Flexible interconnection device and control method thereof

Abstract

The invention relates to the technical field of power distribution network flexible interconnection, and particularly provides a flexible interconnection device and a control method thereof, the flexible interconnection device comprises a three-phase wire inlet port, a three-phase wire outlet port, a three-phase parallel transformer, a voltage regulating mechanism, a three-phase series transformer and a controller; a primary winding of the three-phase series transformer is connected between the three-phase wire inlet port and the three-phase wire outlet port; one ends of three-phase primary windings of the three-phase parallel transformer are respectively connected with a three-phase bus, and the other ends are mutually connected; each phase of primary winding of the three-phase parallel transformer is provided with three groups of combined secondary windings, and each combined secondary winding is connected to the three-phase series transformer through a corresponding voltage regulating mechanism; and the controller is used for adjusting the gear of the corresponding combined secondary winding by utilizing the voltage adjusting mechanism. According to the technical scheme provided by the invention, protection selectivity of the power distribution network supporting normal interconnection operation is realized, a theoretical foundation is laid for construction of the interconnection type power distribution network based on flexible interconnection equipment, and the method has guiding significance in engineering application and popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible interconnection of distribution networks, and in particular to a flexible interconnection device and a control method thereof. Background Art

[0002] The explosive growth of new distributed sources and loads, such as distributed photovoltaics and electric vehicles, has posed significant challenges to the capacity and reliability of distribution networks. Flexible interconnection equipment, enabling cross-connection of power flows between lines, unlocks the potential of distribution equipment resources, and enhances power reliability, is considered an effective solution to this challenge.

[0003] However, current flexible interconnected equipment generally adopts an all-power electronic technology route, which has a low fault current tolerance level and lacks the ability to ride through faults. After a system fault occurs, it switches to open-loop operation, which goes against the original intention of normal closed-loop operation to improve system reliability. Summary of the Invention

[0004] In order to overcome the above-mentioned defects, the present invention proposes a flexible interconnection device and a control method thereof.

[0005] In a first aspect, a flexible interconnection device is provided, comprising:

[0006] Three-phase incoming line port, three-phase outgoing line port, three-phase parallel transformer, voltage regulating mechanism, three-phase series transformer and controller;

[0007] A primary winding of a three-phase series transformer is connected between the three-phase incoming line port and the three-phase outgoing line port;

[0008] One end of the three-phase primary windings of the three-phase parallel transformer is connected to the three-phase busbars respectively, and the other ends are connected to each other;

[0009] Each primary winding of each phase of the three-phase parallel transformer is provided with three sets of combined secondary windings, and each combined secondary winding is connected to the three-phase series transformer through its corresponding voltage regulating mechanism;

[0010] The controller is used to adjust the gear position of the corresponding combined secondary winding using a voltage regulating mechanism.

[0011] Preferably, the voltage regulating mechanism includes: a first switch unit, a second switch unit, a third switch unit, a fourth switch unit, a fifth switch unit, a sixth switch unit, a seventh switch unit and an eighth switch unit;

[0012] The first switch unit and the second switch unit are connected, and the connection point is a first common point of the voltage regulating mechanism;

[0013] The third switch unit and the fourth switch unit are connected, and the connection point is the second common point of the voltage regulating mechanism;

[0014] The fifth switch unit and the sixth switch unit are connected, and the connection point is the third common point of the voltage regulating mechanism;

[0015] The seventh switch unit and the eighth switch unit are connected, and the connection point is the fourth common point of the voltage regulating mechanism;

[0016] The series structure formed by the first switch unit and the second switch unit, the series structure formed by the third switch unit and the fourth switch unit, the series structure formed by the fifth switch unit and the sixth switch unit, and the series structure formed by the seventh switch unit and the eighth switch unit are connected in parallel with each other; the two parallel connection points of each series structure are respectively the fifth common point and the sixth common point of the voltage regulating mechanism.

