JP2942030B2 - Deterioration detector for lightning arrester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to prevent a permanent ground fault by immediately discharging a power line to the ground by a lightning arrester function when a power line receives a lightning strike, and by suppressing and blocking a subsequent flow that occurs thereafter. The present invention relates to a lightning arrester insulator deterioration detector for a transmission line.

[0002]

2. Description of the Related Art In recent years, lightning arresters have begun to be used in power transmission lines to prevent power failures due to lightning surge currents. This lightning arrester has a voltage-
It accommodates a current limiting element made of non-linear zinc oxide etc. with current characteristics, and if this current limiting element deteriorates due to repeated lightning strikes unexpectedly or unexpected moisture absorption, the insulation as a lightning arrester will deteriorate I do.

Therefore, in order to ensure the reliability of the transmission line, it is necessary to periodically detect the deterioration of the lightning arrester and check it, and if an abnormality is found, replace it with a new one. is there. For this reason, conventionally, for example, the deterioration state of the lightning arrester is detected by measuring the insulation resistance between the arc horn on the ground side and the power receiving side supported by the lightning arrester.

[0004]

However, this conventional method for measuring insulation resistance not only requires a power outage due to its method, but also causes an operator to approach the support arm of the tower, and to use the arc horn as a lightning arrester insulator. Since the measurement is performed by connecting the lead wires of the measuring device, there is a problem that the measuring operation is troublesome and dangerous.

[0005] Conventionally, a bifurcated detection rod, which is engaged with the arc ring on the ground side and the power application side of the lightning arrester, is supported at the tip of the insulating operation rod, and both detection rods have the lightning arrester insulator. Some were connected with a measuring device for measuring resistance.

However, this defective detector can measure the resistance value of the lightning arrester in a live state, but has a problem in protection and safety of the measuring device. That is, the lightning arrester has its own capacitance, and when the operating voltage is applied, a voltage corresponding to the air discharge gap and the capacitance of the lightning arrester is induced in the lightning arrester. This voltage will generally be 10-25% of the operating voltage. Therefore, when a measuring device is connected to the arc ring of the lightning arrester, a high voltage is applied to the measuring device, causing dielectric breakdown of the measuring device, and the high voltage may be transmitted to the worker through the insulating operation rod with reduced insulation. There was a safety problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art. It is an object of the present invention to reliably protect a measuring instrument and to provide a lightning arrester. An object of the present invention is to provide a lightning arrester insulator deterioration detector capable of easily and safely measuring the electrical characteristics of an insulator in a live state.

[0008]

In order to achieve the above object, in the lightning arrester insulator deterioration detector according to the present invention, a grounding side attached to the lightning arrester and a grounding side attached to the tip of an operating rod made of insulating material are provided. A bifurcated detection unit having a pair of contacts capable of contacting the arc horn on the power receiving side is provided, and connected to the detection unit on the operation rod to measure the electrical characteristics of the lightning arrester. A high-voltage protection circuit is connected to the detection unit, and the capacitance of the lightning arrester and the capacitance of the air discharge gap are set at the input side of the high-voltage protection circuit. A capacitor having a capacitance three to three orders of magnitude larger is connected.

[0009]

[Action] According to the deterioration detector of the lightning arrester configured as described above, the contact at the tip of the detecting part is brought into contact with both arc horns of the lightning arrester, and in this state, the electric resistance of the lightning arrester, such as the insulation resistance. Characteristic can be measured with a measuring instrument.
At the start of the measurement operation, a voltage corresponding to the air discharge gap and the capacitance of the lightning arrester itself is induced in the lightning arrester when an operation voltage is applied to the lightning arrester. This voltage reduces the shared voltage of the lightning arrester by charging the capacitor, prevents dielectric breakdown of the measuring device due to abnormally high voltage, and makes it easy and safe to improve the electrical characteristics of the lightning arrester in the live state. Can be measured.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. First, an example of a lightning arrester device using the lightning arrester insulator deterioration detector of this embodiment will be described.
As shown in FIG. 2, a support insulator 3 for a transmission line composed of a long trunk insulator is suspended and fixed by a plurality of bolts at the tip of the support arm 2 of the tower 1, and a wire clamp 4 is provided at the lower end thereof. The transmission line 5 is supported. A mounting bracket 6 is fixed to the distal end of the support arm 2 and extends horizontally in a direction orthogonal to the line direction. A lightning arrester 7 is fixed to the lower end of the mounting bracket 6 in a hanging manner.

The lightning arrester 7 has a pressure-resistant insulating cylinder (not shown) formed in a cylindrical shape from a tensile material such as FRP, and a voltage mainly composed of zinc oxide (ZnO) housed in series therein. -A resistance element 8 having a non-linear current characteristic, ground-side and power-supplying-side electrode fittings 9 and 10 in the form of caps fitted and fixed to both ends of the pressure-resistant insulating cylinder, and provided on the outer periphery of the pressure-resistant insulating cylinder. And a molded rubber 11. Annular arc rings 12 and 13 are provided on both electrode fittings 9 and 10 of the lightning arrester 7 so as to be opposed to each other, and the arc rings 12 and 13 reduce damage of the mold rubber 11 at the time of creepage flashing. .

A horn-shaped discharge electrode 14 on the power supply side is attached to the wire clamp 4 of the support insulator 3. The power-supply-side electrode fitting 10 at the tip of the lightning arrester 7 includes:
A horn-shaped discharge electrode 15 on the ground side is attached. The discharge electrodes 14 on the power application side and the ground side,
Numerals 15 are opposed to each other with a predetermined air discharge gap G.

Next, a deterioration detector of the lightning arrester 7 will be described. The operating rod 21 is formed of a plurality of insulating tubes so as to be extendable and contractible, and a fork-like detecting portion 22 made of a conductive material is provided at the tip thereof. Have been. The operating rod 21 has a substrate 23
A mounting plate 24 is rotatably attached to the tip of the mounting plate 24 so as to extend substantially in a T-shape. A pair of support plates 25 are attached to both ends of the mounting plate 24 so as to be position-adjustable in the longitudinal direction. The two supporting plates 25 have an arc-shaped connecting plate 2
6 are fixed at both ends thereof so as to be position-adjustable.

A detection rod 2 is provided at the tip of each of the support plates 25.
7, 28 are rotatably mounted at the base end, and are adjusted and fixed at predetermined rotation positions. One detection rod 27
Hook-shaped contact 29 opening inward at the tip of
And a ground-side arc ring 12 of the lightning arrester 7.
Can be locked in contact. An arc-shaped contact 30 that opens toward the tip is provided at the tip of the other detection rod 28, and can be engaged with the power-supply-side arc ring 13 of the lightning arrester 7.

A measuring instrument 31 is provided at the tip of the operating rod 21 and is electrically connected to the detecting section 22. Then, the contacts 29 and 30 at the tip of the detection unit 22 are connected to the lightning arrester 7.
In this state, the resistance of the lightning arrester 7 is measured by the measuring device 31 in a state where the lightning arrester 7 is in contact with the arc rings 12 and 13, and the measurement result is notified by the buzzer 38.

Reference numeral 32 in FIG. 1 indicates an equivalent circuit of the lightning arrester device, and V is the operating voltage of the line (for example, 34.5 to 1).
10 kV) and Vs is the induced voltage of the lightning arrester 7 (maximum 10
-25 kV), Vg is the voltage of the air discharge gap G (≒ V),
.., Cn are the capacitances of the supporting insulator 3, Cs is the capacitance of the lightning arrester 7 (for example, 10 to 20 pF), Cg is the capacitance of the air discharge gap G (for example, 5 pF), Rs Is the resistance of the lightning arrester 7, Rg is the resistance of the air discharge gap G, and Vm is the voltage (1 kV or less) between the detection rods 27 and 28.

As shown in FIG. 1, both contacts 29 and 30 of the deterioration detector which can be brought into contact with the arc rings 12 and 13 of the lightning arrester 7 are provided with a high-voltage protection circuit 33 constituting a measuring instrument 31. Is connected. This protection circuit 33 is a capacitor Cx (capacitance 1000-2000 pF) for reducing the induced voltage of the commercial frequency applied to the measuring instrument 31.
And resistors R1, R2, for the filter for absorbing the lightning surge current.
R3, and filter capacitors Cf1 and Cf2 for absorbing lightning surge current. And
The capacitance Cg of the air discharge gap G and the lightning arrester 7
The capacitance Cx is compared with the capacitances Cg and Cs by 2 to 3 so that an inequality relationship of Cg <Cs≪Cx is established between the capacitance Cs of the capacitor and the capacitance Cx of the capacitor. It is set to a numerically higher value.

The high voltage protection circuit 33 includes the contact 2
A contact display circuit 34 for judging whether or not 9 and 30 have touched the arc rings 12 and 13 and lighting and displaying the lamp is connected, and a high-frequency oscillation circuit 35 is connected. Further, a judgment circuit 36 for judging the measured resistance value of the resistance element 8 of the lightning arrester 7 is connected to the high frequency oscillation circuit 35. Further, the determination circuit 36 is connected to a setting switching circuit 37 for setting a reference resistance value as a failure notification reference of the lightning arrester. Further, a buzzer 38 for generating a notification sound when the measured resistance value falls below a set value is connected to the determination circuit 36. The notification sound of the buzzer 38 can be visually recognized by the operator through a confirmation hole 39 formed in the base end of the operation rod 21 as shown in FIG.

