JPH0492329A - Vacuum breaker - Google Patents

Abstract

PURPOSE:To make it easy to cut off a large interrupting current by driving a current limiting rod so as to interlock with a contact parting operation of a vacuum bulb, and connecting the resisting part of the current limiting rod in series to the vacuum bulb so as to limit the interrupting current. CONSTITUTION:An electric current flows from the upper part conductor 8 through a slide contact part 11, the short circuit conductor 9 of a current limiting rod 7A and a slide contact part 11 on the lower side to a fixed side conductor 12, and flows further through a vacuum bulb l and a movable contact part 4 to a movable side conductor 3, and is supplied to an unillustrated load. That is, simultaneously with the start of a contact parting operation of an operation mechanism to drive the vacuum bulb l, a resisting body 10 starts to be inserted into the vacuum bulb l, and just before contact points start to separate, the resisting body 10 having a prescribed resisting value can be inserted in series into the current supply circuit of the vacuum bulb l, and further as a space between contact points widens, the resisting value can be increased so that it is possible to obtain a vacuum breaker capable of limiting and cutting off a large short circuit current easily.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention particularly relates to a vacuum circuit breaker provided with a current limiting mechanism.

(Prior art) Conventionally, circuit breakers have been used to isolate an abnormal section such as a short circuit that occurs in a power system and prevent it from spreading to other sections. Vacuum circuit breakers are widely used in power systems.

FIG. 5 is a side view showing the general configuration around the vacuum valve of the vacuum circuit breaker.

In the figure, a vacuum valve 1 in which a fixed side contact and a movable side contact are disposed in a vacuum container so as to be able to freely come into contact with and separate from each other has an upper end fixed to a fixed side conductor 22 provided at the upper part. On the other hand, the movable contact of the vacuum valve 1 is connected to the movable conductor 23 via the movable current-carrying shaft 17 and the movable contact portion 4 . Further, a pressure spring 5 is inserted into a stopper 13 below the movable contact portion 4, and the lower end of the stopper 13 is connected to an operating rod 6 via a connecting portion.
The lower end of the operating rod 6 is connected to an operating mechanism (not shown).

In the vacuum circuit breaker configured in this way, when the contacts are closed as shown in the figure, the current flows from the fixed conductor 22 through the contacts of the vacuum valve 1 and the movable contact portion 4 to the movable conductor 23.
Electric power is supplied to a load (not shown) connected to the movable conductor 23.

Further, the pressure spring 5 applies contact pressure between the contacts when the contacts are closed, thereby preventing temperature rise due to contact resistance of the contacts due to energization and opening of the contacts due to electromagnetic force such as overcurrent.

On the other hand, when interrupting the current, the movable side contacts of the vacuum valve 1 are opened by driving the operating shaft 6 downward by an operating mechanism (not shown), and the arc between the contacts generated at that time is removed by the vacuum circuit breaker. It is naturally cut off at the current zero point due to the rapid insulation recovery characteristic of .

Incidentally, a vacuum circuit breaker has excellent breaking characteristics, but its breaking ability is greatly influenced by the composition of the contact and the area of the surface receiving the arc. The required area of the surface of this contact that receives the arc is determined by the magnitude of the current and is not affected much by the magnitude of the voltage. For this reason, conventional vacuum circuit breakers have been commonly used in power systems with voltages from 3.6 kV to 36 kV and short circuit currents up to 63 kV.

(Problems to be Solved by the Invention) On the other hand, in a low voltage power system of 1 kV or less, it is required to interrupt a short circuit current of about 100 kA. However, for the above reasons, even if the voltage is lower, vacuum circuit breakers cannot reduce the surface area of the contacts that receive the arc, so they are larger than air circuit breakers, and as a result, it is not possible to downsize the vacuum valve. .

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to obtain a vacuum circuit breaker equipped with a vacuum valve that has a small external size and is capable of interrupting a large short circuit current.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention provides a fixed conductor on one side of a vacuum valve,
In a vacuum circuit breaker, in which a drive part is provided on the other side of the vacuum valve to drive the movable shaft of the vacuum valve via a flip spring, an upper conductor is provided on one side of the fixed conductor, and a conductor is connected between the upper conductor and the drive part. A current-limiting rod is provided, one end of which engages with the contact portion provided on the upper conductor and the fixed-side conductor, and the other end connected to the drive portion, and the current-limiting rod has a resistor at one end that connects and separates from the contact portion of the upper conductor. and an intermediate short-circuit part that contacts the contact part of the fixed side conductor;
By providing an insulating part on the other side of this short-circuit part, a current limiting rod is linked to the opening operation of the vacuum valve, and a resistor part is inserted in series with the vacuum valve to limit the large breaking current, making the contact small. This is a vacuum circuit breaker that can be easily shut off.

