more than the set value I _0s , and is displayed on the alarm device 17 in the same manner as above. Therefore, even if performance deterioration occurs in either the upper or lower lightning arrester unit, the performance deterioration can be accurately detected with considerably high accuracy. As a result, the lightning arrester can be inspected and repaired at the optimal time, and the reliability of the entire lightning arrester can be improved.

Note that the present invention is not limited to the embodiments described above. In the embodiment shown in Fig. 3, the performance deterioration detection device was applied to a lightning arrester composed of two lightning arrester units, but even if it is applied to a lightning arrester composed of three or more lightning arrester units, each leakage current By appropriately setting the upper limit value, lower limit value, and set value, it is possible to obtain the same effects as in the embodiment.

Furthermore, as in the device of the first invention, only the upper and lower limits of the leakage current flowing through the internal elements of the lowermost lightning arrester unit are set, and when the leakage current exceeds the upper limit, the The performance deterioration of the lower lightning arrester unit may be displayed, and if the leakage current falls below the lower limit value, the performance deterioration of the upper lightning arrester unit may be displayed. Even in this case,
Deterioration of lightning arrester performance can be detected with high accuracy.

Furthermore, in addition to displaying the performance deterioration on the alarm device 17, an alarm buzzer or the like may be sounded.

〔Effect of the invention〕

As explained above, according to the present invention, the leakage current of the ZnO element located at the lower end of the lowermost lightning arrester unit of a lightning arrester consisting of a plurality of stacked lightning arrester units is measured, and this leakage current is determined in advance. If the leakage current value exceeds a predetermined upper limit, it can be determined that the performance of the lowermost lightning arrester unit has deteriorated, and if the leakage current value falls below a predetermined lower limit, it can be determined that the performance of the upper lightning arrester unit has deteriorated. Therefore, even if performance deterioration occurs in any one of the multiple lightning arrester units, it is possible to accurately detect the occurrence of performance deterioration, so inspection and repair of the lightning arrester can be carried out at the optimal time, increasing the reliability of the entire lightning arrester. can improve sex.

In addition to determining the performance deterioration of the lowermost lightning arrester unit due to the leakage current of the ZnO element, we also measured the leakage current flowing through the outer surface of the insulator tube in the lowermost lightning arrester unit. Deterioration in the performance of the upper lightning arrester unit is determined when the leakage current of the ZnO element exceeds a predetermined set value and falls below the lower limit value, so the occurrence of performance deterioration of the lightning arrester unit can be further prevented. Can be detected with high accuracy. Therefore, the above-mentioned effect becomes even more remarkable.

[Brief explanation of the drawing]

1 and 2 are vertical cross-sectional views showing a schematic configuration of a lightning arrester using ZnO elements, and FIG. FIG. 4 is an explanatory diagram for explaining the operation of the detection device. 1, 1a, 1b...Insulator tube, 2, 2a, 2b...ZnO
Element, 3, 3a, 3b... Internal element, 4, 4b... Grounding frame, 5, 5a... High pressure flange, 6a, 6b...
Lightning arrester unit, 7a, 7b... intermediate flange, 1
1, 14...Measurement line, 12...Element leakage current measuring device,
13... Conductive tape, 15... Surface leakage current measuring device, 16... Judgment device, 17... Alarm device.

Claims (1)

[Claims] 1. In a performance deterioration detection device for a lightning arrester configured by stacking a plurality of lightning arrester units in which a plurality of zinc oxide nonlinear resistor elements are stacked in an insulator tube, the lowermost one of the plurality of lightning arrester units An element leakage current measuring device for measuring the leakage current of the zinc oxide non-linear resistor element located at the lower end, and a surface leakage current measuring device for measuring the leakage current of the outer surface of the insulator tube in the lowermost lightning arrester unit. a measuring device, and when the current value measured by the element leakage current measuring device is greater than or equal to a predetermined upper limit value, and when this current value is less than or equal to a predetermined lower limit value and the surface leakage current measuring device; 1. An apparatus for detecting performance deterioration of a lightning arrester, comprising an alarm means for issuing an alarm when a current value measured by the current value is equal to or greater than a predetermined set value.