In the lightning-resistant horn insulator device configured as described above, when a surge current caused by a lightning strike is applied to the transmission line 5, the current is applied to the air discharge gap G between the two discharge electrodes 14 and 15. And flows to the support arm 2 of the tower 1 through the resistance element 9 and the mounting bracket 6 incorporated in the lightning arrester 7, and is discharged from the tower 1 to the ground. Further, the subsequent flow generated thereafter is suppressed and cut off by the air discharge gap G between the discharge electrodes 14 and 15 and the resistance element 9 in the lightning arrester 7.

When detecting the deterioration state of the lightning arrester 7 in the live state, the worker climbs the step 1a provided on the steel tower 1 to the same height as the lightning arrester 8, and operates the aforementioned deterioration detector. After gripping the rod 21, one of the contacts 29 on the detection unit 22 is contact-locked to the ground-side arc ring 12 of the lightning arrester 7, and then the other contact 30 is connected to the power-supplying arc ring 13 of the lightning arrester 7. Is brought into contact engagement. Then, the insulation resistance of the lightning arrester 7 between the two arc rings 12 and 13 is measured by the measuring device 31 via the detecting unit 22, and if the lightning arrester 7 is defective, an alarm sound is generated by the buzzer 38. The deterioration state of the lightning arrester 7 can be detected by the confirmation hole 39.

Therefore, the arc rings 12 of the lightning arrester 7,
It is possible to easily and safely measure the insulation resistance of the lightning arrester 7 without the need for a troublesome operation of connecting a lead wire of a detection unit to the device 13 or reading the measured values one by one.

In the deterioration detector of this embodiment,
The capacitance Cs of the lightning arrester 7 is provided on the input side of the high-voltage protection circuit 33.
Also, since the capacitor Cx having a capacitance two to three orders of magnitude larger than the capacitance Cg of the air discharge gap G is connected in parallel with the lightning arrester 7, the lightning arrester 7 is When the operating voltage V is applied, a voltage corresponding to the air discharge gap G and the capacitance Cs of the lightning arrester itself is induced in the lightning arrester 7. This voltage reduces the voltage shared by the lightning arrester 7 by charging the capacitor Cx, prevents the application of an abnormally high voltage to the measuring instrument 31, prevents its dielectric breakdown, and prevents lightning in the live state. The electrical characteristics of the insulator 7 can be easily and safely measured.

The present invention is not limited to the configuration of each of the above embodiments, but can be embodied with the following modifications. (1) Provide an insulating coating on the outer surfaces of the detection rods 27 and 28 of the detection unit 22, the support plate 25, and the like.

(2) The measuring device 31 is configured to measure an electric characteristic value equivalent to an insulation resistance such as a current value. (3) The measuring device 31 is configured to record electrical measured values.

(4) Normally, an abnormality in the measured value is indicated by a light display.

[0026]

Since the present invention is constructed as described above, the contact at the tip of the detection unit can be easily connected to the arc ring of the lightning arrester to measure the electrical characteristics of the lightning arrester. It has an excellent effect that it can be easily and safely performed in a live state.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram of a lightning arrester insulator deterioration detector embodying the present invention.

FIG. 2 is a front view of the lightning arrester device showing a use state of the deterioration detector of the lightning arrester.

[Explanation of symbols]

7 Lightning arrester, 12, 13 arc ring, 21 operation rod, 22 detector, 29, 30 contact, 31 measuring device, 33 high voltage protection circuit, Cx capacitor, Cs capacitance of lightning arrester, Cg of air discharge gap Capacitance.

Continuation of the front page (56) References JP-A-63-158471 (JP, A) JP-A-62-209373 (JP, A) JP-A-59-65269 (JP, A) JP-A-2-60890 (JP) , U) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01R 31/12-31/20

Claims (1)

(57) [Claims] An operation rod made of an insulating material is provided at a tip thereof with a bifurcated detection unit having a pair of contacts capable of contacting an arc horn on a grounding side and a power receiving side attached to a lightning arrester, A lightning arrester insulator deterioration detector provided with a measuring device for measuring the electrical characteristics of the lightning arrestor connected to the detecting portion on the operating rod, wherein a high-voltage protection circuit is connected to the detecting portion, A deterioration detector for a lightning arrester, wherein a capacitor having a capacitance two to three orders of magnitude larger than the capacitance of the lightning arrester and the capacitance of the air discharge gap is connected to the input side of the high voltage protection circuit.