JP3019560B2 - Test method for follow-up interruption of lightning arrester for transmission line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test method for verifying the ability of a lightning arrester for a transmission line to interrupt a downstream current, and more particularly to a lightning arrester for a transmission line comprising a current limiting element and an air gap in series. The apparatus verifies the breaking ability of the air gap when the current from the operating frequency power supply following the impulsive lightning current that has passed in series with the current limiting element and the air gap is interrupted at the air gap, As a method for testing the wake of a lightning arrester for a transmission line, only the AC power supply is used as a test power supply, the gap in the atmosphere is short-circuited with a fuse, and the fuse is melted and vaporized with the AC power supply. The present invention relates to a continuation current interruption test method for interrupting a current flowing through a current limiting element at an air gap.

[0002]

2. Description of the Related Art Conventionally, a follow-up cutoff test of a lightning arrester has been carried out by using an impulse power supply for generating an impulse current simulating an impulsive lightning current and a current for supplying a current from an operating frequency power supply following the impulsive lightning current. Usually, two AC power supplies are used as test power supplies. This is because the lightning arrester usually consists of stacked lightning arresters with a rated voltage lower than its rated voltage, and the performance verification of the lightning arrester can be performed by verifying the performance of the lightning arrester element that does not require a large test power supply. It is due to something. However, lightning arresters for power transmission lines have a plate-shaped non-linear resistance element stacked at a height corresponding to the rated voltage of the lightning arrester, and a current-limiting element that is housed in an insulating cylinder. The air gap with only one gap is arranged in series with the air gap, and the air gap discharges during a lightning strike, and the lightning current flows through the current-limiting element. (Continuous flow) is interrupted by an air gap. Therefore, to verify the ability of the air gap to follow the downstream current, an AC power supply having an output voltage equal to the rated voltage of the lightning arrester and the air gap that is always insulated can be discharged, and And an impulse power supply capable of supplying an impulse current having the same duration. However, the rated voltage of the transmission line lightning arrester is, for example, 84 kV.
It is a high voltage such as 140 kV, and it is economically difficult to prepare an impulse power supply corresponding to such a rated voltage.

[0003] Therefore, as a method of equivalently verifying the ability to interrupt the downstream flow of the air gap without using an impulse power supply, only an AC power supply is used as a test power supply, and the air gap is short-circuited with a fuse and the AC power supply is used. A fuse is melted and vaporized, and a follow-current cutoff test method is adopted in which a current flowing through a current limiting element passing through an air gap after the melt vaporization is cut off by the air gap. FIG. 5 shows an example of a conventional test circuit configuration for performing a follow-current cutoff test by this method. In the figure, reference numeral 2 is short-circuited generator 3 is protected breaker, 4-on switch, a current adjusting reactor 5, 6 the step-up transformer, 7A current limiting element of the lightning protection device 7, 7B is lightning arrester 1 Is the air gap.

A test in this circuit is performed as follows. That is, prior to the test, the gap 7B in the atmosphere is short-circuited by a fuse 8 made of a thin metal wire, and the transformer 6 is connected to the secondary side of the transformer 6 so that the rated voltage of the lightning arrester 7 can be output.
Of the primary winding or the secondary winding. After that, the protection circuit breaker 3 is turned on to start the short-circuit generator 2,
When the terminal voltage of the short-circuit generator 2 reaches a predetermined value, the closing switch 4 is closed. As a result, the current that has passed through the current limiting element 7A flows through the fuse 8, and the fuse 8 melts and evaporates in a time corresponding to the current and the wire diameter of the fuse 8, and the gap between the two electrodes of the air gap 7B is closed. The atmosphere becomes a metal vapor atmosphere, and a current passing through the current limiting element 7A flows in the atmosphere. This current is determined by the secondary voltage of the step-up transformer 6 applied to the current limiting element 7A, that is, the rated voltage of the lightning arrester 7 and the nonlinear characteristic of the current limiting element 7A. The sum of the surface leakage current and the normal peak value of about 10 A, which has an irregular pulse repetition waveform due to the contamination of the insulating cylinder outer peripheral surface of the element 7A,
This current is cut off in the air gap after the fuse is vaporized. In order to be able to verify equivalently the interrupting ability of the air gap at this time, the wire diameter and length of the fuse to be used should be the air gap with a smaller electrode gap and the high air gap corresponding to this air gap. The results of the equivalence test between the test using only the AC power supply and the fuse using the stacked nonlinear resistance elements and the test using the AC power supply and the impulse power supply together without using the fuse were excluded. It is decided by inserting.

