Power electronic change-over switch and hybrid on-load tap-changer

Abstract

The invention discloses a power electronic change-over switch and a hybrid on-load tap-changer, and relates to the field of power electronics, and the power electronic change-over switch comprises a first switch assembly and a second switch assembly. One end of the first switch assembly is connected with one end of the second switch assembly to form a current convergence point; the other end of the first switch assembly and the other end of the second switch assembly are respectively used for connecting different paths in a mechanical change-over switch; the first switch assembly and the second switch assembly conduct or disconnect current according to a switching instruction, and control the current to be switched in different paths; each of the first switch assembly and the second switch assembly is composed of one or more series-connected anti-parallel semiconductor switch device stages. According to the invention, the arc energy of the current in the change-over switch during switching of different paths is reduced, the arcing time of the tap switch is shortened, and the service life of the contact of the tap switch is prolonged.

Description

Technical Field

[0001] The invention relates to the field of power electronics, and in particular to a power electronic switching switch and a hybrid on-load tap changer. Background Art

[0002] Among the key primary electrical equipment in the UHV DC transmission system, the on-load tap changer is one of the important components of the DC converter transformer. The on-load tap changer can be roughly divided into two categories: one is the traditional mechanical tap changer, which achieves switching through insulating oil or vacuum arc extinguishing. This type of technology is generally inherited from the on-load tap changer for the AC system. The relevant technology is mature, and all converter transformer tap changers adopt mechanical solutions. The other type is the power electronic tap changer, which can achieve rapid arc extinguishing or even arc-free switching through the application of high-power power electronic units in the tap changer.

[0003] Regardless of mechanical or power electronic type, on-load tap changers are basically composed of two parts, namely: tap selector and transfer switch. There are usually two groups of tap selectors, one for use and one for idle. One group is used to conduct load current, and the other group is used for no-load gear shifting. The transformer taps can be selected step by step, that is, the transformer "gear" can be increased or decreased step by step. There are also generally two groups of transfer switches, which are arranged symmetrically, corresponding to the two groups of tap selectors, and can switch the current between the paths to realize the switching of the tap selector between the "use" and "idle" states.

[0004] Switches can be divided into two types: mechanical and hybrid. The hybrid switch adds a power electronic switch path in parallel to the original mechanical type, and realizes current switching by turning on and off the power electronic device.

[0005] However, the hybrid switching switch in the prior art is limited by the electrical structure. Under certain switching actions and arc current directions, due to poor closing synchronization and the inability of power electronic devices to close instantaneous currents, the tap changer has problems such as long arcing time and short contact life. Summary of the invention

[0006] In order to solve the problems of long arcing time and short contact life in the hybrid switching switch in the prior art.

[0007] The purpose of the present invention is to adopt the following technical solutions to achieve:

[0008] In a first aspect, the present invention provides a power electronic switching switch, comprising a first switch component and a second switch component;

[0009] One end of the first switch component and one end of the second switch component are connected to form a current junction; the other end of the first switch component and the other end of the second switch component are respectively used to connect different paths in the mechanical switching switch; the first switch component and the second switch component turn on or off the current according to the switching instruction, and control the current to switch between different paths;

[0010] The first switch assembly and the second switch assembly are both composed of one or more anti-parallel semiconductor switch device stages connected in series.

[0011] Preferably, the anti-parallel semiconductor switch device stage comprises a control unit, a resistance-capacitance loop and two semiconductor switch devices connected in anti-parallel;

[0012] The control unit includes a voltage-equalizing resistor and two semiconductor switch device driving boards; the voltage-equalizing resistor is connected in series between the two semiconductor switch device driving boards, and the two semiconductor switch device driving boards are respectively connected in parallel to the two ends of the semiconductor switch devices connected in reverse parallel;

[0013] The RC loop includes a damping capacitor and a damping resistor; the damping capacitor and the damping resistor are connected in series and then connected in parallel to the two ends of the semiconductor switch device connected in reverse parallel.

