JPS6218014A - Evaporative cooling induction electric apparatus - 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 [Field of the Invention] The present invention relates to a separate type evaporative cooling induction electric appliance in which a non-condensable insulating gas and a condensable cooling medium are separated by a closed insulating container.

[Prior art and its problems]

In recent years, there has been an increasing demand for high-voltage, large-capacity transformers, reactors, and other induction appliances to be non-flammable and flame-retardant, mainly from the standpoint of disaster prevention. Fluorocarbon with condensing properties.

Evaporative cooling induction electric appliances that use condensate such as chlorofluorocarbon as a cooling medium and insulating gas such as SF or gas as an insulating medium are attracting attention, and compared to insulating oil, they use much less expensive cooling medium and can be cooled. There is a need for induction electric appliances that have excellent performance and can be used at high voltages.

FIG. 5 is a schematic side sectional view showing an example of an evaporative cooling induction electric appliance, and FIG. 6 is a schematic side sectional view showing an example of an evaporative cooling induction electric appliance of a dispersion type and FIG. 6 of a separate type. In the case of the condensate dispersion type, the disk winding 6, which is housed in a tank 1 containing a cooling medium 10 and an insulating gas 9 and is made up of a plurality of sexy coils 4 wound around an iron core 2 and an inter-section duct 7, is a winding. The condensate is stored in an insulating container 5 formed to surround the condensate, and is transferred via condensate transfer means 11 to 13 to a dispersion device 14 disposed above the iron core 2, where it is dispersed through small holes 15t. Liquid flow 10A of condensate 10
As a result, the iron core 2 is evaporatively cooled, and the insulating container 5
The disk winding immersed in the condensate 10 stored in the condensate is cooled by the latent heat of vaporization of the condensate, and the vapor 1 of the condensate is vaporized.
0B is configured to be condensed again in a condenser 6 and returned to the bottom of the tank 1.

In the dispersion-type evaporative cooling induction electric appliance configured as described above, the iron core and the winding can be simultaneously and efficiently evaporatively cooled without causing liquid drying up.
Since the condensate is distributed over multiple locations, the amount of expensive condensate used is large, resulting in an economic disadvantage.In addition, since winding cooling relies only on the latent heat of vaporization of the condensate, the winding temperature does not reach the boiling point temperature of the cooling medium. In addition, as the electrical load of the induction appliance increases, a large amount of bubbles are generated in the insulation tank 5, and the withstand voltage performance of the winding 6 is reduced.

On the other hand, in the separate type shown in FIG.
is stored in a sealed insulating container 25, and a pair of upper and lower circulation passages 2
The condensate 1 is connected to the circulation pump 21 and the heat exchanger 26 via 2.23, and is enclosed so that the winding 6 is immersed in the closed circulation system including the sealed insulating container 25, the heat exchanger 26, etc.
The condensate 100 is formed to separate the insulating gas 9 contained in the tank 1 from the insulating gas 9 contained in the tank 1, and the condensate 100 circulates between the sealed insulating container 25 and the heat exchanger 26 by the pump 21. It is configured to cool the winding f113. Therefore, the amount of condensate used can be reduced, and the sensible heat and latent heat of the condensate can be used to cool the windings, and there are fewer restrictions on the boiling point temperature of the cooling medium.
There is an advantage that an advantageous cooling medium can be selected by comprehensively evaluating cooling performance and price.

By the way, in general, the withstand voltage performance of a condensable cooling medium is high in the liquid phase and low in the gas phase, so whether the winding is a distributed type or a separate type, the winding with many localized electric field concentration parts is It has the advantage that an induction electric appliance can be obtained which can be immersed in liquid phase insulation and can be wound with less local electric field concentration.

However, as the condensate in which the windings are immersed boils, the area near the windings becomes a mixture of gas and liquid insulation, which goes against the improvement of cooling performance and reduces withstand voltage performance. This has the disadvantage that increasing the voltage is hindered.

4 and 7 are side sectional views of the main parts showing the above-mentioned characteristics, and
The inner and outer peripheral side of the disc winding consisting of the sexy winding coil 4 and the inter-section duct 7 is housed in an insulating container 5t or 15 to hold the axial duct 8, and the condensate 10 is contained in the container. It is assumed that the space outside the container is filled with insulating gas 9. When voltage is applied to the windings in such a state, an electric field is locally concentrated at the corner of the section coil 40 due to the potential difference between the section coils and the ground potential of the section coil, and the condensate near the corner is 1
A high electric field portion occurs at the 00 portion. Now, the temperature of the coil increases due to the current flowing through the winding, and the condensate 1
When the boiling point temperature of 0 is exceeded, the condensate in contact with the surface of the steam coil 4 begins to boil, and the vaporized vapor becomes bubbles that travel along the bottom and side surfaces of the steam coil and float to the axial duct 8. During the process in which the air bubbles gather and float in the axial duct, the air bubbles 10D grow, and a state as shown in the figure appears in which the air bubble density is high at the corner of the section coil located above in the axial direction. In such a state, the bubble 10D is exposed to a high electric field, or because its dielectric constant is smaller than that of the condensate, the electric field is further concentrated on the bubble based on the principle of capacitance partial pressure. There is a risk that spark discharge will occur in the bubbles, which have a lower voltage strength than the liquid phase, and this will trigger an insulation accident such as dielectric breakdown between the section coils. This is a serious weakness that hinders higher voltage.

In addition, as shown in Fig. 5, the condensate 1 in the insulating tank 5 is
By applying the pressure of the insulating gas 9 to the liquid level of 0°, it is expected that the steam bubbles 10 will be crushed and the withstand voltage strength will increase. The withstand voltage strength of the gas phase that can be achieved by adding hydrogen is only about twice that of the liquid phase, and there is a problem that the influence of vapor bubbles cannot be eliminated, so further improvement is required. .

[Purpose of the invention]

The present invention has been made in view of the above-mentioned situation, and it eliminates the influence of vapor bubbles generated due to boiling of condensate on the withstand voltage performance of the winding, and therefore provides a separate type evaporator with excellent withstand voltage performance. The purpose is to provide cooling induction appliances.

[Key points of the invention]

The present invention provides an airtight enclosure that surrounds and accommodates the windings and is formed to communicate with a heat exchanger installed externally in a tank through a pair of upper and lower circulation passages, and stores enough condensed liquid of a cooling medium to immerse the windings. an insulating container, and an insulating container, and a communication pipe disposed substantially coaxially with the container and the winding to maintain a separation distance between the container and the winding, respectively, through a communicating pipe. a double insulating container consisting of an inner insulating container formed to communicate with the heat exchanger; and distribution holes for the condensate formed in a side plate of the inner insulating container so as to communicate with both axial passages; It is equipped with a circulation passage and a flow rate regulating valve disposed at least on the outlet side of the communication pipe, and when the induction electric equipment is under light load, condensed liquid is circulated within the winding in the inner insulating container to perform sensible heat cooling. When the load is heavy, by adjusting the flow control valve, the condensate that has flowed into the inner insulated container is guided into the axial passage of the outer sealed insulated container through the communication hole and circulated to the heat exchanger side via the communication pipe. With this structure, when the induction electric appliance is under heavy load, the steam bubbles generated when the condensate near the @ line boils are immediately sent to the shaft of the outer hermetically insulated container through the flow holes close to the bubble generating part along with the condensate. Since the vapor bubbles are guided by the directional passage and away from the vicinity of the windings, it is possible to eliminate the vapor bubbles present in the high electric field part at the corner of the section coil, and also to prevent the bubbles from accumulating near the section coil located at the upper position in the axial direction. Therefore, it is possible to prevent deterioration in voltage resistance performance due to vapor bubbles.

[Embodiments of the invention]

The present invention will be explained below based on examples.

FIG. 1 is a schematic side sectional view showing an embodiment of the present invention. In the figure, a winding 6 wound around an iron core 2 housed in a tank 1 containing an insulating gas 9 such as SF or gas is a condensate of a condensable cooling medium such as 70% carbon or fluorocarbon.
&: Airtight insulating container 35 formed airtight so that it can be stored.
and an inner insulating container disposed inside this sealed insulating container 65 and formed to maintain a separation distance between the sealed insulating container 65 and the winding 3 to form axial passages 38 and 39 for the condensate 10, respectively. It is housed in a double insulated container consisting of 66. Further, the sealed insulating container 35 is connected to a heat exchanger 26 provided externally to the tank 1 via a pair of upper and lower circulation passages 32A, 32B, and an upper circulation passage 52.
A is provided with a flow rate regulating valve 31A, and an inner insulating container 66
communicates with the axial passage 69 on the anti-winding side through a plurality of communication holes 37 distributed and formed in the side plate, and its upper end communicates with the heat exchanger 26 via the communication pipe 33 and the flow rate adjustment valve 31B. A liquid supply/drainage valve 43 is provided at the lower end. Therefore, the condensate 10 is transferred to a closed insulating container 66, a heat exchanger 26. The insulating gas 9 in the tank 1 circulates in a closed circuit consisting of a circulation pump 21, a circulation passage, and a communication pipe.
The winding A is electrically insulated near the winding by a double insulating container and the condensate 10 stored therein, and by an insulating gas 9 in the part away from the winding 6.
is held by.