[0017] Furthermore, the three-phase parallel transformer includes: an A-phase parallel transformer, a B-phase parallel transformer, and a C-phase parallel transformer; the three-phase series transformer includes: an A-phase series transformer, a B-phase series transformer, and a C-phase series transformer; the secondary windings of the primary windings of each phase parallel transformer include a combined secondary winding of phase A, a combined secondary winding of phase B, and a combined secondary winding of phase C;

[0018] The fifth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the A-phase parallel transformer is connected to the head end of the secondary winding of the A-phase series transformer, the sixth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the A-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the B-phase parallel transformer, the sixth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the B-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the C-phase parallel transformer, and the sixth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the C-phase parallel transformer is respectively connected to the tail end of the secondary winding of the A-phase series transformer, the tail end of the secondary winding of the B-phase series transformer, and the tail end of the secondary winding of the C-phase series transformer;

[0019] The fifth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the A-phase parallel transformer is connected to the head end of the secondary winding of the B-phase series transformer, the sixth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the A-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the B-phase parallel transformer, the sixth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the B-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the C-phase parallel transformer, and the sixth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the C-phase parallel transformer is respectively connected to the tail end of the secondary winding of the A-phase series transformer, the tail end of the secondary winding of the B-phase series transformer, and the tail end of the secondary winding of the C-phase series transformer;

[0020] The fifth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the A-phase parallel transformer is connected to the head end of the secondary winding of the B-phase series transformer, the sixth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the A-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the B-phase parallel transformer, the sixth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the B-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the C-phase parallel transformer, and the sixth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the C-phase parallel transformer is respectively connected to the tail end of the secondary winding of the A-phase series transformer, the tail end of the secondary winding of the B-phase series transformer, and the tail end of the secondary winding of the C-phase series transformer.

[0021] Furthermore, the combined secondary winding includes: a first regulating winding, a second regulating winding and a current limiting winding;

[0022] The first regulating winding has a head end connected to a first common point of the voltage regulating mechanism corresponding to the combined secondary winding, and a tail end connected to a head end of the second regulating winding;

[0023] The first end of the second regulating winding is connected to the second common point of the voltage regulating mechanism corresponding to the combined secondary winding, and the tail end is connected to the first end of the current limiting winding;

[0024] The head end of the current limiting winding is connected to the third common point of the voltage regulating mechanism corresponding to the combined secondary winding, and the tail end is connected to the fourth common point of the voltage regulating mechanism corresponding to the combined secondary winding.

[0025] Furthermore, the controller is specifically used to control the voltage regulating mechanism to adjust the number of turns of the corresponding combined secondary winding by adjusting the on-off state of each switch unit in the voltage regulating mechanism.

[0026] Furthermore, the controller is specifically configured to adjust the on / off state of each switch unit in the voltage regulating mechanism in the following manner when the flexible interconnection system operates normally:

[0027] When the X phase of the flexible interconnection system operates normally, the on-off state of each switch unit in the voltage regulating mechanism is adjusted as follows:

[0028] Adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the A-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and fourth switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the B-phase parallel transformer to be forward-conducted, and the second, third, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the C-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected;

[0029] Wherein, X = a, b or c.

[0030] Furthermore, the controller is specifically configured to adjust the on / off state of each switch unit in the voltage regulating mechanism in the following manner when a short circuit fault occurs in the X phase of the flexible interconnection system:

[0031] Regulate the first and eighth switch units of the voltage regulating mechanisms corresponding to the X-phase combined secondary windings of the A, B, and C phase parallel transformers to be forward conductive, and disconnect the second, third, fourth, fifth, sixth, and seventh switch units;

[0032] Wherein, X = a, b or c.

[0033] In a second aspect, a control method for a flexible interconnection device is provided, the control method for the flexible interconnection device comprising:

[0034] The voltage regulating mechanism is controlled by adjusting the on-off state of each switch unit in the voltage regulating mechanism to adjust the number of turns of the corresponding combined secondary winding.

[0035] Preferably, when the flexible interconnection system operates normally, the on-off state of each switch unit in the voltage regulating mechanism is adjusted in the following manner:

[0036] When the X phase of the flexible interconnection system operates normally, the on-off state of each switch unit in the voltage regulating mechanism is adjusted as follows:

[0037] Adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the A-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and fourth switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the B-phase parallel transformer to be forward-conducted, and the second, third, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the C-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected;

[0038] Wherein, X = a, b or c.

[0039] Preferably, when a short circuit fault occurs in the X phase of the flexible interconnection system, the on-off state of each switch unit in the voltage regulating mechanism is adjusted in the following manner:

[0040] Regulate the first and eighth switch units of the voltage regulating mechanisms corresponding to the X-phase combined secondary windings of the A, B, and C phase parallel transformers to be forward conductive, and disconnect the second, third, fourth, fifth, sixth, and seventh switch units;

[0041] Wherein, X = a, b or c.

