JPS6311854B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a capacitor bank safety device for preventing an explosion accident of a plurality of unit capacitors connected in parallel and used collectively. It is related to.

[Conventional technology and its problems]

Generally, large-capacity capacitors are assembled from a set of unit capacitors with a standard size of 100 KA or more, due to handling and installation location considerations. When forming a collection of unit capacitors, if they are connected in series, only the voltage of the unit capacitors needs to be taken into account.However, if they are connected in parallel as shown in Figure 1, unfortunately, the internal insulation of the unit capacitors is If damage occurs and the terminals become short-circuited,
Not only the energy of the unit capacitor where dielectric breakdown occurred, but also a large amount of energy from other capacitors connected in parallel externally flows into the faulty capacitor, and this excessive energy causes the case of the faulty capacitor to break, causing an explosion. Developing into a serious accident.

The conventional method to prevent this is to operate a movable piece using the electromagnetic force of the current flowing into and out of a unit capacitor (or a group of capacitors) to short-circuit the terminals of the capacitor, as shown in Figure 2. It is something that makes you

In this method, normal current and fault current generate electromagnetic force in exactly the same direction, so normal current and fault current are distinguished only by the magnitude of the current, and there is a lack of clarity in distinguishing between normal and fault conditions. It has some drawbacks.

[Means for solving problems]

The present invention aims to eliminate these defects, clearly distinguish between faulty current and normal current, and completely prevent current from flowing into the faulty capacitor.

That is, in a capacitor bank consisting of a plurality of unit capacitors connected in parallel, the present invention sets adjacent unit capacitors as a set, a part of each lead wire on the same polarity side is used as a movable piece, and a capacitor and other parts are placed outside of each movable piece. Fixed metal plates connected to the poles via lead wires are arranged in close proximity, and the paired movable pieces are arranged so that the magnetic force generated by the current in the same direction during normal operation acts on the movable pieces in the direction of attraction, If one of the capacitors fails, the current from the other capacitor flows in opposite directions to the pair of movable pieces, and the mutual repulsion of the magnetic forces urges the movable pieces apart, causing them to come into contact with the fixed metal. This invention relates to a capacitor bank safety device characterized by short-circuiting both ends of a capacitor.

〔Example〕

FIG. 3 shows one embodiment of the invention. 1a,
1b is a pair of unit capacitors 4a and 4b.
A pair of movable pieces 2 forming part of the lead wires connected to respective terminals of
A fixed metal plate 3 contacts the fixed metal plate 1b to close the circuit, and 3 is a low impedance lead wire connecting the fixed metal plate 2 and one terminal of the capacitors 4a and 4b.

The pair of movable pieces 1a and 1b are arranged close to each other so that when current flows in the same direction, an attractive action is exerted on the movable pieces 1a and 1b due to magnetic field interaction formed by the right-handed screw rule. Therefore, when both unit capacitors 4a, 4b are in good condition, the normal currents flowing through the movable pieces 1a, 1b are in the same direction, and as mentioned above, the attraction between the movable pieces works and they will not come into contact with the fixed metal plate 2. do not have.

Now, when internal dielectric breakdown occurs in one of the unit capacitors, for example, the unit capacitor 4a, an accumulated current flows from the other capacitor 4b forming a pair therewith. That is, a current is generated in the capacitor 4b→1b→1a→4a, and the current flows in opposite directions in the movable pieces 1a and 1b. As a result, the magnetic force generated in the movable pieces 1a and 1b acts in the direction of separation from each other, and the movable pieces 1a and 1b
1b is deformed outward, and one or both of the movable pieces comes into contact with the fixed metal plate 2, forming a short circuit and eliminating current flow into the faulty capacitor.

In the embodiment shown in Fig. 3, a parallel circuit is constructed using a pair of unit capacitors, but the present device can also be put to practical use even if a suitable number of unit capacitors are assembled and regarded as the unit capacitor in Fig. 3. It's something you get.

〔Effect of the invention〕

In fact, according to the present invention, part of the lead wires of the pair of capacitors is made into a movable piece, and the direction of current flowing through the movable piece of the other normal capacitor is reversed between normal conditions and when one capacitor is faulty. By utilizing the fact that the generated magnetic force is opposite, it is possible to apply attraction and separation effects to both movable pieces, so that accidents can be discriminated and a complete short circuit can be formed only in the event of a failure, ensuring the safety of the capacitor bank. It has a calming effect.

[Brief explanation of the drawing]

1 and 2 are proof drawings of a known device, and FIG. 3 is an embodiment of the present invention. 1a and 1b are movable pieces, 2 is a fixed metal plate, 3 is a lead wire, and 4a and 4b are capacitors.

Claims (1)

[Claims] 1 In a capacitor bank consisting of multiple unit capacitors connected in parallel, adjacent unit capacitors are grouped together, a part of the lead wire on the same polarity side is used as a movable piece, and the outside of each movable piece is connected to the other pole of the capacitor and the lead. Fixed metal plates connected via wires are arranged in close proximity, and the pair of movable pieces is arranged so that the magnetic force generated by the current in the same direction during normal operation acts on the movable pieces in the direction of attracting each other. When the other capacitor malfunctions, the current from the other capacitor flows in opposite directions to the pair of movable pieces, and the mutual repulsion of the magnetic forces urges the movable pieces apart, causing them to contact the fixed metal and pull both ends of the capacitor apart. Capacitor bank safety device characterized by short circuit.