JPS59186312A - Gas insulated electromagnetic induction machine - Google Patents

Abstract

PURPOSE:To reduce the volume of a gas storage, the capacity of a compressor and the like by a method wherein the pressure control is performed only in the region where the temperature of mixed gas is higher than the specified value. CONSTITUTION:The temperature of mixed gas 4 in a container 3 is detected by a temperature detector 19 and the gas pressure is not controlled until the temperature reaches the specified value. When the temperature of the mixed gas is not lower than the specified value, pressures in the container 3 and a gas storage 10 are detected by pressure detectors 12, 16 respectively and a pressure controller 11 controls a compressor 13, control valves 14, 17 and the like so as to keep the gas pressure in the container 3 within a specified region. When the temperature of the mixed gas 4 is below the specified value, the pressure is not controlled. By controlling like this, the quantity of responsive gas movement between the container and the gas storage is reduced. Therefore, the volume of the gas storage, the capacity of the compressor and the like can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure control device for controlling the pressure within a container of a gas insulated electromagnetic induction device such as a gas insulated transformer.

The following explanation will be given using a gas insulated transformer as an example5.
Conventionally, gas insulated transformers use a single non-condensable gas for both insulation and cooling, or add a refrigerant that is condensable and liquid at room temperature, and apply this to the windings and core. There are methods of cooling by spraying or lowering the temperature by using the latent heat of vaporization or sensible heat of the liquid.

The dielectric strength of such a gas insulated transformer has a close relationship with the pressure of the insulating gas or vaporized refrigerant gas sealed inside. If the gas pressure during equipment use is reduced, the dielectric strength becomes turbulent, the insulation dimensions can be reduced, and the equipment body can be made smaller, but in order to withstand this high pressure, the wall thickness of the container container must be increased. 1 weight etc. increases. On the other hand, if the pressure is too low, the wall thickness and weight of the container will decrease, but the dielectric strength will decrease and the insulation dimensions will increase, resulting in an increase in the size of the container body. Therefore, it is necessary to use it within an appropriate pressure range.

Conventionally, insulating gas was filled in advance so that the pressure of the insulating gas or the pressure of the mixed gas with evaporated refrigerant gas at the maximum operating temperature of the 41'+ container was below the specified upper limit, and during use, There are methods that do not adjust the pressure, and methods that are equipped with a gas storage tank in addition to the main unit, and when the temperature and pressure are high, the insulating gas or mixed gas is discharged into the storage tank to control the pressure inside the container below a certain level. there were. This invention belongs to the latter method of controlling pressure.

FIG. 1 shows a schematic configuration of a conventional pressure-controlled gas insulated transformer. In the figure, (1) is the winding, (2) is the iron core, and (3
) is a container for storing the windings and core, (4) is a non-condensable insulating gas (4a) that insulates and cools the windings (1) and core (2), and a refrigerant having condensing and insulating properties. evaporated gas (4b) (hereinafter referred to as refrigerant gas) is a mixed gas, (5) is the above refrigerant in the liquid phase (hereinafter referred to as refrigerant liquid)
, (6) is a cooler for cooling the heat generated from winding W (I + iron core (2), etc.), (7), (8), (9) is a cooler for cooling the refrigerant liquid (5), winding (1) , pump for spraying on the iron core (2), ijL pipe and sprayer, gas storage tank, 0
υ is a pressure control device, (2) is a pressure detector that detects the gas pressure in the container (3), ←4 is the volume, fV (3) to the gas storage tank 01, or from the gas storage tank (l[) to the container ( 3)
, a compressor capable of pumping mixed gas (4) in both directions, 04 is a control valve, αO is a container (3) and a gas storage tank OO
), 0Q is a pressure detector that measures the gas pressure in the gas storage tank, α force is a control valve, and 0 barrel is a 3m bypass pipe that connects the container (3) and the bottom of the gas storage tank (4). be.

A conventional gas insulated transformer is constructed as described above. For example, when the transformer is stopped or operated with no load or light load, the winding (1) and the iron core (
2), the temperature of the mixed gas (4), refrigerant liquid (5), etc. is low;
Therefore, since the vapor pressure of the refrigerant gas (4b) is also low, the insulation of the winding is maintained mainly by the dielectric strength of the insulating gas (4a).

