JPH05273295A - Defect detection apparatus of suspension-type lightning-arresting insulator - Google Patents

Abstract

PURPOSE:To obtain the deterioration detection apparatus, of a lightning-arresting insulator wherein its accuracy to detect a defective lightning-arresting insulator is excellent and its measuring operation can be performed simply. CONSTITUTION:In the defect detection apparatus of a suspension-type lightning- arresting insulator, one pair of contactors 23, 25 which come into contact with said suspension-type lightning-arresting insulator 2 are installed at the tip part of an insulating rod 21. A resistance 29, a coil 30 and a capacitor 31 are connected in parallel with the contactors 23, 25. The electrostatic capacity of the capacitor 31 is sufficiently larger than the electrostatic capacity of the lightning- arresting insulator 2; it forms a resonance circuit together with said coil 30 and said resistance 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when a lightning surge current flows through a transmission line or a distribution line, quickly discharges it to the ground and suppresses and cuts off the subsequent flow of commercial frequency. The present invention relates to a suspension type lightning insulator failure detection device that can be used.

[0002]

2. Description of the Related Art Generally, in a transmission line, when a lightning surge current enters the transmission line, the current flashes over between the arc horn on the ground side and the arc horn on the charging side provided at both ends of a support insulator that supports the transmission line. Flow to the support arm of the tower body, and then a continuous current based on the operating voltage causes a ground fault. This is interrupted by the circuit breaker at the substation and then re-applied to recover from the accident. In order to prevent such a ground fault, a lightning protection insulator mounted on a support arm of a tower body is used in a transmission line support insulator device. This lightning protection insulator accommodates therein a current limiting element made of zinc oxide or the like having a non-linear voltage-current characteristic. This current limiting element may be deteriorated due to repeated lightning strikes, moisture absorption, etc. beyond expectations. As a result, the function as a lightning protection insulator is reduced.

Therefore, in order to ensure the reliability of the power transmission line, it is necessary to periodically inspect the lightning protection insulator to detect a defective state, and to replace it with a new one when an abnormality is found. is there.

Conventionally, in order to detect a defect of the suspension type lightning arrestor, a pair of contacts are brought into contact with each other between cap metal fittings of the insulators located above and below to measure the shared voltage of the insulator to judge the quality of the insulator body. The way is done. That is, the voltage applied to both ends of the lightning protection insulator appears as a constant shared voltage in each insulator, but if there is an insulator that is deteriorated and becomes defective, the shared voltage of that insulator is the shared voltage of other normal insulators. Detected smaller than.

[0005]

However, in the method of measuring the shared voltage, in the lightning arrester device in which the usual suspension type insulator series and the suspension type lightning conductor series are connected, the capacitance of the lightning insulator is usually Since it is larger than that of the insulator, the sharing voltage is considerably smaller in the lightning arrestor as shown in FIG. Therefore, there is a problem that a difference between a normal insulator and a deteriorated insulator is small and it is difficult to detect a defect.

Therefore, the present invention has been made by paying attention to the problems existing in such a conventional technique, and its purpose is to provide excellent accuracy in detecting a defective lightning protection insulator and to simplify the measurement work. (EN) Provided is a suspension-type lightning insulator defect detection device which can be performed.

[0007]

In order to achieve the above object, according to the present invention, the accommodating cylinder provided in the cap portion of the lightning protection insulator body is provided with a current limiting element having a non-linear voltage-current characteristic. A device for detecting a defect of a suspension type lightning arrestor, which is used in a suspension type lightning arrester device which is housed and whose upper and lower ends are sealed by sealing members to serve as electrodes and which measures a shared voltage between the electrodes. , A pair of contacts that come into contact with the suspended lightning arrestor are provided at the tip of the insulating rod, and a resistor, a coil and a capacitor are connected in parallel with the contactor, and the capacitance of the capacitor is the capacitance of the lightning arrester. The gist is to form a resonance circuit with the coil and the resistor which are sufficiently larger.

[0008]

According to the present invention, with the above-mentioned structure, the contactor of the detector is brought into contact with both electrodes of the accommodating cylinder of the lightning protection insulator, and the shared voltage of the insulator is measured. A resonance circuit is formed by the resistor, the coil, and the capacitor connected in parallel to the contactor. Therefore, the apparent impedance of the lightning arrestor is only the resistance component, and the detected shared voltage is large.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied as a defect detecting device for a suspension type lightning arrester will be described with reference to FIGS.

As shown in FIG. 2, a plurality of suspension type lightning arrestors 2 are connected in series to a support arm 1 of a steel tower, and a plurality of normal suspension insulators 3 are connected in series to the lower part thereof. Further, a power transmission line 4 is supported on the normal suspension insulator 3. Further, arc horns 5, 6 and 7 are mounted on both ends of the lightning protection insulator 2 and the suspension insulator 3 for suppressing burnout of the insulator series during a surface flashover.

As shown in FIG. 3, the lightning protection insulator 2 has a cap metal fitting 10 fitted and fixed to a head portion 9 of an insulator body 8 and a pin metal fitting 11 fitted and fixed inside the head portion 9. ing. Further, a housing cylinder 13 is integrally formed on the cap portion 12 of the insulator body 8, and a voltage-
A current limiting element 14 mainly composed of zinc oxide having a non-linear current characteristic is housed in series. The upper and lower openings of the accommodating cylinder 13 are internal sealing electrodes 15 and 1 which constitute a sealing member.
5a and the external sealing electrodes 16 and 16a are hermetically sealed. The external sealing electrode 16 a is connected to the pin fitting 11 and the lead wire 18.

The external sealing electrode 16 and the cap metal fitting 10 are electrically connected by a lead wire 19, and an arc guide 20 is fixed to the cap metal fitting 10 by a screw in correspondence with the lead wire 19. In the unlikely event that the current limiting element 14 is conductively broken due to an unexpected intrusion of a lightning surge current, the arc is transferred between the outer arc horns 5 and 6 shown in FIG. 2 to prevent burnout at the time of a surface flashover of the lightning protection insulator. It is supposed to suppress.

The defect detection device for detecting a defect of the lightning protection insulator is constructed as follows. As shown in FIG. 4, the mounting arm 22 is attached to the tip of the insulating rod 21,
A first contact 23 made of a conductive material is fixed to the arm 22 so that the mounting angle can be adjusted. Further, another mounting arm 24 made of a conductive material is supported on the tip end of the insulating rod 21, and a second contact 25 also made of a conductive material is connected and supported on the mounting arm 24 so that the mounting angle can be adjusted. Has been done. A meter 28 is connected to the base end of the insulating rod 21 via a lead wire 27. The meter 28 is electrically connected to the contact 23 and the second contact 25. In the insulating rod 21, as shown in the equivalent circuit of FIG. 1, a resistor 29, a coil 30, and a capacitor 31 are connected in parallel to the first contact 23 and the second contact 25, respectively, to form a resonance circuit. is doing. At this time, the capacitance of the capacitor 31 is C, the inductance of the coil 30 is L, and the resistance value of the resistor 29 is R. Normal,
The capacitance C ₀ of the lightning protection insulator 2 is about 150 pF, and the capacitance C of the capacitor 31 incorporated in the rod 21 is set sufficiently larger than that.

Next, the operation of the suspended-type lightning arrester defect detection device having the above-described structure will be described. As shown in FIGS. 2 and 3, the tip of the first contactor 23 is brought into contact with the cap fitting 10 of the suspension type lightning protection insulator 2 located on the upper side, and the suspension located on the lower side of the lightning protection insulator 2 is suspended. The tip of the second contact 25 is brought into contact with the cap fitting 10 of the type lightning protection insulator 2 to make it electrically conductive. In this state, the shared voltage of the suspension type lightning arrester 2 is measured.
An equivalent circuit for measuring the shared voltage of the lightning protection insulator 2 is a resonance circuit in which the capacitance C ₀ of the lightning protection insulator 2 is included and a capacitor 31, a coil 30, and a resistor 29 are arranged in parallel as shown in FIG. To be done. The impedance Z of this circuit is

[0015]

## EQU1 ## Z = 1 / ((1 / R) ² + (ωC + ωC ₀ −1 / ωL) ² ) ^1/2 Since the capacitance C of the capacitor is sufficiently larger than the capacitance C ₀ of the lightning protection insulator 2, C >> C ₀ ,
The above formula is

[0016]

## EQU2 ## Z = 1 / ((1 / R) ² + (ωC-1 / ωL) ² ) ^1/2 . At this time, if the inductance value L of the coil is set to a value that resonates with the electrostatic capacitance C of the capacitor, that is,

[0017]

Equation 3] ωC = 1 / ωL or, L = 1 / ω ² C, and becomes a Z = R.

Therefore, in measurement, the apparent capacitance becomes small and the shared voltage becomes large. In FIG. 6, the curve indicated by ● is a shared voltage characteristic when measured by a normal defect detection device. Further, the curve indicated by ◯ shows the shared voltage of each insulator when measured by the defect detecting device of the above-mentioned embodiment, and at this time, the measurement position 1 (insulator located at the top of the lightning arrestor. It continues to 2 and 3)
It was an attempt to measure the lightning protection insulator of. This lightning protection insulator shows normal characteristics, and if there is a defect, the shared voltage becomes small as shown by the dotted line.

By incorporating the resonance circuit in the defect detecting device as described above, the measured shared voltage of the lightning protection insulator is detected greatly, and it is possible to accurately determine whether or not the insulator is defective.

The present invention is not limited to the construction of the above-mentioned embodiment, but is freely possible within the scope of the invention, for example, by making the insulating rod 21 expandable and contractible by combining a plurality of tubes having different diameters. Can be configured to.

[0021]

According to the present invention, the shared voltage can be measured with high accuracy by the resonance circuit incorporated in the defect detecting device.
This has the effect of easily detecting defects.

[Brief description of drawings]

FIG. 1 is an equivalent circuit diagram showing a usage state of a defect detection device for a suspended lightning arrester, which is an embodiment of the present invention.

FIG. 2 is a front view showing the entire suspension type lightning arrestor and a defect detection method.

FIG. 3 is a sectional view of a main part of a suspended lightning arrester.

FIG. 4 is a front view showing a defect detection device for a suspended lightning arrester, which is an embodiment of the present invention.

FIG. 5 is an equivalent circuit diagram including a defect detection device and a suspended lightning arrester.

FIG. 6 is a characteristic diagram showing the shared voltage of the lightning protection insulator and the normal insulator measured by the defect detection device of the embodiment.

FIG. 7 is a characteristic diagram showing a shared voltage of each insulator measured by a conventional defect detection device.

[Explanation of symbols]

2 Suspended type lightning arrestor, 12 Cap section, 13 Housing cylinder, 1
4 Current Limiting Element, 15, 15a Internal Sealing Electrodes Comprising Sealing Member, 16 and 16a External Sealing Electrodes Comprising Sealing Member, 21 Insulating Rod, 23 First Contactor, 25
Second contactor, 29 resistor, 30 coil, 31 capacitor.

Claims (1)

[Claims] 1. An accommodating cylinder provided in a cap portion of a lightning protection insulator body accommodates a current limiting element having a non-linear voltage-current characteristic, and upper and lower ends of the accommodating cylinder are sealed by sealing members. Used in a suspension type lightning arrester device that is sealed as an electrode and measures the shared voltage between both electrodes, in a defect detection device for a suspension type lightning arrester, a pair of insulating rod tips that contact the suspension type lightning arrestor. , A resistor, a coil and a capacitor are connected in parallel with the contact, the capacitance of the capacitor is sufficiently larger than the capacitance of the lightning arrester, and a resonance circuit is formed with the coil and the resistor. Detecting device for suspended type lightning arrester characterized by.