JP2019149264A - Switching device and electrode replacement method thereof - Google Patents

Abstract

To formulate a planed update and maintenance by directly measuring and accurately estimating an electrode consumption amount so as to solve the problems in the conventional art that the electrode consumption amount is conservatively estimated from an estimated equation using a coefficient depending on a breaking current value, the number of breaking times, and a material of a contact point.SOLUTION: An antenna capable of detecting an electromagnetic wave generated by an arc is provided to a switching device, and the electromagnetic wave of the arc generated between main contact point electrodes immediately before a closing of the main contact point electrodes or simultaneously with an opening thereof. The generation time of the arc is measured from a signal of the electromagnetic wave generated by the arc, and an electrode consumption amount is derived from a time difference between the generation time of the arc and an output time of a trip signal that notifies a start of a projection operation or an electrode opening operation of the main contact point electrodes.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a switchgear used in a power system and an electrode replacement method thereof.

  In order to supply power stably, high reliability is required in the power system. Electric power equipment such as a switch constituting the power system is the center for realizing a stable supply of electric power, and when the switch causes an accident, various losses due to a power failure occur. In recent years, switch aging operation has increased, and it is important to promote equipment renewal and repair by accurately diagnosing the remaining life of the switch and prevent accidents due to aging. Yes.

Among the components that make up a switch, one of the functional losses that has a high impact on the health of the switch is the amount of wear of the main contact electrode. Since the number of operations per year varies from several to several hundred times depending on the state of the installed power system, and there are products of various ratings and types, the main contact electrode consumption per unit The amount is very different. When replacing the main contact electrode, the inside of the switch was visually inspected at an appropriate time to determine whether or not the main contact electrode needs to be replaced. There were wasted elements such as planned power outage procedures and outages associated with securing and inspection. In recent years, with the spread of gas insulated switchgear and gas circuit breakers filled with highly insulating SF ₆ gas in the tank, the shut-off performance per unit has improved and the installation volume has been reduced, while the SF ₆ gas There is also a drawback that the additional work time for inspection becomes longer due to the addition of the collection and filling work. Therefore, it is desirable to reduce the inspection cycle. For each switch, it is necessary to carry out the inspection work after clearly knowing from the outside the replacement timing of the main contact electrode according to the amount of consumption of the main contact electrode.

In Patent Document 1, the amount of consumption of the main contact electrode is grasped from the outside without visual inspection, and is based on the peak-to-peak i _PP of the breaking current value, the constants α and β determined by the contact material, and the arc time t. Electrode consumption estimation formula {i _PP / 2 · 2 ^1/2 } ^β · t (α: contact material, i _PP : breaking current value, t: arc time) is calculated for each interruption of current, and the number of interruptions The amount of consumption of the main contact electrode of the switch is calculated from the integrated value.

Japanese Patent Laid-Open No. 4-169027

  As described above, in the prior art, the consumption amount of the main contact electrode is estimated from an estimation formula using a cutoff current value, the number of interruptions, and a coefficient depending on the contact material. The estimation formula includes errors due to arc duration and current asymmetry, and may have low accuracy.

  An object of the present invention is to provide a switchgear and an electrode replacement method for the switchgear that make it possible to estimate a consumption amount with high accuracy.

  The object is to provide a first electrode, a second electrode movable relative to the first electrode, a driving means for driving the second electrode based on a start signal, the first electrode and the second electrode. Arc detecting means for detecting an arc between the first electrode and the second electrode, and a ratio of a time difference between the time when the occurrence of the arc is detected and the time of the start signal. This is achieved by a switchgear provided with a calculation means for calculating an electrode consumption amount of the first electrode and the second electrode.

  According to the present invention, it is possible to provide a switchgear and an electrode replacement method thereof that enable estimation of a consumption amount with high accuracy.

