JP4011050B2 - Vacuum switchgear - Google Patents

Description

The present invention relates to a vacuum switchgear which uses SF ₆ gas as an insulating medium, in particular suppress the amount of insulating medium such as SF ₆ gas, to a vacuum switchgear in harmony with the environment.

  A conventional switchgear will be described by taking a 22/33 kV, 66/77 kV class extra high-voltage transformer facility as an example.

  This class of switchgear is required to reduce the size and seal of the switchgear due to problems such as contamination of the charging part, safety, noise, etc., along with construction costs, soaring land, and gas-insulated switchgear (GIS: Gas Insulated). Switchgear) and cubicle type gas insulated switchgear (C-GIS) have been developed.

In GIS, each electric device is covered with a pipe-shaped metal container, and high-pressure SF ₆ gas is sealed as an insulating medium, which is miniaturized and sealed.

  In contrast, C-GIS requires GIS to have higher reliability, safety, simplification of maintenance and inspection, and at the same time, can be constructed on a small site in a short period of time and harmonize with the surrounding environment. It is a switchgear that was developed to cope with the above.

  This is a cubicle-type container that uses a low-pressure insulating gas in the vicinity of atmospheric pressure. Each electrical device is stored in a single unit and the interior is divided into structural units. The appearance is the same as other closed switchboards. It is.

Thus, recently, a large number of switchgears using SF ₆ gas as an insulating medium have been operated.

  FIG. 6 is a longitudinal sectional view showing a configuration example of this type of typical cubicle type gas insulated switchgear.

In FIG. 6, SF ₆ gas 2 is sealed in the inside of a box 1 whose outer periphery is hermetically surrounded by mild steel plates, and is divided into a power receiving chamber 1a, a circuit breaker chamber lb, and a busbar chamber 1c. Yes.

  In the power receiving chamber 1 a, a cable head 3 divided into gas and air is attached to the side surface of the box 1, and a lightning arrester 4 and a voltage detection insulator 5 are accommodated, and each is connected by a connection conductor 7. The cable 9 is connected to a power cable 9 that passes through the current transformer 8.

  Further, the circuit breaker chamber 1b accommodates a circuit breaker 11 containing a vacuum valve (not shown) through a lower insulating spacer 10a that is gas-separated from the power receiving chamber 1a. And is connected to an upper insulating spacer 10b separated from the bus bar chamber 1c by gas.

The circuit breaker 11 uses high vacuum as an insulating and arc-extinguishing medium. The disconnector 6 uses SF ₆ gas as an insulating and arc-extinguishing medium.

By the way, in the switchgear having such a configuration, the disconnector 6 uses SF ₆ gas as an insulating and arc-extinguishing medium. The SF ₆ gas is known to have about 100 times the arc extinguishing performance compared to the air and about 3 times the insulation performance. This SF ₆ gas is a colorless, odorless, tasteless, non-flammable and very stable gas under normal operating conditions, and is non-toxic.

However, when the SF ₆ arc discharge in a gas is generated, SF _{6 gas, SOF 2, S0 2, SO} 2 F 2, SOF 4, HF, generates decomposition products and decomposition gases such as SiF _4. Since the decomposition product and decomposition gas of SF ₆ gas are highly toxic, special processing and management are required when recovering the decomposed gas.

  Since the interruption current and the like are interrupted by the circuit breaker 11, no decomposition products or decomposition gas is generated, but the busbar switching and the line switching in the substation are performed by the disconnector 6.

  Therefore, the disconnector 6 is required to take responsibility for breaking the loop current. This loop current has a current value close to the rated current, and at that time, the disconnecting device 6 generates decomposition products and decomposition gas. And when collecting the gas of such a disconnector, it is difficult to handle such as collecting through the adsorbent.

SF ₆ gas is a greenhouse gas that causes global warming, and has a greenhouse effect coefficient 24,000 times that of carbon dioxide. Therefore, at the “3rd Conference of Parties to the United Nations Framework Convention on Climate Change (COP3)” held in Kyoto in December 1997, SF ₆ gas was also added as a reduction target gas. Response has been required. Thus, it is desirable not to use SF ₆ gas as an insulating and arc-extinguishing medium for disconnectors also from the environmental viewpoint.

  Thus, a vacuum disconnector in which the insulating medium of the disconnector is evacuated can be considered, but there is a problem that the price as a switchgear increases.

  On the other hand, in order to solve such a problem, the following is known (for example, refer to Patent Document 1).

