Novel power flow controller for alternating current power grid interconnection

Abstract

The invention discloses a novel power flow controller for alternating current power grid interconnection, and relates to the technical field of electrical equipment, the novel power flow controller comprises a column A excitation coil, a column B excitation coil and a column C excitation coil, and the column A excitation coil, the column B excitation coil and the column C excitation coil are fixedly sleeved on a three-phase iron core. By installing the three-phase iron core, the magnet exciting coil and other structures, physical interconnection of three power grid ports is achieved, the problems that in a multi-port interconnection scene, a traditional electromagnetic scheme is complex in structure and high in cost are solved, and the cost and the occupied area are reduced.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment technology, specifically to a novel power flow controller for AC power grid interconnection. Background Technology

[0002] Power systems typically employ devices based on power electronics technology to regulate active and reactive power flow. Traditional electromagnetic power flow controllers are connected in series with the lines and have voltage regulation or phase shifting functions. They are equivalent to two-port devices. In multi-port scenarios, multiple units need to be combined, resulting in high costs, large footprints, and low safety, reliability, and operating efficiency.

[0003] Connecting two electromagnetic power flow controllers and placing them in a tank with three sets of three-phase terminals enables three-terminal interconnected power flow control. However, this method is complex, requiring two three-phase iron cores, each with multiple coils. Not only do the coils on individual cores need to be interconnected, but the coils between cores also need to be connected, resulting in a complex lead structure. Furthermore, when overvoltage enters the line ports, these connections can cause complex overvoltage oscillations, compromising the insulation safety of the leads and coils. Summary of the Invention

[0004] The purpose of this invention is to provide a novel power flow controller for AC power grid interconnection, so as to solve the technical problem mentioned in the background art that a single power flow controller cannot interconnect three-port or multi-port voltage systems of the same level.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a novel power flow controller for AC power grid interconnection, comprising an A-phase excitation coil, a B-phase excitation coil, and a C-phase excitation coil, which are fixedly mounted on a three-phase iron core. The A-phase, B-phase, and C-phase excitation coils are respectively connected to the A-phase terminal, B-phase terminal, and C-phase terminal of port one. The three-phase iron core is equipped with a combination of an A-phase voltage and phase regulating coil and an on-load tap changer at port two, a B-phase voltage and phase regulating coil and an on-load tap changer at port two, a C-phase voltage and phase regulating coil and an on-load tap changer at port two, an A-phase voltage and phase regulating coil and an on-load tap changer at port three, a B-phase voltage and phase regulating coil and an on-load tap changer at port three, and a C-phase voltage and phase regulating coil and an on-load tap changer at port three.

[0006] Preferably, the A-phase voltage and phase regulating coil and on-load tap changer combination of port two, the B-phase voltage and phase regulating coil and on-load tap changer combination of port two, the C-phase voltage and phase regulating coil and on-load tap changer combination of port two, the A-phase voltage and phase regulating coil and on-load tap changer combination of port three, the B-phase voltage and phase regulating coil and on-load tap changer combination of port three, and the C-phase voltage and phase regulating coil and on-load tap changer combination of port three are respectively connected to the A-phase terminal, B-phase terminal, C-phase terminal of port two, A-phase terminal, B-phase terminal, and C-phase terminal of port three.

[0007] Preferably, the voltage regulating coil in the combination of the voltage regulating coil and the on-load tap changer of the A phase of port two is connected in series with the A phase terminal of port two, the voltage regulating coil in the combination of the voltage regulating coil and the on-load tap changer of the B phase of port two is connected in series with the B phase terminal of port two, and the voltage regulating coil in the combination of the voltage regulating coil and the on-load tap changer of the C phase of port two is connected in series with the C phase terminal of port two.

[0008] Preferably, the excitation coil of column A provides excitation for the voltage regulating coil in the combination of the voltage regulating and phase regulating coil and the on-load tap changer in port two, and for the voltage regulating coil in the combination of the voltage regulating and phase regulating coil and the on-load tap changer in port three. The excitation coil of column A provides excitation for the phase regulating coil in the combination of the voltage regulating and phase regulating coil and the on-load tap changer in port two, the phase regulating coil in the combination of the voltage regulating and phase regulating coil and the on-load tap changer in port two, the phase regulating coil in the combination of the voltage regulating and phase regulating coil and the on-load tap changer in port three, and the phase regulating coil in the combination of the voltage regulating and phase regulating coil and the on-load tap changer in port three.

