JPS60249807A - Enclosed switchboard - 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 [Technical Field of the Invention] The present invention relates to a closed switchboard in which a plurality of electrical devices are housed in a closed container filled with an insulating gas such as SF&gas, and particularly relates to a closed switchboard that houses a plurality of electrical devices or The present invention relates to temperature detectors for conductors that connect these electrical devices.

[Technical Background of the Invention and its Problems] In recent years, 66/100/2000 power receiving/transforming equipment for electric power and general industry has been developed.
77kV class closed switchboards are made of S, which has excellent insulation properties, in order to reduce the installation space, reduce production costs, and facilitate operation.
There is a tendency for closed switchboards (hereinafter referred to as gas cubicles) containing F&gas to be used.

Here, the outline of the configuration of the gas cubicle will be explained with reference to FIG. In the figure, a sealed container 1 made of metal and filled with SF6 gas includes a lightning arrester 2, an instrument transformer 3, a disconnector 4 connected to an operating mechanism (not shown), and a disconnector 4 connected to an operating mechanism (not shown). A fixed or movable breaker 6, an instrument current transformer 7, and a cable head 8 connected to a power transformer or load (not shown) are attached. The conductor 9, which has one end connected to the cable head 8, is connected to each of the electrical devices described above. The other end of the conductor 9 is connected to a bus bar 10 that connects adjacent closed switchboards.

Further, the airtight container 1 is provided with an opening 11 for carrying in and inspecting the electrical equipment, and after the electrical equipment has been installed and inspected, it is opened through a backing 12 to maintain airtightness. A lid 13 is provided.

By the way, the pressure of the SF and gas inside the closed container 1 is related to the insulation properties, so it is necessary to maintain a predetermined pressure. Therefore, the sealed container 1 has a structure that can maintain sufficient airtightness to prevent SF gas from leaking.
After installing electrical equipment and filling it with SFg gas, it becomes extremely difficult to inspect the internal electrical equipment while maintaining airtightness. Therefore, if the tightening force at the connection between the conductor and electrical equipment decreases, or if the resistance of the contact increases after repeated opening and closing operations, it may cause poor continuity or an abnormal temperature rise, and the insulation It is necessary to constantly monitor the temperature rise of the electrical equipment and conductor connections, etc., because there is a risk of not only deterioration of the electrical equipment but also short circuits that may destroy the electrical equipment. Conventionally, the temperature of the enclosed SF6 gas was measured using a thermal lightning pair as a method of monitoring abnormal temperature rises while maintaining sufficient insulation between the sealed container and the electrical equipment housed therein. However, with this method, it is difficult to accurately measure the temperature rise due to the temperature outside the sealed container and interference with the measurement signal current due to electromagnetic induction. Furthermore, since the measurement is indirect, it is extremely difficult to accurately detect areas where the temperature has risen abnormally or to measure the progress of the temperature rise.

On the other hand, there is non-contact measurement using infrared rays, but due to the large external dimensions of the infrared thermometer itself and the objective head, it is difficult to measure multiple points due to space constraints, and the part to be measured and the measuring device are placed in a straight line. Due to the need for specific positional relationships, storage electrical equipment with complex circuit configurations naturally imposes restrictions and cannot perform adequate measurements, and infrared thermometers are expensive and not common. was there.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and is capable of easily and easily controlling temperature rise changes in electrical equipment in a closed container filled with an insulating gas and conductors connecting this electrical equipment. The purpose of the present invention is to provide a gas cubicle that can be detected in a highly reliable manner.

[Summary of the Invention] The present invention provides a closed switchboard in which a plurality of electrical devices are housed in a closed container filled with an insulating gas, and the plurality of electrical devices are connected by conductors. A temperature sensing part made of multiple shape memory alloys with different temperatures is attached, and temperature rises and changes in temperature are detected by optical signals generated by the operation of the temperature sensing parts, and temperature rises can be detected by adjusting the load. This is a gas cubicle vehicle that can reduce the amount of gas and prevent accidents from occurring.

[Embodiments of the Invention] First, a shape memory alloy related to the present invention will be described.

As is well known, shape memory alloys have the property of returning to their pre-deformed shape when heat is applied to them after they have been deformed below a certain temperature; they return to their previously memorized shape and do not respond to changes in temperature thereafter. (hereinafter referred to as unidirectional shape memory alloy), and remembers the shape of the high temperature side and the low temperature side, respectively.
Some alloys have a shape on the high temperature side when the transformation temperature is abnormal, and a shape on the low temperature side below the transformation temperature (hereinafter referred to as bidirectional shape memory alloys). This shape memory phenomenon is caused by martensitic transformation,
This is also caused by thermoelastic martensitic transformation, in which the difference between the transformation temperature and the reverse transformation temperature is small, and its reverse transformation. Currently, about 20 types of alloys that exhibit shape memory effects have been announced, but the only practical shape memory alloys are nickel-titanium alloys and certain copper alloys. These generally have excellent characteristics such as (1) high shape recovery performance, (2) high recovery stress, (3) long fatigue life, and (4) excellent corrosion resistance. Tables 1, 2 and 3 show typical properties of the t'Ji-Ti alloy.

Note that it is desirable to select a material for the shape memory alloy that does not deteriorate the characteristics of SF and gas.

(Margin below) Table 1 Table 2 Table 3 Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows an example in which the conductor 9 is connected at the intermediate portion to connect a plurality of electrical devices housed in a sealed container (not shown), and the adjacent conductors 9a and 9b are connected to the bolt 14 and the nut. 15, and a temperature sensor 16, which will be described in detail later, is placed adjacent to this connection.
Attach to the conductor 9a with appropriate small screws. Thus, the temperature of the connection portion of the conductor 9 is detected by a circuit as shown in FIG.

That is, light from a light source provided in the light receiver 17 is irradiated to the temperature detector 16 via the optical fiber 18, and an optical signal corresponding to the detected temperature is transmitted to the light receiver 17 via the optical fiber 18.
The signal is extracted and converted into an electric signal, amplified by an amplifier 19, displayed digitally or analogously on a display 20, and, if necessary, operates a circuit breaker 6 via another control device to cut off the power.

Next, details of the temperature detector 16 will be explained with reference to FIG. In the figure, reference numeral 21 denotes a mounting seat that is attached to the conductor 9a with a suitable screw. Since the material constituting the main part of the present invention is a shape memory alloy, this mounting seat is provided with cooling fins or holes (not shown) so that the maximum usable temperature scar (transformation temperature) is approximately 110°C. This increases the surface area and adjusts the heat dissipation. Thus, one end of the temperature sensing member 22 is attached to the mounting seat 21. This temperature-sensitive member 22 includes three bidirectional shape memory alloys 22a having different transformation temperatures,
22b and 22c are deformed into an arcuate shape below their respective transformation temperatures, and then fixed together in a wave-like manner by means of fixing means such as caulking, and the memorized shape can be freely repeated depending on the temperature. A baffle plate 23, the details of which will be described later, is attached to the other end of the temperature sensing member 22. This shield plate 23 is the fifth
As shown in the figure, it is formed from a rectangular plate and has three openings 23a, 23b, and 23c. Also,
A cover 24 that accommodates the temperature sensing member 22 and the shielding plate 23 is attached to the mounting seat 21, and a light emitting head 25 and a light receiving head 26 are attached to the cover 24 facing each other. Here, the light emitting head 25 and the light receiving head 26 are always completely blocked from light by the shield@23, and the 3g shape memory alloys 22a, 22b, 22c of the temperature sensitive member 22 are
They are mounted at positions such that light passes through the openings 23a, 23b, and 23C when the shape is restored at or above each transformation temperature. For example, if the transformation temperatures of three bidirectional shape memory alloys are 70°C, 90°C, and 100°C, the temperature T can be reduced to 1670°C, 70°C by combining with other auxiliary equipment.
≦T≦90℃, 90℃≦T≦ 110℃, 110℃≦T
can be displayed.

With this configuration, the outer size of the temperature detector 16 is reduced, and it becomes easy to detect temperature in a narrow area, which was difficult with the conventional configuration. Furthermore, since the detected signal is transmitted through the optical fiber 18, there will be no interference even if there is a strong electric field inside the sealed container 1, and the temperature sensor 16 has high mechanical strength and flexibility. In addition to the miniaturization of the external size, temperature detection at multiple points can be easily performed even in a narrow space. Furthermore, since the optical fiber 18 is an insulator, complete insulation is maintained between it and the airtight container 1, no special insulating support member is required, and it is resistant to chemical atmospheres, so special measures are required even in locations with poor environments. do not need.

On the other hand, since the temperature sensing member 22 is in direct contact with the conductor 9a via the mounting seat 21, there is no error in temperature detection and accurate temperature detection can be performed.

Note that the present invention is not limited to the above-mentioned embodiments,
As shown in FIG. 6, three unidirectional shape memory alloys 30a, 30b, and 30c are used as the temperature-sensitive member 30. The spring 31 may be used to apply an external force that overcomes the mechanical properties of the shape memory alloy. Alternatively, if necessary, openings may be provided in the covers 24 and 32 to allow the SF gas to flow therethrough.

[Effects of the Invention] Since the present invention is configured as described above, it is possible to accurately detect the temperature of an electrical device housed in a closed container filled with an insulating gas and a conductor connected to this electrical device. By detecting abnormalities, especially abnormalities in temperature rise, it is possible to prevent major accidents such as destruction of a sealed container due to an increase in internal pressure. In addition, it is possible to control the temperature rise by adjusting the load, to increase the number of inspections and intervals, to facilitate maintenance, and to extend the period of use of the gas cubicle. Furthermore, since the external shape is small, it is easy to install inside a closed container, and multiple installations are possible.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the configuration of a gas cubicle related to the present invention, FIG. 2 is a front view showing an enlarged main part of an embodiment of the present invention, and FIG. 3 is a temperature diagram of an embodiment of the present invention. A schematic circuit diagram showing a detection method, FIG. 4 is a cross-sectional view of a temperature detection section according to an embodiment of the present invention, and FIGS. The side view and FIG. 6 are cross-sectional views showing other embodiments of the temperature detection section of the present invention. 1... Sealed container 2... Lightning arrester 3... Instrument transformer 4... Disconnector 5... Earthing device 6... Breaker 7... Instrument current transformer 9... Conductor 18...Optical fiber 22.30...Temperature sensitive member 23...Shining plate 25...Light emitting head 26...Light receiving head Agent Patent attorney Noriyuki Chika (and 1 other person) ) 1st
Figures 7, 34- Figure 2 Figure 3 Figure 4 Figure 6

Claims (2)

[Claims] (1) In a closed switchboard in which a plurality of electrical devices are housed in a closed container filled with insulating gas, and the plurality of electrical devices are connected by conductors, the operation follows the temperature changes of the electrical devices or the conductors. A closed switchboard characterized by being equipped with a temperature detector that generates an optical signal. (2) The temperature detector consists of a temperature sensing part made of multiple shape memory alloys with different transformation temperatures, and a barrier part that is connected to the temperature sensing part and has multiple holes that transmit light. A closed switchboard according to claim 1, characterized in that: