JP6363442B2 - Trigger gap - Google Patents

Description

  Embodiments of the present invention relate to a trigger gap used for a synthetic charging test of a power switchgear.

  The power switchgear is used for fault current interruption, system switching, equipment maintenance, and the like in the power system. Such a power switchgear includes a pair of electrodes, and opens and closes an electric circuit by contacting and separating these electrodes. When an accident current is detected, a shut-off signal is input to the power switchgear, and the power switchgear opens each electrode in order to cut off the current when triggered by this shut-off signal.

  As a type test item of such a power switchgear, there is an input test. The input test is a test for verifying the input capability of the switchgear. In the charging test, the switchgear is closed while the rated voltage is applied to the open switchgear. At this time, when the electrodes of the switchgear approach each other up to a predetermined distance, dielectric breakdown occurs between the electrodes before mechanical contact, and a discharge called pre-arc occurs. The electrodes are not mechanically connected, but are electrically connected so that a short-circuit current is passed through the switchgear. Through the above process, the switchgear input capability is verified.

  In the input test with a single power source called direct input test, there is a limit to the rated voltage of the switchgear that can be tested although it depends on the capacity of the test facility. The test is carried out by the input test.

  In the synthetic charging test, a current called the main current that is energized when closing the switchgear and a rated voltage applied between the electrodes of the switchgear before the pre-arc occurs during the closing operation are supplied by separate power sources. To do.

  In other words, the composite input test circuit for performing the composite input test includes a switch device to be tested, a current source circuit that has a power source and supplies a main current to the switch device, and a rated voltage applied to the electrodes of the switch device that has a power source. A voltage source circuit for applying. In the synthesis input test, since the current source circuit and the voltage source circuit are separate circuits, the supply start of the main current must be controlled to be synchronized when the pre-arc occurs. In this regard, as a high power related standard, it is stipulated that the main current must be supplied within 300 μs immediately after the switchgear generates a pre-arc. For this reason, a switch called a trigger gap is provided in the current source circuit, and a main current is supplied to the switchgear by controlling the trigger gap in accordance with the occurrence of the pre-arc.

  The trigger gap is required to switch the current source circuit within 300 μs after the occurrence of the pre-arc without causing dielectric breakdown between the gaps by the voltage applied by the voltage source. Further, when switching is performed, it is necessary to perform switching by causing dielectric breakdown between the gaps in a state where only the current source voltage, which is one tenth of the voltage applied by the voltage source, is applied between the gaps.

IEC 62271-101 High-voltage switchgear and controlgear-Part 101: Synthetic testing Yoshiaki Kudo, Kensaku Miyazaki, Nobuyuki Miyake, Katsumi Suzuki “Trigger Characteristics of Trigger Gap for Synthetic Input Test” Proceedings of the IEEJ National Convention, March 10, 1999, 1999, Vol. 6, p. 6453

  Next, the configuration of the conventional trigger gap and the process in which the trigger gap is switched and the main current is supplied will be described.

  A conventional trigger gap includes a pair of opposing electrodes and a trigger electrode each having a hemispherical shape. The counter electrode and the trigger electrode are arranged such that their hemispherical portions face each other with a predetermined gap therebetween.

The trigger electrode is provided with a T-shaped space, and one direction of the T-shaped space is provided on the central axis common to both electrodes, and the other direction is provided in a direction perpendicular to the central axis. It has been. A cylindrical trigger electrode is inserted and disposed in the space on the central axis, and one end of the trigger electrode faces the counter electrode. An insulator is disposed in a space in a direction orthogonal to the central axis, and is connected to the other end of the trigger electrode. All these members are installed in a gas tank, and the gas tank is filled with SF ₆ gas.

  The gap length between the opposing electrode and the electrode with a trigger is maintained at a distance that does not cause dielectric breakdown at the rated voltage of the switchgear that performs the synthetic insertion test. The trigger electrode is connected to a power supply circuit configured with a capacitor or the like that is charged in advance with a gap.

  The power supply circuit is connected to the trigger electrode at the timing of switching the trigger gap in the synthesis insertion test, and the trigger voltage is applied to the trigger electrode. Then, a spark discharge is generated between the counter electrode and the trigger electrode, and the two electrodes are electrically connected. Thus, the trigger gap is switched and the main current is supplied to the switchgear.

  As described above, the gap length between the opposing electrode and the electrode with trigger is maintained at a distance that does not cause dielectric breakdown at the rated voltage of the switchgear that performs the synthetic insertion test. However, if the gap length of the insulation distance required when the rated voltage is applied is secured, it becomes impossible to generate the trigger voltage necessary for switching the trigger gap, that is, to generate a spark discharge between the gaps. May not be able to be switched.

  Therefore, it is necessary to connect a plurality of trigger gaps in series for switching. In addition, when a plurality of units are used, adjustment of the voltage sharing ratio of each trigger gap and a configuration for controlling the plurality of units at the same time are separately required, which causes a problem that the test becomes complicated.

  The trigger gap according to the present embodiment has been made to solve the above-described problems, and has improved the withstand voltage performance between the gaps compared to the prior art, and the trigger gap can be combined and tested with a single trigger gap. The purpose is to provide.

To achieve the above object, the trigger gap of this embodiment is a trigger gap pair of first and second electrodes are provided so as to face each other with a gap, the first The electrode is an electrode with a trigger for generating arc plasma, the second electrode is provided with a replacement part in a portion of the electrode with trigger that is exposed to the arc plasma , and the electrode with trigger is provided inside. A pressure accumulator chamber, a trigger electrode for generating arc discharge between the accumulator chamber wall and a nozzle that communicates the accumulator chamber and the gap. The arc plasma generated in the pressure accumulating chamber by discharge is increased in pressure in the pressure accumulating chamber and discharged to the second electrode facing the nozzle through the nozzle.

It is sectional drawing which shows the whole structure of the trigger gap which concerns on 1st Embodiment. It is a synthetic injection test circuit diagram using a trigger gap according to the first embodiment. It is a circuit diagram which shows a part of current source circuit. It is sectional drawing which shows the whole structure of the trigger gap which concerns on 2nd Embodiment. It is sectional drawing which shows the whole structure of the trigger gap which concerns on 3rd Embodiment.

[First Embodiment]
(Constitution)
In the following, the trigger gap of this embodiment and the synthesis input test circuit using the same will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the overall configuration of the trigger gap of the present embodiment. FIG. 2 is a synthetic injection test circuit diagram using the trigger gap according to the first embodiment.

  As shown in FIG. 2, the composite input test circuit includes a power switchgear TO to be tested, a current source circuit C that has a power supply G and supplies a main current to the switchgear TO, and a switchgear that has a power supply. And a voltage source circuit (not shown) for applying a rated voltage to the TO electrode. As for the current source circuit C and the voltage source circuit, a known configuration can be used as the basic configuration, so that the description thereof is omitted. However, as shown in FIG. 2, the current source circuit C includes a power source G, a coil L, a transformer. It has Tr1, trigger gap TG, auxiliary circuit breaker AB, and switch device TO to be tested. The voltage source circuit has a power source and a transformer Tr2. The voltage source circuit is not shown in FIG. 2, but is arranged on the transformer Tr2 side.

  The overall configuration of the trigger gap TG of this embodiment will be described. The trigger gap TG is a switch provided in a current source circuit C that supplies a main current to the switchgear TO in the combined charging test circuit of the power switchgear TO. As shown in FIG. 2, the trigger gap TG is provided between the switchgear TO and the power source G and in parallel with the auxiliary circuit breaker AB.

  As shown in FIG. 1, the trigger gap TG includes a pair of counter electrodes 1 and a trigger electrode 2 provided via a gap 8. In the current source circuit C, both electrodes 1 and 2 are provided between the power source G of the current source circuit C and the switch device TO to be tested.

Both electrodes 1 and 2 are conductors each having a hemispherical shape, and are arranged with their curved portions of the hemisphere facing each other with a predetermined gap 8 therebetween. Both electrodes 1 and 2 are made of carbon, for example. Both electrodes 1 and 2 are provided in a gas tank filled with a gas serving as an insulating medium such as SF ₆ gas. In this embodiment, the insulating medium is a gas that is turned into plasma. Therefore, since the structure for supplying plasma gas in a structure such as a general plasma cutting machine is unnecessary, the structure can be simplified.

  The electrode 2 with a trigger is for generating a plasma by gasifying an insulating medium in the gas tank into a plasma. Specifically, the trigger-equipped electrode 2 includes a pressure accumulating chamber 4 provided therein, a trigger electrode 5 provided in the pressure accumulating chamber 4 for generating arc discharge, and a nozzle communicating the pressure accumulating chamber 4 and the gap 8. 3 and an insulator 7 connected to the trigger electrode 5.

  In the pressure accumulating chamber 4, the pressure of the arc plasma 6 generated therein increases. Therefore, the pressure accumulation chamber 4 is configured to be easily closed. Specifically, the pressure accumulating chamber 4 is a space formed by the inner wall of the electrode with trigger 2 and extends in a cylindrical shape having the same diameter from the center of the bottom surface of the electrode with trigger 2 having a hemispherical shape toward the counter electrode 1. The diameter is reduced from the middle and the shape is narrowed. Since the tapered portion of the pressure accumulating chamber 4 is narrowed, the inner wall surface of the trigger electrode 2 forming the portion covers the tip of the trigger electrode 5. A nozzle 3 is provided at the tapered end of the taper shape.

  The nozzle 3 makes the pressure accumulation chamber 4 in the electrode with trigger 2 communicate with the gap 8 between the counter electrode 1 and the electrode with trigger 2. More specifically, the nozzle 3 is a hemispherical curved portion of the trigger electrode 2 facing the counter electrode 1, and is provided on the central axis of the counter electrode 1 and the trigger electrode 2. In other words, the nozzle 3 is provided at a position where the length of the gap 8 of the electrode with trigger 2 is the shortest.

  On the other hand, an inner space wider than the cylindrical portion of the pressure accumulating chamber 4 is provided on the bottom surface side of the electrode with trigger 2 on the side opposite to the counter electrode 1. The insulator 7 is provided in this internal space. The insulator 7 has a flat plate shape. The insulator 7 is a support insulator for the trigger electrode 5. That is, the cylindrical trigger electrode 5 is attached to the insulator 7 toward the counter electrode 1, and the insulator 7 supports the trigger electrode 5 and insulates the trigger electrode 2 from the trigger electrode 5.

  The trigger electrode 5 is a cylindrical conductor and is disposed in the pressure accumulation chamber 4. The trigger electrode 5 generates arc discharge. The trigger electrode 5 extends from the insulator 7 toward the counter electrode 1, but its tip does not extend to the tapered portion of the pressure accumulation chamber 4. That is, the tip of the trigger electrode 5 is located in the middle of the cylindrical portion of the pressure accumulating chamber 4, and the space of the pressure accumulating chamber 4 on the counter electrode 1 side from the tip of the trigger electrode 5 becomes a space for generating arc discharge. Yes. Since the tapered portion of the pressure accumulating chamber 4 is narrowed toward the nozzle 3, the inner wall of the trigger electrode 2 that forms the portion faces the tip of the trigger electrode 5.

  As shown in FIG. 3 showing a part of the current source circuit, the trigger electrode 5 is connected to a power source C0 with a gap T therebetween, and the power source C0 is a capacitor, for example, and is charged in advance. The power source C0 is configured such that a voltage can be applied to the trigger electrode 5 at the timing when the trigger gap TG is switched in the composite charging test. That is, when the gap T is discharged and a voltage is applied from the power source C0, an arc discharge is generated between the tip of the trigger electrode 5 and the inner wall of the trigger electrode 2 constituting the pressure accumulating chamber 4, and an arc plasma 6 is generated. It is like that.

(Function)
In the synthesis input test, first, a voltage is applied between the electrodes of the switchgear TO to be tested by the power source of the voltage source circuit. At this stage, since the trigger gap TG is not electrically connected, the power source G of the current source circuit C is disconnected from the switchgear TO. When a pre-arc occurs between the electrodes by applying a voltage between the electrodes of the switchgear TO, the trigger gap TG is switched.