(Example) Hereinafter, one example of the vacuum circuit breaker of the present invention will be described with reference to the drawings.

FIG. 1 is a side view showing the main parts of the vacuum circuit breaker of the present invention when the contacts of the vacuum valve 1 have completed closing.

In the figure, at the rear end of the fixed conductor 2 to which the upper end of the vacuum valve 1 is fixed, a recess is provided on the inner periphery of a vertically penetrating through hole. A contact (not shown) is inserted, which is pressurized in the axial direction by a spring (not shown) attached thereto, to form the slide contact portion 11 .

Further, an upper conductor 8 is provided above the fixed side conductor 2,
A slide contact portion 11 similar to the rear end of the fixed conductor 2 is provided at the front end of the upper conductor 8, and the rear end of the fixed conductor 2 serves as a power supply terminal.

On the other hand, a through hole is provided in the center of the movable conductor 3,
A current limiting rod 7A is inserted from above into the through hole of the movable conductor 30 and the sliding contact portion 11 of the fixed conductor 2 and the upper conductor 8, and the lower end of the current limiting rod 7A has its front end connected to the movable contact portion 4. It is fixed to the rear end of the inserted lever 12. At the upper end of this current limiting rod 7A, there is a resistor 1 that protrudes upward from the upper conductor 8 when the vacuum valve 1 is closed, as shown in the figure.
0 is provided at the lower end of this resistor 10, which has the same diameter as this resistor IO and whose lower end is connected to the fixed side conductor 2 in the figure.
A short-circuiting conductor 9 slightly protruding downward is fixed concentrically to the lower end of the short-circuiting conductor 9, and an insulator 14 having the same diameter as the shorting conductor 9 is fixed concentrically to the lower end of the short-circuiting conductor 9. The road frame is 1.5A.

Further, a stopper 13 whose upper end is connected to the lower end of the movable current-carrying shaft 1γ passes through the through hole at the front end of the lever 12, and a pressure spring 4 is attached to the portion of the stopper 13 that protrudes upward from the lever 12. is inserted, and the upper end of the pressure spring 5 engages with a flange portion provided at the upper end of the stopper 13. Furthermore, the upper end of the operating rod 6 is connected to the intermediate portion of the lever 12, and the lower end of the operating rod 6 is connected to a circuit breaker operating mechanism (not shown).

The above-mentioned resistor 10 is called a non-inductive mica ceramic resistor, and uses Ohmlex (trade name), which is a mixture of copper powder and carbon powder mixed with mica powder and special glass at a fixed ratio, and is insulating. The body 14 is made of the same porcelain as the insulator.

Now, in the vacuum circuit breaker configured in this way, current flows from the upper conductor 8 through the slide contact part 11, through the short circuit conductor 9 of the current limiting rod 7A, and from the lower slide contact part 11 to the fixed side conductor 12. It further flows to the movable conductor 3 via the vacuum valve 1 and the movable contact portion 4, and is supplied to a load (not shown).

However, due to the operation of the circuit breaker operating mechanism (not shown), the operating rod 6
When the vacuum valve 1 is opened by driving the current limiting rod 7A downward, the resistor 10 at the upper end also lowers as the current limiting rod 7A lowers and fits into the slide contact portion 11 of the upper conductor 8. At the same time, the pressure spring 5 also extends by the amount of the downward movement, but the vacuum valve 1
The contacts inside are still closed and energized, although the contact pressure is reduced.

Next, when the operating rod 6 is further lowered, the resistor 10 at the upper end of the current limiting rod 7A is lowered as shown in FIG. enters the open state, but at this time vacuum valve 1
Since the current flowing through is limited by the resistor 10, it becomes small, and the voltage applied between the contacts also becomes low, so that the arc that occurs is easily extinguished.

That is, in the vacuum circuit breaker configured as described above, the resistor 10 begins to be inserted into the vacuum valve 1 at the same time as the opening operation of the operating mechanism that drives the vacuum valve 1 starts, and a predetermined resistance is applied just before the contact opens. A resistor of a certain value can be inserted in series into the current-carrying circuit of the vacuum valve 1, and the resistance value can be increased as the contact gap widens, making it possible to limit large short-circuit currents and easily interrupt them. It becomes a vacuum circuit breaker that can be used.

Next, FIG. 3 is a side view of essential parts showing another embodiment of the vacuum circuit breaker of the present invention.