[0005]

However, even when a follow-current cutoff test is performed using a fuse having a predetermined wire diameter and length, the fuse melts and vaporizes after the current starts flowing through the lightning arrester. (This time is a discontinuous high resistance when the fuse is melted and vaporized, and the current changes discontinuously at this vaporization time, at least at the time of the next zero crossing. (This time is referred to as the fusing time, and the melting and vaporization is also referred to as fusing.), And the true breaking ability of the gap in the atmosphere is determined regardless of the success or failure of the current breaking in the gap in the atmosphere. There was a problem that was difficult. In addition, due to the variation in the fusing time, the duration of the current flowing through the current-limiting element becomes abnormally long, and the current-limiting element is broken, which may cause a problem in repeating the test.

SUMMARY OF THE INVENTION It is an object of the present invention that the time from the start of the current flow to the fuse from the AC power supply to the melting and vaporization does not vary, which makes it possible to evaluate the test results for determining the gap breaking capability in the atmosphere. It is an object of the present invention to provide a method for testing a lightning arrester for a power transmission line, which is easier and can prevent a decrease in test efficiency.

[0007]

According to the present invention, there is provided a lightning arrester for a transmission line comprising a current limiting element and an air gap in series. , A follow-up cutoff test for a lightning arrester for a transmission line, which verifies the breaking ability of the air gap when the current from the operating frequency power supply following the impulsive lightning current passed in series with As a method, only an AC power supply is used as a test power supply, the fuse in the atmosphere is short-circuited with a fuse, and the fuse is melted and vaporized by the AC power supply. The following flow interruption test method to interrupt at the gap,
The AC current comprises a short-circuit power supply for outputting a short-circuit current, the test circuit comprises a main circuit in which a lightning arrester is connected in series to the short-circuit power supply, and an auxiliary circuit in which a circuit breaker is connected in parallel with a current limiting element. With the circuit breaker turned on, a short-circuit current is supplied to the fuse from the short-circuit power supply to melt and vaporize the fuse, and at the same time as the melt-vaporization, the circuit breaker is turned off and the circuit breaker passing current is transferred to the current limiting element. Or a method in which the current passing through the current-limiting element is interrupted at the gap in the atmosphere, or the AC power supply comprises a short-circuit power supply for outputting a short-circuit current and an auxiliary power supply for outputting a current for melting and vaporizing the fuse. The test circuit comprises a main circuit in which a lightning arrester is connected in series to the short-circuit power supply, and an auxiliary circuit in which an auxiliary power supply is connected in parallel with a fuse via a circuit breaker. Or auxiliary power A current is supplied to the fuse to melt and vaporize, and immediately before the melt and vaporization, the lightning arrester is connected to the short-circuit power supply and the circuit breaker is turned off, and the current flowing from the short-circuit power supply through the current-limiting element is cut off at the air gap. Method. In the method of using the auxiliary power supply together with the short-circuit power supply, it is preferable that the auxiliary power supply be a short-circuit generator having a short-circuit capacity smaller than that of the short-circuit power supply or a transformer having the short-circuit power supply on the primary side.

[0008]

According to the present invention, a current passing through a non-linear element constituting a current limiting element is very small, usually 1 A or less, based on the non-linear characteristic under an AC power supply equal to the rated voltage of the lightning arrester. The surface leakage current based on the contamination of the outer peripheral surface of the insulating cylinder of the current limiting element has a peak value of about 10 A, which is considerably large, but shows a repetitive waveform of an irregular pulse,
The inventors pay attention to the fact that the energy supplied to the fuse within a certain period of time is inevitable, and this causes the variation of the fuse blowing time.
Therefore, a stable sine wave current is used to blow the fuse,
In addition, by fusing the fuse as a current equal to or greater than the current at which the fusing time of the fuse begins to fluctuate, the fusing time no longer varies, and the fusing time for each current or the start of sine wave current flow to the fuse The relationship between the energy injected between the gap electrodes and the success or failure of the air gap interruption during the time from the time until the final interruption in the air gap to the air gap, the electrode gap in the air gap is reduced, and the height corresponding to this is reduced. Using the non-linear resistance element stacked in the above, the AC power supply and the impulse power supply are used together, and when the continuity interruption is performed without a fuse, the relation between the injected energy between the gap electrodes and the success or failure of the interruption is compared. By this means, it is possible to more correctly determine the ability to block the downstream flow of the air gap. further,
Conventionally, the fusing time fluctuates greatly, the duration of the current flowing through the current-limiting element becomes abnormally long, and the nonlinear resistance element in the current-limiting element causes thermal destruction. Efficiency is also improved.