[0009] Preferably, the A-phase terminal, B-phase terminal, and C-phase terminal of port one pass through the oil tank via high-voltage bushings, an oil storage tank is fixedly connected to the top of the outer wall of the oil tank, and a plate radiator is connected to the oil tank via a pipe.

[0010] Preferably, the excitation coils of column A, column B, and column C are configured with either a delta connection or a star connection.

[0011] Preferably, when the excitation coils A, B, and C of column A are connected in a star configuration, the tail ends of the excitation coils A, B, and C are connected to the neutral point.

[0012] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention achieves physical interconnection of three power grid ports by installing a three-phase iron core, excitation coil and other structures, which solves the problem of complex structure and high cost of traditional electromagnetic solutions in multi-port interconnection scenarios, and reduces cost and footprint. 2. This invention, through the installation of a combination of voltage and phase regulating coils and on-load tap changers, achieves interconnection between three ports on a single iron core, improving technical and economic efficiency, realizing multi-port power flow collaborative control of a single device, and enhancing safety and reliability. Attached Figure Description

[0013] Figure 1 This is a front view structural diagram of the present invention; Figure 2 This is a front view schematic diagram of the plate-type heat sink of the present invention; Figure 3 This is a schematic diagram of the triangular wiring structure of the present invention; Figure 4 This is a schematic diagram of the star-shaped wiring structure of the present invention.

[0014] In the diagram: 1. Phase A terminal of Port 1; 2. Phase B terminal of Port 1; 3. Phase C terminal of Port 1; 4. Phase A terminal of Port 2; 5. Phase B terminal of Port 2; 6. Phase C terminal of Port 2; 7. Phase A terminal of Port 3; 8. Phase B terminal of Port 3; 9. Phase C terminal of Port 3; 10. Excitation coil of Column A; 11. Excitation coil of Column B; 12. Excitation coil of Column C; 13. Phase A voltage and phase regulating coil and on-load tap changer assembly of Port 2. 14. The combination of phase B voltage and phase regulating coil and on-load tap changer at port 2; 15. The combination of phase C voltage and phase regulating coil and on-load tap changer at port 2; 16. The combination of phase A voltage and phase regulating coil and on-load tap changer at port 3; 17. The combination of phase B voltage and phase regulating coil and on-load tap changer at port 3; 18. The combination of phase C voltage and phase regulating coil and on-load tap changer at port 3; 19. Neutral point; 20. Oil tank; 21. Oil conservator; 22. Plate radiator. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0017] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0018] Example 1, please refer to Figure 1 , Figure 3 and Figure 4 A novel power flow controller for AC power grid interconnection includes a column A excitation coil 10, a column B excitation coil 11, and a column C excitation coil 12. These coils are fixedly mounted on a three-phase iron core. The coils are respectively connected to phase A terminal 1, phase B terminal 2, and phase C terminal 3 of port one. The three-phase iron core is equipped with the following combinations: A-phase voltage and phase regulating coil and on-load tap changer assembly 13 (port 2), B-phase voltage and phase regulating coil and on-load tap changer assembly 14 (port 2), C-phase voltage and phase regulating coil and on-load tap changer assembly 15 (port 2), A-phase voltage and phase regulating coil and on-load tap changer assembly 16 (port 3), B-phase voltage and phase regulating coil and on-load tap changer assembly 17 (port 3), and C-phase voltage and phase regulating coil and on-load tap changer assembly 18 (port 3). The following combinations of the following terminals are connected to the following terminals respectively: Phase A voltage and phase modulation coil and on-load tap changer assembly 13 of port 2, Phase B voltage and phase modulation coil and on-load tap changer assembly 14 of port 2, Phase C voltage and phase modulation coil and on-load tap changer assembly 15 of port 2, Phase A voltage and phase modulation coil and on-load tap changer assembly 16 of port 3, Phase B voltage and phase modulation coil and on-load tap changer assembly 17 of port 3, and Phase C voltage and phase modulation coil and on-load tap changer assembly 18 of port 3: Phase A terminal 4 of port 2, Phase B terminal 5 of port 2, Phase C terminal 6 of port 2, Phase A terminal 7 of port 3, Phase B terminal 8 of port 3, and Phase C terminal 9 of port 3.

