JPS59163728A - Dc breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved arc-extinguishing fluid spraying mechanism using a DC breaker.

Figure 1 shows a buffer-type blowing mechanism used in conventional direct current and disconnectors. . (2) is a cylinder that is fixed to the operating rod (1) and moves in the left and right direction together with the operating rod, and (3) is a piston that forms a buffer chamber (4) between it and the cylinder (2). ing. (5) is a movable contact fixed to the operating rod (1), (6) is a fixed contact that can make contact with and separate from this movable contact (5), and (7) is a movable contact (5) in the flow guide. ) and the fixed contact (6).

In the above configuration, the shutoff operation is performed by the operating rod (1
) is pulled to the left, the movable contact (5) fixed to the operating rod (1) and the cylinder (2) also move in the same direction with the bow 175.
This compresses the gas in the compression chamber (4) formed by the cylinder (2) and the piston (3).

As the opening operation progresses, the operating rod (1i) moves further to the left (1i:
When driven to lJ, the movable contact (5) and fixed contact (6) are separated, and an arc (8) is generated between the contacts. During this time,
Since the gas in the Neutuffer chamber (4) is continuously compressed, the high-pressure gas is blown out from the buffer chamber (4) into the flow guide and hits the arc (8) generated in the flow guide. It will be done.

By the way, the DC breaker configured as described above is disconnected by a circuit configuration as shown in FIG. 2. In the figure, (
9) is a breaker, (10) is a capacitance for commutation assistance, (11) is a surge suppressor formed of a metal oxide resistor, etc., and (12) is a part that is stray in the circuit or is artificially inserted. It is inductance.

In a device configured in this way, as shown in the same figure, a breaker part (
9) is opened, and the fixed contact (6) and o shown in Fig. 1 are opened.
As the distance between the r# contacts (5) increases, the arc resistance ra of the arc generated between both contacts increases.

On the other hand, the arc that occurs in the circuit configuration shown in Figure 2 is
It is known that when the arc resistance satisfies condition (1) with θ ra > 27, the arc becomes unstable, and as a result, expanded vibration occurs in 1c as shown in FIG. That is, as a result of this expanded vibration is being superimposed on the external current I, a current zero point is generated in the cutoff portion (9), and the cutoff portion is cut off. That is, the mechanism of the gas blowing shown in FIG. 1 is to increase arc resistance and cause arc instability.

However, in the spraying mechanism configured as shown in Fig. 1, the cylinder (2) is moved by the operation rod (1).
) etc. are heavy, and the movable parts must move against the gas pressure generated by the compression of the pan 7a chamber, so the operating mechanism (not shown) becomes large. The drawback is that...

The present invention aims to provide a DC breaker that reduces the force applied to the operating mechanism and at the same time provides an inexpensive and efficient blowing mechanism.

FIG. 4 shows an embodiment of a DC breaker having a gas blowing mechanism according to the present invention. In the figure, (20) is a cylinder, (4
0) is a buffer chamber formed inside this cylinder (2o), (50) is a fixed contact fixed to the cylinder (2o), and (60) is a movable contact that can come into contact with and separate from this fixed contact (5o). , (70) #- is the 70-guide fixed to the cylinder (2o), and (80) is the fixed contact (5o).
This is the arc that occurs between A and A (60).

In the circuit breaker configured as described above, when the movable contact (6) is pulled to the right by an operating mechanism (not shown), the fixed contact (5o) and the movable contact (6o) are opened and separated.
An arc occurs between both contacts. At this time, the generated arc rapidly heats the gas in the buffer 1 chamber (40) due to the arc energy, so the pressure of the gas in the buffer 1 chamber increases, and due to the difference between the gas pressure outside the buffer chamber, the 70-guide (70, flows out to the outside of the chamber through the inside of the guide (70). At this time, the arc passing through the inside of the guide (70) is blown to cool the arc. In this case, the heating of the surrounding gas by the arc is Since the pressure rises quickly and is controlled, a pressure increase equal to or higher than that of the 1-pan 7A type can be obtained, and the breaking performance is improved.

In addition, by using such a blowing mechanism, the pressure in the ivy buffer chamber is automatically increased by the heat of the arc, so
Compared to the compression mechanism of a buffer-type breaker, it not only has a simpler configuration, but also has the advantage of being smaller because the operating mechanism (not shown) is not subject to back pressure due to the pressure increase in the seven buffer chambers. .

In the above embodiment, the gas flow from the cylinder is blown out to both the fixed contact and the movable contact.
0- configuration, but it is clear that similar effects can be expected with a so-called single 70-configuration in which either one of the channels is closed.

In addition, air or nitrogen can flow into SF6 gas, and the flow rate is extremely high, so even if the gas in the buffer chamber is heated by the arc, it will quickly escape through the flow path, so sufficient spray pressure cannot be obtained. Although difficult, these gases are
It has a strong negative arc characteristic, that is, α in the above equation (1) is large, and therefore, as is clear from equation (1), it has the effect of reducing the arc resistance that causes arc instability. It can increase. Therefore, mixing these gases with SF6 can reduce the overall gas flow rate compared to air or nitrogen alone;
It is possible to obtain a sufficient blowing pressure, and at the same time, it is possible to utilize the strong negative arc characteristics of air and nitrogen gas, which are favorable for DC circuit breakers.

[Brief explanation of drawings]

Fig. 1 shows a conventional buffer type gas blowing mechanism, Figs. 2 and 3 show the breaker principle, Fig. 2 is a circuit diagram, Fig. 3 is an operating characteristic diagram, and Fig. 4 is a diagram showing the shutoff principle. It is a figure showing the gas blowing mechanism of one example of the present invention. In the figure, (20) is a cylinder, (40) is a buffer chamber, (50) is a fixed contact, (60) is a discontinuation contact, and (70) is a fixed contact.
) is a flow guide, and (SO) is an arc.

Claims (3)

[Claims] (1) In a DC breaker that has a commutation auxiliary circuit composed of capacitance, inductance, gap, etc. in parallel with the breaker, the fluid spraying force for arc extinguishing is replaced by the arc energy of the arc itself. A DC breaker characterized by being obtained by heating and expanding arc fluid. (2) The DC breaker according to claim 1, wherein the arc-extinguishing fluid is SF6 gas. (3) The DC breaker according to claim 1, wherein the arc-extinguishing fluid is a mixed gas of SF6 and air or SF6 and nitrogen.