In particular, in the method using a short-circuit power supply and an auxiliary power supply as the AC current, a short-circuit generator having a short-circuit capacity smaller than the short-circuit power supply as the auxiliary power supply or a short-circuit power supply on the primary side is provided. By using a transformer of the type described above, the reactor for adjusting the current supplied to the fuse becomes small, so that it is easy to supply the current by changing it at a small pitch, and a large amount of test data can be easily obtained. There is an advantage that the flow blocking ability can be determined more accurately.

[0010]

FIG. 1 shows a first embodiment of a test circuit configuration based on the method of the present invention. In the figure, the same circuit elements as those in FIG. The test circuit includes a short-circuit generator 2, a protective circuit breaker 3, a closing switch 4, a current regulating reactor 5, and a step-up transformer 6, and a short-circuit power supply 1 that outputs a short-circuit current from a secondary terminal of the step-up transformer 6. And a lightning arrester 7 connected in series, and an auxiliary circuit in which a circuit breaker 9 is connected in parallel to a current limiting element 7A of the lightning arrester 7 . Therefore, the short-circuit power supply 1 and the lightning arrester
The electrical connection with 7 is made by closing the protection circuit breaker 3 on the primary side of the step-up transformer 6 and then closing the closing switch 4. A test using this circuit configuration is performed as follows.

First, prior to the test, the air gap 7B of the lightning arrester 7 is short-circuited with a fuse 8, and the rated voltage of the lightning arrester 7 is output to the secondary side of the step-up transformer 6.
The primary or secondary winding tap is switched. next,
The protection circuit breaker 3 (SW1 in FIG. 2) is turned on and the short circuit generator 2 is turned on.
When the terminal voltage of the short-circuit generator 2 reaches a predetermined value, the closing switch 4 (SW2 in FIG. 2) is turned on. From this closing time T ₁ (FIG. 2), a short-circuit current I ₁ flows to the fuse 8 via the circuit breaker 9, and this fuse causes the fuse 8 to move at the time T 1.
Fusing at ₂ The breaker 9 is turned off immediately before the fuse 8 is blown.
F, the short-circuit current I ₁ in the circuit breaker 9 is cut off at its zero point, and thereafter, only the current I ₂ passing through the current limiting element 6A flows through the air gap 7B where the fuse is melted and vaporized, and It will be cut off by the middle gap 7B.
Current I ₃ in FIG. 2 shows the entire time course of the current passing through the air in the gap 7B.

By setting the current supplied to the fuse 8 via the circuit breaker 9 to a value equal to or greater than the current at which the fusing time of the fuse 8 begins to vary, the fuse 8 exhibits a constant fusing time for each current. The variation in the duration of the current flowing through the current limiting element after fusing is also small, and the evaluation of the test result for determining the ability to interrupt the downstream flow of the air gap becomes easy. Conventionally, the fusing time greatly fluctuates, the duration of the current flowing through the current limiting element becomes abnormally long, and the nonlinear resistance element in the current limiting element causes thermal destruction.
There are no cases where testing is interrupted, and testing efficiency is improved.