Sectional view showing the configuration of the gas insulated switchgear Sectional view showing the configuration of the circuit breaker Enlarged view showing circuit breaker closing operation Simplified diagram showing an embodiment of main contact electrode consumption measurement in this example The figure which shows the timing of the trip signal which notifies the main circuit current at the time of making operation, the electromagnetic wave which the preceding arc emits, and the making operation start A diagram showing the difference in distance from the tip of the fixed electrode to the tip of the movable electrode at the blocking position before and after electrode consumption Figure showing the prediction method of main contact electrode replacement time Enlarged view showing the circuit breaker opening operation The figure which shows the timing of the trip signal which notifies the main circuit current at the time of opening operation, the light which an arc emits, and the opening operation start A diagram showing the difference in distance from the fixed electrode tip to the movable electrode tip at the loading position before and after electrode consumption

  Regarding the measurement of the electrode consumption of the switch described above, this embodiment will be described with reference to the drawings with reference to the gas insulated switchgear and the gas circuit breaker incorporated in the gas insulated switchgear.

FIG. 1 is a cross-sectional view illustrating a configuration of a gas insulated switchgear according to an embodiment. The gas insulated switchgear includes a circuit breaker 1, a disconnect switch 2, a ground switch 3, an instrument current transformer 4, an instrument transformer 5, and the like. The high voltage conductor 6 is a cylindrical conductor made of a metal material such as aluminum or copper, and is supported and fixed by an insulating spacer 8 in a ground tank 7 of a cylindrical metal container. The insulating spacer 8 is sandwiched between the ground tanks 7 so that it is mounted in the ground tank 7 in a state of being orthogonal to the axis of the ground tank 7, and the high voltage conductor 6 is connected to the embedded conductor of the insulating spacer 8, The axis of the ground tank 7 and the axis of the high voltage conductor 6 coincide. The ground tank 7 is filled with SF ₆ gas having high insulation performance.

  Drawing 2 is a sectional view showing the composition of circuit breaker 1 concerning an embodiment. The circuit breaker 1 includes a fixed side electrode 10, a fixed side electrode 11, a movable side electrode cover 12, and a nozzle 13 among the main contacts. The fixed side electrode 10 and the fixed side electrode 11 are connected to a hydraulic operating device or a spring operating device via an operating rod. In the circuit breaker 1 of FIG. 1, the fixed side electrode 10 and the fixed side electrode 11 are in the blocking position, and move in the direction of the arrows in the drawing for the closing operation.

  FIG. 3 is a diagram showing a state during the closing operation of the circuit breaker 1. In FIG. 3A, the fixed side electrode 10 and the fixed side electrode 11 are in the blocking position. After the input operation of the fixed side electrode 10 and the fixed side electrode 11 is started, the fixed side electrode 10 and the fixed side electrode 11 approach each other as shown in FIG. As the fixed side electrode 10 and the fixed side electrode 11 approach, a leading arc 14 is generated between the fixed side electrode 10 and the fixed side electrode 11. The leading arc 14 emits an electromagnetic wave, and a current flows between the fixed side electrode 10 and the fixed side electrode 11. FIG. 3C shows a state after the closing operation is completed. At this time, the fixed side electrode 10 and the fixed side electrode 11 are connected and closed, and the leading arc 14 disappears.

  FIG. 4 is a diagram showing an embodiment of main contact electrode consumption measurement. The circuit breaker 1 is connected to the main circuit 15, and the electromagnetic wave measurement antenna 16 and the trip circuit 17 that generate an arc are connected to the arithmetic device 18. FIG. 4 (a) shows the state before the start of charging, and the trip circuit is in an open state. When the closing operation starts, the trip circuit is closed as shown in Fig. 4 (b). A voltage is applied to the terminal of the trip circuit 17 simultaneously with the start of the closing operation. This voltage is measured by the arithmetic unit 18. An antenna 16 and an arithmetic unit 18 for measuring an electromagnetic wave generated by an arc are attached to the hand hole 9 in FIG.

  FIG. 5 shows the signal 19 of the main circuit current flowing through the main circuit 15 during the closing operation of FIG. 4, the signal 19 of the electromagnetic wave emitted by the preceding arc 14 measured using the antenna 16 for measuring the electromagnetic wave emitted by the arc, and the start of the closing operation. It is the figure which showed the timing of the trip signal 21 which informs. As shown in FIG. 6, the trip signal 21 is output at the closing operation start time a, the leading arc 14 is generated when the fixed side electrode 10 and the fixed side electrode 11 are approached, and the antenna for electromagnetic wave measurement generated by the arc. 16 outputs an electromagnetic wave signal 20 generated by a preceding arc. The main circuit current flows through the main circuit 15 simultaneously with the time of occurrence of the preceding arc. The time difference Tab between the closing operation start time a and the preceding arc occurrence time b is measured by the arithmetic unit 18 in FIG. At this time, since it is only necessary to know the closing operation start time a, the signal for measuring the closing operation start time a is not limited to the trip signal but may be an auxiliary contact signal. The same applies to the occurrence time b of the preceding arc. The detector for measuring the occurrence time b of the preceding arc is not limited to the antenna 16 for measuring the electromagnetic wave emitted by the arc, and can measure the occurrence time b of the arc. Any detector may be used. For example, a photodetector may be used. Similarly to the antenna 16 for measuring the electromagnetic wave emitted by the arc, a detector for measuring the light emitted by the arc is also attached to the hand hole 9 shown in FIG.

FIG. 6 is a diagram showing the difference in distance from the tip of the fixed electrode 10 to the tip of the fixed electrode 11 at the blocking position before and after electrode consumption. FIG. 6A shows a blocking position before electrode consumption, and FIG. 6B shows a blocking position after electrode consumption. When the electrode is depleted, the fixed-side electrode from a tip of the fixed-side electrode 10 in the blocking position after electrode consumption as compared with the distance L ₁ to the tip of the fixed electrode 11 from the tip of the fixed electrode 10 at the blocking position before the electrode wear distance _{L 2} to the tip of the 11 becomes longer. The difference between L ₁ and L ₂ is the electrode consumption amount ΔL ₁₂ . The electrode consumption amount ΔL ₁₂ is obtained from the ratio of the relative speed V ₁ obtained from the moving speeds of the fixed side electrode 10 and the fixed side electrode 11 during the closing operation and the time difference Tab between the closing operation start time a and the preceding arc occurrence time b. Can be sought. In advance, L ₁ and V ₁ are stored in the arithmetic unit 18, and L ₂ is derived from V ₁ and Tab after measuring the time difference Tab between the starting operation start time a and the preceding arc occurrence time b. ΔL ₁₂ can be calculated as follows using Equation (1).
ΔL ₁₂ = L ₂ -L ₁
= Tab × V ₁ -L ₁ (1)

FIG. 7 shows a method of predicting the main contact electrode replacement time. The horizontal axis in FIG. 7 is the date, and the vertical axis is the amount of electrode consumption. As shown in FIG. 7, from the electrode consumption amount ΔL ₁₂ stored in the arithmetic unit 18, the replacement time of the electrode consumption amount is predicted by obtaining the time when the electrode consumption amount becomes a threshold value by linear approximation.

  FIG. 8 is a diagram illustrating a state in which the circuit breaker 1 is opened. In FIG. 8A, the fixed side electrode 10 and the fixed side electrode 11 are connected and are in the closing position. After starting the opening operation, the fixed side electrode 10 and the fixed side electrode 11 move in the direction of the arrow in FIG. At this time, an arc 13 is generated between the fixed side electrode 10 and the fixed side electrode 11. The arc 13 emits light, and at this time, the main circuit current flows through the main circuit due to the arc 13. FIG. 8C shows a state after completion of the opening operation. Since the fixed side electrode 10 and the fixed side electrode 11 are in the cut-off position, and the distance between the fixed side electrode 10 and the fixed side electrode 11 is sufficiently long, the arc 13 disappears and the main circuit current becomes zero.

  FIG. 9 shows a signal 19 of the main circuit current flowing in the main circuit 15 during the opening operation, an arc light signal 24 measured using the detector 23 for measuring the light emitted by the arc, and a trip signal for informing the start of the opening operation. It is the figure which showed the timing of 21. FIG. As shown in FIG. 9, the trip signal 21 is output at the opening operation start time c, and the arc 13 is generated at the same time when the fixed electrode 10 and the fixed electrode 11 are opened. While the arc is on, the main circuit current flows through the main circuit 15, but immediately after the arc extinction time e, the main circuit current becomes zero. 4 is used to measure the time difference Tcd between the opening operation start time c and the arc occurrence time d.