  In this, a fixed electrode and a ground electrode are provided at both ends of a cruciform vacuum valve, and a current-carrying shaft and a movable electrode having a position as a fulcrum are provided when orthogonal to them.

  However, since the structure of the vacuum valve is complicated, the number of parts increases, and the price of the vacuum valve becomes very high. Further, since the structure is complicated, it is not easy to assemble the vacuum valve, so that a highly reliable vacuum valve cannot be obtained. Further, since the movable shaft moves in the circumferential direction via the bellows, an excessive load in the bending direction is applied to the bellows, and there is a problem that the strength and long-term reliability are lacking.

  In addition, there is known one in which a ground electrode is provided in a vacuum valve having a pair of contactable contacts (see, for example, Patent Document 2).

However, an operating mechanism for opening and closing both contacts and further opening and closing with the ground electrode is not disclosed. The operation mechanism has a complicated problem because it must open and close both contacts and the ground electrode.
JP-A-9-153320 (FIG. 1) Japanese Utility Model Publication No. 55-164735 (Fig. 1)

The conventional vacuum switchgear has a problem that a highly reliable vacuum valve cannot be obtained because the structure of the vacuum valve is complicated. There is also a problem that the operation mechanism is complicated. For this reason, it is difficult to realize a switchgear that does not use SF ₆ gas.

An object of the present invention, including construction and simple and reliable vacuum valve closed position, the open position, disconnecting position location, further a high operating mechanism reliable opening and closing the 4 position including the ground position, The object is to provide a vacuum switchgear that is in harmony with the environment.

In order to achieve the above object, the vacuum switchgear according to the present invention includes a vacuum valve body in which both ends of an insulating container filled with an insulating medium are hermetically sealed with metal members, and the one metal member is penetrated. a fixed electrode fixed to the metal member Te, together with the other metal member of the movable current-carrying rod penetrates so as to be movable, is fixed to the movable current-carrying rod via a bellows, and to face the fixed electrode a movable electrode provided, Rutotomoni provided opposite to the fixed electrode side of the movable electrode, to face the movable current-carrying rod, and the smaller the ground electrode than the outer diameter of the opposite portions of inner diameter the movable electrode, wherein Closed position, open position, and disconnection, which are disposed between the ground electrode and the metal members at both ends, respectively, two insulating cylinders constituting the insulating container, and the movable electrode in contact with the contact of the fixed electrode Position, and front Both the continuously linearly moving the 4 position of the ground position in contact with the ground electrode, characterized in that it comprises a movable electrode in series arranged operating mechanism.

According to the vacuum switchgear of the present invention, a vacuum valve high construction simple and reliable, closed position, the open position, disconnecting position location, further ground position loss is small operating force of the opening and closing operation of the 4 position, including Therefore, it is possible to provide an environment-friendly vacuum switchgear having a simple and reliable operation mechanism.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 is a longitudinal sectional view showing a configuration of a vacuum valve in a vacuum switching device according to a first embodiment.

  In FIG. 1, both end openings of an insulating cylinder 21 made of ceramic or glass are sealed with a fixed side end plate 22 and a movable side end plate 23 to form an airtight container.

  A fixed energizing shaft 25 to which a fixed electrode 24 is bonded is supported and fixed to the fixed end plate 22, and a movable electrode 26 is fixed to the movable energizing shaft 27 so as to face the fixed electrode 24. The movable energizing shaft 27 is connected to an operation mechanism described later.

  Further, on the side where the fixed electrode 24 and the movable electrode 26 are in contact with each other, contacts 28a and 28b made of various materials are arranged on the respective electrodes according to the use of the vacuum valve 20.

On the other hand, a bellows 29 is provided between the movable energizing shaft 27 and the movable side end plate 23 so that the movable electrode 26 can move linearly.

  Further, an arc shield 32 is provided in an electrically floating manner around the fixed electrode 24 and the movable electrode 26 so as to prevent the insulating cylinder 21 from being damaged by the metal vapor when the current is interrupted.

Here, the position where each of the contacts 28a and 28b are in contact with the closed position, to move the movable electrode 26, the gap length between each contact is the open position the position at the time of d _1. Furthermore, to move the movable electrode 26, the gap length between each contact is a disconnected position to the position at the time of d _2.

Next, in the vacuum valve 20 configured as described above, when a circuit breaker opening command is issued from a control circuit of a vacuum switching device (not shown), the movable electrode 26 moves and the contacts 28a and 28b are moved. gap length between is the position of d ₁ (open position).

