Electromagnetic shielding type air-core reactor

Abstract

To provide an electromagnetically shielded air-core reactor that can be used in a circuit in which AC and DC voltages or currents are superimposed each other and enables the manufacturing cost thereof to be reduced.SOLUTION: An electromagnetically shielded air-core reactor 300 includes: a first coil 302; a second coil 314; a first electromagnetic shield 304 located on the side of the first coil and the second coil; a second electromagnetic shield 306 arranged above the first coil; a third electromagnetic shield 308 arranged below the second coil, a tank 310; and an insulating oil 312 housed in the tank, the first coil is arranged vertically above the second coil at a predetermined distance from the second coil. As a result, an electromagnetically shielded air-core reactor can be used in a circuit in which AC and DC voltages or currents are superimposed each other, and the manufacturing cost of the electromagnetically shielded air-core reactor can be reduced.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an electromagnetic shielding type air-core reactor having an electromagnetic shield for shielding a magnetic flux (magnetic field) formed by an alternating current flowing through an air-core coil.

Background Art

[0002] In various electric circuits, reactors are used for various purposes. Among them, an air-core reactor may be used in an alternating current circuit.

[0003] For example, Patent Document 1 below discloses an air-core reactor having an electromagnetic shield (hereinafter also referred to as an electromagnetic shielding type air-core reactor). In this air-core reactor, a conductive electromagnetic shield is disposed around an air-core coil that is an inductor, and a magnetic field generated by an alternating current flowing through the coil is canceled by a reverse magnetic field generated by eddy currents flowing through the electromagnetic shield due to electromagnetic induction action, thereby suppressing the leakage of the magnetic field to the outside from the electromagnetic shield.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] The electromagnetic shielding type air-core reactor as disclosed in Patent Document 1 is assumed to be used in a circuit where only an alternating current flows, and its use in a circuit where a direct current flows is not assumed. Therefore, in a circuit where a direct current flows, the operation of the electromagnetic shielding type air-core reactor has not been verified.

[0006] In a circuit (for example, a DC power transmission circuit) where an alternating current and a direct current are superimposed, it is preferable if an electromagnetic shielding type air-core reactor manufactured for an alternating current circuit can be used. The circuits used for DC power transmission are disclosed in, for example, Patent Documents 2 to 4 above.

[0007] Also, depending on the circuit, it may be necessary to use a plurality of electromagnetic shielding type air-core reactors. Therefore, in such a case, it is preferable if the manufacturing cost can be reduced.

[0008] Accordingly, an object of the present invention is to provide an electromagnetic shielding type air-core reactor that can be used in a circuit where an alternating voltage or current and a direct voltage or current are superimposed. Another object of the present invention is to provide an electromagnetic shielding type air-core reactor that can reduce the manufacturing cost.

Means for Solving the Problems

[0009] The electromagnetic shielding type air-core reactor according to the first aspect of the present invention includes a coil, a conductive member disposed around the coil, a housing member that houses the coil and the conductive member, and a liquid insulating member housed in the housing member. An alternating voltage or current and a direct voltage or current are superimposed and applied to the coil.

[0010] Thereby, the electromagnetic shielding type air-core reactor can be used in a circuit where an alternating voltage or current and a direct voltage or current are superimposed.

[0011] The electromagnetic shielding type air-core reactor according to the second aspect of the present invention includes a first coil, a second coil, a conductive member disposed around the first coil and the second coil, a housing member that houses the first coil, the second coil, and the conductive member, and a liquid insulating member housed in the housing member. The first coil is disposed vertically above the second coil with a predetermined interval from the second coil. The conductive member has a cylindrical member disposed on the side portions of the first coil and the second coil, a first plate-like member disposed above the first coil, and a second plate-like member disposed below the second coil.

[0012] As a result, compared with the prior art, components can be shared and omitted, manufacturing man-hours and manufacturing costs can be reduced. Also, the height can be made lower than before, it can be miniaturized, and transportation and installation become easier.

[0013] The electromagnetic shielding type air-core reactor according to the third aspect of the present invention includes two units, a housing member that houses the two units, and a liquid insulating member housed in the housing member. Each of the two units has a coil and a conductive member disposed around the coil. The two units are juxtaposed in the horizontal direction.

[0014] As a result, compared with the prior art, components can be shared and omitted, manufacturing man-hours and manufacturing costs can be reduced.

[0015] The electromagnetic shielding type air-core reactor according to the fourth aspect of the present invention includes three units, a housing member that houses the three units, and a liquid insulating member housed in the housing member. Each of the three units has a first coil, a second coil, and a conductive member disposed around the first coil and the second coil. The first coil is disposed vertically above the second coil with a predetermined interval from the second coil. The conductive member has a cylindrical member disposed on the side portions of the first coil and the second coil, a first plate-like member disposed above the first coil, and a second plate-like member disposed below the second coil. The three units are juxtaposed in the horizontal direction.

[0016] As a result, compared with the prior art, components can be shared and some components can be omitted, thereby reducing the manufacturing man-hours and manufacturing costs. Also, the height can be made lower than before, enabling miniaturization and reducing the installation space.

[0017] The electromagnetic shielding type air-core reactor according to the fifth aspect of the present invention includes six units, a housing member that houses the six units, and a liquid insulating member that is housed in the housing member. Each of the six units has a coil and a conductive member disposed around the coil. The six units are juxtaposed in the horizontal direction.

[0018] As a result, components can be shared and some components can be omitted, thereby reducing the manufacturing man-hours and manufacturing costs.

Advantages of the Invention

[0019] According to the present invention, the electromagnetic shielding type air-core reactor can be used in a circuit where AC and DC voltages or currents, such as in a DC power transmission circuit, are superimposed.

[0020] By housing a plurality of electromagnetic shielding type air-core reactors in one housing member (tank), compared with the prior art, components can be shared and some components can be omitted, thereby reducing the manufacturing man-hours and manufacturing costs.

[0021] Also, the height can be made lower than before, enabling miniaturization. Therefore, transportation and installation become easier, and the installation space can be reduced.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0023] In the following embodiments, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0024] (Configuration of Electromagnetic Shielding Type Air-Core Reactor) Referring to FIGS. 1 to 3, the electromagnetic shielding type air-core reactor 100 according to an embodiment of the present invention includes a coil 102, a first electromagnetic shield 104 disposed on the side of the coil 102, a second electromagnetic shield 106 disposed above the coil 102, a third electromagnetic shield 108 disposed below the coil 102, a tank 110, and insulating oil 112 filled in the tank 110. The electromagnetic shielding type air-core reactor 100 also includes a member (not shown) for supporting and fixing each component accommodated in the tank 110.

[0025] The coil 102 is a coil for ensuring a predetermined reactance against an alternating current of a fundamental wave (for example, 50 Hz or 60 Hz) and a harmonic alternating current generated by an alternating current system or an AC-DC converter that converts alternating current and direct current. The coil 102 is, for example, an air-core coil in which a conductive wire is wound multiple times to form a cylindrical shape (for example, a circular cylindrical shape).

[0026] The first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 are for preventing a time-varying magnetic flux (hereinafter also referred to as an alternating magnetic flux) formed by an alternating current flowing through the coil 102 from leaking to the surroundings. When the alternating magnetic flux leaks around the coil 102, eddy currents are generated in the surrounding conductive members, causing heat generation.

[0027] The first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 are formed of a non-magnetic member with high conductivity (for example, aluminum) and are electrically grounded. The first electromagnetic shield 104 is formed in a cylindrical shape (for example, a circular cylindrical shape) that is higher than the coil 102 and is arranged to accommodate the coil 102. The second electromagnetic shield 106 and the third electromagnetic shield 108 are formed in a plate shape (for example, a disk shape) with a predetermined thickness. The second electromagnetic shield 106 is arranged near one of the two openings of the cylindrical first electromagnetic shield 104, and the third electromagnetic shield 108 is arranged near the other opening. The coil 102, the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 are preferably arranged so that their axes coincide.