In the evaporative cooling induction electric appliance configured as described above, when the electrical load is light and the winding temperature is lower than the boiling point of the condensate, the flow rate adjustment valve 31B is closed and the valve 31A on the circulation passage side is opened. Therefore, the condensate 10 is transferred to the inner insulating container 3.
The insulation in the vicinity of the windings is made of condensate with high voltage strength and does not contain vapor bubbles. It is held by the liquid 10 and high withstand voltage performance can be obtained.

Next, when the electrical load on the induction device increases and the winding temperature exceeds the boiling point temperature of the condensate, the flow rate adjustment valve 51A on the circulation path 52A side is almost closed, and the flow rate adjustment valve 31B on the communication pipe 33 side is closed. By almost fully opening the
Since it is possible to apply a radial component force to the condensate 10 that has flowed into the axial passage 38 of the inner insulating container 36 from the lower circulation passage 32B and guide it to the axial passage 390111 through the circulation hole 67, each of the windings 6 The vapor bubbles generated by the cefsilane coil can be discharged along with the condensate to the axial passage 39 side on the side opposite to the winding by using the radial component force. Therefore, the side plate of the inner insulating container 36 has a communication hole large enough to allow steam bubbles to pass through! By forming +7 distributed in the axial and radial directions, steam bubbles in the axial passage 38 on the winding side in contact with the corners of the sexy coil can be quickly eliminated, so that the steam It is possible to prevent deterioration in voltage resistance performance due to air bubbles.

FIG. 2 is an explanatory diagram showing the state of steam bubbles in the above-mentioned embodiment. As it flows into the axial passage 39, the steam bubbles 10 are
D flows out from the flow hole toward the axial passage 39, and the liquid stream 20 of condensate containing vapor bubbles is led to the heat exchanger through the axial passage 59. Since the axial passage 39 is located away from the high electric field section 1QC, there is no risk of spark discharge occurring during aeration, and the amount and size of bubbles in the high electric field section 10C are significantly reduced. It is possible to significantly improve the voltage resistance performance of the winding.

In addition, the air bubbles generated in each cefsilane coil can be discharged from the distribution holes formed laterally and can be prevented from accumulating and staying at the corner of the cefsilane coil located axially upper in the axial passage 38. , the flow velocity of the condensate in the axial passage 38 is slow on the downstream side, whereas it becomes faster on the axial passage 39 side.
Since the suction action to draw the steam to the 9 side can be automatically generated, steam bubbles can be eliminated more effectively.

In addition, if a variable volume part such as a bellows is provided in the circulation passage or the communication pipe in FIG.
The internal pressure of the steam bubbles can be increased, and the withstand voltage performance can be further improved. In addition, the flow rate adjustment valves 31A, 3
By configuring 1B to be controlled based on the output signal from a detector that detects the load state of the induction electric device, such as a current transformer, it is possible to save labor for switching work and to efficiently perform sensible heat cooling and boiling cooling. I can do it.

FIG. 5 is a side sectional view of a main part showing a different embodiment of the present invention, in which the axial passage 3 between the inner insulating container 46 and the winding 3 is shown.
Liquid stopper 49 that closes 8 for each plurality of sex coils 4
are provided alternately on the inner diameter side and the outer diameter side in the axial direction of the winding 3 to cause the condensate 10 to flow in a zig-zag pattern in the duct 7 between the sectors 1 and 2, and to control the flow in the duct 7 between the sectors 1 and 1. This embodiment differs from the previous embodiment in that the communication holes 47 are formed in a distributed manner in the side plate portion of the inner insulating container 36 on the side opposite to the downstream side.

FIG. 4 is an explanatory diagram showing the state of steam bubbles in the above-mentioned embodiment. By flowing the condensate in a zig-zag pattern through the inter-section duct 7, a radial component force is forced on the flow of the condensate. The steam bubbles 10D can be quickly discharged to the axial passage 69 side through the distribution holes 47 formed in the downstream side plate that directly receives the component force of this flow. Not only the steam bubbles attached to the lower surface of 4, but also the steam bubbles near the high electric field part 10G are eliminated as soon as they grow, aggregate, and the deterioration of withstand voltage performance due to steam bubbles is more effectively prevented. can do.

〔Effect of the invention〕

As described above, the present invention includes a closed insulating container formed to store windings and condensate separately from an insulating gas space and communicate with a heat exchanger via a pair of upper and lower circulation passages and a flow rate regulating valve; Inside the container, the container and each of the windings are arranged to maintain a distance that should form an axial passage for the condensate, and the side plate has distribution holes that communicate with both axial passages. At the same time, a double insulating container is provided with an inner insulating container whose upper end is formed to communicate with the heat exchanger via a communication pipe and a flow rate adjustment valve, and when the induction electric equipment is under a light load, the flow rate on the circulation path side is adjusted. When the valve is mainly opened, the condensate circulates in the axial direction inside the inner insulating container, and sensible heat cooling is performed.When the load is heavy, the flow rate adjustment valve on the communication pipe side is mainly opened, and the condensate flows through the circulation hole. As a result, during sensible heat cooling, the high electric field area near the windings is insulated by the condensate liquid with high withstand voltage strength, and during heavy loads, As the condensate moves radially through the flow holes, a radial component force is generated in the flow of the condensate, and the vapor bubbles generated by the boiling of the condensate on the coil surface of each section of the winding are circulated. The withstand voltage of the winding caused by the presence of many vapor bubbles in the high electric field area near the corner of the cefsilane coil can be discharged through the hole to the axial passage side of the closed insulating container where there is less local electric field concentration. can prevent performance deterioration,
It is possible to provide an evaporative cooling induction electric appliance that has high insulation reliability and is capable of increasing voltage.

In addition, the flow velocity of the condensate in the axial passages on the winding side and the anti-winding side, which are connected to each other through the circulation hole, is lower on the winding side and higher on the anti-winding side as it goes downstream, so This naturally causes steam bubbles to be sucked out to the axial passage side on the side opposite to the winding, and therefore steam bubbles tend to accumulate near the axially upper section coil, reducing the withstand voltage performance. This provides the advantage of eliminating the conventional problem of large size. Furthermore, if the condensate is made to flow in a zig-zag pattern in the duct between sections of the winding, and a communication hole is provided on the downstream side of the duct, the radial direction of the flow of the condensate may be reduced. Since the force can be increased, steam bubbles can be more actively discharged, and there is an advantage that deterioration in voltage resistance performance due to steam bubbles can be more effectively prevented.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing an embodiment of the present invention, Fig. 2 is an explanatory diagram showing the state of steam bubbles, Fig. 5 is a side sectional view of main parts showing a different embodiment, and Fig. 4 is a steam bubble. Fig. 5 is a side sectional view showing an example of a conventional scatter type evaporative cooling induction appliance, Fig. 6 is a side sectional view showing an example of a separate type, and Fig. 7 is a vapor bubble in the conventional technology. It is an explanatory view showing a state. 1...tank, 2...iron core, 6...winding, 4...
・Section coil, 5...Insulating container, 7...Top 2
212 duct, 9... Insulating gas, 10... Condensate, 10C... High electric field part, 10D... Steam bubble, 20
... Condensate containing bubbles, 21 ... Circulation pump, 2
5.35... Sealed insulated container, 26... Heat exchanger, 3
6.46... Inner insulating container, 57.47... Communication hole, 38... Axial passage (winding side), 39... Axial passage (counter-winding side), 31A, 51 B -fflt!
J4 valve control, 22.23.52A. 32B... Circulation passage, 35... Communication pipe, 49...
Liquid stop 4 Fig. 2 Fig. 13 Fig. 4 Fig. 5 Fig. 6 Fig. 7

Claims (1)

[Scope of Claims] 1) A winding wound around an iron core and housed in a tank having an external heat exchanger and containing an insulating gas, and a winding that surrounds and houses this winding and is connected via a circulation passage. The device includes a sealed insulating container communicating with the heat exchanger, and the winding is cooled by a condensed liquid of an insulating medium circulating through the sealed insulating container and the heat exchanger, wherein a sealed insulating container and a closed insulating container are provided inside the sealed insulating container. an inner insulating container formed to maintain an axial passage between the windings and the heat exchanger via a communication pipe, and a side plate of the inner insulating container having the sealed insulating container 1. An evaporative cooling induction electric appliance characterized by comprising: a plurality of liquid introducing holes distributed and formed so as to communicate with each other; and a flow rate regulating valve provided in the circulation passage and the communication pipe. 2) In the product described in claim 1, the winding is composed of a layered assembly of a flat ring-shaped section coil and an inter-section duct, and the winding is arranged alternately on the inner diameter side and the outer diameter side of the section coil for each of the plurality of section coils. An evaporative cooling induction electric appliance characterized in that it is equipped with a liquid stopper and that communication holes are distributed in a side plate of an inner sealed container in a portion facing the downstream side of condensate flowing in a zig-zag pattern in an inter-section duct. 3) The evaporative cooling induction electric appliance according to claim 1, characterized in that the flow rate regulating valves provided in each of the circulation passage and the communication pipe are controlled by an output signal of a load information detection means of the induction electric appliance. .