[0042] In a third aspect, a computer device is provided, comprising: one or more processors;

[0043] The processor is configured to execute one or more programs;

[0044] When the one or more programs are executed by the one or more processors, the control method of the flexible interconnection device is implemented.

[0045] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed, the control method of the flexible interconnection device is implemented.

[0046] The above one or more technical solutions of the present invention have at least one or more of the following beneficial effects:

[0047] The present invention relates to the technical field of flexible interconnection of distribution networks, specifically providing a flexible interconnection device and a control method thereof, comprising: a three-phase incoming port, a three-phase outgoing port, a three-phase parallel transformer, a voltage regulating mechanism, a three-phase series transformer, and a controller; the primary winding of the three-phase series transformer is connected between the three-phase incoming port and the three-phase outgoing port; one end of the three-phase primary winding of the three-phase parallel transformer is respectively connected to a three-phase busbar, and the other ends are connected to each other; each phase primary winding of the three-phase parallel transformer is provided with three groups of combined secondary windings, each combined secondary winding is connected to the three-phase series transformer via its corresponding voltage regulating mechanism; the controller is configured to use the voltage regulating mechanism to adjust the gear position of its corresponding combined secondary winding. The technical solution provided by the present invention, based on a multi-winding transformer with a series-parallel structure, simultaneously supports the construction of an interconnected network in steady state, achieves power flow transfer and load balancing, and limits short-circuit current according to demand in the event of a system fault, supporting the selectivity of the distribution network in normal closed-loop operation. The current-limiting reactor function is integrated into the flexible interconnection equipment, greatly reducing the equipment size. By simply increasing the number of turns of the secondary winding of the parallel transformer appropriately and orderly investing it according to the system's transient current limiting requirements to increase the equipment's short-circuit reactance and thus limit the short-circuit current, the system adaptability of the series-parallel transformer as a flexible interconnected equipment is improved, making the construction of a widely interconnected distribution network in the future possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a main structural block diagram of the flexible interconnection device according to an embodiment of the present invention;

[0049] Figure 2 is an equivalent circuit diagram of a series-parallel transformer according to an embodiment of the present invention;

[0050] Figure 3 This is a current path diagram of the system under normal operation according to an embodiment of the present invention;

[0051] Figure 4 This is a current path diagram after the current limiting winding is put into operation under a short-circuit fault in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0054] As disclosed in the background, the explosive growth of new distributed sources and loads, such as distributed photovoltaics and electric vehicles, has posed significant challenges to the capacity and reliability of distribution networks. Flexible interconnection equipment, enabling cross-connection of power flows between lines, unlocks the potential of distribution equipment resources, and improves power reliability, is considered an effective solution to this challenge.

[0055] However, current flexible interconnected equipment generally adopts an all-power electronic technology route, which has a low fault current tolerance level and lacks the ability to ride through faults. After a system fault occurs, it switches to open-loop operation, which goes against the original intention of normal closed-loop operation to improve system reliability.

[0056] To improve the above-mentioned problems, the present invention relates to the field of flexible interconnection technology for distribution networks, specifically providing a flexible interconnection device and a control method thereof, comprising: a three-phase incoming port, a three-phase outgoing port, a three-phase parallel transformer, a voltage regulating mechanism, a three-phase series transformer, and a controller; the primary winding of the three-phase series transformer is connected between the three-phase incoming port and the three-phase outgoing port; one end of the three-phase primary winding of the three-phase parallel transformer is respectively connected to the three-phase busbar, and the other end is connected to each other; each phase primary winding of the three-phase parallel transformer is provided with three groups of combined secondary windings, and each combined secondary winding is connected to the three-phase series transformer through its corresponding voltage regulating mechanism; the controller is used to adjust the gear position of its corresponding combined secondary winding using the voltage regulating mechanism. The technical solution provided by the present invention is implemented based on a multi-winding transformer with a series-parallel structure, and simultaneously supports the construction of an interconnected network in steady state, realizes power flow transfer and load balancing, and limits short-circuit current according to demand in the event of a system fault, supporting the selectivity of the distribution network in normal closed-loop operation. The current limiting reactor function is integrated into the flexible interconnection equipment, greatly reducing the equipment volume. By simply increasing the number of turns of the secondary winding of the parallel transformer appropriately and orderly putting it into use according to the system's transient current limiting requirements to increase the equipment's short-circuit reactance and thus limit the short-circuit current, the system adaptability of the series-parallel transformer as a flexible interconnected equipment is improved, making the construction of a widely interconnected distribution network in the future possible.

[0057] The above scheme is described in detail below.

[0058] Example 1

[0059] See attached Figure 1 , Figure 1 FIG. 1 is a main structural block diagram of a flexible interconnection device according to an embodiment of the present invention. Figure 1 As shown, the flexible interconnection device in the embodiment of the present invention mainly includes: a three-phase incoming line port, a three-phase outgoing line port, a three-phase parallel transformer, a voltage regulating mechanism, a three-phase series transformer and a controller;

[0060] A primary winding of a three-phase series transformer is connected between the three-phase incoming line port and the three-phase outgoing line port;

[0061] One end of the three-phase primary windings of the three-phase parallel transformer is connected to the three-phase busbars respectively, and the other ends are connected to each other;

[0062] Each primary winding of each phase of the three-phase parallel transformer is provided with three sets of combined secondary windings, and each combined secondary winding is connected to the three-phase series transformer through its corresponding voltage regulating mechanism;

[0063] The controller is used to adjust the gear position of the corresponding combined secondary winding using a voltage regulating mechanism.

[0064] In this example, the voltage regulating mechanism includes: a first switch unit, a second switch unit, a third switch unit, a fourth switch unit, a fifth switch unit, a sixth switch unit, a seventh switch unit and an eighth switch unit;

[0065] The first switch unit and the second switch unit are connected, and the connection point is a first common point of the voltage regulating mechanism;

[0066] The third switch unit and the fourth switch unit are connected, and the connection point is the second common point of the voltage regulating mechanism;

[0067] The fifth switch unit and the sixth switch unit are connected, and the connection point is the third common point of the voltage regulating mechanism;

[0068] The seventh switch unit and the eighth switch unit are connected, and the connection point is the fourth common point of the voltage regulating mechanism;

[0069] The series structure formed by the first switch unit and the second switch unit, the series structure formed by the third switch unit and the fourth switch unit, the series structure formed by the fifth switch unit and the sixth switch unit, and the series structure formed by the seventh switch unit and the eighth switch unit are connected in parallel with each other; the two parallel connection points of each series structure are respectively the fifth common point and the sixth common point of the voltage regulating mechanism.

[0070] In one embodiment, the three-phase parallel transformer includes: an A-phase parallel transformer, a B-phase parallel transformer, and a C-phase parallel transformer; the three-phase series transformer includes: an A-phase series transformer, a B-phase series transformer, and a C-phase series transformer; the secondary windings of the primary windings of each phase parallel transformer include a combined secondary winding of phase A, a combined secondary winding of phase B, and a combined secondary winding of phase C;

[0071] The fifth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the A-phase parallel transformer is connected to the head end of the secondary winding of the A-phase series transformer, the sixth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the A-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the B-phase parallel transformer, the sixth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the B-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the C-phase parallel transformer, and the sixth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the C-phase parallel transformer is respectively connected to the tail end of the secondary winding of the A-phase series transformer, the tail end of the secondary winding of the B-phase series transformer, and the tail end of the secondary winding of the C-phase series transformer;

[0072] The fifth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the A-phase parallel transformer is connected to the head end of the secondary winding of the B-phase series transformer, the sixth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the A-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the B-phase parallel transformer, the sixth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the B-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the C-phase parallel transformer, and the sixth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the C-phase parallel transformer is respectively connected to the tail end of the secondary winding of the A-phase series transformer, the tail end of the secondary winding of the B-phase series transformer, and the tail end of the secondary winding of the C-phase series transformer;

[0073] The fifth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the A-phase parallel transformer is connected to the head end of the secondary winding of the B-phase series transformer, the sixth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the A-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the B-phase parallel transformer, the sixth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the B-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the C-phase parallel transformer, and the sixth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the C-phase parallel transformer is respectively connected to the tail end of the secondary winding of the A-phase series transformer, the tail end of the secondary winding of the B-phase series transformer, and the tail end of the secondary winding of the C-phase series transformer.

[0074] In one embodiment, the combined secondary winding includes: a first regulating winding, a second regulating winding and a current limiting winding;

[0075] The first regulating winding has a head end connected to a first common point of the voltage regulating mechanism corresponding to the combined secondary winding, and a tail end connected to a head end of the second regulating winding;

[0076] The first end of the second regulating winding is connected to the second common point of the voltage regulating mechanism corresponding to the combined secondary winding, and the tail end is connected to the first end of the current limiting winding;

[0077] The head end of the current limiting winding is connected to the third common point of the voltage regulating mechanism corresponding to the combined secondary winding, and the tail end is connected to the fourth common point of the voltage regulating mechanism corresponding to the combined secondary winding.

[0078] In a specific embodiment, Figure 1 As shown, taking the parallel transformer A phase as an example, winding N 并1A For the primary winding of the parallel transformer, adjust the winding 1N 并2Aa1 , regulating winding 2N 并2Aa2 , current limiting winding N 并2Aa3 Together they form the first set of windings on the secondary side of the A phase of the parallel transformer, and the regulating winding 1N 并2Aa1 , regulating winding 2N 并2Aa2 , current limiting winding N 并2Aa3 After being reassembled by the voltage regulating mechanism composed of the switch array, it is connected in series with the secondary winding of phase A of the series transformer, and then transformed by the series transformer and superimposed into the system. 并2Ab1 , regulating winding 2N 并2Ab2 , current limiting winding N 并2Ab3 Together they form the second set of windings on the secondary side of the A phase of the parallel transformer, and the regulating winding 1N 并2Ab1 , regulating winding 2N 并2Ab2 , current limiting winding N 并2Ab3 After being reassembled by the voltage regulating mechanism composed of the switch array, it is connected in series with the secondary winding of phase B of the series transformer, and then transformed by the series transformer and superimposed into the system. 并2Ac1 , regulating winding 2N 并2Ac2 , current limiting winding N 并2Ac3 Together they form the third set of windings on the secondary side of the A phase of the parallel transformer, and the regulating winding 1N 并2Ac1 , regulating winding 2N 并2Ac2 , current limiting winding N 并2Ac3 The voltage regulator mechanism formed by the switch array is reassembled and connected in series with the secondary winding of phase C of the series transformer. After being transformed by the series transformer, it is superimposed on the system. The connection of the phase B and C windings of the parallel transformer is similar and will not be repeated here.

[0079] Figure 1 In, N 并1A : Number of turns of the primary winding of phase A of the parallel transformer, N 并2Aa1 : The number of turns of the first winding of the secondary side of the parallel transformer A phase, regulating winding 1, N 并2Aa2 : The number of turns of the first winding of the secondary side of the parallel transformer A phase, regulating winding 2, N 并2Aa3 : The number of turns of the first set of windings on the secondary side of the parallel transformer A phase, U1A 、U 1B 、U 1C : Three-phase voltage of the system on the left side of the series transformer, U 2A 、U 2B 、U 2C : Three-phase voltage of the system on the right side of the series transformer, U 3A 、U 3B 、U 3C : The three-phase voltage superimposed by the series transformer in the system, N1: The number of turns of the primary winding of the parallel transformer, N T : Number of turns of the primary winding of the series transformer.

[0080] When the system is operating normally, the voltage regulating mechanism composed of the switch array realizes the A-phase regulating winding 1N of the secondary side of the parallel transformer through different combinations of the opening and closing states of each switch device in the switch array. 并2Aa1 , regulating winding 2N 并2Aa2 , and B phase regulating winding 1N 并2Ab1 , regulating winding 2N 并2Ab2 , and C-phase regulating winding 1N 并2Ac1 , regulating winding 2N 并2Ac2 By using different connection modes, the superimposed voltage in the series system can be adjusted to achieve power flow transfer and load balancing between interconnected lines.

[0081] When a short circuit fault occurs in the system, the voltage regulating mechanism composed of the switch array uses different combinations of the opening and closing states of each switch device in the switch array to adjust the current limiting winding N according to the fault current limiting requirements of the system and the protection selectivity coordination requirements. 并2Aa3 and / or current limiting winding N 并2Ab3 and / or current limiting winding N 并2Ac3 It is connected in series to the secondary circuit to increase the leakage reactance of the secondary winding of the parallel transformer, thereby achieving the purpose of limiting the short-circuit current.

[0082] Taking phase A as an example (phase B, C and so on), assume that the output gear of the voltage regulating mechanism composed of the parallel transformer phase A switch array is S Aa The inductance corresponding to the minimum unit number of turns of the secondary winding of phase A of the parallel transformer is L σ , the minimum unit leakage reactance is X σ =ωL σ (ω is the angular frequency), then the leakage reactance of the secondary winding of phase A of the parallel transformer is X 并2A for:

[0083] X 并2A =S Aa ·ωL σ

[0084] Among them, the output gear of the voltage regulating mechanism is:

[0085]

[0086] K i Indicates the state of each switch unit (1 indicates forward conduction, -1 indicates reverse conduction, and 0 indicates disconnection).

[0087] After converting the secondary side parameters of the series-parallel transformer to the primary side, its equivalent circuit is as follows: Figure 2 As shown, the series transformer and the parallel transformer are both transformed into ideal transformers with a transformation ratio of 1:1. 1A : Primary loop current of series-parallel transformer, I 2A : Secondary loop current of series-parallel transformer, X 串1A 、X 串1B 、X 串1C : Equivalent leakage reactance of the three-phase primary side of the series transformer, X 串2A : Equivalent leakage reactance of the secondary side of phase A of the series transformer, X 并1A 、X 并1B 、X 并1C : Equivalent leakage reactance of the three-phase primary side of the parallel transformer, X 并2A 、X 并2B 、X 并2C : Equivalent leakage reactance of the three-phase secondary side of the parallel transformer, X 串2A : Equivalent leakage reactance of the secondary side of phase A of the series transformer, n 并A 、n 并B 、n 并C : Transformation ratio of three-phase parallel transformer, n 串2A : A-phase series transformer ratio;

[0088] The secondary circuit voltage of the series-parallel transformer is The equation is:

[0089]

[0090] in, is the current vector of the secondary circuit of the series-parallel transformer;

[0091] Substituting the leakage reactance formula into the equation, we get:

[0092]

[0093] Among them, S Aa 、S Ba 、S Ca The output gear of the voltage regulating mechanism composed of the parallel transformer A, B, and C phase switch array, n 串A is the series transformer ratio;

[0094] The secondary loop current is:

[0095]

[0096] Assuming that the parallel transformer is a three-phase symmetrical transformer with the same three-phase winding ratio, the parallel transformer ratio n 并 =n 并A =n 并B =n 并C ,but:

[0097]

[0098] It can be seen that by changing the output gear S of the voltage regulating mechanism composed of the parallel transformer A, B, and C phase switch arrays Aa 、S Ba 、S Ca That is, by reorganizing the secondary windings of the parallel transformers through the voltage regulating mechanism, the leakage inductance of the secondary windings of the parallel transformers can be increased, thereby suppressing the short-circuit current.

[0099] In one embodiment, the controller is specifically configured to control the voltage regulating mechanism to adjust the number of turns of the corresponding combined secondary winding by adjusting the on-off state of each switch unit in the voltage regulating mechanism.

[0100] In one embodiment, the controller is specifically configured to adjust the on / off state of each switch unit in the voltage regulating mechanism in the following manner when the flexible interconnection system operates normally:

[0101] When the X phase of the flexible interconnection system operates normally, the on-off state of each switch unit in the voltage regulating mechanism is adjusted as follows:

[0102] Adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the A-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and fourth switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the B-phase parallel transformer to be forward-conducted, and the second, third, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the C-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected;

[0103] Where X = a, b or c. The current path is as follows Figure 3 shown.

[0104] In one embodiment, the controller is specifically configured to adjust the on / off state of each switch unit in the voltage regulating mechanism in the following manner when a short circuit fault occurs in the X phase of the flexible interconnection system:

[0105] Regulate the first and eighth switch units of the voltage regulating mechanisms corresponding to the X-phase combined secondary windings of the A, B, and C phase parallel transformers to be forward conductive, and disconnect the second, third, fourth, fifth, sixth, and seventh switch units;

[0106] Where X = a, b or c. The current path is as follows Figure 4 shown.

[0107] Example 2

[0108] The present invention also provides a control method for a flexible interconnection device, the control method for the flexible interconnection device comprising:

[0109] When the flexible interconnection system operates normally, the on / off state of each switch unit in the voltage regulating mechanism is adjusted in the following manner:

[0110] When the X phase of the flexible interconnection system operates normally, the on-off state of each switch unit in the voltage regulating mechanism is adjusted as follows:

[0111] Adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the A-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and fourth switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the B-phase parallel transformer to be forward-conducted, and the second, third, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the C-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected;

[0112] Wherein, X = a, b or c.

[0113] The control method of the flexible interconnection device includes:

[0114] When a short circuit fault occurs in phase X of the flexible interconnection system, the on / off states of the switch units in the voltage regulating mechanism are adjusted as follows:

[0115] Regulate the first and eighth switch units of the voltage regulating mechanisms corresponding to the X-phase combined secondary windings of the A, B, and C phase parallel transformers to be forward conductive, and disconnect the second, third, fourth, fifth, sixth, and seventh switch units;

[0116] Wherein, X = a, b or c.

[0117] Example 3

[0118] Based on the same inventive concept, the present invention also provides a computer device, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of the control method of a flexible interconnection device in the above embodiment.

[0119] Example 4

[0120] Based on the same inventive concept, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It can be understood that the computer-readable storage medium here can include both built-in storage media in the computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space. These instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of a control method for a flexible interconnection device in the above embodiment.

[0121] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0122] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0123] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0124] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A flexible interconnection device, characterized in that: The device comprises: a three-phase incoming line port, a three-phase outgoing line port, a three-phase parallel transformer, a voltage regulating mechanism, a three-phase series transformer and a controller; A primary winding of a three-phase series transformer is connected between the three-phase incoming line port and the three-phase outgoing line port; One end of the three-phase primary windings of the three-phase parallel transformer is connected to the three-phase busbars respectively, and the other ends are connected to each other; Each primary winding of each phase of the three-phase parallel transformer is provided with three sets of combined secondary windings, and each combined secondary winding is connected to the three-phase series transformer through its corresponding voltage regulating mechanism; The controller is used to adjust the gear position of the corresponding combined secondary winding using the voltage regulating mechanism; The voltage regulating mechanism includes: a first switch unit, a second switch unit, a third switch unit, a fourth switch unit, a fifth switch unit, a sixth switch unit, a seventh switch unit and an eighth switch unit; The first switch unit and the second switch unit are connected, and the connection point is a first common point of the voltage regulating mechanism; The third switch unit and the fourth switch unit are connected, and the connection point is the second common point of the voltage regulating mechanism; The fifth switch unit and the sixth switch unit are connected, and the connection point is the third common point of the voltage regulating mechanism; The seventh switch unit and the eighth switch unit are connected, and the connection point is the fourth common point of the voltage regulating mechanism; The series structure formed by the first switch unit and the second switch unit, the series structure formed by the third switch unit and the fourth switch unit, the series structure formed by the fifth switch unit and the sixth switch unit, and the series structure formed by the seventh switch unit and the eighth switch unit are connected in parallel with each other; the two parallel connection points of each series structure are respectively the fifth common point and the sixth common point of the voltage regulating mechanism.

2. The device according to claim 1, wherein The three-phase parallel transformer includes: an A-phase parallel transformer, a B-phase parallel transformer, and a C-phase parallel transformer; the three-phase series transformer includes: an A-phase series transformer, a B-phase series transformer, and a C-phase series transformer; the secondary windings of the primary windings of each phase parallel transformer include a combined secondary winding of phase A, a combined secondary winding of phase B, and a combined secondary winding of phase C; The fifth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the A-phase parallel transformer is connected to the head end of the secondary winding of the A-phase series transformer, the sixth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the A-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the B-phase parallel transformer, the sixth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the B-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the C-phase parallel transformer, and the sixth common point of the voltage regulating mechanism corresponding to the a-phase combined secondary winding of the C-phase parallel transformer is respectively connected to the tail end of the secondary winding of the A-phase series transformer, the tail end of the secondary winding of the B-phase series transformer, and the tail end of the secondary winding of the C-phase series transformer; The fifth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the A-phase parallel transformer is connected to the head end of the secondary winding of the B-phase series transformer, the sixth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the A-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the B-phase parallel transformer, the sixth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the B-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the C-phase parallel transformer, and the sixth common point of the voltage regulating mechanism corresponding to the b-phase combined secondary winding of the C-phase parallel transformer is respectively connected to the tail end of the secondary winding of the A-phase series transformer, the tail end of the secondary winding of the B-phase series transformer, and the tail end of the secondary winding of the C-phase series transformer; The fifth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the A-phase parallel transformer is connected to the head end of the secondary winding of the B-phase series transformer, the sixth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the A-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the B-phase parallel transformer, the sixth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the B-phase parallel transformer is connected to the fifth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the C-phase parallel transformer, and the sixth common point of the voltage regulating mechanism corresponding to the c-phase combined secondary winding of the C-phase parallel transformer is respectively connected to the tail end of the secondary winding of the A-phase series transformer, the tail end of the secondary winding of the B-phase series transformer, and the tail end of the secondary winding of the C-phase series transformer.

3. The device according to claim 1, wherein The combined secondary winding includes: a first regulating winding, a second regulating winding and a current limiting winding; The first regulating winding has a head end connected to a first common point of the voltage regulating mechanism corresponding to the combined secondary winding, and a tail end connected to a head end of the second regulating winding; The first end of the second regulating winding is connected to the second common point of the voltage regulating mechanism corresponding to the combined secondary winding, and the tail end is connected to the first end of the current limiting winding; The head end of the current limiting winding is connected to the third common point of the voltage regulating mechanism corresponding to the combined secondary winding, and the tail end is connected to the fourth common point of the voltage regulating mechanism corresponding to the combined secondary winding.

4. The device according to claim 2, wherein The controller is specifically used to control the voltage regulating mechanism to adjust the number of turns of the corresponding combined secondary winding by adjusting the on-off state of each switch unit in the voltage regulating mechanism.

5. The device according to claim 2, wherein The controller is specifically used to adjust the on / off state of each switch unit in the voltage regulating mechanism in the following manner when the X phase of the flexible interconnection system operates normally: Adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the A-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and fourth switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the B-phase parallel transformer to be forward-conducted, and the second, third, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the C-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected; Wherein, X = a, b or c.

6. The device according to claim 2, wherein The controller is specifically used to adjust the on / off state of each switch unit in the voltage regulating mechanism in the following manner when a short circuit fault occurs in the X phase of the flexible interconnection system: Regulate the first and eighth switch units of the voltage regulating mechanisms corresponding to the X-phase combined secondary windings of the A, B, and C phase parallel transformers to be forward conductive, and disconnect the second, third, fourth, fifth, sixth, and seventh switch units; Wherein, X = a, b or c.

7. A control method for the flexible interconnection device according to any one of claims 1 to 6, characterized in that: The method comprises: The voltage regulating mechanism is controlled by adjusting the on-off state of each switch unit in the voltage regulating mechanism to adjust the number of turns of the corresponding combined secondary winding.

8. The method according to claim 7, wherein When the X phase of the flexible interconnection system operates normally, the on-off state of each switch unit in the voltage regulating mechanism is adjusted as follows: Adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the A-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and fourth switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the B-phase parallel transformer to be forward-conducted, and the second, third, fifth, sixth, seventh, and eighth switch units to be disconnected; adjust the first and second switch units of the voltage regulating mechanism corresponding to the X-phase combined secondary winding of the C-phase parallel transformer to be forward-conducted, and the third, fourth, fifth, sixth, seventh, and eighth switch units to be disconnected; Wherein, X = a, b or c.

9. The method according to claim 7, wherein When a short circuit fault occurs in phase X of the flexible interconnection system, the on / off states of the switch units in the voltage regulating mechanism are adjusted as follows: Regulate the first and eighth switch units of the voltage regulating mechanisms corresponding to the X-phase combined secondary windings of the A, B, and C phase parallel transformers to be forward conductive, and disconnect the second, third, fourth, fifth, sixth, and seventh switch units; Wherein, X = a, b or c.

10. A computer device, characterized in that: include: one or more processors; The processor is configured to execute one or more programs; When the one or more programs are executed by the one or more processors, the control method of the flexible interconnection device according to any one of claims 7 to 9 is implemented.

11. A computer-readable storage medium, characterized in that A computer program is stored thereon, and when the computer program is executed, the control method of the flexible interconnection device according to any one of claims 7 to 9 is implemented.

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