[0028] When an alternating magnetic flux is formed at the position of the conductive member, a current (eddy current) is generated within a shallow range from the surface of the conductive member so that the magnetic flux does not pass through the inside of the conductive member (so as to cancel the magnetic flux inside the conductive member). Therefore, the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 can suppress the leakage of the alternating magnetic flux formed by the coil 102 to the outside of the space accommodating the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108. Thereby, heat generation in the tank 110 described later can be suppressed.

[0029] Note that the first electromagnetic shield 104 may be formed by a plurality of short - circuit coils. Each short - circuit coil is formed by winding a wire a plurality of times in the height direction and the diameter direction of the cylindrical first electromagnetic shield 104, and both ends of the wire are electrically connected (see, for example, Patent Document 1). The first electromagnetic shield 104 is formed by, for example, 20 to 30 short - circuit coils.

[0030] The tank 110 is a hermetic container for accommodating the coil 102, the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108, and is formed of a member such as iron, for example. The inside of the tank 110 is filled with insulating oil 112 for electrical insulation and cooling. The filling of the insulating oil 112 is performed in a state where the inside of the tank 110 accommodating the coil 102, the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 is evacuated in order to prevent the insulating oil 112 from deteriorating due to oxidation. Note that the insulating oil 112 is not limited to oil, and any insulating material in a liquid state at normal temperature may be used.

[0031] Note that the electromagnetic - shielding type air - core reactor 100 includes an oil - volume adjusting device (not shown) for coping with deposition changes due to temperature changes of the insulating oil 112, a mechanical protection device (not shown), and the like. The mechanical protection device is, for example, a pressure - releasing device for reducing pressure when a short - circuit accident occurs inside the tank 110 and the internal pressure rises.

[0032] The electromagnetic shielding type hollow reactor 100 is used in a circuit (hereinafter referred to as an AC / DC superposition circuit) in which AC and DC voltages or currents that are used in a known DC power transmission system or the like are superimposed. DC power transmission has characteristics such as being suitable for long-distance power transmission because it transmits only active power and enables system connection (asynchronous connection) at different fundamental frequencies (for example, 50 Hz / 60 Hz). Note that the AC / DC superposition circuit includes not only circuits used in DC power transmission between regions with different fundamental frequencies but also circuits used in DC power transmission within a region with the same fundamental frequency.

[0033] Referring to FIG. 4, the AC magnetic flux F1 is a magnetic flux formed when an AC current flows through the coil 102, and the DC magnetic flux F2 is a magnetic flux formed when a DC current flows through the coil 102. The magnetic flux direction (magnetic field direction) of both is indicated by an arrow. The magnetic flux direction of the DC magnetic flux F2 does not change with time, but when the direction of the AC current flowing through the AC magnetic flux F1 reverses, the magnetic flux direction reverses. Therefore, as described above, the AC magnetic flux F1 is shielded by the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 and is not formed at the position of the tank 110. On the other hand, since the DC magnetic flux F2 does not change with time, it cannot be shielded by the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 and is also formed at the position of the tank 110. However, since the DC magnetic flux F2 does not change with time, it does not generate eddy currents in the tank 110, and heat generation due to the DC magnetic flux F2 does not occur. By forming the tank 110 of a ferromagnetic material such as iron, the magnetic flux can be concentrated inside the wall surface of the tank 110 so that the DC magnetic flux F2 does not leak to the outside of the tank 110.

[0034] According to the circuit to be used, the inductance of the electromagnetic shielding type air-core reactor 100 is appropriately designed. The proportionality constant between the current flowing through the coil 102 and the magnetic flux generated thereby is the inductance, and the greater the magnetic flux generated, the greater the inductance of the coil. Since the electromagnetic shielding type air-core reactor 100 is used in an AC-DC superposed circuit, it will have different inductances in the cases of AC and DC. In the case of AC, to some extent, the AC magnetic flux is cancelled out by the electromagnetic shields (the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108), so the inductance of the reactor is the value obtained by subtracting the reduction amount due to the electromagnetic shields from the value of the coil 102 itself. On the other hand, in the case of DC, since the electromagnetic shields (the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108) have no influence, the inductance of the reactor coincides with the inductance of the coil 102 itself.

[0035] As described above, the electromagnetic shielding type air-core reactor 100 shown in FIGS. 1 to 3 can be used not only in an AC circuit but also in an AC-DC superposed circuit. The electromagnetic shielding type air-core reactor 100 can be used, for example, in the circuit shown in FIG. 5.

[0036] Referring to FIG. 5, one end of the first reactor 200 is connected to the first terminal 220, the other end of the first reactor 200 is connected to one end of the second reactor 202 at the first node 232, and the other end of the second reactor 202 is connected to the second terminal 222. Similarly, one end of the third reactor 204 is connected to the third terminal 224, the other end of the third reactor 204 is connected to one end of the fourth reactor 206 at the second node 234, and the other end of the fourth reactor 206 is connected to the fourth terminal 226. One end of the fifth reactor 208 is connected to the fifth terminal 228, the other end of the fifth reactor 208 is connected to one end of the sixth reactor 210 at the third node 236, and the other end of the sixth reactor 210 is connected to the sixth terminal 230. The electromagnetic shielding type air-core reactor 100 shown in FIGS. 1 to 3 can be used for each of the first reactor 200 to the sixth reactor 210.

[0037] The circuit shown in Fig. 5 can be connected via the first terminal 220 to the sixth terminal 230 and a circuit composed of electrical components (such as a switching element, a rectifying element, a filter element, etc.) arranged around it. Three-phase alternating currents I1 to I3 are supplied from the power supply 240 to the first node 232, the second node 234, and the third node 236, respectively. The alternating current I1 is branched at the first node 232, and a current of 1 / 2 of the alternating current I1 flows through each of the first reactor 200 and the second reactor 202. Similarly, a current of 1 / 2 of the alternating current I2 flows through each of the third reactor 204 and the fourth reactor 206, and a current of 1 / 2 of the alternating current I3 flows through each of the fifth reactor 208 and the sixth reactor 210. Also, a direct current I4 flows between the first terminal 220 and the second terminal 222 through the first reactor 200 and the second reactor 202. Similarly, a direct current I5 flows between the third terminal 224 and the fourth terminal 226 through the third reactor 204 and the fourth reactor 206, and a direct current I6 flows between the fifth terminal 228 and the sixth terminal 230 through the fifth reactor 208 and the sixth reactor 210. Therefore, an alternating current and a direct current are superimposed and flow through each of the first reactor 200 to the sixth reactor 210.

[0038] (First Modification Example) In the above, the case where the electromagnetic shielding air-core reactor 100 is used for the first reactor 200 to the sixth reactor 210 in the circuit of Fig. 5 has been described, but the electromagnetic shielding air-core reactor 300 shown in Fig. 6 may also be used. Referring to Fig. 6, the electromagnetic shielding air-core reactor 300 includes a first coil 302, a second coil 314, a first electromagnetic shield 304 arranged on the side portions of the first coil 302 and the second coil 314, a second electromagnetic shield 306 arranged above the first coil 302, a third electromagnetic shield 308 arranged below the second coil 314, a tank 310, and insulating oil 312 filled in the tank 310. The electromagnetic shielding air-core reactor 300 also includes a member (not shown) for supporting and fixing each component housed in the tank 310.

[0039] The first coil 302 and the second coil 314 are each formed in the same manner as the coil 102 described above. The first coil 302 and the second coil 314 are formed to have the same size and the same shape (i.e., using the same type of conductive wire, having the same winding direction, and the same number of turns). The first electromagnetic shield 304, the second electromagnetic shield 306, and the third electromagnetic shield 308 are each formed and arranged in the same manner as the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 described above. Further, the tank 310 is formed in the same manner as the tank 110 described above and is filled with insulating oil 312.

[0040] For example, an electromagnetic shielding type air-core reactor 300 can be used for each of the pair of the first reactor 200 and the second reactor 202, the pair of the third reactor 204 and the fourth reactor 206, and the pair of the fifth reactor 208 and the sixth reactor 210 in FIG. 5. In that case, in the electromagnetic shielding type air-core reactor 300 used as the pair of the first reactor 200 and the second reactor 202, one end of the first coil 302 is connected to a first terminal (corresponding to the first terminal 220 in FIG. 5) that can be connected from the outside of the electromagnetic shielding type air-core reactor 300, the other end of the first coil 302 is connected to one end of the second coil 314, and is connected to a second terminal (corresponding to the first node 232 in FIG. 5) that can be connected from the outside of the electromagnetic shielding type air-core reactor 300, and the other end of the second coil 314 may be connected to a third terminal (corresponding to the second terminal 222 in FIG. 5) that can be connected from the outside of the electromagnetic shielding type air-core reactor 300. In the electromagnetic shielding type air-core reactor 300 used as the pair of the third reactor 204 and the fourth reactor 206, it is sufficient that the first to third terminals respectively correspond to the third terminal 224, the second node 234, and the fourth terminal 226 in FIG. 5. In the electromagnetic shielding type air-core reactor 300 used as the pair of the fifth reactor 208 and the sixth reactor 210, it is sufficient that the first to third terminals respectively correspond to the fifth terminal 228, the third node 236, and the sixth terminal 230 in FIG. 5.

[0041] The magnetic fluxes formed by the first coil 302 and the second coil 314 in FIG. 6 are shown in FIGS. 7 and 8. FIGS. 7 and 8 show two types of magnetic flux patterns that can be formed by the arrangement and connection of the first coil 302 and the second coil 314. Referring to FIG. 7, an alternating magnetic flux F3 is formed when an alternating current flows through the first coil 302, and an alternating magnetic flux F4 is formed when an alternating current flows through the second coil 314. On the other hand, a direct magnetic flux F5 and a direct magnetic flux F6 are formed when a direct current flows through the first coil 302 and the second coil 314. Referring to FIG. 8, an alternating magnetic flux F7 is formed when an alternating current flows through the first coil 302, and an alternating magnetic flux F8 is formed when an alternating current flows through the second coil 314. On the other hand, a direct magnetic flux F9 is formed when a direct current flows through the first coil 302 and the second coil 314.

[0042] As described above, the first coil 302 and the second coil 314 are of the same size and the same shape (the same winding direction, the same number of turns). Even if they are arranged coaxially, there are four types of combinations regarding the arrangement direction and the connection between the ends (regarding the arrangement, there are two ways to arrange the first coil 302 and the second coil 314 in the same direction or in the reverse direction, and regarding the connection between the ends, there are two ways depending on which of the two ends of the second coil 314 one end of the first coil 302 is connected to). Thereby, there are two types of combinations regarding the directions of the alternating current and the direct current flowing through the first coil 302 and the second coil 314.

[0043] For example, when the first coil 302 and the second coil 314 are arranged in the same direction, a corresponding pair of ends of the first coil 302 and the second coil 314 are connected to form, for example, the first node 232 in FIG. 5. If each of the corresponding pair of unconnected ends is the first terminal 220 and the second terminal 222 in FIG. 5, then in the first coil 302 and the second coil 314, the alternating current flows in the same direction and the direct current flows in the opposite direction. Therefore, as shown in FIG. 7, magnetic flux is formed. When the first coil 302 and the second coil 314 are arranged in the same direction, if a non-corresponding pair of ends of the first coil 302 and the second coil 314 are connected to form, for example, the first node 232 in FIG. 5, and each of the non-corresponding pair of unconnected ends is the first terminal 220 and the second terminal 222 in FIG. 5, then in the first coil 302 and the second coil 314, the alternating current flows in the opposite direction and the direct current flows in the same direction. Therefore, as shown in FIG. 8, magnetic flux is formed.

[0044] Even when the first coil 302 and the second coil 314 are arranged in the opposite direction, magnetic flux is formed as shown in FIG. 7 or FIG. 8 according to the connection between the ends of the first coil 302 and the second coil 314.

[0045] FIG. 9 shows a configuration in which two sets of the configurations of the coil 102, the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 in FIGS. 1 to 3 are accommodated in one tank. That is, the electromagnetic shielding type air-core reactor 900 includes a first unit 920 including a coil 902, a first electromagnetic shield 904, a second electromagnetic shield 906, and a third electromagnetic shield 908 corresponding to the coil 102, the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 respectively, and a second unit 922 having the same configuration as the first unit 920, which are arranged vertically and accommodated in the tank 910. The tank 910 is filled with insulating oil 912.

[0046] When comparing the electromagnetic shielding type air-core reactor 300 in Fig. 6 with the electromagnetic shielding type air-core reactor 900 in Fig. 9, the electromagnetic shielding type air-core reactor 300 does not have two plate-shaped electromagnetic shields arranged between the coils arranged vertically, which the electromagnetic shielding type air-core reactor 900 has. Since the electromagnetic shield is grounded as described above, the coil to which a high voltage is applied needs to be separated from the electromagnetic shield by a predetermined distance or more in consideration of the insulation between the coil and the ground. Since the electromagnetic shielding type air-core reactor 300 does not have an electromagnetic shield between the first coil 302 and the second coil 314, the first coil 302 and the second coil 314 can be separated so that mutual coupling does not occur between the first coil 302 and the second coil 314, and the distance d1 (see Fig. 6) between the first coil 302 and the second coil 314 can be made smaller than the distance d2 (see Fig. 9) between the coils in the electromagnetic shielding type air-core reactor 900. Therefore, the height of the tank 310 can be made lower than the height of the tank 910, and it can be made more compact.

[0047] In addition, since there is no plate-shaped electromagnetic shield between the first coil 302 and the second coil 314, the number of parts and the manufacturing man-hours can be reduced, and the manufacturing cost can be reduced. Also, by accommodating the two reactors in one tank, mechanical protection devices, oil quantity adjustment devices, etc. can be shared, and this can also reduce the number of parts and the manufacturing man-hours, and reduce the manufacturing cost.

[0048] (Second Modified Example) For the first reactor 200 to the sixth reactor 210 in the circuit of FIG. 5, the electromagnetic shielding air-core reactor 400 shown in FIG. 10 may be used. Referring to FIG. 10, the electromagnetic shielding air-core reactor 400 includes a first unit 420 and a second unit 422, a tank 410 housing them, and insulating oil 412 filled in the tank 410. The first unit 420 includes a coil 402, a first electromagnetic shield 404 disposed on the side of the coil 402, a second electromagnetic shield 406 disposed above the coil 402, and a third electromagnetic shield 408 disposed below the coil 402. The second unit 422 is configured in the same manner as the first unit 420. The first unit 420 and the second unit 422 are arranged adjacent to each other horizontally within the tank 410.

[0049] The coil 402, the first electromagnetic shield 404, the second electromagnetic shield 406, and the third electromagnetic shield 408 are each formed in the same manner as the coil 102, the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 shown in FIGS. 1 to 3. Therefore, repetitive descriptions will not be repeated.

[0050] For example, the electromagnetic shielding air-core reactor 400 can be used for each of the pair of the first reactor 200 and the second reactor 202, the pair of the third reactor 204 and the fourth reactor 206, and the pair of the fifth reactor 208 and the sixth reactor 210 in FIG. 5. In the electromagnetic shielding air-core reactor 400 used for the pair of the first reactor 200 and the second reactor 202, one end of the two ends of the coil 402 may be connected to one end of the two ends of the coil of the second unit 422 to form the first node 232 in FIG. 5, and the remaining two non-connected ends may be the first terminal 220 and the second terminal 222 in FIG. 5. For the electromagnetic shielding air-core reactor 400 used for the pair of the third reactor 204 and the fourth reactor 206 and the electromagnetic shielding air-core reactor 400 used for the pair of the fifth reactor 208 and the sixth reactor 210, the four ends of the two coils may be connected in the same manner.

[0051] An alternating current and a direct current flowing through the coils of the first unit 420 and the second unit 422 form magnetic fluxes similar to those in FIG. 4 in each of the first unit 420 and the second unit 422.

[0052] By accommodating two reactors in one tank like the electromagnetic shielding type air-core reactor 400, mechanical protection devices, oil quantity adjustment devices, etc. can be shared, the number of components and the manufacturing man-hours can be reduced, and the manufacturing cost can be cut.

[0053] (Third modification example) In the circuits of the first reactor 200 to the sixth reactor 210 in FIG. 5, the electromagnetic shielding type air-core reactor 500 shown in FIG. 11 may be used. Referring to FIG. 11, the electromagnetic shielding type air-core reactor 500 includes a first unit 520, a second unit 522, and a third unit 524, a tank 510 housing them, and insulating oil 512 filled in the tank 510. The first unit 520 includes a first coil 502, a second coil 514, a first electromagnetic shield 504 disposed on the sides of the first coil 502 and the second coil 514, a second electromagnetic shield 506 disposed above the first coil 502, and a third electromagnetic shield 508 disposed below the second coil 514. The second unit 522 and the third unit 524 are each configured in the same manner as the first unit 520. The first unit 520, the second unit 522, and the third unit 524 are arranged horizontally in the tank 510.

[0054] The first coil 502, the first electromagnetic shield 504, the second electromagnetic shield 506, the third electromagnetic shield 508, and the second coil 514 are each formed in the same manner as the first coil 302, the first electromagnetic shield 304, the second electromagnetic shield 306, the third electromagnetic shield 308, and the second coil 314 shown in FIG. 6. An alternating current and a direct current flowing through the two coils constituting each of the first unit 520, the second unit 522, and the third unit 524 form magnetic fluxes similar to those in FIG. 7 or FIG. 8 in each of the first unit 520, the second unit 522, and the third unit 524.

[0055] In the electromagnetic shielding type air-core reactor 500, in each of the first unit 520, the second unit 522, and the third unit 524, there is no plate-shaped electromagnetic shield between the two coils, and one cylindrical electromagnetic shield is arranged. Therefore, the height of the electromagnetic shielding type air-core reactor 500 can be made lower than that of the electromagnetic shielding type air-core reactor 900, and it can be made more compact. Also, the number of parts and the manufacturing man-hours can be reduced, and the manufacturing cost can be reduced. By accommodating six reactors in one tank, mechanical protection devices, oil quantity adjustment devices, etc. can be made common, and this can also reduce the number of parts and the manufacturing man-hours, and reduce the manufacturing cost.

[0056] (Fourth Modification Example) In the first reactor 200 to the sixth reactor 210 in the circuit of FIG. 5, the electromagnetic shielding type air-core reactor 600 shown in FIG. 12 may be used. Referring to FIG. 12, the electromagnetic shielding type air-core reactor 600 includes a first unit 620, a second unit 622, a third unit 624, a fourth unit 626, a fifth unit 628, and a sixth unit 630, a tank 610 that houses them, and insulating oil 612 filled in the tank 610. The first unit 620 includes a coil 602, a first electromagnetic shield 604 disposed on the side of the coil 602, a second electromagnetic shield 606 disposed above the coil 602, and a third electromagnetic shield 608 disposed below the coil 602. The second unit 622 to the sixth unit 630 are each configured in the same manner as the first unit 620. The first unit 620 to the sixth unit 630 are arranged horizontally in the tank 610.

[0057] The coil 602, the first electromagnetic shield 604, the second electromagnetic shield 606, and the third electromagnetic shield 608 are each formed in the same manner as the coil 102, the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108 shown in FIGS. 1 to 3. For example, the combination of the first unit 620 and the fourth unit 626 can be configured in the same manner as the first unit 420 and the second unit 422 in FIG. 10. Similarly, the combination of the second unit 622 and the fifth unit 628, and the combination of the third unit 624 and the sixth unit 630 can each be configured in the same manner as the first unit 420 and the second unit 422 in FIG. 10. By the alternating current and direct current flowing through the coils of the first unit 620 to the sixth unit 630, magnetic fluxes similar to those in FIG. 4 are formed in each of the first unit 620 to the sixth unit 630.

[0058] By accommodating six reactors in one tank like the electromagnetic shielding type air-core reactor 600, it is possible to share mechanical protection devices, oil quantity adjustment devices, etc., reduce the number of parts and the manufacturing man-hours, and reduce the manufacturing cost.

[0059] In the above description, the case where the electromagnetic shielding type air-core reactor 100 is rectangular has been described, but it is not limited thereto. The tank 110 only needs to be able to accommodate the coil 102, the first electromagnetic shield 104, the second electromagnetic shield 106, and the third electromagnetic shield 108, and its shape is arbitrary. For example, the tank 110 may be formed in a hollow, sealable cylindrical shape. The same applies to the shapes of the electromagnetic shielding type air-core reactor 300, the electromagnetic shielding type air-core reactor 400, the electromagnetic shielding type air-core reactor 500, and the electromagnetic shielding type air-core reactor 600.

[0060] For example, in FIG. 11, the first unit 520, the second unit 522, and the third unit 524 are arranged in a horizontal row. However, the tank 510 may be formed in a hollow cylindrical shape, and each of the first unit 520, the second unit 522, and the third unit 524 may be arranged at equal distances. For example, each of the first unit 520, the second unit 522, and the third unit 524 may be arranged at an equal distance from the central axis of the cylinder (tank 510) (arranged such that the central axes of the first unit 520, the second unit 522, and the third unit 524 are located at the vertices of an equilateral triangle).

[0061] The circuit shown in FIG. 5 is a three-phase circuit, but it may also be a two-phase circuit. In that case, for example, in the configuration shown in FIG. 11, the configuration may be changed to include only the first unit 520 and the second unit 522 in the tank 510 without including the third unit 524.

[0062] The present invention has been described by explaining the embodiments. However, the above-described embodiments are examples, and the present invention is not limited to only the above-described embodiments. The scope of the present invention is shown by each claim in the claims, and includes all modifications within the meaning and scope equivalent to the language described therein.

Explanation of Reference Numerals

[0063] 100, 300, 400, 500, 600, 900 Electromagnetic Shielded Air Core Reactor 102, 402, 602, 902 Coil 104, 304, 404, 504, 604, 904 First Electromagnetic Shield 106, 306, 406, 506, 606, 906 Second Electromagnetic Shield 108, 308, 408, 508, 608, 908 Third Electromagnetic Shield 110, 310, 410, 510, 610, 910 Tank 112, 312, 412, 512, 612, 912 Insulating Oil 200 First Reactor 202 Second Reactor 204 Third Reactor 206 Fourth Reactor 208 Fifth Reactor 210 Sixth Reactor 220 First Terminal 222 Second Terminal 224 Third Terminal 226 Fourth Terminal 228 Fifth Terminal 230 Sixth Terminal 232 First Node 234 Second Node 236 Third Node 240 Power Supply 302, 502 First Coil 314, 514 Second Coil 420, 520, 620, 920 First Unit 422, 522, 622, 922 Second Unit 524, 624 Third Unit 626 Fourth Unit 628 Fifth Unit 630 Sixth Unit

Claims

1. a coil; a conductive member disposed around the coil; a housing member that houses the coil and the conductive member; and a liquid insulating member housed in the housing member, wherein the coil includes a first coil and a second coil, the first coil is disposed vertically above the second coil with a predetermined interval therebetween, the conductive member includes a cylindrical member disposed on side portions of the first coil and the second coil, a first plate-like member disposed above the first coil, and a second plate-like member disposed below the second coil, the first coil and the second coil are connected in series with each other to form a connection node, a first terminal connectable from the outside, which is connected to an end of the first coil that is not connected to the connection node, a second terminal connectable from the outside, which is connected to the connection node, and a third terminal connectable from the outside, which is connected to an end of the second coil that is not connected to the connection node, and characterized in that it further includes an electromagnetic shielding type air-core reactor.

2. including a plurality of sets of the first coil, the second coil, and the conductive member, each set of the first coil, the second coil, and the conductive member constitutes one unit, the housing member houses a plurality of the units, and the plurality of units are juxtaposed in the horizontal direction, and the electromagnetic shielding type air-core reactor according to Claim 1, characterized in that.

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