When the 8K transformer is started or the load becomes heavy, the heat generated from the winding (1) and iron core (2) causes the mixed gas (4
) and refrigerant liquid (5) become high, and the temperature of the insulating gas (4
The total pressure of the mixed gas (4) increases according to the partial pressures of a) and the refrigerant gas (4b). At this time, the pressure inside the container (3) is prevented from rising above the specified upper limit.
), a pressure detector (6) detects the pressure inside the container (3), and a pressure sensor αQ detects the pressure inside the gas storage tank αQ, so that the pressure inside the container (3) If the pressure is higher than that in the gas storage tank 00), the excess mixed gas (4) is transferred to the gas storage tank 00) by opening the control valve aη using the pressure control device αυ.
and maintain the gas pressure in the container (3) below the specified upper limit. Further, if a certain amount of the mixed gas (4) has already been transferred into the gas storage tank 00 and the pressure inside the container (3) is lower than the pressure inside the gas storage tank head, the control device 01) controls the control valve α.
Close the power, open the control valve (+41) and start the compressor (c), and transfer the mixed gas (4) from the container (3) to the gas storage tank OQ.
The pressure inside the container (3) is kept below the specified upper limit by supplying pressure to the container (3).

On the other hand, the load on the transformer decreases, winding (1) and iron core (
When the amount of heat generated from 2) decreases, the temperature of the mixed gas (4) and refrigerant liquid (5) decreases, and the gas pressure also decreases. At this time, in order to prevent a decrease in the dielectric strength of the winding (1) due to a decrease in gas pressure, the pressure detector (6) and αQ detect the gas pressure in the container (3) and gas storage tank 0Q, and the gas pressure in the gas storage tank head is detected. When the pressure is higher than the pressure inside the container (3), the pressure control device αυ opens the control valve aη to allow the necessary mixed gas (4) to flow from the gas storage tank θ0 into the container (3). ) to maintain the pressure in the container (
Return to 3).

In addition, if the mixed gas (4) in the gas storage tank (10) decreases during this operation and its pressure becomes lower than the pressure in the customer type (3), the pressure control device 0υ will close the control valve Qη. close, open the control valve αΦ, and compress 4'A
(By operating it in the opposite direction and further pressure-feeding the necessary mixed gas (4) from the gas storage tank to the customer type (3), the gas pressure in the customer type (3) is maintained at or above the specified lower limit value. It has become.

However, in the conventional device as mentioned above, the customer type (3
), the pressure of the mixed gas is controlled within a certain range regardless of the temperature of the mixed gas in the transformer. (3) and the gas storage tank (10) is large, the storage tank OQ becomes large, and the compressor (2) also requires a large-capacity one.

This invention was made in order to eliminate the drawbacks of the conventional devices as described above, and the purpose is to obtain a gas insulated electromagnetic induction device that can downsize gas storage tanks, gas compressors, etc. That is.

FIG. 2 is a schematic diagram showing a gas insulated transformer to which an embodiment of the present invention is applied, (1) to (5), (7),
(9) to (g), etc. are all the same as or similar to the conventional ones.

(6A) is a refrigerant liquid cooler, which includes a circulation pump (7) and piping (
8A) and (8B), and after cooling the liquid in the lower part, it is supplied to the sprayer (9), where it is sprayed onto the winding (1) and the iron core (2) for cooling. 0tou is a temperature detector that detects the temperature of the mixed gas (4).

When the gas insulated transformer configured as described above is in a stopped state or in no-load or light-load operation, the temperature inside the container is low and the vapor pressure of the refrigerant gas (4b) is low, as in conventional equipment, so the winding The insulation of the wire (1) is mainly insulating gas (4
It is maintained by the dielectric strength of a).

When the transformer is started or the load becomes heavy, the temperature of the mixed gas (4) and refrigerant liquid (5) increases due to the heat generated from the winding (1) and iron core (2), and the insulating gas (4a)
and the partial pressure of the refrigerant gas (4b) and therefore the mixed gas (4b)
) total pressure increases.

At this time, in the above embodiment, the temperature of the mixed gas (4) in the customer type (3) is detected by the temperature detector 01, and the temperature of the mixed gas (4) in the customer type (3) is detected until this temperature reaches a specified value. The pressure is not controlled.In other words, the pressure is controlled to keep the interior of the customer type (3) in a sealed state.However, at this time, due to the expansion of the mixed gas (4) and the vaporization of the refrigerant liquid (5), Insulating gas (4a
) is assumed to be included. When the temperature of the mixed gas (4) is higher than the specified value, the pressure detector (6) and (IQ) indicate the customer type (
3) and the pressure of the gas storage tank (10), and the customer type (3) is detected.
), the pressure control device 0υ controls the compressor θ and control valve 0 or 0
Operate or operate η etc. to supply mixed gas (4) to customer type (3)
from there to the gas storage tank OL').

On the other hand, when the load on the transformer decreases, the temperature of the mixed gas (4) and refrigerant liquid (5) decreases due to the decrease in heat generated from the winding D) and the iron core (2). At this time, in order to prevent the dielectric strength of the winding from decreasing due to a decrease in gas pressure, pressure detection i (I (2) and a (j
Detect the customer type (3) and the pressure of the gas storage tank (Rυ),
84 < 9 (3) The pressure control device 0]) operates or operates the compressor α and the control valve 0
) and refrigerant liquid (5) are returned to customer type (3) from gas storage tank αq. And temperature sensor 0! ! (Thus, the above control is performed when the detected temperature of the mixed gas (4) is higher than the specified value, but this control operation is discontinued when the temperature of the mixed gas (4) falls to this specified value. ,
At temperatures lower than this, control valves θ4 and Q7J
Close it and make the customer type (3) unblocked.

As mentioned above, this invention provides pressure control for mixed gas (4)
It is characterized in that the process is performed only in a range where the temperature of is higher than a specified value. At this time, the boundary temperature between the range where pressure control is performed and the range where pressure control is not performed is such that the vapor pressure of the refrigerant gas (4b) at that temperature is a value that is ignored with respect to the pressure of the insulating gas (4a) and is as high as possible. Select temperature.

In this way, the dielectric strength of a non-condensable electrically negative gas such as sF6 gas is determined by the number of molecules per unit volume, and the effects of temperature and pressure are secondary. is known, so even if the gas pressure in the volume (3) decreases after the above-mentioned sealing off, the number of molecules of the bonding gas (4a) does not change from the time of sealing off, and the insulation is maintained. 1
: "The value of the 4 powers will be maintained at the time of sealing. Therefore,
As a result, a transformer that performs the above control maintains sufficient dielectric strength even when there is no load or a light load, or even when the transformer is stopped and restarted.

In addition, in the temperature range where pressure control is performed, the mixed gas (
4) from the volume (:3) to the gas storage tank 0,
Although the number of molecules of the insulating gas (4a) in the volume (3) decreases from the time of the lower limit temperature of the pressure control, the number of molecules of the refrigerant gas (4b) increases due to the rise in vapor pressure of the refrigerant liquid (5). do.

Therefore, if SF6 gas is used as the insulating gas and fluorocarbon C8F,60 is used as the refrigerant, the dielectric strength of the gas phase of C8F+60 is
Since it is sufficiently higher than F6 gas (usually about twice as high), even if the mixed gas (4) is transferred from the tank (3) to the storage tank (10), H'A? Ll? il'g power does not go down, but rather goes up.

Furthermore, the vapor pressure of the fluorocarbon 08F160 is, for example, 0.05 abs at 20°C, and the S
It has a negligible value with respect to the gas pressure of F6 gas, and is an appropriate refrigerant that can set the lower limit temperature of the gas pressure control of the present invention to a moderately high value.

The pressure control method according to the present invention described above is shown in FIG. 3 in comparison with a conventional device. The horizontal axis of the figure shows the temperature of the mixed gas (4) in the volume (3), Oa is the minimum operating temperature, Ob
is the gas pressure control lower limit temperature of the present invention, and OC is the lowest operating temperature. The vertical axis in FIG. 3(a) indicates the gas pressure within the volume (3). In the conventional device, the pressure is within the specified upper limit pressure P1. The pressure is controlled within the range of the lower limit pressure P2. - In the device of Rikiki's invention, the temperature range OawO
Since pressure control is not performed within b, the gas pressure changes within a range with the curve al bl as the upper limit and a2b2 as the lower limit. Further, within the temperature range Ob"-OC, the pressure is controlled within the range of P, , P2, just like the conventional device. Note that the curve P1g indicates the vapor pressure of the refrigerant liquid (5).

In the present invention, since pressure adjustment is not performed between Oa and Ob, this amount of gas is not necessary. For example, 0a=-2
0°C (minimum operating temperature for outdoor JRC204 transformers according to the Japan Air Society standard) and ob = ao°C, in terms of temperature Oa, in the conventional device, for the amount of gas sealed in Ob, and , add 20% more insulating gas (4a) to the volume (3)
It needs to be enclosed inside.

Therefore, in the device of the present invention, since this is not necessary, the volume (3) and the amount of response movement between the gas storage tank turns are reduced, the volume of the storage tank Ql is small, and the capacity of the compressor 03 is also small. Benefits accrue.

On the other hand, the dielectric strength characteristics are shown in FIG. 3(b). First, in the conventional device E4, since an extra gas is filled in the range of Oa to Ob, the dielectric strength exhibits a characteristic (2) with the minimum value at point d as shown by the curve a3+dc. In contrast, the device of the present invention exhibits flatter characteristics such as S a4 T d c, and is a form in which the excessive portions of the conventional device are rationally improved.

Furthermore, when the temperature of the mixed gas (4) decreases, the control device αυ is configured such that the pressure control operation is terminated after the gas pressure at the pressure control termination temperature Ob is raised to the upper limit pressure Pl (point bt).
If set, the subsequent pressure will change on the curve alrbl, so it will compensate for the reduction in insulation due to the vapor pressure of the refrigerant liquid (5) further decreasing from the small value P3 (BS point) remaining in ob. Thus, a higher dielectric strength can be ensured than when changing on the curve a2+bB.

Although the above embodiments have been described with respect to gas insulated transformers, it goes without saying that the present invention can also be applied to other magnetic induction devices such as gas insulated reactors. Further, although the case has been described in which the temperature is detected for the mixed gas (4), the same control operation can also be performed by detecting the temperature of the refrigerant liquid (5).

As explained above, this invention detects the temperature and pressure of the mixed gas in the volume and controls the pressure only at temperatures above a specified value, thereby maintaining the amount of gas used while maintaining the dielectric strength at a reasonable value. This has the advantage of reducing the volume of the gas storage tank, the capacity of the compressor, etc.

[Brief explanation of the drawing]

The eleventh factor is a schematic diagram of a conventional gas insulated transformer, FIG. 2 is a schematic diagram of a gas insulated transformer that is an embodiment of the present invention, and the third
The figure is an explanatory diagram of temperature characteristics of gas pressure and dielectric strength of a conventional device and the present invention. In the figure, (1) is a winding wire,
(February, iron core, (3) is customer type, (4) is gold gas production, (
5) is the refrigerant liquid, (10 is the gas storage tank, (l) is the control device, @, OQ is the gas pressure detector, o3 is the compressor, α.0η is the control valve, (1 is the gas temperature detector In each figure, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa Figure 2 Figure 3 (θ) (l!l, IO, bcyC, page 1) Continue ■Applicant Mitsubishi Electric Corporation 2-2-3 Marunouchi, Chiyoda-ku, Tokyo

Claims (3)

[Claims] (1) In a device that insulates and cools an electromagnetic induction device mainly consisting of windings and an iron core by storing it in a container filled with a non-condensable insulating gas and a condensable refrigerant, the above-mentioned container Pressure detection p1 that detects the pressure inside
3, a temperature detector for detecting the temperature of the mixed gas of the insulating gas and the refrigerant gas that has become a gas phase due to evaporation; The gas storage tank is connected to the gas storage tank via piping, control valves, compressors, etc., and the pressure in the six tanks is controlled within the specified pressure range by operating or operating the control valves, compressors, etc. and a control device for adjusting the temperature, and the control device is set to perform the pressure crab only when the temperature of the mixed gas in the container is above a specified temperature and below a maximum operating temperature. Magnetic induction equipment with insulation τ. (2) Pressure adjustment operating range 111 while the temperature of the mixed gas is decreasing
1. The gas according to claim 1, wherein the control device is set to stop the pressure adjustment operation after adjusting the pressure to the upper limit of the operating range of the pressure control device at the lower limit temperature of 1. Insulated electromagnetic induction equipment. (3) The gas-insulated electromagnetic induction device according to claim 1 or 2, characterized in that SF6 gas is used as the insulating gas and fluorocarbon C3F1r,0 is used as the refrigerant.