Next, when there is a command to open (disconnect) the disconnector from the control circuit of the vacuum switchgear, the movable electrode 26 further moves, and the gap length between the respective contacts 28a and 28b is d _2. (Disconnect position).

  In this way, the contact 28b provided on the movable electrode 26 continuously linearly moves between the three positions of the closed position, the open position, and the disconnect position.

In this case, since the contact point of the disconnector is housed in the vacuum vessel, even if the current close to the rated current such as the loop current is cut off, the SF ₆ gas is not used, so that cracked gas and cracked products are generated. There is nothing.

That is, as described above, high vacuum is used as the insulation and arc extinguishing medium of the disconnector without using the SF ₆ gas, which is a greenhouse effect gas. I'm doing it.

  In addition, since the contacts of the circuit breaker and disconnector are housed in the same vacuum vessel and the configuration is simple, the vacuum valve 20 can be mass-produced, and the vacuum switchgear can be reduced in size and cost. Can do.

  In other words, the circuit breaker and disconnector are configured by continuously linearly moving the contact closed position, open position, and disconnection position, so that these can be operated with a single operating mechanism. From this point, the vacuum switchgear can be reduced in size and price.

  Next, FIG. 2 is a longitudinal sectional view showing the configuration of the vacuum valve in the vacuum switchgear according to the second embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. Only different parts are described here.

  That is, in the vacuum valve 20 of the second embodiment, as shown in FIG. 2, a ground electrode 35 is provided at a position facing the movable energizing shaft 27 connected to the movable electrode 26, and the ground electrode facing the movable energizing shaft 27 is provided. The inner diameter of 35 is made smaller than the outer diameter of the movable electrode 26.

Insulating cylinders 21 and 21 are arranged between the ground electrode 35 and the metal end plates 22 and 23 at both ends, respectively, and a position where the contact 28b of the movable electrode 26 is in contact with the contact 28a of the fixed electrode 24. and a closed position, the contacts 28a, the gap length between 28b is a ground position a position of d _6.

  As a result, the four positions of the closed position, the open position, the disconnecting position, and the grounding position can be continuously linearly moved.

In the vacuum valve 20 configured as described above, the movable electrode 26 moves when a grounding command is issued from a disconnection state from a control circuit of the vacuum switching device (not shown) during inspection of the vacuum switching device. Te, the contact 28a, the gap length between 28b is grounded at a position where a _{d 6} (ground position).

  As a result, the four positions of the closed position, the open position, the disconnection position, and the ground contact position continuously linearly move.

  In this case, since the grounding device is accommodated in the vacuum valve 20, the vacuum switchgear can be miniaturized.

  Further, since the configuration of the vacuum valve 20 is simple, it is easy to assemble the vacuum valve 20 and mass production is possible.

  Furthermore, since the number of parts is reduced, the cost of the vacuum switchgear can be reduced.

  In other words, it is possible to operate them with a single operating mechanism by continuously moving the contact closed position, open position, disconnection position, and ground contact position in a straight line. Miniaturization and price reduction can be achieved.

  Next, a vacuum valve in the vacuum switching device according to the third embodiment will be described with reference to FIGS. 1, 3, and 4.

In vacuum interrupter 20 shown in FIG. 1 described above, the contact 28a of the open position, the gap length between 28b and _{d 1,} when the contact 28a of the disconnection position, the gap length between 28b was _{d 2,} each of gap lengths _{d 1} And d ₂ are set to satisfy d ₂ = (1.3 to 2.6) · d ₁ .

In the vacuum valve 20 configured as described above, the relationship between the gap lengths d ₁ and d ₂ is d ₂ = (1.3 to 2.6) · d _1. Therefore, the insulation breakdown probability and the open position can be coordinated.

  That is, in general, the relationship between the breakdown voltage Vb between the electrodes in vacuum and the gap length d is expressed as Vb = a · dn, and the value of n varies depending on the electrode material, but may be approximately 0.6. Are known.

  Further, the probability distribution of dielectric breakdown in vacuum is a normal distribution, and the standard deviation σ at this time represents the variation in breakdown voltage.

Here, allowance of the insulation performance contact 28b provided in movable electrode 26 is in the open position shown in Figure 1, has a 50% breakdown voltage when the V _50, a guideline 2σ against V _50. On the other hand, since the tolerance of the insulation performance at the disconnection position must be considered in terms of reliability and safety, the margin of 3σ is given to V ₅₀ . 3σ is a destruction probability of about 0.1%.

