JPS629630Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of gas-insulated electrical equipment for cold regions, and in particular, a heating device is installed in a part of the electrical equipment to prevent the gas inside the equipment from liquefying at low temperatures. It relates to insulated electrical equipment.

_SF6 gas is an inert gas that has superior properties in insulation, arc resistance, and heat resistance compared to other gases, and is used in electrical equipment that uses it as an insulation or cooling medium, and as an arc extinguishing medium. Electrical equipment used as an arc-extinguishing medium, as well as gas cylinders and disconnectors using it as an arc-extinguishing medium, have come to be widely used.

On the other hand, when electrical equipment such as transformers and switchgear is used in cold regions, it is necessary to withstand the low temperatures (for example -40°C) during the severe cold of winter and operate _normally . It is necessary to prevent this because it liquefies and causes a drop in gas pressure inside the equipment, resulting in a lack of insulation performance and arc extinguishing performance.

Figure 1 shows the gas pressure-temperature characteristics of an electrical device sealed with a gas pressure of 6 kg/cm ² ·g at 20°C. 1st
In the figure, liquefaction begins at the temperature (-28°C) of the intersection point C between the gas pressure-temperature characteristic curve A and the liquefaction curve B.

Measures to improve this situation include placing the entire equipment inside a building, covering the equipment tank with heat insulating material to prevent the ambient temperature from dropping, and equipping the entire equipment or major parts with heaters. ,
Preventing SF ₆ gas from liquefying has been implemented or devised by providing a recess for a liquid reservoir at the bottom of the tank and continuously heating the liquefied gas locally.
These methods have drawbacks such as high equipment costs, increased equipment size and weight, and inefficient heating methods that result in wasted electrical energy.

The present invention was developed to eliminate the above-mentioned drawbacks. A recess for a liquid reservoir is provided at the bottom of the gas insulated equipment tank, liquefied SF ₆ is collected in the recess, and a heater attached to the partition wall of the recess is installed. In addition to providing a heating device such as the above, a bellows or spring balance type receiving tray is provided at the bottom of the recess, and the deviation caused by the gravity of the liquefied gas is used to open and close the heater circuit to heat the liquefied gas. Vaporize again. The purpose is to obtain gas-insulated electrical equipment with an efficient heating device.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. 1 is the gas tank and disconnector, 2 is the tank for the main unit, 3 is liquefied gas, 4 is SF ₆ gas, 5
is a recess provided in the tank bottom 8 for storing the liquefied SF ₆ gas 3. 6 is a liquefaction detection and heater control device. Reference numeral 7 denotes a heater, and the tank bottom 8 has an inclined structure so that the liquefied gas 3 easily collects in the recess 5. The heater control device is composed of a bellows 9, a micro switch 10, an electromagnetic switch 11, and an operating coil 12 of the electromagnetic switch 11, as shown in FIGS. 3a and 3b. The bellows 9 communicates with the recess inside the tank.

Next, we will discuss the effect. SF ₆ sealed in gas shield disconnector 1 during severe winter in cold regions
When the temperature of the gas decreases to a temperature at which the gas 4 starts to liquefy, the SF ₆ gas liquefies and condenses on the inner wall of the tank 2 . This condensed liquefied gas 3 first accumulates on the tank bottom 8 and moves along the slope of the tank bottom 8 into the recess 5.
It accumulates. When the liquefied gas 3 accumulates in the recess 5, its weight causes the bellows 9 to deviate in the vertical direction. When this amount of deviation reaches a predetermined value or more, the contact 10 of the micro switch closes, and the electromagnetic switch 11 closes.
A current flows through the operating coil 12 of the electromagnetic switch, the contact 11 of the electromagnetic switch is closed, and the heater 7 is energized. Heater 7
As a result, the recess 5 is locally heated, and the liquefied gas 3 accumulated in the recess 5 is warmed and vaporized again.
SF ₆ gas becomes 4. When the liquefied gas accumulated in the recess 5 is vaporized and the bellows 9 returns to its original position, the micro switch 10 returns to its original state, opening the electromagnetic switch 11 of the heater circuit and stopping the heater 7.
Therefore, even if the above-mentioned gas shield and disconnector are used at an ambient temperature below the liquefaction temperature of SF ₆ gas, only a small portion of the
Since SF ₆ gas can be kept in a liquefied state, operation can continue without any problems. In general, gas cylinders and disconnectors are designed to operate without problems even if the gas pressure drops to about 10% of the normal level, so as mentioned above, a very small amount of SF ₆ gas is liquefied. too,
The gas tank and disconnector can operate normally. Although the above was explained using examples of gas insulators and disconnectors, it goes without saying that similar effects can be obtained when applied to other gas-insulated electrical equipment, such as gas-insulated transformers and SF ₆ gas-insulated hermetic switchgear. Nor.

