JPS5842693B2 - Denkikikinohogosouchi - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a protection device for electrical equipment such as oil-filled capacitors, and in particular, when an abnormality such as a short circuit occurs in the main body of the electrical equipment, the main body of the electrical equipment is protected by being disconnected from the power source. Regarding protection devices for electrical equipment.

If a short circuit occurs in the capacitor body of an oil-immersed capacitor, an overcurrent will flow into the capacitor body from the electrical circuit.
The accident may escalate and eventually cause the tank to be destroyed.

To prevent such accidents, this type of electrical equipment uses power circuit breakers and fuses. Electrical equipment is disconnected from the electrical circuit by fusing it.

However, when a power breaker is used as a disconnection device, it is not only expensive, but also causes a delay in the operation of the overcurrent detector that operates the breaker, which may lead to an increase in accidents.

Furthermore, when a fuse is used, it is often possible to blow the fuse but not to cut off the electrical circuit.Therefore, while the electrical circuit is being formed by the arc, the pressure inside the tank increases, which may lead to an escalation of the accident.

The present invention has been made in consideration of the above-mentioned points, and aims to provide a safe protection device for electrical equipment that has a simple configuration and can reliably isolate electrical equipment from electrical faults without aggravating the accident. This is the purpose.

In order to achieve such an object, the present invention provides a first electrical path between one terminal of the electrical equipment main body and the disconnection device.
A metal wire with a memory effect is provided so that when an abnormal current flows through the electrical circuit, it contracts and comes into contact with a second electrical circuit connected to the other terminal of the electrical equipment main body, and this metal wire is wound around the second electric circuit at least once so as to maintain a non-contact state with respect to the second electric circuit during normal operation to constitute a short-circuiting device that shorts both terminals of the electrical equipment main body. shall be.

An embodiment of the present invention will be described below with reference to FIG.

A tank 1 houses a capacitor body 2 together with insulating oil, and bushings 3 and 4 are provided on the upper lid of the tank 1.

One end of the capacitor body 2 is connected to the center conductor 6 of the bushing 3 via a lead wire 5.

On the other hand, the other end of the capacitor body 2 is connected to the center conductor 9 of the bushing 4 via a lead wire 7a, a metal wire 8 having a memory effect, which will be described in detail later, and a lead wire 7b.

The leads of the central conductors 6, 9 of the bushing 3.4 are connected to the external electrical circuit via a fuse 10.11 and a switch 12.13, respectively.

By the way, the metal wire 8 and the lead wire 5 that have the above-mentioned memory effect
are arranged in the relationship shown in FIG.

That is, the metal wire 8 is wound around the lead wire 5 at least once or more around the lead wire 5 (in the embodiment, the metal wire 8 is wound around the lead wire 5 at least once or more).
° It is wound, and the lead wire 5 and metal a8 are always wound.
are arranged 1' at intervals so as to be in a non-contact state, and the lead wire 5 and the metal wire 8 constitute a short circuit device 14.

Next, the metal wire 8 having a memory effect will be explained.

As a metal wire having such properties, the registered trademark name of Nitinol, which is a trade name of a titanium and nickel alloy, is known.

If the metal wire made under the Nitinol registered trademark is deformed into a predetermined shape at a temperature of 550°C or higher, it can be plastic-processed into another shape at a temperature lower than the transformation temperature of the metal wire, for example, 135°C ± 10°C. Even if the metal wire has a transformation temperature of 135℃
It has the property of returning to its original shape when heated to ±10°C.

Further, this metal wire is deformed at a speed of 2 m/sec upon return, generating a stress of 60 kg/mdctv.

Therefore, the metal wire 8 is deformed at 550° C. or higher to a state where it is wound at least one turn to a small diameter (such that the metal wire 8 is in direct contact with the lead wire 5) as shown in FIG. The transformation temperature of this metal wire 8 is 13te±1.
At temperatures below 0°C, a large diameter (I
If the lead wire 5 is plastically worked to a diameter such that the lead wire 8 is in a non-contact state with respect to the lead wire 5 and placed at a predetermined interval on the outer periphery of the lead wire 5, the large diameter will be maintained under normal conditions and the temperature will be 135°C ± When it is heated to 10° C., it returns to the pre-memorized small diameter shape and comes into contact with the lead wire 5.

That is, when the capacitor body 1 is normal, the capacitor body 2 beams 1 and 1 wires 5.7a and 7b.

It is connected to an external electrical circuit via the metal wire 8 and the center conductors 6 and 9 of the bushings 3 and 4.

However, if, for example, a short-circuit accident occurs within the capacitor body 2, an overcurrent several times the rated current will flow into the capacitor body 2.

When the metal wire 8 is heated by Joule heat due to this overcurrent and reaches the transformation temperature of 135.degree. C.±10.degree. C., the metal wire 8 instantly contracts and becomes the state shown in FIG.

That is, the lead wire 5 and the metal wire 8 come into contact, and the capacitor body 2 is short-circuited.

As a result, the short circuit current does not flow to the capacitor body 2, but flows through the electrical circuit until the fuses 10 and 11 are blown.
is disconnected from the electrical circuit.

Therefore, no short-circuit current is supplied to the capacitor main body 2, thereby preventing the expansion of accidents such as tank destruction.

Incidentally, the fuse drawer switches 12 and 13 are opened.

On the other hand, since the metal wire 8 is wound one or more turns around the lead wire 5, the lead wire 5 does not separate from the metal wire 8 due to vibrations such as when the capacitor is transported.

Therefore, the relationship between the metal wire 8 and the lead wire 5 as a short-circuiting device is not impaired by vibration, and therefore reliability is achieved.

As explained above, according to the present invention, when an accident occurs in the electrical equipment main body, the fault current flowing into the electrical equipment main body restores the shape of the metal wire with the storage device to short-circuit between both terminals of the electrical equipment main body. Since the main body of the electrical equipment is separated from the circuit, the structure is simple and inexpensive, and furthermore, it is possible to reliably prevent the spread of accidents involving the electrical equipment.

In the above embodiment, a metal material having a memory effect is provided in the tank, but it may be arranged between the center conductor of the bushing and the fuse.

Furthermore, although the bushing has been described as having the center conductor, it goes without saying that the lead wire from the capacitor body may be led out directly from the bushing.

[Brief explanation of the drawing]

Figure 1 shows the features of the present invention! A schematic configuration diagram for explaining the embodiment,
FIGS. 2 and 3 are explanatory diagrams illustrating operating states in which essential parts of the present invention are enlarged. 1... Tank, 2... Capacitor body, 3, 4... Bushing, 5, 7...
Lead wire, 8...Metal wire with memory effect, 1
0,11...Hyuse.

Claims (1)

[Claims] 1 In a device in which a disconnection device is provided in the middle of at least one of the electrical circuits connected to a terminal of the electrical equipment main body, abnormal current is present in the electrical circuit in the middle of the first electrical circuit between the disconnection device and one terminal of the electrical equipment main body. When it flows, it contracts,
A metal wire having a memory effect is provided so as to be in contact with a second electric path connected to the other terminal of the electrical equipment main body, and this metal wire is connected to the second electric path during normal operation. 1. A protection device for an electrical device, comprising a short-circuiting device that shorts both terminals of the electrical device main body by winding at least one turn in the period of the second electric path so as to maintain a non-contact state.