[0019] Furthermore, the power flow controller has three ports: Port 1, Port 2, and Port 3. Each port has three phases: A, B, and C. Specifically, the A-phase terminal 1 of Port 1, the B-phase terminal 2 of Port 1, and the C-phase terminal 3 of Port 1; the A-phase terminal 4 of Port 2, the B-phase terminal 5 of Port 2, and the C-phase terminal 6 of Port 2; the A-phase terminal 7 of Port 3, the B-phase terminal 8 of Port 3, and the C-phase terminal 9 of Port 3; the three core columns on the three-phase core are column A, column B, and column C, and the three excitation coils include excitation coil 10 for column A, excitation coil 11 for column B, and excitation coil 12 for column C. The excitation coil 12 consists of three coils: coil 10 at column A is mounted on column A and connected to terminal 1 of phase A at port one; coil 11 at column B is mounted on column B and connected to terminal 2 of phase B at port one; and coil 12 at column C is mounted on column C and connected to terminal 3 of phase C at port one. The excitation coils 10 at column A, 11 at column B, and 12 at column C can be connected in either a Y-connection or a D-connection. A Y-connection is a star connection, and a D-connection is a delta connection. Port one is connected to the power grid to provide energy to the three excitation coils, thereby establishing a magnetic field throughout the iron core. The six three-phase combination units of ports 2 and 3, including the A-phase voltage and phase regulating coil and on-load tap changer combination 13 and the B-phase voltage and phase regulating coil and on-load tap changer combination 14 of port 2, are integrations of voltage regulating coils, phase regulating coils, and on-load tap changers. Each core column has one excitation coil, two voltage regulating coils, and four phase regulating coils, that is, seven coils are set on each core column, and a total of 21 coils are set on the three core columns. The on-load tap changer on a power flow controller is selected from six three-phase on-load tap changers or 18 single-phase on-load tap changers. The A, B, and C phases of ports 2 and 3 are connected in series to the voltage regulating coil of the corresponding phase and the phase regulating coils of the other two phases. For example, terminal 4 of phase A of port 2 is connected to the voltage regulating coil and on-load tap changer of phase A of port 2. The voltage regulating coil in switch assembly 13 is connected in series. The A-phase terminal 4 of port two is connected in series with the B-phase voltage regulating and phase regulating coil of port two, the phase regulating coil in on-load tap changer assembly 14, the C-phase voltage regulating and phase regulating coil of port two, and the phase regulating coil in on-load tap changer assembly 15. All voltage regulating coils and phase regulating coils are connected to the on-load tap changer. The number of turns of the voltage regulating coil and phase regulating coil is adjusted by adjusting the switch position to change the amplitude or phase angle of the phase voltage. The three-terminal interconnection is achieved by one device, which significantly reduces cost and footprint, avoids the complex wiring and insulation risks of multiple device combinations, and realizes the complex three-terminal interconnection function with a single iron core. The structure is more compact, simple and reasonable, and the technical and economic efficiency is better than two combined devices to achieve the same function.

[0020] Example 2, please refer to Figure 1 , Figure 3 and Figure 4A novel power flow controller for AC power grid interconnection, wherein the voltage regulating coil in the A-phase voltage regulating and phase regulating coil and on-load tap changer assembly 13 of port two is connected in series with the A-phase terminal 4 of port two, the voltage regulating coil in the B-phase voltage regulating and phase regulating coil and on-load tap changer assembly 14 of port two is connected in series with the B-phase terminal 5 of port two, and the voltage regulating coil in the C-phase voltage regulating and phase regulating coil and on-load tap changer assembly 15 of port two is connected in series with the C-phase terminal 6 of port two; The A-phase excitation coil 10 provides excitation for the voltage regulating coil in the A-phase voltage regulating and phase regulating coil and the voltage regulating coil in the on-load tap changer assembly 13 of port two, and the voltage regulating coil in the A-phase voltage regulating and phase regulating coil and the on-load tap changer assembly 16 of port three. The A-phase excitation coil 10 also provides excitation for the phase regulating coil in the B-phase voltage regulating and phase regulating coil and the phase regulating coil in the on-load tap changer assembly 14 of port two, the phase regulating coil in the C-phase voltage regulating and phase regulating coil and the phase regulating coil in the on-load tap changer assembly 15 of port two, the phase regulating coil in the B-phase voltage regulating and phase regulating coil and the phase regulating coil in the on-load tap changer assembly 17 of port three, and the phase regulating coil in the C-phase voltage regulating and phase regulating coil and the phase regulating coil in the on-load tap changer assembly 18 of port three.