FIG. 10 is a diagram showing a difference in distance between the fixed side electrode 10 and the fixed side electrode 11 at the loading position before and after electrode consumption. FIG. 10A shows a loading position before electrode consumption, and FIG. 10B shows a loading position after electrode consumption. When the electrode is depleted, the fixed-side electrode from a tip of the fixed-side electrode 10 in the loading position after electrode consumption than the distance L ₃ to the tip of the fixed side electrode 11 from the tip of the fixed-side electrode 10 in the electrode wear prior to the loading position distance _{L 4} to the tip 11 is shortened. The difference between L ₃ and L ₄ is the electrode consumption amount ΔL ₃₄ . This electrode consumption amount ΔL ₃₄ is a ratio of the relative speed V ₃ obtained from the moving speed of the fixed side electrode 10 and the fixed side electrode 11 during the opening operation, and the time difference Tcd between the opening operation start time c and the arc generation time d. Can be obtained from The arithmetic unit stores L ₃ and V ₃ in advance, and after measuring the time difference Tcd between the opening operation start time c and the arc occurrence time d, L ₄ is derived from V ₃ and Tcd. ΔL ₃₄ can be calculated as follows using equation (2).
ΔL ₃₄ =-(L ₄ -L ₃ )
=-(Tcd × V ₃ -L ₃ ) (2)

According to the embodiment, the amount of consumption of the main contact electrode is derived based on the arc occurrence time and the operation start time of the main contact electrode. Without visual inspection, it is possible to predict the replacement timing of the main contact electrode and the remaining life of the switch, and to make planned updates and repairs. The SF ₆ gas in the gas insulated switchgear and gas circuit breaker which is filled in the tank, since the collection and filling work of the SF ₆ gas is not required, can be shortened supplementary work time for inspection.

1. Circuit breaker,
2. Disconnector,
3. Ground switch,
4). Current transformer for instrument,
5. Instrument transformers,
6). High voltage conductor,
7). Ground tank,
8). Insulation spacer,
9. Handhole,
10. Fixed electrode,
11. Movable electrode,
12 Movable electrode cover,
13. nozzle,
14 Leading arc,
15. Main circuit,
16. Antenna for measuring electromagnetic waves generated by arcs,
17. Trip circuit,
18. Arithmetic unit,
19. Main circuit current signal,
20. Electromagnetic wave signal emitted by the leading arc,
21. Trip signal,
22. arc,
23. Detector to measure the light emitted by the arc,
24. Arc light signal,
a. Input operation start time,
b. Preceding arc occurrence time,
L ₁ . The distance from the tip of the fixed electrode to the tip of the movable electrode at the blocking position before electrode consumption,
L ₂ . The distance from the tip of the fixed electrode to the tip of the movable electrode at the blocking position after electrode consumption,
ΔL ₁₂ . Electrode consumption,
V ₁ . The relative movement speed of the main contact electrode during the closing operation,
c. Opening operation start time,
d. Arc occurrence time,
e. Arc extinction time,
L ₃ . The distance from the tip of the fixed electrode to the tip of the movable electrode at the loading position before electrode consumption,
L ₄ . The distance from the tip of the fixed electrode to the tip of the movable electrode at the loading position after electrode consumption,
ΔL ₃₄ . Electrode consumption,
V ₃ . Relative moving speed of main contact electrode during opening operation

Claims (4)

A first electrode;
A second electrode movable relative to the first electrode;
Driving means for driving the second electrode based on a start signal;
Arc detecting means for detecting an arc between the first electrode and the second electrode;
Based on the relative speed between the first electrode and the second electrode, and the ratio of the time difference between the time when the occurrence of the arc is detected and the time of the start signal, the electrode wear of the first electrode and the second electrode An opening / closing device comprising a calculation means for calculating a quantity. In claim 1,
The arc detecting means detects an arc by electromagnetic waves or light. In claim 2,
Equipped with a tank filled with SF ₆ gas,
The switchgear characterized in that the first electrode and the second electrode are installed inside the tank. A first electrode; a second electrode movable relative to the first electrode; a driving means for driving the second electrode based on a start signal; and between the first electrode and the second electrode Based on the arc detection means for detecting the arc, the relative speed between the first electrode and the second electrode, and the ratio of the time difference between the time when the occurrence of the arc is detected and the time of the start signal, An electrode exchange method for a switchgear comprising an electrode and a calculation means for calculating an electrode consumption amount of the second electrode,
Based on the output of the computing means, predict the replacement time of the first electrode and the second electrode,
An electrode exchange method for a switchgear, wherein the first electrode and the second electrode are exchanged based on the prediction.

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