  The breakdown voltage variation σ between the contacts 28a and 28b varies greatly depending on the contact material, surface state, breaking current, etc., but is considered to be 10 to 23%.

FIG. 3 shows the ratio between the gap length giving 3σ and the gap length giving 2σ (that is, the ratio between d ₂ and d ₁ ) and the breakdown voltage variation (standard deviation) σ from the relationship between the breakdown voltage and the gap length. It is a characteristic view which shows an example of a relationship.

If the standard deviation is 10%, the gap length ratio d ₂ / d ₁ is about 1.3, and if the standard deviation is 23%, the gap length ratio d ₂ / d ₁ is about 2.6.

As described above, the ratio d ₂ and d ₁ of the gap length by which a 1.3 to 2.6, it is possible to obtain a high vacuum switchgear reliable economical insulation.

On the other hand, in the vacuum valve 20 shown in FIG. 1 described above, the gap length between the arc shield 32 which surrounds fixed electrode 24 and movable electrode 26 and the fixed electrode 24 and movable electrode 26 and d _3, the contact 28a of the disconnected position , when the gap length between 28b was _{d 2,} the relationship between the _{d 3} and _{d 2} is set to be _{d 3 = (0.35~0.8) · d} 2.

In the vacuum valve 20 configured as described above, when the relationship between the gap lengths d ₂ and d ₃ is d ₃ = (0.35 to 0.8) · d ₂ , when viewed from the insulating surface The optimum position of the arc shield is determined, and the electric field strength of the movable electrode and the fixed electrode can be reduced.

That is, FIG. 4 is a characteristic diagram showing an example of the relationship between the ratio of d ₃ and d ₂ described above and the electric field intensity E 1 at the end of the fixed electrode 24.

  In FIG. 4, the electric field strength Ec on the vertical axis is the breakdown electric field strength when the material of the fixed electrode 24 is copper.

When the gap length ratio d ₃ / d ₂ is 0.5 or less, the gap length is determined by the gap length between the fixed electrode 24 and the arc shield 32. Therefore, the gap length ratio d ₃ / d ₂ is small in the electric field strength at the electrode end. It gets higher.

When the gap length ratio d ₃ / d ₂ is 0.35, the electric field strength at the end of the fixed electrode 24 reaches the breakdown electric field strength.

When the gap length ratio d ₃ / d ₂ is 0.8 or more, the electric field strength at the end of the fixed electrode 24 is determined between the electrodes, and thus does not become so low.

Further, when the gap length ratio d ₃ / d ₂ is increased, the diameter of the vacuum valve 20 is increased. Therefore, it is desirable from the viewpoint of price that the gap length ratio d ₃ / d ₂ is as small as possible.

Therefore, the fact that a 0.35 to 0.8 the ratio of the ratio d ₃ and d ₂ of the gap length, while suppressing the outer diameter of the vacuum valve 20, it is possible to obtain an excellent vacuum valve 20 of the insulating properties.

  Next, a vacuum valve in the vacuum switchgear according to Embodiment 4 will be described with reference to FIGS.

In vacuum interrupter 20 shown in FIG. 2 described above, the contact 28a of the open position, the gap length between 28b and d _1, the gap length between the movable current-carrying rod 27 and the ground electrode 35 provided on the movable electrode 26 d _In the case of ₅ , the relationship between the gap lengths d ₅ and d ₁ is d ₅ = (1.3 to 1.8) · d ₁ .

In the vacuum valve 20 configured as described above, the relationship between the gap lengths d ₁ and d ₅ is d ₅ = (1.3 to 1.8) · d ₁ , thereby opening the movable contact 28b. The insulation between the contacts at the position and the insulation of the grounding device can be coordinated, and the reliability can be improved.

That is, tolerance of the insulation performance at the ground position, when the disconnected position as well as 50% breakdown voltage V ₅₀ a, it is necessary to 3σ of tolerance with respect to V _50. The tolerance of the insulation performance at the open position is a guideline 2σ against V _50. Since the ground electrode 35 is not responsible for interrupting the current, the electrode surface is relatively less damaged.

  When the present inventors conducted a test for determining the variation in breakdown voltage between the ground electrode 35 and the movable conducting shaft 27, the standard deviation was 10 to 18%.

From the relationship between the gap length giving 3σ and the ratio of gap length giving 2σ (ie, d ₅ / d ₁ ) and the breakdown voltage variation (standard deviation) shown in FIG. 3, the gap length ratio d ₅ / d ₁ Becomes 1.3 to 1.8.

