Connection structure of stationary induction motor

Abstract

To provide a connection structure of a stationary induction motor capable of suppressing heat generation without causing upsizing of equipment.SOLUTION: Included are: a main body tank storing a three-phase stationary induction motor; three phase ducts, one end of which is attached to the main body tank and which individually store three phase leads extracted from the stationary induction motor; one common duct connected to the other end side of each of the three phase ducts so as to connect the three phase ducts; a mating device attached to the common duct to connect the leads to other equipment; and a cooling mechanism including cooling piping connecting a cooling device of the stationary induction motor and the common duct, in which a cooling medium circulates between the main body tank and the cooling device through the three phase ducts and the one common duct.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a connection structure for a stationary induction machine. [Background technology]

[0002] In recent years, there has been an increase in cases where aging static induction equipment is replaced. In such cases, the environmental conditions have changed since the existing equipment was manufactured, transported, and assembled on-site, making it difficult to carry out the same processes and work as the existing equipment under the current conditions, and there are many cases where costs have increased. In particular, when the existing equipment is a shell-type static induction equipment used as a step-up transformer for a power plant, and a core-type static induction equipment is used for replacement, the position of the low-voltage side connection of the generator may differ significantly due to differences in the internal structure of the transformer.

[0003] In addition, even in newly constructed power plants, the configuration of the low-voltage terminal arrangement can result in a distance at the connection with the low-voltage terminal of the step-up transformer, resulting in a distance between the static induction equipment main tank and the low-voltage terminal connection point. Furthermore, typical installation locations that require high safety against accidents include hydroelectric power plants with strict environmental regulations and underground substations in large cities, and in recent years, there have been an increasing number of cases where gas-insulated static induction equipment, which does not have the risk of oil leakage or fire accidents, is used or newly installed when updating static induction equipment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7104550 Summary of the Invention [Problem to be solved by the invention]

[0005] If there is a distance between the low voltage terminal of a static induction electric device and the low voltage connection part of a power plant or substation, the low voltage terminal to the low voltage connection part is connected with an integrated duct or ducts separated for each phase (individual phase ducts). In a large capacity step-up transformer, the low voltage side is connected to the generator, and an extremely large rated current of several thousand amperes flows, and the magnetic flux generated by this large current penetrates the metal walls of various structures between the integrated duct, each phase duct, main tank, and connection point to external equipment, generating eddy currents that contribute to overheating, so it is necessary to increase the duct diameter and widen the cross section to prevent overheating.

[0006] Furthermore, if the duct length is long, an accessory part or stand is required to fix the position of the terminal and support the weight of the duct. Furthermore, when a gas-insulated static induction device is used as the static induction device and gas is inserted at a pressure higher than atmospheric pressure, there are many structural restrictions around the exterior of the static induction device's main housing manufactured in accordance with the pressure vessel standard corresponding to that pressure, and furthermore, the heat capacity of the SF6 gas cooling medium is approximately 1 / 3 that of oil, and there is a problem that the cooling capacity is lower than that of liquid cooling mediums such as insulating oil.

[0007] When the cross section of the duct is enlarged as a measure to reduce the magnetic flux entering the structure, it is necessary to make the opening where the duct connects to the main tank larger, but when the terminals for the three phases are pulled out through the same duct, it is necessary to enlarge the main tank and provide reinforcing parts at the opening in order to ensure the strength required for this opening. This results in higher costs and weight for the entire static induction device, reduced on-site installation space, and concerns about gas leaks from the joints.

[0008] The present invention has been made in response to the above-mentioned conventional circumstances, and its object is to provide a connection structure for a stationary induction motor that can suppress heat generation without increasing the size of the equipment. [Means for solving the problem]

[0009] The connection structure of a stationary induction electric appliance in one embodiment is characterized by having a main tank in which a three-phase stationary induction electric appliance is housed, three phase ducts each having one end attached to the main tank and each individually storing the three-phase leads drawn from the stationary induction electric appliance, a common duct connected to the other end of the three phase ducts to connect the three phase ducts, a connecting device attached to the common duct for connecting the leads to other equipment, and a cooling mechanism having cooling piping connecting a cooling device for the stationary induction electric appliance to the common duct, wherein a cooling medium circulates between the main tank and the cooling device via the three phase ducts and the common duct. Effect of the Invention

[0010] According to an embodiment of the present invention, it is possible to provide a connection structure for a stationary induction device that can suppress heat generation without increasing the size of the device. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic diagram showing the configuration of a connection structure of a stationary induction device according to the first embodiment; [Diagram 2] FIG. 11 is a schematic diagram showing an example of wiring of a low-voltage main circuit of a stationary induction device connection structure according to a second embodiment. [Diagram 3] FIG. 11 is a schematic diagram showing another example of wiring of the low-voltage main circuit of the stationary induction device connection structure according to the second embodiment. [Figure 4] FIG. 11 is a schematic diagram showing a configuration of a main part of a connection structure of a stationary induction device according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (First embodiment) FIG. 1 is a diagram showing the connection structure of a stationary induction motor according to the first embodiment, and is a schematic diagram showing an example of the arrangement of a series of structures required after lead wires are pulled out from a main tank that contains the contents of the three phases collectively.

[0013] Three phase ducts 2, each containing a low-voltage winding lead wire 10 (shown by dotted lines in FIG. 1) for each phase, are drawn out from the main tank 1 of the stationary induction electric device, which houses the internal structure (iron core, windings, etc.) of the stationary induction electric device for three phases (not shown). That is, one end (the lower end in FIG. 1) of each of the three phase ducts 2 is connected to the main tank 1. The lead wire 10 may be a stranded wire or a rod-shaped, plate-shaped, pipe-shaped or other conductor as necessary, and its shape is not important.

[0014] The other ends of the three phase ducts 2 (the upper ends in FIG. 1) are connected to a single common duct 3, and the lead wires 10 are adjusted in position and connected as necessary within the common duct 3, and then connected to an interface device 5 that is connected to external equipment such as a generator or power transmission line. If necessary, the phase ducts 2 and the common duct 3 are collectively referred to as a connection duct 4. The connection duct 4 is spatially continuous with the main tank 1, and shares the same cooling medium (oil, gas, etc.) as the main tank 1.

[0015] From the common duct 3, an upper cooler pipe 6 leading to the cooler 7 is drawn out and connected to the cooler 7. From the bottom of the cooler 7, a lower cooler pipe 8 is connected to the bottom of the main tank 1, and the cooling medium circulation path is structured to include the ducts 2 for each phase and the common duct 3. Note that, although the connection duct 4 is drawn out from the top surface of the tank in this example, it is also applicable to a stationary induction electric appliance in which the connection duct 4 is drawn out from a direction other than the top surface (such as the side surface). Also, FIG. 1 shows a case in which two coolers 7, an upper cooler pipe 6, and a lower cooler pipe 8 are provided on the left and right, but these may be provided one by one, or three or more, and the number is not limited.

[0016] In the first embodiment having the above configuration, the ducts 2 of each phase serve both as a joining point and as a supporting steel material for the common duct 3, so that the frame supporting the common duct 3 can be reduced or simplified, and the connection structure can be made smaller and lighter. In addition, since there is no need to provide a large opening in the main tank 1 for connection, the strength of the main tank 1 can be easily maintained, and the risk of leakage of the cooling medium of the stationary induction electric device can be reduced. In addition, by sharing the flow path of the cooling medium in the upper part of the main tank 1 with the connection duct 4, the cooling piping can be reduced. Furthermore, by using the connection duct 4 as the flow path of the cooling medium, the lead wire 10 of the low-voltage winding, which needs to pass a large current, and the connection duct 4 containing it can be efficiently cooled, and the rise in temperature due to heat generation can be suppressed.

[0017] Second embodiment 2 is a diagram showing the main configuration of the connection structure of a stationary induction electric appliance according to the second embodiment, and is a schematic diagram showing an example of low-voltage side wiring in the stationary induction electric appliance of the first embodiment. Lead wires 10 are connected to both terminals (u1, u2, v1, v2, w1, w2) of the low-voltage winding 9. The lead wires 10 are not connected inside the main tank 1, but are drawn out from the same low-voltage winding 9, i.e., two lead wires 10 connected to the u1 and u2, v1 and v2, and w1 and w2 terminals, respectively, passing through one of the ducts 2 for each phase and connected to the common duct 3.

[0018] The low voltage windings are delta connected, and connections for wiring are made inside the common duct 3, and are drawn out as three-phase AC terminals (u, v, w) by three connection devices 5. Alternatively, for example, as shown in Fig. 3, connections for wiring are not made inside the common duct 3, and the wires are drawn out by six connection devices 5, and are drawn out as three-phase AC terminals so that connections for wiring can be made outside. Note that the layout of the lead wires 10 inside the common duct 3 shown in Fig. 3 is one example for making it easy to assemble the wires after they leave the connection device 5, and the layout of the lead wires 10 can be other than that shown in Fig. 3.

[0019] In addition, in order to suppress heat generation due to magnetic flux, either or both of the common duct 3 and each phase duct 2 can be made of a metal (e.g., aluminum, etc.) with lower magnetic permeability than the metal (e.g., iron-based metal, etc.) that constitutes the main tank 1, or a shield made of a metal with low magnetic permeability (e.g., aluminum, etc.) can be installed on the inner surface of either or both of the common duct 3 and each phase duct 2.

[0020] The two lead wires 10 contained inside each phase duct 2 face each other at the minimum distance required for insulation and structure, supported by a support made of insulating material. This structure can also be applied to a static induction device in which multiple three-phase low-voltage circuits are simultaneously built into one static induction device.

[0021] According to the second embodiment having the above configuration, currents always flow in opposite directions through the two lead wires 10 installed adjacent to each other in each phase duct 2. Therefore, a magnetic flux generated clockwise from one of the two lead wires 10 and a magnetic flux generated counterclockwise from the other always exist with the same magnitude. As a result, the magnetic fluxes generated by the two lead wires 10 are cancelled out in areas other than those sandwiched between the lead wires 10.

[0022] Furthermore, since the current flowing through each lead wire 10 is the same as before it was connected to the delta connection, the magnetic flux generated from each lead wire 10 is also 1 / √3 times larger. These actions make it possible to suppress heat generation in each phase duct 2 due to eddy currents generated by the incidence of magnetic flux generated from the lead wires 10, and to make each phase duct 2 smaller. Also, as described above, each phase duct 2 and the common duct 3 can be made of a metal with low magnetic permeability (e.g., aluminum, etc.) as necessary, and by installing an electromagnetic shield made of a metal with low magnetic permeability (e.g., aluminum, etc.), it is possible to prevent incidence of magnetic flux, enabling further measures to suppress overheating.

[0023] Third embodiment Fig. 4 is a diagram showing the connection structure of the static induction device according to the third embodiment, and is a schematic diagram showing the insertion positions of the insulators required to prevent the generation of circulating current in the entire static induction device. In Fig. 4, the same reference numerals are attached to the parts corresponding to the connection structure of the static induction device shown in Fig. 1.

[0024] In the third embodiment, as shown in Fig. 4, a common duct stand 11 is provided between the main tank 1 and the common duct 3, and the common duct 3 is supported on the main tank 1 by this common duct stand 11. Note that, although not shown in Fig. 4, the third embodiment also has a cooling mechanism, which is composed of a cooler 7, upper cooler piping 6, lower cooler piping 8, etc., and circulates a refrigerant through the main tank 1, each phase duct 2, and common duct 3, as in the first embodiment.

[0025] In this third embodiment, an insulating plate 12 is inserted into the surface where the main tank 1 meets the common duct stand 11, which is a structure that supports the common duct 3 for the main tank 1, and an insulating spacer 13 is inserted into the flange surface that forms the boundary between the main tank 1 and each phase duct 2.

[0026] In the connection structure of the stationary induction electric appliance as shown in Fig. 4, when leakage magnetic flux generated in the lead wire 10 enters the common duct 3 and each phase duct 2, a current is generated. The generated current forms a circulating current along a closed circuit of a metal structure, for example, the main tank 1 - each phase duct 2 - common duct 3 - common duct stand 11 - main tank 1, and causes overheating of the duct and the main tank. In the third embodiment, by inserting an insulator such as an insulating plate 12 and an insulating spacer 13 into this circulation flow path, the formation of a closed circuit can be prevented, and the risk of overheating of the structure due to the circulating current can be suppressed.

[0027] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0028] 1...main tank, 2...each phase duct, 3...common duct, 4...connecting duct, 5...interface device, 6...upper cooler piping, 7...cooler, 8...lower cooler piping, 9...winding, 10...lead wire, 11...common duct stand, 12...insulating plate, 13...insulating spacer.

Claims

1. A main tank containing a three-phase static induction device; Three phase ducts, one end of which is attached to the main tank and which individually house three phase leads drawn from the stationary induction device; a common duct connected to the other end side of each of the three phase ducts so as to connect the three phase ducts; a connection device attached to the common duct for connecting the lead to other equipment; a cooling mechanism including a cooling pipe connecting the cooling device of the stationary induction machine and the common duct, in which a cooling medium circulates between the main tank and the cooling device through the three phase ducts and the one common duct; A connection structure for a stationary induction device, comprising:

2. The stationary induction machine has three windings, one for each phase, and includes two leads for each of the three windings, each of which is drawn out from both ends of the three windings, for a total of six leads. Two leads through which currents flow in opposite directions and are drawn from one of the windings of each phase are housed in the same duct for each phase; The six leads drawn out from the three phase ducts are aligned in the common duct and drawn out from the six connecting devices.

2. The stationary induction device connection structure according to claim 1.

3. The stationary induction machine has three windings, one for each phase, and includes two leads for each of the three windings, each of which is drawn out from both ends of the three windings, for a total of six leads. Two leads through which currents flow in opposite directions and are drawn from one of the windings of each phase are housed in the same duct for each phase; The six leads drawn out from the three phase ducts form a delta connection in the common duct and are drawn out from the three connecting devices.

2. The connection structure of the stationary induction device according to claim 1 .

4. Either or both of the phase ducts and the common duct are made of a metal having a lower magnetic permeability than the main tank.

4. A connection structure for a stationary induction device according to claim 1.

5. An electromagnetic shield made of a metal having a lower magnetic permeability than the main tank is attached to the inner surface of either or both of the phase ducts and the common duct.

4. A connection structure for a stationary induction device according to claim 1.

6. A spacer made of an insulating material is provided between the main tank and each of the phase ducts, and there is no electrical continuity between the main tank and each of the phase ducts.

4. A connection structure for a stationary induction device according to claim 1.

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