JPH01626A - Current limiting device - 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 [Industrial Field of Application] The present invention relates to a current-limiting and interrupting device that limits and interrupts short-rated current tIL.

[Conventional technology]

Figure 3 is an example of Tokko Akira! This is a conventional current limiting device disclosed in Japanese Patent No. 1O-401118. In the figure, ■ is a current-limiting element, ``-'' is a resistor connected in parallel to this current-limiting element, and ``-'' is a switch connected in series with the current-limiting element. An example of a current limiting element is disclosed in, for example, Japanese Utility Model Publication No. 58-118060, and its entire structure is shown in FIG.

In Fig. 4', the 1llFi first electrode is formed into a cylindrical shape from a conductive metal such as copper or a copper alloy, and one end has a terminal screw for screwing the bus bar screwed therein. A female thread with a bottom is formed in the center. (A 21-piece insulating tube made of hollow pipe-shaped heat-resistant, alkali-resistant material, such as P1
It is made of 7+7 porcelain and one end is in contact with the first electrode tube.

Reference numeral 131 is a metal reinforcing tube, which is formed into a cylindrical shape and has a hollow hole inside, and the electrode tube and the insulating tube 1! If! :It is stored from the power tube. +41 is a powder of glass, mica, etc., which is added to the first electrode tube III, the seven-metal reinforcing strip 131, and the insulating tube I! The first and metal reinforcing tubes 11 and 131 are insulated from each other by an insulator molded after high-temperature firing together with 1, and these and the insulating tubes 1 are integrally fixed.・-+l$)
n the second electrode is a conductive metal such as copper%rs1
It is fixed to the metal reinforcing tube 131 by screwing a female screw provided on the outer periphery to the female screw provided in the hollow hole of the metal reinforcing tube.

1F) Made of alkali metals such as sodium sodium,
When a current to be limited, such as a short-circuit current or an overload current, passes through it, it vaporizes into a high-resistance material due to the Joule heat generated by the current, and when the current is constantly on, the current limiting material 161 is a good conductor of electricity. A sealing material (8) for sealing the current limiting material (7) is a movable sealing material provided in the hollow bottom hole of the second electrode 161 so as to be actuated in the axial direction by the vaporization of the current limiting material 171. Piston, t91d The current limiting material (7) inserted into the recess of the piston (81) and the O ring (!0) which maintains the airtightness of the pressure buffer fluid II force described below, are hollow with a pair of poles. A spacer inserted into the hole receives the impact of the piston (8) when the flow restricting material (7) is vaporized. 8) A pressure buffer fluid made of an inert gas that cushions the impact, OIJ, is a sealing body for sealing the above pressure buffer fluid a.

Next, the operation will be explained. In the limit fIf shown in FIG. 3, when a short current flows through the interrupting device, the switch opens and the resistance of the current limiting element increases, thereby limiting the short circuit current.

The energy stored in the circuit tries to be injected into the current limiting element, but since the resistor Qll is connected in parallel to the current limiting element 211 processes.The operation of the current limiting element (a) is as follows.

When the short circuit current flows, the current limiting material 17 filled in the insulating tube 121 is heated by self-Joule heat and vaporized. When vaporization occurs, the unsealing resistance of the current limiting material (7) increases rapidly, and short circuit current is significantly limited. '1I
(fL restriction material 1)) becomes a high-pressure plasma through vaporization, so the pressure in the hole in the insulating tube (21) increases, but the piston (8) rotates in the direction shown in Figure 4 and moves to the right. hand,
Pressure rise is suppressed. Since the insulating cylinder 121 is reinforced by the metal reinforcing cylinder (3) via the insulator (4), it will not be damaged by the pressure suppressed by the piston (8).

The limited current Iri is cut off by the switch (to).

After the cutoff, the energy power of the current limiting element is lost, so
The current limiting material (force) that had been vaporized is cooled and becomes solid or liquid. Therefore, the pressure inside the inner hole of the insulating cylinder (2) also decreases, and the piston (8) is moved by the force of the pressure buffer fluid 0. It is pushed back and self-recovers to the state before operation.

The linearity of the current flowing through each part is shown in Figure 5. In Figure 5, the curve B shows the waveform of the short-circuit current that would flow in the absence of a current-limiting device.Curve B is the current that flows through the current-limiting element. After operation, the current limited by the current limiting element, that is, the current 74Bm flows, where C is the current flowing through the resistor, D is the current flowing through the switch, and is the sum of B and C.

[The intermediary point that Hatsu- tries to resolve]

Conventional current-limiting place devices are configured as described above and move back and forth, but they open and close! - is a casing that interrupts the short circuit current when the current zero point is 2, and the current limiter is connected to the current limiter can. The purpose is to - [Means for solving the problem] The current limiting circuit breaker according to the present invention includes a resistor connected in parallel to a series body of a current limiting element and a first switch, and a second resistor connected in series to the series body. A switch is connected.

[Effect]

The current limiting device in this invention includes 1. By blocking the follow-on current flowing to the current-limiting element with the first switch, damage to the current-limiting element is reduced and its life is extended, thereby limiting I5!
Extend the life of the interrupter.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 122 is a second switch, (2) is a first switch, crane is a current limiting element, and QIl is a resistor. Current limiting element (
(to) is completely similar to the one shown in Figure 4. That is,
A resistor 3υ is connected in parallel to the current limiting element and the first switch in series, and a second switch is connected in series to the series body.

When a short circuit current flows, the first switch device and the second switch device start the opening operation, and at the same time, the current limiting element (a)
Start making. The current limiting operation of the current limiting element is the same as that described in the conventional example, so the explanation will be omitted. Figure 2 shows the flow through each part.

In FIG. 2, %A indicates the short circuit current that would flow in the absence of a current limiting device. B indicates the current flowing through the current-limiting element node, but in the present invention, by providing the first switch d, no follow-on current flows through the current-limiting element (to). In addition, the short circuit current is significantly limited by the current limiting element, and this limited current is easily cut off by the first switch because VC is very small. Since the energy stored in the circuit is consumed as the current flows through the resistance Fi (Wl)K, the occurrence of abnormal voltage is suppressed.

The current flowing through the resistor is indicated by C.

〔Effect of the invention〕

As described above, according to the VC of the present invention, the IC can be used as a current limiting element.
Since a resistor is connected in parallel to the series switch of the first switch and a second switch is connected in series to the above series switch, damage to the current limiting element can be reduced and the life of the current limit breaker can be extended. There is.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a current limiting and breaking device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the device shown in FIG. 1, and FIG. 3 is a circuit diagram showing a conventional current limiting and breaking device #. FIG. 4 is a sectional view showing the current limiting element used in the devices shown in FIGS. 1 and 3, and FIG. 5 is an explanatory diagram of the operation of the device shown in FIG. In the figure, @ is a current limiting element, 311 is a resistor, ■ is a second switch, and 121 is a switch of 9J1. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A current limiting and breaking device comprising: a resistor connected in parallel to a series body of a current limiting element and a first switch; and a second switch connected in series to the series body.