FIG. 3 shows a second embodiment of the test circuit configuration based on the method of the present invention. In this embodiment, the test circuit comprises the same main circuit as in the first embodiment, and an auxiliary power supply 11 for supplying a current for blowing a fuse comprises a circuit breaker 10 and a reactor 12 in parallel with an air gap 7B of a lightning arrester 7. And an auxiliary circuit connected thereto. Usually, a short-circuit test site in a factory is provided with a large-capacity short-circuit generator and a small-capacity short-circuit generator, and the small-capacity short-circuit generator is connected to the auxiliary power supply 1.
Can be used as 1. In addition, it is of course possible to use a small transformer using the short-circuit generator 2 as a power supply as an auxiliary power supply. Since the reactor 12 for adjusting the current supplied from the auxiliary power supply 11 to the fuse 8 is smaller than the reactor 5 of the main circuit, the switching operation is easy, and the current can be easily switched in multiple stages at a small pitch. Data can be obtained easily. The test is performed as follows.

First, prior to the test, the lightning arrester7In the atmosphere
The gap 7B is short-circuited by the fuse 8, and the step-up transformer
Lightning arrester on the secondary side of 67So that the rated voltage of
The primary or secondary winding tap is switched. Next,
Protection circuit breaker 3 (SW1 in FIG. 4)
Start and generate a predetermined terminal voltage in the short-circuit generator 2
The closing switch 4 (SW2 in FIG. 4) waits for closing. Supplement
A short-circuit generator different from the short-circuit generator 2 is used as the auxiliary power supply 11
In this case, the terminal voltage of this generator is almost the same as that of the short-circuit generator 2.
At the same time, it is raised to a predetermined value. Both generator terminal voltages are
At the point where the value has risen to the predetermined value at time T₁(Fig. 4)
10 is supplied to supply a current to the fuse 8. fuse
8 at time T_TwoFusing and changes to high resistance
You. Time T_TwoJust before, that is, fuse 8 is still
When the closing switch 4 is turned on at the time when it is not blown,
Current flowing through the current limiting element 7A from the short-circuit power supply 1
I ₁(See FIG. 4) is the current I from the auxiliary power supply 11_ThreeSuperimposed on
And flow At this time, the terminal voltage of the fuse 8 is low.
That the high voltage of the step-up transformer 6 is applied to the auxiliary power supply 11
There is no. The breaker 10 is disconnected from the fuse 8 at the time T_TwoJust before
When the fuse 8 is blown, the fuse
Current through the current limiting element in the air gap 7B
Flows.

By performing the above test while switching the reactor 12 and using a large current value that does not cause a variation in the fusing time of the fuse 8, it is useful for determining the ability of the air gap to follow the downstream flow. A lot of data can be obtained.

[0016]

As described above, according to the present invention, in a lightning arrester for a transmission line having a current limiting element and an air gap in series, the lightning arrester for a transmission line passes through the current limiting element and the air gap in series. As a method for testing the continuity interruption of a lightning arrester for a transmission line, a method for verifying the interruption capability of the air gap when the current from the operating frequency power supply following the impact shock lightning current interrupted at the air gap is used. Only the AC power supply is used as the power supply, the fuse in the atmosphere is short-circuited with a fuse, and the fuse is melted and vaporized with the AC power supply. A current interruption test method, wherein the alternating current comprises a short-circuit power supply for outputting a short-circuit current, and a test circuit comprises: a main circuit comprising a lightning arrester connected in series to the short-circuit power supply;
An auxiliary circuit in which a circuit breaker is connected in parallel with the current limiting element. When the circuit breaker is ON, a short-circuit current is supplied from a short-circuit power supply to a fuse to melt and vaporize the fuse. OFF to transfer the current passing through the circuit breaker to the current limiting element so that the current passing through the current limiting element is interrupted at the gap in the atmosphere, or the AC power supply includes a short-circuit power supply for outputting a short-circuit current; An auxiliary power supply for outputting a current for melting and vaporizing the fuse; a test circuit comprising: a main circuit in which a lightning arrester is connected in series to the short-circuit power supply;
An auxiliary circuit in which an auxiliary power supply is connected in parallel with the fuse through a circuit breaker. The circuit breaker is turned on, a current is supplied from the auxiliary power supply to the fuse, and the fuse is vaporized. Is connected to the short-circuit power supply and the circuit breaker is turned off, so that the current flowing from the short-circuit power supply through the current limiting element is cut off at the gap in the atmosphere. The evaluation of the test results for the determination of the downstream flow blocking ability of the air gap became easier. Furthermore, in the conventional case, the fusing time greatly fluctuates, the duration of the current flowing through the current limiting element becomes abnormally long, and the nonlinear resistance element in the current limiting element causes thermal destruction. The test efficiency was also improved.