In the same figure, the difference from FIG. 1 is that the movable side conductor 3
A slide contact portion 11 is provided in the through hole at the center of the fixed conductor 2, and there is no slide contact portion 11 in the through hole at the rear end of the fixed side conductor 2.
Instead, a block conductor 16 provided with a slide contact portion 11 is provided at the upper and lower portions of this through hole, and a disconnection rod 17B is formed with the bypass rod 15A in FIG. The position 14 is inside the through hole of the fixed conductor 2 during simultaneous closing.

In the vacuum circuit breaker configured in this way, when the vacuum bubble 1 is closed, current flows from the upper conductor 8 to the short circuit conductor 9 and from the upper lock conductor 16 to the fixed conductor 2.
A part of it passes through the lower block conductor 16 to the side path conductor 15.
The current is directly shunted from B to the movable conductor 3.

However, as shown in FIG. 4, when the operating rod 6 is driven downward by the circuit breaker operating mechanism (not shown), the resistor 10 is inserted in series on the power supply side of the vacuum valve 1, as in FIG.
When the opening is completed, most of the resistor 10 is inserted, so
In addition to being a vacuum breaker that can easily interrupt large short-circuit currents as shown in Fig. 1, the power supply side and load side are disconnected by the insulator 14 when the circuit is opened, as shown in Fig. 1. I can do it.

Furthermore, in this embodiment, the current flowing to the vacuum valve 1 can be reduced by diverting the current to the bypass conductor 15B, so the fixed side contact and the movable side contact can be made smaller, and the contact pressure can also be reduced. Therefore, not only can the vacuum valve 1 and the operating mechanism be made smaller, but also the restrictions on the composition of each contact can be reduced by reducing the current flowing to the fixed side contact and the movable side contact, which improves the breaking property. It becomes possible to select the contact material of the vacuum valve which can further improve the selection.

[Effects of the Invention] As described above, according to the present invention, the fixed side conductor is provided on one side of the vacuum valve, and the drive section that drives the movable shaft of the vacuum valve is provided on the other side of the vacuum valve via a wire spring. In a vacuum circuit breaker, an upper conductor is provided on one side of the fixed conductor, and one end engages with a contact part provided on the upper conductor and the fixed conductor between the upper conductor and the drive part, and the other end is connected to the drive part. A current-limiting rod is provided, and this current-limiting rod has a resistance section at one end that comes into contact with and separates from the contact section of the upper conductor, a short-circuit section in the middle that contacts the contact section of the fixed side conductor, and an insulating section on the other side of this short-circuit section. By establishing a section,
The current-limiting rod is driven in conjunction with the opening operation of the vacuum valve, and the resistance part of the current-limiting rod is connected in series with the vacuum valve to limit the interrupting current, making it easy to interrupt large interrupting currents. It is possible to obtain a vacuum circuit breaker that can be used.

[Brief explanation of the drawing]

FIG. 1 is a side view of the essential parts of an embodiment of the vacuum circuit breaker of the present invention, showing when the vacuum valve is closed, and FIG. FIG. 3 is a side view of main parts showing another embodiment of the vacuum circuit breaker of the present invention, and is a diagram showing the vacuum valve when closed. FIG. 4 is a diagram showing the vacuum circuit breaker of the present invention when the valve is open. FIG. 5 is a side view showing the main parts of a conventional vacuum circuit breaker. 1... Vacuum valve 3... Movable side conductor 6... Operating rod 8... Upper conductor 10... Resistor 14... Insulator 1.5B... Side conductor 2... Fixed side conductor 5...Pressure spring 7...Limiting rod 9...Short conductor 12...Lever 15A...Shunting bar Agent Patent attorney Yoshiaki Inomata (1 person) No. Figure 2

Claims (1)

[Scope of Claims] A vacuum circuit breaker in which a fixed conductor is provided on one side of the vacuum valve, and a drive unit that drives a movable shaft of the vacuum valve via a wipe spring is provided on the other side of the vacuum valve, An upper conductor is provided on one side of the fixed conductor, and one end is engaged with a contact portion provided on the upper conductor and the fixed conductor between the upper conductor and the drive section, and the other end is connected to the drive section. A current-limiting rod is provided, and the current-limiting rod has a resistance portion at one end that comes into contact with and separates from the contact portion of the upper conductor, a short-circuit portion in the middle that contacts the contact portion of the fixed-side conductor, and a short-circuit portion of the short-circuit portion. A vacuum circuit breaker characterized by having an insulating part on the other side.