  Thereby, the insulation between the ground electrode 35 and the movable conducting shaft 27 can be coordinated with the insulation at the disconnection position, and an economical and highly reliable vacuum switchgear can be obtained.

  Next, an operation mechanism for operating the vacuum valve in the vacuum switchgear according to Embodiment 5 will be described with reference to FIG.

  FIG. 5 is a longitudinal sectional view showing the configuration of the operation mechanism in the vacuum switching apparatus according to the first embodiment, and corresponds to the vacuum valve of FIG. FIGS. 5A, 5B, and 5C show configurations at a closed position, an open position, and a disconnection position, respectively.

  In FIG. 5, the operation mechanism 50 is configured by arranging two sets of mechanism portions 60 and 70 in series.

  Here, from the side close to the vacuum valve 20, the blocking mechanism 60 and the disconnecting mechanism 70 are used.

In other words, the movable shaft 61 of the blocking mechanism portion 60 is connected to the movable energizing shaft 27 of the vacuum valve 20 via the insulating rod 36, and the movable shaft 71 of the disconnecting mechanism portion 70 is connected to the frame 62 of the blocking mechanism portion 60. The threaded portion 71a is engaged. The engagement length S is set to (d ₂ -d ₁ ) or more.

  Further, as apparent from FIG. 5, the operation mechanism 50 is linearly disposed on the movable energizing shaft 27. And three positions, a closed position, an open position, and a disconnection position, are formed.

On the other hand, in the vacuum valve operating mechanism 50 corresponding to FIG. 2, the engagement length S between the threaded portion 71 a of the disconnecting mechanism portion 70 and the frame 62 of the blocking mechanism portion 60 is equal to or greater than (d ₆ −d ₁ ). I am doing so.

  Then, four positions including the ground contact position are formed.

  As described above, since the operation mechanism 50 is disposed on the axis of the movable energizing shaft 27, the operating force can be directly transmitted to the movable energizing shaft 27, and there is little loss of the operating force, which is simple and reliable. A vacuum switchgear having a high operating mechanism can be realized.

The longitudinal cross-sectional view which shows Example 1 of the vacuum valve in the vacuum switchgear by this invention. The longitudinal cross-sectional view which shows Example 2 of the vacuum valve in the vacuum switchgear by this invention. The characteristic view for demonstrating each effect | action in the Example 1 and Example 2. FIG. The characteristic view for demonstrating each effect | action in the Example 1 and Example 2. FIG. The longitudinal cross-sectional view which shows Example 5 of the vacuum valve in the vacuum switchgear by this invention. The longitudinal cross-sectional view which shows the structural example of the conventional typical cubicle type gas insulated switchgear.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Switchgear box 1a Power receiving chamber 1b Breaker chamber 1c Busbar chamber 2 SF ₆ Gas 3 Cable head 4 Lightning arrester 5 Electric detection insulator 6 Disconnector 7 Connection conductor 8 Current transformer 9 Cable 10a, 10b Spacer 11 Breaker 12 Connection Busbar 13 Operating mechanism 14a, 14b Control box 20 Vacuum valve 21 Insulating cylinder 22 Fixed end plate 23 Movable end plate 24 Fixed electrode 25 Fixed energizing shaft 26 Movable electrode 27 Movable energizing shaft 28a Fixed side contact 28b Movable side contact 29 Bellows 32 Arc shield 35 Ground electrode 36 Insulating rod 50 Operating mechanism 60 Interrupting mechanism parts 61, 71 Movable shaft 62 Frame 70 Disconnecting mechanism part 71a Screw part

Claims (1)

In the vacuum valve body in which both ends of the insulating container enclosing the insulating medium are hermetically sealed with metal members,
A fixed electrode penetrating the one metal member and fixed to the metal member;
With penetrating the other metal member such that the movable current-carrying rod can move, is fixed to the movable current-carrying rod via a bellows, and a movable electrode provided and to face the fixed electrode,
Rutotomoni provided opposite to the fixed electrode side of the movable electrode, to face the movable current-carrying rod, and the smaller the ground electrode than the outer diameter of the inner diameter of the opposite portions said movable electrode,
Two insulating cylinders arranged between the ground electrode and the metal members at both ends, constituting the insulating container;
It said movable electrode, a closed position in contact with the contacts of the fixed electrode, an open position, disconnected position, and when continuously linearly moving the 4 position of the ground position in contact with the ground electrode both the movable A vacuum switchgear comprising an operation mechanism arranged in series with an electrode.

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