[0021] Furthermore, port one serves as the excitation port. The excitation coil of each phase connected to port one provides excitation for the corresponding voltage regulating coils of ports two and three, and also provides excitation for the phase-adjusting coils of the other two phases connected in series from the two ports. The excitation coils 10 (A), 11 (B), and 12 (C) are 120° out of phase, serving as the system's reference excitation with a 120° phase difference. Ports two and three are controlled ports. The final output voltage of each phase at each port is synthesized from the voltage vector generated by the voltage regulating coil of that phase and the phase-adjusting coils of the other two phases. The voltage regulating coil is mainly responsible for changing the amplitude of the voltage vector, while the phase-adjusting coil is mainly responsible for changing the phase of the voltage vector. Furthermore, the A and B phases of ports two and three... The amplitudes of the three phases A, B, and C can be discretely adjusted using an on-load tap changer. By changing the tap position, the on-load tap changer increases or decreases the effective number of turns of the corresponding coil connected in series in the circuit, thereby changing the amplitude of the induced voltage of the coil in a fixed, step-like manner. This adjustment is discrete and step-by-step. By independently adjusting the number of turns of the voltage regulating coil of phase A, the phase regulating coil of phase B, and the series coil of phase C, the on-load tap changer is equivalent to adjusting the amplitude of the voltage vectors of three different phases: 0°, -120°, and +120°. Thus, after the three-phase voltage vectors are synthesized, a new voltage vector with discretely adjustable amplitude and phase can be obtained, thereby realizing discrete adjustment of the voltage amplitude and phase between the three ports. The voltage regulating coils and phase regulating coils connected to ports two and three employ six three-phase on-load tap changers or eighteen single-phase on-load tap changers. These switches can be adjusted independently, thus decoupled voltage amplitude and phase angle adjustments. This enables active and reactive power control between three interconnected power grids. Active power flow control is primarily achieved by changing the phase angle, while reactive power flow control is primarily achieved by changing the voltage amplitude. The power flow controller can be used for interconnection between three voltage systems of the same level. By adjusting the on-load tap changers in stages, it alters the voltage, current, and phase angle between the three lines, thereby controlling the active and reactive power flow of the power grid. Furthermore, two or more such controllers can be combined to form a power flow controller with more interconnected ports, enabling more complex inter-power grid interconnections.

[0022] Example 3, please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 A novel power flow controller for AC power grid interconnection, wherein the A-phase terminal 1, B-phase terminal 2, and C-phase terminal 3 of port one pass through the oil tank 20 via high-voltage bushings, and an oil storage tank 21 is fixedly connected to the top of the outer wall of the oil tank 20, and a plate radiator 22 is connected to the oil tank 20 via a pipe.