In particular, in the method in which the fuse blowing current is supplied from the auxiliary power supply, a large number of test data to be evaluated can be easily obtained, and the determination of the ability to interrupt the downstream current can be performed more accurately.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a test circuit configuration based on the method of the present invention.

FIG. 2 is an explanatory diagram comparing a control sequence showing the control contents of the test circuit shown in FIG. 1 and its time sequence with a current waveform of each part in each control stage.

FIG. 3 is a circuit diagram showing a second embodiment of the test circuit configuration based on the method of the present invention.

FIG. 4 is an explanatory diagram showing a comparison between a control sequence of the test circuit shown in FIG. 3 and a time sequence thereof, and a current waveform of each unit in each control stage.

FIG. 5 is a circuit diagram showing an example of a conventional test circuit configuration.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Short-circuit power supply 2 Short-circuit generator 3 Protection circuit breaker 4 Closing switch 5 Reactor 6 Step-up transformer 7 Lightning arrester (lightning arrester for transmission line) 7A Current limiting element 7B Atmospheric gap 8 Fuse 9 Circuit breaker 10 Circuit breaker 11 Auxiliary power supply

Claims (4)

(57) [Claims] 1. A lightning arrester for a power transmission line comprising a current limiting element and an air gap in series, wherein a lightning current from an operating frequency power source following an impulsive lightning current passing through the current limiting element and the air gap in series is provided. As a method for testing the shunt current of a lightning arrester for a transmission line, which verifies the interrupting ability of the air gap when the current is interrupted at the air gap, only an AC power supply is used as a test power supply, and the air gap is fused. A fuse is melted and vaporized by an AC power supply by short-circuiting in the AC current, and the current limiting element passing current passing through the air gap after the melting and vaporization is interrupted by the air gap. A test circuit comprising: a main circuit in which a lightning arrester is connected in series to the short-circuit power supply; and an auxiliary circuit in which a circuit breaker is connected in parallel with the current limiting element. With the circuit breaker turned on, a short-circuit current is supplied to the fuse from the short-circuit power supply to melt and vaporize, and almost simultaneously with the melt-vaporization, the circuit breaker is turned off to transfer the circuit breaker passing current to the current limiting element and pass the current limiting element. A method for testing the continuity of a lightning arrester for a transmission line, wherein the current is interrupted at a gap in the atmosphere. 2. A lightning arrester for a transmission line comprising a current limiting element and an air gap in series, wherein the lightning current from the operating frequency power source is based on an impact lightning current passing in series with the current limiting element and the air gap. As a method for testing the shunt current of a lightning arrester for a transmission line, which verifies the interrupting ability of the air gap when the current is interrupted at the air gap, only an AC power supply is used as a test power supply, and the air gap is fused. A fuse is melted and vaporized by an AC power supply at the AC power supply, and the current limiting element passing current passing through the air gap after the melt vaporization is cut off by the air gap. A short-circuit power supply for outputting a current, and an auxiliary power supply for outputting a current for melting and vaporizing the fuse, wherein a test circuit comprises: a main circuit having a lightning arrester connected in series to the short-circuit power supply; Consists auxiliary circuit auxiliary power in parallel with the Yuzu is connected via a circuit breaker, the breaker O
N, a current is supplied from the auxiliary power supply to the fuse to melt and vaporize, and immediately before the fusion and vaporization, the lightning arrester is connected to the short-circuit power supply, the circuit breaker is turned off, and the current flowing from the short-circuit power supply through the current-limiting element. A method for testing the continuity of lightning arresters for power transmission lines, characterized in that the airflow is interrupted by an air gap. 3. The method according to claim 2, wherein the auxiliary power supply connected in parallel with the fuse via the circuit breaker is a short-circuit generator having a short-circuit capacity smaller than the short-circuit power supply of the main circuit. A method for testing a lightning arrester for a transmission line, comprising: 4. The method of claim 2, wherein the auxiliary power supply connected in parallel with the fuse via the circuit breaker is a transformer having a short circuit power supply of a main circuit on a primary side. A method for testing a lightning arrester for a power transmission line, comprising: