JP5222230B2 - Vacuum circuit breaker pressure diagnostic device - Google Patents

Description

  The present invention relates to a pressure diagnostic device for a vacuum circuit breaker used in a switchgear and the like, and more particularly to a pressure diagnostic device for a vacuum circuit breaker that can diagnose the pressure soundness of the vacuum circuit breaker during operation of the switchgear.

  In recent years, in order to meet the needs for low cost and space saving, switchgear with vacuum circuit breaker housed in an insulating container, switchgear with multiple functions of shutoff, disconnection and grounding in a single vacuum container, etc. It has been commercialized (for example, Patent Document 1).

JP 9-153320 A

  The withstand voltage performance and the breaking performance of the vacuum circuit breaker depend on the pressure inside the vacuum vessel which is a component. In general, a Paschen curve representing a correlation between a discharge voltage and a product of a pressure inside a vacuum vessel and a distance between electrodes is known as an indicator of discharge characteristics in vacuum. FIG. 5 is a characteristic diagram showing the correlation between the pressure inside the vacuum vessel and the discharge voltage when the gap length between the electrodes is 5 mm. As shown in FIG. 5, when the pressure inside the vacuum vessel rises above a certain value (when the degree of vacuum is lowered), the insulation performance is drastically lowered. The vacuum circuit breaker is required to be regularly inspected because the pressure may rise not only due to the failure of the vacuum vessel but also due to long-term permeation of the atmospheric gas.

  As a general inspection method, the vacuum circuit breaker is opened, the voltage specified by the manufacturer is applied across the pole, and if no discharge occurs, the internal pressure is judged normal. A voltage test is being performed. Many conventional switchgears have a structure in which the vacuum circuit breaker can be pulled out of the switchgear. For this reason, the circuit breaker to be inspected is removed while the bus of the switchgear is applied and the load supplied from the circuit breaker is removed, so that the operation state of the other feeder is maintained and the circuit breaker to be inspected is maintained. Pressure health can be checked. On the other hand, in the recent switchgear, the voltage soundness of the vacuum circuit breaker is evaluated by applying a voltage from a grounding switch for inspection or a cable head. In any switchgear, in order to confirm the pressure soundness of the mounted vacuum circuit breaker, the load connected to the circuit breaker must be interrupted.

  The present invention has been studied in view of the above-described background, and includes a circuit breaker to be inspected, and can easily and safely diagnose the pressure soundness of the vacuum circuit breaker without causing a power failure in all feeders of the switchgear. It aims at providing the pressure diagnostic device of a vacuum circuit breaker.

In order to achieve the above object, the first invention provides a vacuum vessel including a pair of contacts that can be contacted and separated, and a metal part that is electrically insulated from the contacts, and from the inside of the vacuum vessel to the outside. A pressure diagnostic device for a vacuum circuit breaker comprising the pair of contacts penetrating through the metal and a conductor connected to each of the metal parts, wherein the metal parts are electrically connected to the conductors of the metal parts. The DC voltage generator for charging, the capacitor row having one end connected to the metal part and the other end connected to the ground, and the discharge detection device for measuring a potential difference of a part of the capacitor row Means for measuring the potential fluctuation of the metal part, and the DC voltage generator is connected to the capacitor string via a resistor for suppressing an overvoltage when the DC voltage is turned on or off .

The second invention is Oite the first inventions, the a means for measuring the voltage fluctuation of the DC voltage generator and the metal portion, the resistance for suppressing current when the event discharge And connected to the metal part.

Furthermore, the third invention, Oite the first inventions shall connect the impedance matching resistor in parallel with a portion of the capacitor banks.

A fourth aspect of the present invention is Oite the second inventions, it is assumed to connect the impedance matching resistor in parallel with a portion of the capacitor banks.

Further, the fifth invention, Oite the fourth inventions, the capacitor bank, the discharge current suppressing resistor, a unit accommodating the overvoltage suppression resistor and the resistor for the impedance matching, the unit electrically respectively The DC voltage generator to be connected, the discharge detector, and an insulated wire for connecting the discharge current suppressing resistor and the metal part in the unit are provided.

  According to the pressure diagnostic device for a vacuum circuit breaker of the present invention, a DC voltage is superimposed on a metal part arranged in a vacuum vessel, and a high voltage in which the DC voltage is superimposed on a system voltage is applied between the contact and the metal part. Since it was made possible, the vacuum pressure of the vacuum circuit breaker can be diagnosed while the vacuum circuit breaker is in operation. As a result, it is possible to diagnose the pressure soundness of the vacuum circuit breaker without causing a power failure in all feeders including the bus bar of the switchgear and the circuit breaker to be inspected.

It is a side view which shows the switchgear which connected one embodiment of the pressure diagnostic device of the vacuum circuit breaker of the present invention in a partial section. It is a front view of the switchgear seen from A arrow in FIG. It is a side view explaining operation | movement of the switchgear to which one Embodiment of the pressure diagnostic apparatus of the vacuum circuit breaker of this invention is applied. It is explanatory drawing which shows the discharge detection signal in one Embodiment of the pressure diagnostic apparatus of the vacuum circuit breaker of this invention. It is a characteristic view which shows the correlation of atmospheric pressure and discharge voltage when the gap length between electrodes is 5 mm. It is a side view which shows the switchgear which connected other embodiments of the pressure diagnostic device of the vacuum circuit breaker of the present invention in a partial section. It is a side view which shows the switchgear which connected other embodiment of the pressure diagnostic apparatus of the vacuum circuit breaker of this invention in a partial cross section.

Embodiments of a pressure diagnostic device for a vacuum circuit breaker according to the present invention will be described below with reference to the drawings.
FIG. 1 is a side view showing a partial cross section of a switchgear to which an embodiment of a pressure diagnostic device for a vacuum circuit breaker according to the present invention is connected, and FIG. 2 is a front view of the switchgear as viewed from arrow A in FIG. FIG. 3 is a side view for explaining the operation of the switchgear to which an embodiment of the pressure diagnostic device for a vacuum circuit breaker according to the present invention is applied.

  First, the structure of the opening / closing device 1000 will be described. In FIG. 1 and FIG. 2, an insulating container 1 in which an insulating gas 1G such as dry air or SF6 gas is enclosed is provided with three vacuums between two insulating partition plates 3 for improving interphase insulation. The valve 11 is housed, and is detachably attached to the insulating container body 2 formed of epoxy resin, the main body insulating plate 4B, the fixed insulating plate 4A, and the fixed insulating plate 4A provided on the lower and upper sides of the insulating container main body 2. The bus-bar insulating plate 6 is provided. A grounding layer is provided on the outer surface of the insulating container 1 to ensure safety when an operator or the like comes into contact.

  The inside of the vacuum valve 11 is vacuum-sealed, and provided with a metal case 12 and ceramic bushings 13, 14 protruding above and below the metal case 12, and outside the upper insulation bushing 13 and the lower insulation bushing 14. A fixed conductor 16 and a test conductor 17 as a metal part are attached to a sealing metal fitting 15 provided in FIG. 1, and a movable conductor 19 is provided on the right side of FIG. As shown in FIG. 1, the vacuum valve 11 is formed in a substantially T shape in a side view.

  The fixed conductor 16 extends from the inside of the vacuum valve 11 toward the upper outside, and is fixed to the support portion 4C of the fixed insulating plate 4A by a bolt 22 together with the bus-side conductor 23A. A fixed contact 16A made of a refractory metal member such as a Cu—Cr alloy is provided at the inner end of the fixed conductor 16. The bus bar side conductor 23 </ b> A is connected to the bus bar 23 </ b> B of the bus bar insulating plate 6.

  A bellows 25 is provided on the inner diameter of the sealing metal fitting 15 provided on the lower bushing 14, and the test conductor 17 attached to the bellows 25 is supported by an insulating guide 24 and a fixed guide 29, and responds to contact of the movable conductor 19 by a spring 26. To move in the axial direction. The test conductor 17 is fastened and fixed with a stop plate 27 compressing a spring 26 provided in the middle and a flexible conductor 28 made of a plurality of thin copper plates with a nut 31 fitted into the protruding end. Therefore, when the movable conductor 19 comes into contact with the test conductor 17, the downward pressing force of the movable conductor 19 and the compressive force of the spring 26 that directs the test conductor 17 upward act on the movable conductor 19 and the test conductor 17. Contact stability with the conductor 17 can be ensured. The test conductor 17 is connected to the test terminal 32 via the flexible conductor 28.

  The movable conductor 19 extending in a direction perpendicular to the axial direction moves between the fixed conductor 16 and the test conductor 17 with the main shaft 35 as a fulcrum, and is in contact with or separated from both. The main circuit is turned on and off by the contact and separation of the fixed contact 16A and the movable contact 19A.