[0023] Furthermore, the A-phase terminal 1, B-phase terminal 2, and C-phase terminal 3 of port one are the three phase line leads of port one of the power flow controller. Internally, these three terminals are connected to the A-phase excitation coil 10, B-phase excitation coil 11, and C-phase excitation coil 12 respectively via high-voltage leads. Externally, these three terminals pass through the tank wall of the tank 20 via high-voltage cable plugs or sleeves and are connected to the corresponding phase lines of the external AC power grid. The three terminals of port two and port three, namely the A-phase terminal 4, B-phase terminal 5, and C-phase terminal 6 of port two, the A-phase terminal 7, B-phase terminal 8, and C-phase terminal 9 of port three, also pass through the tank wall of the tank 20 via high-voltage cable plugs or sleeves. Therefore, the tank 20 is equipped with 3 sets of three-phase high-voltage cable plugs or sleeves, totaling 9 high-voltage cable plugs or sleeves. The top of the oil tank 20 is connected to the oil conservator 21 via a pipe, and the side wall or bottom of the oil tank 20 is connected to the plate radiator 22 via a pipe. The oil tank 20 contains and protects the core electromagnetic components, including the three-phase iron core, excitation coil, voltage regulating coil, phase regulating coil, and some internal leads. In the oil-immersed design, the oil tank 20 is filled with insulating oil, which provides an insulating medium for the internal live components and transfers the heat generated during operation to the tank wall and plate radiator 22 through oil convection.

[0024] Example 4, please refer to Figure 1 , Figure 3 and Figure 4A novel power flow controller for AC power grid interconnection, wherein the excitation coil 10 of column A, the excitation coil 11 of column B, and the excitation coil 12 of column C are configured with either delta connection or star connection.

[0025] Furthermore, in the delta connection method, one end of the excitation coil 10 at column A is connected to the other end of the excitation coil 12 at column C; one end of the excitation coil 11 at column B is connected to the other end of the excitation coil 10 at column A; and one end of the excitation coil 12 at column C is connected to the other end of the excitation coil 11 at column B. The three connection points serve as the input terminals of phases A, B, and C, respectively, and are led out to phase A terminal 1, phase B terminal 2, and phase C terminal 3 at port one. The excitation coils 10 at column A, 11 at column B, and 12 at column C are connected end to end to form a closed delta circuit. The delta connection can provide a path for the third harmonic current, allowing it to circulate inside the triangle without flowing into the power grid, which helps to improve the voltage waveform and reduce the impact of harmonics on the power grid. In the star connection method, the same-named or different-named ends of the excitation coil 10 of column A, the excitation coil 11 of column B, and the excitation coil 12 of column C are connected together. The other three ends of the excitation coil 10 of column A, the excitation coil 11 of column B, and the excitation coil 12 of column C are respectively used as the input terminals of phases A, B, and C, and are led out to phase A terminal 1, phase B terminal 2, and phase C terminal 3 of port one.

[0026] Example 5, please refer to Figure 1 and Figure 4 A novel power flow controller for AC power grid interconnection, wherein when the excitation coil 10 of column A, the excitation coil 11 of column B, and the excitation coil 12 of column C are connected in a star configuration, the tail ends of the excitation coil 10 of column A, the excitation coil 11 of column B, and the excitation coil 12 of column C are connected to the neutral point 19.

[0027] Furthermore, when using a star connection, the same-named or different-named ends of the excitation coil 10 of column A, the excitation coil 11 of column B, and the excitation coil 12 of column C are connected together to form a common point, namely the neutral point 19, which can be led out through a neutral point bushing. The neutral point 19 can be grounded or ungrounded. Leading out a ground can provide a zero-sequence current path for the system, which is beneficial for the configuration of system relay protection and fault diagnosis.

[0028] Working principle: The power flow controller consists of a three-phase iron core, 21 coils, 6 three-phase on-load tap changers or 18 single-phase on-load tap changers. Each iron core column is fitted with 1 excitation coil, 2 voltage regulating coils and 4 phase regulating coils. Terminal 1 of phase A, terminal 2 of phase B, and terminal 3 of phase C of port 1 are connected to the power grid to supply power to the A-phase excitation coil 10, B-phase excitation coil 11, and C-phase excitation coil 12 on the three-phase iron core column. The three-phase excitation coils are 120° apart, establishing a three-phase reference electromagnetic environment. The output voltage of terminal 4 of phase A of port 2 is transmitted through the voltage regulating coil voltage of column A (used to adjust the amplitude).

[0029] The voltage regulating and phase regulating coils, whether in phase or out of phase, are interconnected by leads and connected to different on-load tap changers. By changing the tap position of the tap changer, the number of turns in series with the voltage regulating and phase regulating coils is changed to obtain different voltage and current vectors. After superposition, the phase between the three ports is changed, thereby discretely regulating the magnitude of voltage and current and phase angle.