[0014] Furthermore, it also includes an energy supply unit to provide power input for the control unit, and the energy supply unit includes a current limiting reactor, a step-down transformer, an isolation transformer and an energy supply cable;

[0015] The energy supply cable is connected in series with the current limiting reactor and is respectively connected to two output terminals of the step-down transformer, and the step-down transformer is electrically connected to the isolation transformer; the energy supply cable runs through the energy supply magnetic ring.

[0016] Preferably, it further comprises a press-fitting unit; the press-fitting unit comprises a first press-fitting unit and a second press-fitting unit;

[0017] The first press-fit unit and the second press-fit unit press-fit half the number of semiconductor switch devices in the first switch assembly and the second switch assembly respectively, and the polarity arrangement directions of the semiconductor switch devices in the first press-fit unit and the second press-fit unit are opposite; the semiconductor switch devices of the same level in the first press-fit unit and the second press-fit unit are connected in parallel.

[0018] Furthermore, the first press-fitting unit and the second press-fitting unit have the same structure, and the first press-fitting unit includes a metal pressure-bearing end plate, an insulating pull rod and a disc spring;

[0019] Metal pressure-bearing end plates are fixed at both ends of the insulating pull rod, and half of the semiconductor switch devices in the first switch assembly and the second switch assembly are placed on the metal pressure-bearing end plate on one side, and a disc spring is fixed on the metal pressure-bearing end plate on the other side. The disc spring applies pressure to half of the semiconductor switch devices in the first switch assembly and the second switch assembly for press-fitting.

[0020] Furthermore, it also includes a heat sink, which is arranged between two adjacent semiconductor switch devices.

[0021] Furthermore, the press-fit unit and the RC circuit form a primary device, and the control unit and the energy supply unit form a secondary device; the primary device and the secondary device are arranged in upper and lower layers.

[0022] Furthermore, the control unit includes a first control unit and a second control unit, and the first control unit and the second control unit are arranged above the first press-fitting unit and the second press-fitting unit respectively.

[0023] Still further, it includes structural equipment, the structural equipment including support insulators;

[0024] The support insulator comprises a bottom support insulator and an intermediate support insulator;

[0025] The bottom support insulator is installed on the upper surface of the base, the top of the bottom support insulator is installed with an equipment frame, the middle support insulator is installed on the equipment frame, and the top of the middle support insulator is installed with an equipment frame; the equipment frame supports the primary equipment and / or secondary equipment.

[0026] Preferably, the semiconductor switch device level includes thyristor devices and / or IGBT tubes.

[0027] In a second aspect, the present invention proposes a hybrid on-load tap changer, comprising a mechanical switching switch, a transition resistor and a power electronic switching switch as described in any one of the above; the transition resistor is connected in series between the mechanical switching switch and the power electronic switching switch.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention provides a power electronic switching switch. The first switch component and the second switch component are respectively connected to different paths in a mechanical switching switch by adopting a first switch component and a second switch component which are composed of one or more series-connected anti-parallel semiconductor switch devices. The first switch component and the second switch component conduct or disconnect current according to a switching instruction, control the current to switch between different paths, reduce the arc energy of the current in the switching switch when switching between different paths, shorten the arcing time of the tap switch, and increase the contact life of the tap switch.

[0030] The present invention provides a hybrid on-load tap changer, which connects a power electronic switch with a mechanical switch and a transition resistor, and enables the mechanical switch to be turned on or off with zero voltage through the mutual cooperation of the power electronic switch and the mechanical switch, thereby realizing the switching of current in different paths. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of a power electronic switch and a hybrid on-load tap changer in Embodiment 1 of the present invention;

[0032] Figure 2 This is a wiring diagram of the thyristor stage circuit in Embodiment 1 of the present invention;

[0033] Figure 3 This is a wiring diagram of a thyristor press-fit unit in Embodiment 1 of the present invention;

[0034] Figure 4 The anti-parallel thyristor press-fit unit and its wiring diagram in Example 1 of the present invention;

[0035] Figure 5 This is a schematic diagram of the energy supply unit in Example 1 of the present invention;

[0036] Figure 6 This is a three-dimensional structural exploded view of the power electronic switching switch in Example 1 of the present invention.

[0037] In the figure: 1 is the first press-fit unit; 2 is the second press-fit unit; 3 is the first connection point; 4 is the second connection point; 5 is the current converging point; 6 is the thyristor; 7 is the heat sink; 8 is the metal pressure-bearing end plate; 9 is the insulating pull rod; 10 is the energy supply magnetic ring; 11 is the first energy supply unit; 12 is the second energy supply unit; 13 is the first control unit; 14 is the second control unit; 15 is the first resistance-capacitance circuit; 16 is the second resistance-capacitance circuit; 17 is the supporting insulator; 18 is the metal beam; 19 is the insulating beam; 20 is the thyristor driving board; 21 is the current limiting reactor; 22 is the step-down transformer; 23 is the isolation transformer. DETAILED DESCRIPTION

[0038] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0041] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0043] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0044] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0045] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0046] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0047] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0048] Embodiment 1:

[0049] An embodiment of the present invention provides a power electronic switching switch, including a first switch component Q1 and a second switch component Q2.

[0050] One end of the first switch component and one end of the second switch component are connected to form a current confluence point; the other end of the first switch component and the other end of the second switch component are respectively used to connect different paths in the mechanical switching switch; the first switch component and the second switch component turn on or off the current according to the switching instruction, and control the current to switch in different paths.

[0051] The first switch assembly and the second switch assembly are both composed of one or more anti-parallel semiconductor switch device stages connected in series.

[0052] A power electronic switching switch in an embodiment of the present invention adopts a first switch component and a second switch component composed of one or more series-connected anti-parallel semiconductor switch devices, and the first switch component and the second switch component are respectively connected to different paths in a mechanical switching switch. The first switch component and the second switch component turn on or off the current according to the switching instruction, and control the current to switch between different paths. The instantaneous current of the anti-parallel semiconductor switch device is used as a transition to achieve zero-voltage opening and closing of the mechanical switch, thereby reducing the arc energy when the current in the switching switch switches between different paths, shortening the arcing time of the tap switch, and increasing the contact life of the tap switch.

[0053] The power electronic switching switch in the embodiment of the present invention can be implemented using a variety of semiconductor switch devices, including thyristor devices and / or IGBT tubes. The thyristor device is used as an example for description below. The IGBT tube and other semiconductor switch devices have the same structure.

[0054] Specifically, Figure 1 As shown, in the embodiment of the present invention, the first switch component Q1 and the second switch component Q2 are power electronic switch sub-units using thyristors 6 as switch devices, and each switch sub-unit is composed of two thyristor paths in parallel; the thyristors in the two thyristor paths are arranged with opposite polarities to each other, and a single thyristor 6 in each thyristor path is called a stage, and two thyristors 6 with opposite polarities at the same stage are connected in parallel and are called an anti-parallel thyristor stage. In the embodiment of the present invention, the number of series-connected anti-parallel thyristor stages is greater than or equal to one.

[0055] Figure 1 There is a current confluence point 5 (point N) between the first switch component Q1 and the second switch component Q2, and the connection points between the first switch component Q1, the second switch component Q2 and the mechanical switch are the first connection point 3 (point S1) and the second connection point 4 (point S2), respectively.

[0056] Specifically, in the embodiment of the present invention, the anti-parallel semiconductor switch device level includes a control unit, a resistor-capacitor circuit and two semiconductor switch devices connected in reverse parallel; the control unit includes a voltage-equalizing resistor and two semiconductor switch device driving boards; the voltage-equalizing resistor is connected in series between the two semiconductor switch device driving boards, and the two semiconductor switch device driving boards are respectively connected in parallel to the two ends of the semiconductor switch devices connected in reverse parallel; the resistor-capacitor circuit includes a damping capacitor and a damping resistor; the damping capacitor is connected in series with the damping resistor, and then connected in parallel to the two ends of the semiconductor switch devices connected in reverse parallel.

[0057] Preferably, the wiring schematic diagram of a single anti-parallel thyristor stage in the embodiment of the present invention is as shown in the attached figure. Figure 2 As shown, each stage includes: two thyristors 6 connected in anti-parallel, a set of damping capacitors C buf, a set of damping resistors R buf , two thyristor drive boards 20 and their shared voltage balancing resistor R DC ; Among them, the damping capacitor C buf With damping resistor R buf connected in series and then connected in parallel to both ends of the thyristor stage; the two thyristor drive boards 20 and the voltage balancing resistor R DC connected in series, and then connected in parallel to both ends of the thyristor stage, and the voltage balancing resistor R DC It must be located between the two thyristor drive boards 20 .

[0058] From the attached Figure 1 It can be seen that the polarity direction of the left tube of the first switch component Q1 is consistent with that of the right tube of the second switch component Q2, and the polarity direction of the right tube of the first switch component Q1 is consistent with that of the left tube of the second switch component Q2. In this embodiment, five-level anti-parallel thyristors are used in the first switch component Q1 and the second switch component Q2, and the wiring schematic diagrams of the first switch component Q1 and the second switch component Q2 are appropriately changed.

[0059] Specifically, the power electronic switch in the embodiment of the present invention further includes a press-fit unit, and the press-fit unit includes a first press-fit unit 1 and a second press-fit unit 2 .

[0060] The first switch component Q1 and the second switch component Q2 are installed by a first press-fit unit 1 and a second press-fit unit 2. The first press-fit unit 1 and the second press-fit unit 2 respectively press-fit half the number of thyristors in the first switch component Q1 and the second switch component Q2. The polarity arrangement directions of the thyristors in the first press-fit unit 1 and the second press-fit unit 2 are opposite to each other.

[0061] Specifically, as attached Figure 3 As shown, the first switch component Q1 is between the first connection point 3 (point S1) and the current confluence point 5 (point N), and the second switch component Q2 is between the second connection point 4 (point S2) and the current confluence point 5 (point N). Figure 3 It can be found that the left tube of the first switch component Q1 and the right tube of the second switch component Q2 can be connected in series in the same thyristor press-fit unit (the first press-fit unit 1 in the figure). Similarly, the right tube of the first switch component Q1 and the left tube of the second switch component Q2 can be connected in series in the same thyristor press-fit unit (the second press-fit unit 2 in the figure); at the same time, parallel wiring is set at both ends of each level of thyristors with opposite polarities and the same level respectively located in the first press-fit unit 1 and the second press-fit unit 2 to realize anti-parallel connection of thyristors of the same level, that is, the two thyristors 6 of each anti-parallel thyristor level are respectively located in the first press-fit unit 1 and the second press-fit unit 2.

[0062] Specifically, as attached Figure 4As shown, the structures of the first press-fitting unit 1 and the second press-fitting unit 2 in the embodiment of the present invention are the same; taking the structure of the first press-fitting unit 1 as an example, the first press-fitting unit 1 in the embodiment of the present invention includes a metal pressure-bearing end plate 8, an insulating pull rod 9 and a disc spring; both ends of the insulating pull rod 9 are fixed with metal pressure-bearing end plates 8, half of the semiconductor switch devices in the first switch component Q1 and the second switch component Q2 are placed on the metal pressure-bearing end plate 8 on one side, and a disc spring is fixed on the metal pressure-bearing end plate on the other side, and the disc spring applies pressure to half of the semiconductor switch devices in the first switch component Q1 and the second switch component Q2 for press-fitting.

[0063] Preferably, the thyristors 6 inside the thyristor press-fitting unit are connected in series with each other in a consistent order, and there is a metal pressure-bearing end plate 8 at each end of the press-fitting unit. The two metal pressure-bearing end plates 8 are connected by four insulating pull rods 9 parallel to each other, and a disc spring is arranged on the inner side of one of the metal pressure-bearing end plates 8. The metal pressure-bearing end plate 8, the insulating pull rod 9, and the disc spring together constitute a set of pressure-bearing mechanisms to provide appropriate pressing force for the thyristor 6, that is, the thyristor press-fitting unit adopts the metal pressure-bearing end plate 8, the insulating pull rod 9, and the disc spring to provide the pressing force; the advantage of using the insulating pull rod 9 is that the four sides of the press-fitting unit can be hollowed out, which is convenient for setting various interfaces in these four directions.

[0064] Specifically, in the embodiment of the present invention, a heat sink 7 is arranged in the thyristor press-fitting unit, and the two poles of each thyristor 6 are arranged with a heat sink 7 to be connected with the cathode and anode end surfaces thereof; a wiring terminal is arranged on a certain side surface of the heat sink 7 in the horizontal direction, and the wiring terminal is offset to a certain end surface of the heat sink 7 in the vertical direction; the heat sink 7 is arranged alternately on the front and back sides along the series connection direction of the thyristors 6, and the wiring terminals are oriented in the same direction, that is, the wiring terminals are arranged on the side of the heat sink 7, and the heat sink wiring terminals of the first press-fitting unit 1 and the second press-fitting unit 2 are both oriented to another group, and the heat sink wiring terminals of the same anti-parallel thyristor stage are connected using a flexible conductor; adjacent heat sinks 7 with the same wiring terminal height can span the distance between two thyristor stages. This arrangement method reduces the types of parts, maintains a large air clearance, and provides sufficient installation and operation space.

[0065] The power electronic switch structure in the embodiment of the present invention can be divided into three parts: primary equipment, secondary equipment, and structural equipment;

[0066] The primary equipment includes: a thyristor pressing unit and a resistor-capacitor circuit unit; the thyristor pressing unit includes a first pressing unit 1 and a second pressing unit 2.

[0067] The secondary equipment includes: control unit and energy supply unit.

[0068] The structural equipment includes: supporting insulators 17, metal beams 18, insulating beams 19 and other accessories.

[0069] Specifically, the structure of the power electronic switch is in a layered arrangement, wherein: the primary equipment is arranged on the same layer, and the secondary equipment is arranged on the same layer. This arrangement is more convenient for realizing equipotential treatment of the internal structure of the switch; one feasible way of layered arrangement is: the primary equipment is arranged on the lower layer, and the secondary equipment is arranged on the upper layer. Another feasible way of layered arrangement is just the opposite, that is, the primary equipment and the secondary equipment are arranged on the upper and lower layers, and the upper and lower positions can be interchanged. In this embodiment, the primary equipment is located on the lower layer, and the secondary equipment is located on the upper layer.

[0070] Preferably, Figure 6 As shown, the thyristor components of the first switch assembly Q1 and the second switch assembly Q2 are distributed and pressed in two sets of press-fit units, and each set of press-fit units contains half of the thyristor components of the first switch assembly Q1 and the second switch assembly Q2; the two sets of press-fit units are adjacent to each other and arranged in parallel in the same layer, and the connection terminals of the heat sink 7 in each set of press-fit units are all facing the other press-fit unit, and the heat sink 7 connection terminals of the same-level anti-parallel thyristors 6 are connected by flexible conductors; connecting conductors are set at both ends of one set of press-fit units, corresponding to the connection points S1 and S2, and connecting conductors are set in the middle position of the other set of press-fit units, corresponding to the junction point N; for example, connecting conductors are set at both ends of the first press-fit unit 1 (or the second press-fit unit 2), corresponding to the attached Figure 3 The first connection point 3 (point S1) and the second connection point 4 (point S2) in the wiring point are provided, and the middle position of the second press-fit unit 2 (or the first press-fit unit 1) is provided with a connecting conductor, corresponding to the attached Figure 3 The current converging point 5 (point N) in.

[0071] Each anti-parallel thyristor stage is configured with (or shares) a set of RC circuits, each set of RC circuits includes a set of damping resistors and a set of damping capacitors; in this embodiment, a total of 10 sets of RC circuits are configured, and each group is evenly divided into two groups of first RC circuits 15 and second RC circuits 16, with 5 sets in each group. The first RC circuits 15 and the second RC circuits 16 are arranged on the outside of the first thyristor press-fit unit 1 and the second press-fit unit 2, respectively. From the top view, it can be found that the arrangement order of the primary equipment is the first RC circuit 15, the first press-fit unit 1, the second press-fit unit 2, and the second RC circuit 16. The RC circuit and the press-packed unit are connected in an interval-bridge manner. When each group of RC circuit units is connected to the thyristor stage in the corresponding press-packed unit, each interval of one thyristor is connected to one RC circuit; that is, the five sets of RCs in the first RC circuit 15 are respectively connected to the thyristor stages 1, 3, 5, 7, and 9 in the first press-packed unit 1, and the five sets of RCs in the second RC circuit 16 are respectively connected to the thyristor stages 2, 4, 6, 8, and 10 in the second press-packed unit 2.

[0072] Specifically, in the embodiment of the present invention, the control unit is composed of a thyristor driving board 20 and a voltage-equalizing resistor, and each group of press-fit units corresponds to a group of control units, so the control unit in the present invention includes a first control unit 13 and a second control unit 14, and the number of control boards in the first control unit 13 and the second control unit 14 is equal to the number of thyristors; the first control unit 13 and the second control unit 14 are respectively arranged on the upper layer of the thyristor press-fit unit, that is, the first control unit 13 and the second control unit 14 are located in the upper layer of the switch structure, and are respectively arranged directly above the first press-fit unit 1 and the second press-fit unit 2, and several groups of voltage-equalizing resistor units are arranged in the middle of the two groups of control units, that is, the voltage-equalizing resistor units are arranged in the middle position of the two groups of control units; the number of voltage-equalizing resistor units is equal to half of the number of control boards.

[0073] Specifically, the power electronic switch in the embodiment of the present invention further includes an energy supply unit, which provides power input for the thyristor control unit, as shown in the attached Figure 5 As shown, the energy supply unit includes a current limiting reactor 21, a step-down transformer 22, an isolation transformer 23, a plurality of energy supply magnetic rings 10 and an energy supply cable.

[0074] Preferably, the isolation transformer 23 is arranged separately from the switch body (or arranged independently of the switch body), and the step-down transformer 22 and the current limiting inductor 21 are integrated (or integrated into) the switch body; the control unit corresponding to the power supply magnetic ring 10 is divided into two groups, namely the first power supply unit 11 and the second power supply unit 12, and the number of power supply magnetic rings in each group is equal to the number of control boards; the first power supply unit 11 and the second power supply unit 12 are respectively arranged on the outside of the first control unit 13 and the second control unit 14; the power supply cable is connected in series with the current limiting inductor 21 and then connected to the two output terminals of the step-down transformer 22, and the power supply cable runs through all the power supply magnetic rings 10 as a whole.

[0075] The energy supply unit uses an industrial frequency input inverter to generate a high-frequency power supply, isolates the voltage through a high-frequency isolation transformer, transmits energy, and forms a single-turn high-frequency current bus. The current bus passes through all energy supply magnetic ring transformers in turn, and outputs a stable DC voltage through a rectifier-stabilized power supply to form a multi-channel drive power supply. Through a switching power supply and an inverter, the 220VAC / 50Hz voltage is converted into a 20kHz high-frequency AC voltage, which is supplied to each level of semiconductor devices through an isolation transformer, cable, energy supply magnetic ring, and rectifier-stabilized power supply.

[0076] Specifically, in the embodiment of the present invention, the structural equipment includes a supporting insulator; the supporting insulator includes a bottom supporting insulator and an intermediate supporting insulator; the bottom supporting insulator is installed on the upper surface of the base, the top of the bottom supporting insulator is installed with an equipment frame, the intermediate supporting insulator is installed on the equipment frame, and the top of the intermediate supporting insulator is installed with the equipment frame; the equipment frame supports the primary equipment and / or secondary equipment.

[0077] Preferably, in the embodiment of the present invention, the structural equipment is responsible for supporting and positioning all primary equipment and secondary equipment in the switch, and at the same time meets the requirements of potential isolation and equipotential connection; the structural equipment is upright on the ground in a supporting form, and is divided from bottom to top into a base, a bottom support insulator 17, a primary equipment frame, an intermediate support insulator 17, and a secondary equipment frame; the base and the support insulator 17 provide support force for the entire switch and isolate it from the ground potential; wherein the primary equipment frame and the secondary equipment frame use metal beams 18 and insulating beams 19 to form a rectangular structure, the metal beams 18 are used to support the weight of the equipment, and the insulating beams 19 are used to connect the metal beams in the direction of the equipment potential span. Among them, the bottom support insulator 17 is installed on the upper surface of the base, and an installation plane is formed on the upper flange surface of the bottom support insulator 17 to support the primary equipment frame; the primary equipment frame includes two metal beams 18 and two insulating beams 19, the metal beams 18 are used to support and install the primary equipment, and the insulating beams 19 are used to connect the two metal beams 18 in the potential span direction to form a frame structure; the intermediate support insulator 17 is used to isolate the potential difference between the primary equipment and the secondary equipment; the secondary equipment frame has the same structure as the primary equipment frame.

[0078] Embodiment 2:

[0079] The present invention based on the same inventive concept also provides a hybrid on-load tap changer, including a power electronic switch and a mechanical switch part thereof; wherein the wiring schematic diagram of the power electronic switch and the mechanical switch part thereof is as shown in Figure 1 As shown, the power electronic transfer switch of the hybrid on-load tap changer is connected in parallel with the mechanical transfer switch, and its main path uses power electronic devices as the basic switch unit.

[0080] As attached Figure 1 As shown, the main path is divided into two groups, the first switch component Q1 and the second switch component Q2, that is, the power electronic switch is composed of two sets of thyristor components, namely the first switch component Q1 and the second switch component Q2. The connection points of the first switch component Q1, the second switch component Q2 and the mechanical switch are the first connection point 3 (point S1) and the second connection point 4 (point S2), which are connected to the odd and even gears of the mechanical switch as the two ends of the power electronic switch, and the odd and even gears are the taps of the on-load tap changer; there is a current confluence point 5 (point N) between the first switch component Q1 and the second switch component Q2, which is connected to the power supply as one end of the power electronic switch.

[0081] Specifically, a transition resistor R is connected between the power electronic switch and its mechanical switch, wherein the transition resistor R is used for commutation suppression, and the switching of the tap is achieved through the cooperation between the opening and closing of the mechanical switch and the on and off of the power electronic device.

[0082] The working process of a hybrid on-load tap changer in an embodiment of the present invention is as follows: when the first switch component Q1 is closed, the second switch component Q2 is disconnected, the switch Ka is disconnected, the switch Ka is short-circuited by the first switch component Q1, and is turned off with zero voltage, thereby effectively suppressing the size of the arc generated by the mechanical contact during the switch switching process.

[0083] At the moment when the current is 0, the first switch component Q1 is disconnected, the second switch component Q2 is closed, and the switch Kc switches from the gear position CR1 to the gear position CR2; the first switch component Q1 is closed, and a circulating current is generated in the circuit, which is suppressed by the transition resistor R. The circulating current time is minimized as much as possible, and the second switch component Q2 is disconnected when U=0. At this time, the current supplies power to the even gear through the first switch component Q1, and the switch Kd switches from the gear position CT1 to the gear position CT2; the first switch component Q1 is disconnected, and the switch Kb is closed to complete the switching.

[0084] In the embodiment of the present invention, the power electronic switching switch is connected to the mechanical switching switch, and the power electronic switching switch and the mechanical switching switch cooperate with each other in turning on and off, so that the mechanical switching switch can be turned on or off with zero voltage, thereby realizing the switching of current in different paths.

[0085] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A power electronic switch, characterized in that: including a first switch assembly and a second switch assembly; One end of the first switch component and one end of the second switch component are connected to form a current junction; the other end of the first switch component and the other end of the second switch component are respectively used to connect different paths in the mechanical switching switch; the first switch component and the second switch component turn on or off the current according to the switching instruction, and control the current to switch between different paths; The first switch assembly and the second switch assembly are both composed of one or more anti-parallel semiconductor switch device stages connected in series.

2. A power electronic switch according to claim 1, characterized in that: The anti-parallel semiconductor switch device stage includes a control unit, a resistance-capacitance loop and two semiconductor switch devices connected in anti-parallel; The control unit includes a voltage-equalizing resistor and two semiconductor switch device driving boards; the voltage-equalizing resistor is connected in series between the two semiconductor switch device driving boards, and the two semiconductor switch device driving boards are respectively connected in parallel to the two ends of the semiconductor switch devices connected in reverse parallel; The RC loop includes a damping capacitor and a damping resistor; the damping capacitor and the damping resistor are connected in series and then connected in parallel to the two ends of the semiconductor switch device connected in reverse parallel.

3. A power electronic switch according to claim 2, characterized in that: It also includes an energy supply unit, which provides power input for the control unit, and the energy supply unit includes a current limiting reactor, a step-down transformer, an isolation transformer and an energy supply cable; The energy supply cable is connected in series with the current limiting reactor and is respectively connected to two output terminals of the step-down transformer, and the step-down transformer is electrically connected to the isolation transformer; the energy supply cable runs through the energy supply magnetic ring.

4. A power electronic switch according to claim 1, characterized in that: It also includes a press-fitting unit; the press-fitting unit includes a first press-fitting unit and a second press-fitting unit; The first press-fit unit and the second press-fit unit press-fit half the number of semiconductor switch devices in the first switch assembly and the second switch assembly respectively, and the polarity arrangement directions of the semiconductor switch devices in the first press-fit unit and the second press-fit unit are opposite; the semiconductor switch devices of the same level in the first press-fit unit and the second press-fit unit are connected in parallel.

5. A power electronic switch according to claim 4, characterized in that: The first press-fitting unit and the second press-fitting unit have the same structure, and the first press-fitting unit comprises a metal pressure-bearing end plate, an insulating pull rod and a disc spring; Metal pressure-bearing end plates are fixed at both ends of the insulating pull rod, and half of the semiconductor switch devices in the first switch assembly and the second switch assembly are placed on the metal pressure-bearing end plate on one side, and a disc spring is fixed on the metal pressure-bearing end plate on the other side. The disc spring applies pressure to half of the semiconductor switch devices in the first switch assembly and the second switch assembly for press-fitting.

6. A power electronic switch according to claim 4, characterized in that: The device also includes a heat sink, which is arranged between two adjacent semiconductor switch devices.

7. A power electronic switch according to claim 3 or 4, characterized in that: The press-fit unit and the RC circuit form a primary device, and the control unit and the energy supply unit form a secondary device; the primary device and the secondary device are arranged in upper and lower layers.

8. A power electronic switch according to claim 7, characterized in that: The control unit includes a first control unit and a second control unit, and the first control unit and the second control unit are arranged above the first press-fitting unit and the second press-fitting unit respectively.

9. A power electronic switch according to claim 7, characterized in that: Also included is structural equipment, the structural equipment including support insulators; The support insulator comprises a bottom support insulator and an intermediate support insulator; The bottom support insulator is installed on the upper surface of the base, the top of the bottom support insulator is installed with an equipment frame, the middle support insulator is installed on the equipment frame, and the top of the middle support insulator is installed with an equipment frame; the equipment frame supports the primary equipment and / or secondary equipment.

10. A power electronic switch according to claim 1, characterized in that: The semiconductor switch device stage includes thyristor devices and / or IGBT tubes.

11. A hybrid on-load tap changer, characterized in that: It comprises a mechanical switching switch, a transition resistor and a power electronic switching switch according to any one of claims 1 to 10; the transition resistor is connected in series between the mechanical switching switch and the power electronic switching switch.

Images