  The movable conductor 19 extends from the inside of the vacuum valve 11 to the outside on the right side in FIG. 1 and penetrates the bellows 36 fixed to the sealing fitting 15. With the bellows 36, the movable conductor 19 can be moved while maintaining vacuum hermeticity. The material of the movable contact 19A is the same as that of the fixed contact 16A described above. The movable conductor 19 is sandwiched between the connecting conductors 37, and the main shaft 35 inserted into the through holes of both conductors is fixed by tightening a nut to a screw at the tip of the main shaft 35 (not shown).

  In FIG. 3, by driving the operating mechanism portion 38 connected to the outer end of the movable conductor 19, the inner portion of the movable conductor 19 is rotated upward and downward via the main shaft 35, and the four portions shown in FIG. Can stop in position. That is, as the movable conductor 19 rotates, the movable contact 19A contacts the fixed contact 16A, the turning position Y1, the cutting position Y2 that turns downward from the turning position to cut off the current, and the lower position It is turned to the side and does not break down due to lightning, etc., and the disconnection position Y3 has taken a sufficient insulation distance on the load conductor side so that the worker does not get an electric shock. Are four positions of the test position Y4 in contact with.

  At the test position Y4, if the test terminal 32 is grounded, the load connected to the cable 43 can be grounded. Further, the soundness of the cable 43 can be evaluated by applying a predetermined DC voltage from the test terminal 32. In this vacuum valve 11, the movable contact 19A, the fixed contact 16A, and the test conductor 17 are gathered in one place in a vacuum that is a higher insulating medium than SF6 gas and the like, so that it is significantly smaller than a conventional switchgear. Can be

  The U-shaped metal fitting 38A of the operation mechanism portion 38 and the distal end portion of the movable conductor 19 inserted therein are connected by a pin 38B. The U-shaped fitting 38A is attached to one end of the insulating operation rod 38C. An operation lever 38D that connects the other end of the insulating operation rod 38C and one end thereof is attached to the shaft 38E at the other end. As a result, the movable conductor 19 can be moved as described above by rotating the shaft 38E by an operating mechanism (not shown) provided outside the insulating container 1.

  The connection conductor 37 is connected to the load side conductor 41. The load-side conductor 41 forms an L-shaped energization part, and is connected to the cable head 45 and the load cable 43 at the tip thereof.

Next, the configuration of the pressure diagnostic apparatus 100 will be described with reference to FIG.
A general pressure diagnostic method is to open the circuit breaker, apply a voltage specified by the manufacturer between the electrodes, and determine that the internal pressure is normal if no discharge occurs. In the present embodiment, the switchgear 1000 is operated, that is, the fixed conductor 16, the fixed contact 16A, the movable contact 19A and the movable conductor 19 in the vacuum valve 11 are charged to the system voltage (the movable conductor 19 described above). Is stopped at the entry position Y1), a DC voltage is applied to the test terminal 32. At this time, a DC voltage is superimposed on the system voltage between the main circuit and the test terminal 32 (between the fixed conductor 16 and the test conductor 17 in the vacuum valve 11). Is set to a value that is specified, it is equivalent to a general vacuum circuit breaker pressure diagnosis method. That is, it is possible to diagnose the pressure of the vacuum circuit breaker by actively using the system voltage while operating the switchgear 1000.

  In FIG. 1, a rubber bushing 101 for applying a DC voltage is attached to the test terminal 32. If the test terminal itself has a sufficient insulation performance, the rubber bushing 101 is unnecessary. The center conductor 102 of the rubber bushing 101 is screwed into the test terminal 32, and the rubber bushing 101 is sandwiched between the test terminal 32 and the center conductor 102. One end of an insulated wire 103 is attached to the tip of the center conductor 102. The other end of the insulated wire 103 is connected to the high voltage terminal 105 of the unit 104.

  The output of the DC voltage generator 106 is connected to the DC voltage input terminal 107 of the unit 104. Both the unit 104 and the DC voltage generator 106 are connected to the ground bus of the switchgear 1000. The DC voltage generator 106 can be replaced by an insulation resistance meter owned by an electric equipment inspection operator.