Next, another embodiment of the present invention will be explained with reference to FIGS. 4a and 4b.

Components that are the same as those in FIGS. 3a and 3b are designated by the same reference numerals and their explanations will be omitted. In the figure, reference numeral 13 denotes a spring-loaded tray, and 14 denotes an outer box for accommodating the tray 13 and for sealing the tank 2 of the gas inlet and disconnector from the outside air. As for the operation, since the bellows 9 described above is simply replaced with the receiving plate 13, the contact 10 of the micro switch closes when the deflection of the receiving plate 13 exceeds a predetermined value due to the gravity of the liquefied gas. , operating coil 1 of electromagnetic switch 11
2, the contact 11 of the electromagnetic switch closes, and the heater 7 is energized. The recess 5 is locally heated by the heater 7, and the liquefied gas 3 accumulated in the recess 5 is removed.
is heated and vaporized again to become SF ₆ gas 4.
When the liquefied gas 3 accumulated in the recess 5 is vaporized and the saucer 13 returns to its original position, the micro switch 10 returns to its original state and closes the electromagnetic switch 11 of the heater circuit to stop the heater.

As mentioned above, the present invention provides electrical equipment that uses SF ₆ gas with a recess for a liquid reservoir at the bottom of the gas insulated equipment tank, collects liquefied SF ₆ in the recess, and installs the liquefied SF 6 in contact with the partition wall of the recess. At the same time, a bellows or spring-loaded tray is installed at the bottom of the recess, and the heater circuit is opened and closed using the deflection caused by the gravity of the liquefied gas, thereby heating the liquefied gas. By doing this, even in the harsh winter months of cold regions,
This has the effect of preventing SF ₆ gas from liquefying and allowing equipment to operate normally. In addition to economical advantages such as the fact that the cost is extremely low compared to methods such as collecting liquefied gas in a reservoir recess and continuously heating it, and saving electric energy for heating, the device can be made smaller and lighter. This has the effect of ensuring that the equipment can be operated automatically even in severe cold weather.

[Brief explanation of the drawing]

Figure 1 is a gas pressure-temperature characteristic curve diagram of SF ₆ gas.
Fig. 2 is a schematic diagram of a gas shield disconnector showing an embodiment of the present invention, and Figs. 3a and 3b are local enlarged views and circuit diagrams of an embodiment of the liquefaction detection and heater control device shown in Fig. 2. Figures 4a and 4b are partially enlarged views and circuit diagrams of another embodiment of the liquefaction detection and heater control device. DESCRIPTION OF SYMBOLS 1... Gas chamber disconnector, 2... Tank, 3... Liquefied gas, 4... SF ₆ gas, 5... Recess, 6... Liquefaction detection and heater control device, 7... Heater, 8...
...tank bottom, 9 ... bellows, 10 ... micro switch, 11 ... electromagnetic switch, 12 ... operation coil, 13 ... saucer, 14 ... outer box, A ...
Gas pressure-temperature characteristic curve, B... liquefaction curve.

Claims (1)

[Scope of utility model registration request] A recess is provided at the bottom of the gas insulated electrical equipment tank,
In order to make the recess the deepest part, the bottom of the tank is sloped, and a heating device is placed close to the outer wall of the recess so that the lower part of the outside of the tank can be moved to communicate with the inside of the recess. 1. A gas-insulated electrical device comprising a device that opens and closes the electrical circuit for the heating device by the operation of a switch that operates in conjunction with the displacement of the receiving tray.