  That is, the power source C 0 of the current source circuit C charged in advance is connected to the trigger electrode 5 and a voltage is applied to the trigger electrode 5. Then, an arc discharge is generated between the tip of the trigger electrode 5 and the inner wall of the tapered electrode 2 having a trigger shape constituting the pressure accumulating chamber 4, and arc plasma 6 is generated in the pressure accumulating chamber 4. Note that the bottom surface, which is a planar portion of the electrode with trigger 2, is covered, and arc plasma does not advance toward the rear end of the trigger electrode 5.

  Thus, the arc plasma 6 generated in the vicinity of the tip of the trigger electrode 5 is easily blocked because the tapered portion of the pressure accumulating chamber 4 is directed to the tip of the trigger electrode 5. Therefore, the pressure of the arc plasma 6 increases in the pressure accumulation chamber 4. The arc plasma 6 whose pressure has been increased is discharged toward the counter electrode 1 through the nozzle 3 provided on the counter electrode 1 side of the pressure accumulating chamber 4.

  The arc plasma 6 emitted from the nozzle 3 causes the dielectric breakdown between the trigger electrode 2 and the counter electrode 1, and the gap 8 is electrically connected. Accordingly, the main current is supplied from the power source G of the current source circuit C to the switchgear TO. The main current is supplied within 300 μs after the occurrence of the pre-arc. As described above, the composite charging test is performed in which the main current is supplied to the switchgear TO using the trigger gap TG and the switchability of the switchgear TO is verified.

(effect)
The trigger gap TG of the present embodiment is a trigger gap provided so that the pair of counter electrodes 1 and the trigger electrode 2 are opposed to each other through the gap 8. The trigger electrode 2 generates the arc plasma 6. A pressure accumulating chamber 4 provided inside, a trigger electrode 5 provided in the pressure accumulating chamber 4 for generating an arc discharge between the inner wall of the pressure accumulating chamber 4, a pressure accumulating chamber 4 and a gap 8; The arc plasma 6 generated in the pressure accumulating chamber 4 by arc discharge is increased in pressure in the pressure accumulating chamber 4 and discharged to the opposing electrode 1 through the nozzle 3.

  As a result, the pressure rises in the pressure accumulating chamber 4 and the arc plasma 6 is emitted, so that the arc plasma 6 advances and accelerates. Therefore, it is possible to cause a dielectric breakdown between gaps having a longer gap length than the conventional trigger gap. That is, the withstand voltage performance between the gaps can be improved as compared with the conventional case.

  In particular, when a switchgear with a rated voltage of 245 kV or higher is the subject of the input test, with the conventional trigger gap, if the gap length of the insulation distance required when the rated voltage is applied is secured, the trigger gap is switched, that is, between the gaps. Therefore, it is impossible to generate a trigger voltage necessary for spark discharge in the case, and the trigger gap cannot be switched. Therefore, conventionally, it is necessary to use a plurality of trigger gaps connected in series, and in that case, it is necessary to adjust the voltage sharing ratio of each trigger gap and to use a synchronous control technique for simultaneously controlling the plurality of trigger gaps. Yes, the test was complicated.

  However, according to the present embodiment, the usable test voltage range can be expanded, so that even a switchgear with a rated voltage of 245 kV or more can be subjected to an input test with a single trigger gap TG. Therefore, it is possible to simplify the synthesis input test circuit.

[Second Embodiment]
(Constitution)
A second embodiment will be described with reference to FIG. The basic configuration of the second embodiment is the same as that of the first embodiment. In the following, only differences from the first embodiment will be described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and detailed description thereof will be omitted.

  FIG. 4 is a cross-sectional view showing the overall configuration of the trigger gap according to the second embodiment. As shown in FIG. 4, the counter electrode 1 includes a replacement unit 10 at a portion of the trigger electrode 2 exposed to the arc plasma. Examples of the portion exposed to the arc plasma include a portion irradiated with the arc plasma from the trigger electrode 2. The exchange unit 10 is configured to be able to exchange a cassette as a separate body from the counter electrode 1 main body. This exchange part 10 may be formed with the same material as the counter electrode 1, or may be formed with a different material. In the present embodiment, the exchange unit 10 is formed of a material different from that of the counter electrode 1. This different material is a low wear metal that is less worn by arc plasma than the counter electrode 1 body, and includes, for example, tungsten.

(Action / Effect)
(1) The counter electrode 1 of this embodiment is provided with the exchange part 10 that can be exchanged with the part of the trigger-equipped electrode 2 exposed to the arc plasma. As a result, the portion exposed to the arc plasma in the process of repeatedly using the trigger gap TG wears out, but the maintenance only needs to be replaced by the replacement unit 10. That is, since it is not necessary to replace the entire counter electrode 1, the maintenance becomes easy.

(2) The replacement part 10 is made of a low wear metal that is less worn by arc plasma than the counter electrode 1 body. Thereby, an electrode lifetime can be lengthened.

[Third Embodiment]
A third embodiment will be described with reference to FIG. The basic configuration of the third embodiment is the same as that of the first embodiment. In the following, only differences from the first embodiment will be described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and detailed description thereof will be omitted.

  FIG. 5 is a cross-sectional view showing the overall configuration of the trigger gap according to the third embodiment. As shown in FIG. 5, instead of the counter electrode 1 of the first embodiment, an electrode 2 with a trigger is provided. That is, both of the pair of electrodes opposed to each other via the gap 8 are the trigger electrodes 2. Since both have the same configuration, description thereof is omitted.

  In the present embodiment, since the pair of electrodes are both electrodes 2 with trigger, arc plasma 6 is emitted from both electrodes 2 with trigger. Therefore, it is possible to cause a dielectric breakdown between gaps longer than in the first embodiment. Therefore, since the gap between the electrodes can be further increased, the withstand voltage performance between the gaps can be further improved. According to the trigger gap TG of the present embodiment, the usable test voltage range can be further expanded.

[Other Embodiments]
In the present specification, a plurality of embodiments according to the present invention have been described. However, these embodiments are presented as examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and gist of the invention.

  For example, although not particularly mentioned in the first to third embodiments, the pair of electrodes of the trigger gap TG may be configured such that the other electrode is movable relative to one electrode. good. Thereby, since it can be set as desired gap length, desired withstand voltage performance can be obtained. For example, in the first embodiment, the counter electrode 1 can be fixed, the trigger electrode 2 can be connected to a moving mechanism, and the trigger electrode 2 can be moved with respect to the counter electrode 1.

DESCRIPTION OF SYMBOLS 1 ... Counter electrode 2 ... Trigger electrode 3 ... Nozzle 4 ... Accumulation chamber 5 ... Trigger electrode 6 ... Arc plasma 7 ... Insulator 8 ... Gap 10 ... Replacement part AB ... Auxiliary circuit breaker C ... Current source circuit C0 ... Power source G ... Power supply L ... Coil T ... Gap TG ... Trigger gap TO ... Switchgear Tr1 ... Transformer Tr2 ... Transformer

Claims (4)

A trigger gap provided so that a pair of first electrode and second electrode face each other with a gap interposed therebetween,
It said first electrode is a triggering with electrodes for generating the arc plasma,
The second electrode includes a replacement part in a portion of the trigger electrode exposed to the arc plasma,
The electrode with a trigger is
A pressure accumulation chamber provided inside,
A trigger electrode provided in the pressure accumulation chamber for generating arc discharge with the pressure accumulation chamber wall;
A nozzle for communicating the pressure accumulation chamber and the gap,
A trigger gap, characterized in that arc plasma generated in the pressure accumulating chamber by the arc discharge rises in pressure in the pressure accumulating chamber and is discharged to the second electrode facing through the nozzle. It said switching unit, a trigger gap according to claim 1, characterized in that it is constituted by a small low wear metals wear by the arc plasma than the second electrode body.   The trigger gap according to claim 1, wherein both the first electrode and the second electrode are the electrodes with a trigger. The said 1st electrode and the said 2nd electrode were comprised so that the other electrode could move relatively with respect to one electrode, The any one of Claims 1-3 characterized by the above-mentioned. Trigger gap.