Next, the internal configuration of the unit 104 will be described with reference to FIG.
The unit 104 contains a total of five elements, three resistors A, B, and C and two capacitors C0 and C1. The resistor A, one end of which is connected to the high-voltage terminal 105, suppresses the discharge current below the limit (sensing limit) felt by humans even if a discharge occurs between the main circuit and the test terminal 32 during diagnosis. belongs to. Even if other elements in the unit 104 break down due to this resistance A and a high voltage is output to the DC voltage generator 106 or the discharge detector 108 operated by the operator, the safety of the operator Can be secured.

  The human detection limit is said to be about 1 mA. For example, when the system voltage is 22 kV, the safety of the worker can be ensured by setting the resistance A to 12.7 MΩ or more determined by the following equation.

Ground voltage 22 / √3kV ÷ Sensing limit 1mA = 12.7MΩ ・ ・ ・ (1)
One end of the resistor B is connected to the DC voltage input terminal 107. The resistor B is for suppressing overvoltage when the DC voltage generator 106 is turned on and off (ON / OFF), and will be described in detail later. Note that the other end of the resistor B is connected to the other end of the resistor A. That is, a DC voltage is applied to the test terminal 32 via the resistor A and the resistor B.

  The discharge from the main circuit to the test terminal 32 is detected by a capacitor voltage dividing method. A capacitor string in which capacitors C0 and C1 are connected in series is prepared, and one end thereof is connected to a connection point between the resistors A and B and the other end is connected to the ground. The potential difference between both ends of the capacitor C1 on the ground side of the capacitor row becomes an input of the discharge detection device 108. A high voltage is induced at the connection point between the resistors A and B by the discharge from the main circuit to the test terminal 32, and the voltage dividing ratio of the capacitors C 0 and C 1 having the same voltage is input to the discharge detection device 108.

  An oscilloscope may be used for the discharge detection device 108 so that the discharge waveform can be measured, or a buzzer circuit or a relay circuit that operates when a discharge occurs may be simply connected. Note that a resistor C is connected in parallel with the capacitor C1, but this is for impedance matching to prevent the measurement voltage from changing due to the input impedance of the connected oscilloscope, buzzer circuit, or relay circuit. A small resistance is inserted in advance.

Next, the procedure for using the pressure diagnostic apparatus 100 of the present invention described above will be described.
First, the test terminal 32 is detected by a high voltage voltage detector, and it is confirmed that no pressure deterioration has occurred in the vacuum valve 11. Next, the rubber bushing 101 is inserted into the test terminal 32 with an insulating operation rod (not shown), and the central conductor 102 is fastened to the test terminal 32 with the insulation operation rod to fix the rubber bushing 101. The insulated wire 103, the unit 104, the DC voltage generator 106, and the discharge detector 108 are connected, and the other end of the insulated wire 103 is connected to the center conductor 102 with an insulation operation rod, and the preparation for diagnosis is completed. . In this state, the DC voltage generator 106 is turned on (ON), and the discharge detector 108 confirms whether or not a discharge has occurred from the main circuit to the test terminal 32.

  Next, the principle of operation of the pressure diagnostic apparatus 100 of the present invention will be described with reference to FIGS. FIG. 4 is an explanatory diagram showing a discharge detection signal in one embodiment of the pressure diagnostic device for a vacuum circuit breaker according to the present invention. Specifically, the input signal waveform to the discharge detection device 108 when the DC voltage is turned on and off (ON / OFF) by the DC voltage generator 106 and when a discharge occurs between the main circuit and the discharge terminal 32. Indicates.

  When the DC voltage generator 106 is turned on (ON), if no discharge is generated between the main circuit and the test terminal, the circuit of the DC voltage generator 106-resistor B-capacitor C0-capacitor C1-ground-DC voltage generator 106 is used. As a result, a transient phenomenon occurs, and both ends of the capacitor C1, that is, the input signal of the discharge detection device 108 has a waveform W1 in FIG. When the resistor B is not present, the peak of the transient voltage rises to a waveform W11, which exceeds the allowable input voltage of the discharge detection device 108.

  If there is no discharge between the main circuit and the test terminal, the capacitor C0 is charged with the applied DC voltage. At this time, since the capacitor C1 is short-circuited by the resistor C, the input voltage of the discharge detection device 108 settles to zero (waveform W2).

  When a discharge occurs between the main circuit and the test terminal while the DC voltage is being applied, the electric charge accumulated in the capacitor C0 is connected to the resistor A, the test terminal 32, the discharge path in the vacuum valve 11, the main circuit, and the system. Discharged by the transformer-ground-capacitor C1-capacitor C0-resistor A circuit, the input signal of the discharge detector 108 becomes a voltage in which the AC component of the system voltage is superimposed on the transient vibration, as shown by the waveform W3. .

  When the discharge between the main circuit and the test terminal is stopped, a transient phenomenon occurs again in the circuit of the DC voltage generator 106-resistor B-capacitor C0-capacitor C1-ground-DC voltage generator 106, and the capacitor C0 becomes a DC voltage. The both ends of the capacitor C1, that is, the input signal of the discharge detection device 108 becomes the same as W1 (waveform W4).

  When the DC voltage is cut off (OFF), the electric charge accumulated in the capacitor C0 is discharged by the circuit of the capacitor C0-resistance B-DC voltage generator 106-ground-capacitor C1-capacitor C0, and the input signal of the discharge detection device 108 Becomes a waveform W5.

  Note that when a discharge occurs between the main circuit and the test terminal in a state where no DC voltage is applied, only the AC component is input to the discharge detection device 108, and the waveform thereof becomes W6.

  In the present embodiment, the fixed conductor 16, the fixed contact 16A, the movable contact 19A and the movable conductor 19 in the vacuum valve 11 are charged to the system voltage (the movable conductor 19 is stopped at the entry position Y1). As described above, the state in which the system voltage is applied to only one of the fixed contact 16A and the movable contact 19A, the state in which the movable conductor 19 is stopped at the cut position Y2, and the movable conductor 19 is stopped at the disconnecting position Y3. Similarly, the vacuum circuit breaker pressure diagnosis can be performed in any state.

  According to one embodiment of the pressure diagnostic device for a vacuum circuit breaker of the present invention, a DC voltage is superimposed on the test conductor 17 disposed in the vacuum vessel, and the DC voltage is added to the system voltage between the contact and the test conductor 17. Since a high voltage superimposed on can be applied, the vacuum pressure of the vacuum circuit breaker can be diagnosed while the vacuum circuit breaker is in an operating state. As a result, it is possible to diagnose the pressure soundness of the vacuum circuit breaker without causing a power failure in all feeders including the bus bar of the switchgear and the circuit breaker to be inspected. In addition, even if a discharge occurs between the main circuit and the test terminal, or other elements of the unit 104 break down and a high voltage is output to the DC voltage generator 106 or the discharge detector 108 side, the resistor A Since the discharge current is limited below the human detection limit, the operator's safety can be ensured. Furthermore, since this discharge current is less than the operating current of the protection relay of the system, there is no fear of causing a system ground fault by mistake.

Next, another embodiment of the pressure diagnostic device for a vacuum circuit breaker according to the present invention will be described with reference to FIG. FIG. 6 is a side view showing, in partial cross section, a switchgear connected to another embodiment of the pressure diagnostic device for a vacuum circuit breaker according to the present invention. In FIG. 6, the same reference numerals as those in FIG. 1 are the same parts, and detailed description thereof is omitted.
When an instantaneous signal is generated during pressure diagnosis in the vacuum circuit breaker pressure diagnosis apparatus 100 of the present invention, it may be difficult to identify whether this signal is a true discharge or noise. In such a case, it is often desirable to continuously monitor the occurrence of discharge for a while. In the case of an embodiment of the present invention, since a direct current high voltage is applied, for example, it is necessary for an operator to always stay in the vicinity of the pressure diagnosis device, for example, to ensure insulation of the insulated wire 103. For this reason, in the case where a continuous monitoring period of several hours or more is required, it is difficult to cope with it in the embodiment of the present invention.
By using another embodiment of the pressure diagnostic device for a vacuum circuit breaker according to the present invention, the occurrence of discharge from the main circuit to the test terminal 32 can be monitored for a while. The procedure for this temporary monitoring is shown below.
(1) Remove the insulated wire 103 from the test terminal 32 side with an insulating operation rod. In this case, even if the discharge is generated between the main circuit and the test terminal and the discharge continues, the discharge current is limited to 1 mA or less by the resistance A of the unit 104. There is no safety problem without lasting.
(2) As shown in FIG. 6, the discharge from the main circuit to the test terminal 32 is monitored by the discharge detection device 108. Specifically, a metal terminal 110 molded on the rubber bushing 101 and a separately provided capacitor C2 are connected by a measurement electric wire 111, and the capacitance between the center conductor 102 and the metal terminal 110 is divided by the capacitor C2. The potential of the test terminal 32 is monitored by a pressure circuit.

  According to another embodiment of the pressure diagnostic device for a vacuum circuit breaker of the present invention, the potential of the test terminal 32 is monitored by the capacitance between the center conductor 102 and the metal terminal 110 and the voltage dividing circuit of the capacitor C2. , The occurrence of high voltage sites can be prevented. As a result, the pressure diagnostic device can be safely and unattended for a while and placed in the vicinity of the vacuum circuit breaker. Moreover, since the insulation performance with respect to the measurement electric wire 111 is not special, for example, it is possible to arrange a pressure diagnostic device in the enclosure of the switchgear, and the operation reliability of the switchgear equipment is not impaired.

Next, still another embodiment of the pressure diagnostic device for a vacuum circuit breaker according to the present invention will be described with reference to FIG. FIG. 7 is a side view showing in partial cross section a switchgear connected to still another embodiment of a pressure diagnostic device for a vacuum circuit breaker according to the present invention.
By using still another embodiment of the pressure diagnostic device for a vacuum circuit breaker according to the present invention, a DC withstand voltage test for evaluating the soundness of a cable can be performed while the switchgear 1000 is operated. As a specific procedure,
(1) In the corresponding vacuum circuit breaker, the movable conductor 16 is positioned at the test position Y4 shown in FIG.
(2) As shown in FIG. 7, the insulated wire 103, the unit 104, and the DC voltage generator 106 are connected, and the other end of the insulated wire 103 is connected to the center conductor 102 by an insulation operation rod.
(3) A DC voltage is applied to the test terminal 32. At this time, a DC voltage is superimposed on the system voltage between the main circuit and the cable 43, and the superimposed voltage may be set to a withstand voltage value specified by the manufacturer.

  According to still another embodiment of the pressure diagnostic device for a vacuum circuit breaker of the present invention, a direct current withstand voltage test for evaluating the soundness of the cable 43 can be performed in a state where the bus bar 23B is energized. As a result, even if the test terminal 32 is discharged, the resistance A suppresses the discharge current below the human detection limit, so that the safety of the operator who operates the DC voltage generator 106 can be ensured. Further, since the discharge current is equal to or less than the operating current of the system protection relay, there is no possibility of a system ground fault occurring.

DESCRIPTION OF SYMBOLS 1 Insulation container 11 Vacuum valve 32 Test terminal 100 Pressure diagnostic device 101 Rubber bushing 103 Insulated wire 104 Unit 106 DC voltage generator 108 Discharge detection device A Resistance B Resistance C Resistance C0 Capacitor C1 Capacitor

Claims (5)

Connected to each of the pair of contacts and the metal part penetrating from the inside of the vacuum container to the outside, a vacuum container containing a pair of contactable and separable contacts, and a metal part electrically insulated from the contact A vacuum circuit breaker pressure diagnostic device comprising:
A direct-current voltage generator electrically connected to the conductor of the metal part and for applying power to the metal part;
Means for measuring potential fluctuations in the metal part, comprising a capacitor string having one end connected to the metal part and the other end connected to the ground, and a discharge detector for measuring a potential difference of a part of the capacitor string; With
The DC voltage generator is connected to the capacitor row through a resistor for suppressing an overvoltage when a DC voltage is turned on or off, and the pressure diagnostic device for a vacuum circuit breaker. The pressure diagnostic device for a vacuum circuit breaker according to claim 1 ,
The DC voltage generator and the means for measuring the potential fluctuation of the metal part are connected to the metal part via a resistor for suppressing current in the event of discharge. Pressure diagnostic device. The pressure diagnostic device for a vacuum circuit breaker according to claim 1 ,
An impedance matching resistance is connected in parallel with a part of the capacitor row. The pressure diagnostic device for a vacuum circuit breaker according to claim 2 ,
An impedance matching resistance is connected in parallel with a part of the capacitor row. The pressure diagnostic device for a vacuum circuit breaker according to claim 4 ,
A unit containing the capacitor array, the discharge current suppression resistor, the overvoltage suppression resistor and the impedance matching resistor;
The DC voltage generator electrically connected to the unit, the discharge detector,
A pressure diagnostic apparatus for a vacuum circuit breaker, comprising: an insulated wire that connects the discharge current suppression resistor and the metal part in the unit.

Images