[0030] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A novel power flow controller for AC power grid interconnection, characterized in that: The system includes a column A excitation coil (10), a column B excitation coil (11), and a column C excitation coil (12). These coils are fixedly mounted on a three-phase iron core. The coils are connected to the A-phase terminal (1), B-phase terminal (2), and C-phase terminal (3) of port one, respectively. The heart is equipped with a combination of A-phase voltage and phase regulating coil and on-load tap changer at port 2 (13), B-phase voltage and phase regulating coil and on-load tap changer at port 2 (14), C-phase voltage and phase regulating coil and on-load tap changer at port 2 (15), A-phase voltage and phase regulating coil and on-load tap changer at port 3 (16), B-phase voltage and phase regulating coil and on-load tap changer at port 3 (17), and C-phase voltage and phase regulating coil and on-load tap changer at port 3 (18).

2. A novel power flow controller for AC power grid interconnection according to claim 1, characterized in that: The A-phase voltage and phase regulating coil and on-load tap changer combination (13) of port 2, the B-phase voltage and phase regulating coil and on-load tap changer combination (14) of port 2, the C-phase voltage and phase regulating coil and on-load tap changer combination (15) of port 2, the A-phase voltage and phase regulating coil and on-load tap changer combination (16) of port 3, the B-phase voltage and phase regulating coil and on-load tap changer combination (17) of port 3, and the C-phase voltage and phase regulating coil and on-load tap changer combination (18) of port 3 are respectively connected to the A-phase terminal (4) of port 2, the B-phase terminal (5) of port 2, the C-phase terminal (6) of port 2, the A-phase terminal (7) of port 3, the B-phase terminal (8) of port 3, and the C-phase terminal (9) of port 3.

3. A novel power flow controller for AC power grid interconnection according to claim 1, characterized in that: The voltage regulating coil in the A-phase voltage regulating coil and on-load tap changer assembly (13) of port two is connected in series with the A-phase terminal (4) of port two; the voltage regulating coil in the B-phase voltage regulating coil and on-load tap changer assembly (14) of port two is connected in series with the B-phase terminal (5) of port two; and the voltage regulating coil in the C-phase voltage regulating coil and on-load tap changer assembly (15) of port two is connected in series with the C-phase terminal (6) of port two.

4. A novel power flow controller for AC power grid interconnection according to claim 1, characterized in that: The A-phase excitation coil (10) provides excitation for the voltage regulating coil in the A-phase voltage regulating and phase regulating coil and the on-load tap changer assembly (13) of port two, and the voltage regulating coil in the A-phase voltage regulating and phase regulating coil and the on-load tap changer assembly (16) of port three. The A-phase excitation coil (10) provides excitation for the phase regulating coil in the B-phase voltage regulating and phase regulating coil and the on-load tap changer assembly (14) of port two, the phase regulating coil in the C-phase voltage regulating and phase regulating coil and the on-load tap changer assembly (15) of port two, the phase regulating coil in the B-phase voltage regulating and phase regulating coil and the on-load tap changer assembly (17) of port three, and the phase regulating coil in the C-phase voltage regulating and phase regulating coil and the on-load tap changer assembly (18) of port three.

5. A novel power flow controller for AC power grid interconnection according to claim 1, characterized in that: The A-phase terminal (1), B-phase terminal (2), and C-phase terminal (3) of port one pass through the oil tank (20) through high-pressure bushings. An oil storage tank (21) is fixedly connected to the top of the outer wall of the oil tank (20). A plate radiator (22) is connected to the oil tank (20) through a pipe.

6. A novel power flow controller for AC power grid interconnection according to claim 1, characterized in that: The excitation coil (10) of column A, the excitation coil (11) of column B, and the excitation coil (12) of column C are selected from either delta connection or star connection.

7. A novel power flow controller for AC power grid interconnection according to claim 1, characterized in that: When the excitation coil (10) of column A, the excitation coil (11) of column B, and the excitation coil (12) of column C are connected in a star configuration, the tail ends of the excitation coil (10) of column A, the excitation coil (11) of column B, and the excitation coil (12) of column C are connected to the neutral point (19).

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