Arc-free on-load tap changer, switching control method, and electrical equipment

Abstract

The present invention belongs to the technical field of power transmission and transformation in a power system, and provides an arc-free on-load tap changer, a switching control method, and an electric device. The arc-free on-load tap changer includes at least two master switches, two changeover switches, and two thyristor auxiliary modules. The two thyristor auxiliary modules are connected in parallel to the master switch that is originally turned on or the master switch that should be turned on according to the required timing during the switching process of the master switch. The master switch and the changeover switch are both rotary switches, and the movable contacts of the master switch and the changeover switch are both mounted on a rotating shaft, and the corresponding fixed contacts of the master switch and the changeover switch are connected to the corresponding transformer tap, and the movable contacts are connected to the fixed contacts of the same shaft during the process of rotating together with the rotating shaft. The opening and closing of the corresponding master switch, the changeover switch, and the control switch are controlled according to a predetermined timing, thereby realizing an uninterrupted transfer of the load current from the master switch that is originally turned on to the master switch that should be turned on, and no arc occurs during the opening and closing process of each switch.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This invention claims priority to a Chinese patent application filed with the China Patent Office on March 9, 2022, bearing application number 202210232941.2 and entitled "Arc-free on-load tap changer, switching control method and electrical equipment", the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the technical field of power transmission and transformation in a power system, and in particular to an arc-free on-load tap changer, a switching control method and an electric device. [Background technology]

[0003] The statements in this section are merely intended to provide background information related to the present invention and do not necessarily constitute prior art.

[0004] Switching a transformer tap from one voltage to another under load conditions while ensuring that the power supply to the power consumers is not interrupted during the switching requires the use of an on-load tap changer. Here, the on-load tap changer refers to a voltage regulation device for changing the connection position of the transformer winding taps suitable for operation under transformer excitation or load. The basic principle is to enable switching between taps on the transformer windings while ensuring that the load current is not interrupted, thereby changing the number of turns of the windings, i.e. the voltage ratio of the transformer, and ultimately achieving the purpose of voltage regulation.

[0005] Traditional on-load tap changers usually use resistive transition to realize the switching process of two taps with different voltages, but the resistive transition has the disadvantage that arcs will occur during the switching process of the switcher.

[0006] Each of the patent documents having application numbers CN2012105791965, CN2013105976862 and CN2014102602640 provides a different arc-free on-load tap changer. However, the oil-immersed on-load tap changer is suitable for driving by a rotating shaft, and the inventors found that the devices proposed in the above applications are mainly used when the circuit is composed of contactor or relay contacts, so the arc-free on-load tap changer composed of contactor or relay is not suitable for use in an oil-immersed transformer.

[0007] The solution for on-load tap changer provided in patent document having application number CN2018102904704 has a structure driven by a rotating shaft. However, the inventors found that in this patent document, various switches are distributed on two or three rotating shafts that are not synchronized with each other, and when some rotating shafts need to rotate, the other rotating shafts need to be stationary, so the operating structure is still complicated, and it lacks a cooperative control mechanism between the rotating shafts, a cooperation means between the movable contacts and fixed contacts of the rotating shafts, and a drive means for the control switch. Summary of the Invention

[0008] In order to solve the technical problems existing in the above-mentioned background art, the present invention provides an arc-free on-load tap changer, a switching control method, and an electrical device which are applied to an oil-immersed transformer driven by a rotating shaft and have the advantages of a simple operating structure and a short time required for completing one switching process.

[0009] To achieve the above objectives, the present invention adopts the following technical solutions:

[0010] A first aspect of the present invention provides an arc-free on-load tap changer.

[0011] In one or more embodiments, the power supply includes at least two master switches, two changeover switches, and two thyristor auxiliary modules, each thyristor auxiliary module includes two control switches, the two master switches include one originally turned on master switch and one to be turned on master switch, the master switches are connected to corresponding circuits of the voltage regulating coil through corresponding transformer taps, and the two thyristor auxiliary modules are connected in parallel to the originally turned on master switch or the to be turned on master switch according to the required timing during the switching process of the master switches; The master switch and the changeover switch are both rotary switches, the movable contacts of the master switch and the changeover switch are both mounted on a rotating shaft, the corresponding fixed contacts of the master switch and the changeover switch are connected to corresponding transformer taps, and the movable contacts are connected to the fixed contacts on the same shaft in the process of rotating together with the rotating shaft, and the opening and closing of the corresponding master switch, changeover switch and control switch are controlled according to a predetermined timing, thereby realizing uninterrupted transfer of load current from the master switch that is originally on to the master switch that should be turned on, and no arc is generated in the process of opening and closing each switch, thereby providing a first arc-free on-load tap changer structure.

[0012] In one embodiment, one end of each of the two thyristor auxiliary modules is floating before the master switch is switched on, or is connected in parallel to the master switch that is originally turned on, and the voltages across the two thyristor auxiliary modules are both zero.

[0013] In one embodiment, the control switch is also a rotary switch, and the movable contact of the control switch is also provided on a rotating shaft.

[0014] In one embodiment, all the fixed contacts of both the master switch and the changeover switch are divided into at least two sets in total, and the fixed contacts of each set are attached to a corresponding rail, and the rails are all centered on a rotation axis and fixed so as not to move.

[0015] In one embodiment, the number of fixed contacts in each set is the same.

[0016] In one embodiment, each set of fixed contacts is attached to a corresponding rail at equal arcs.

[0017] In one embodiment, when all the fixed contacts of both the master switch and the changeover switch are divided into two groups in total, the relationship of the arc degrees of the fixed contacts on the corresponding two rails is as follows: 0<ΔW <W1<0.5W<W2 ΔW=(W-W2) where W and W1 are the radians between the center positions of the fixed contacts and the radians of each fixed contact on the first rail, respectively, and W2 and ΔW are the radians of each fixed contact and the radians of the gap between the fixed contacts on the second rail, respectively.

[0018] In one embodiment, the normal operating condition of the arc-free on-load tap changer prior to switching of the master switch is: One movable contact on the rotating shaft is located on the center line of one fixed contact, and the remaining movable contacts are each located on the center lines of the gaps between the fixed contacts.

[0019] In one embodiment, when there are a total of three movable contacts on the rotating shaft, the first movable contact and the second movable contact are disposed on both sides of the third movable contact, and the arc degree relationship of the three movable contacts is as follows: 0<ΔW <W 1可動 <0.5W <W 2可動 ΔW 可動 =(WW 2可動 ) where W is the arc between the center positions of each fixed contact on the first rail, and W 1可動 , W 2可動 is the arc degree of the first and second movable contacts, and ΔW 可動 is the arc of the gap between the second movable contacts.

[0020] In one embodiment, the arc of the fixed contact is greater than the arc of the movable contact.

[0021] In one embodiment, the arc of the fixed contact is less than or equal to the arc of the movable contact.

[0022] In one embodiment, the opening and closing of the control switch is controlled by a control mechanism.

[0023] In one embodiment, the control mechanism is a mechanical linkage.

[0024] In one embodiment, the mechanical linkage mechanism includes a deflection shaft, the deflection shaft is fixed to the rotation shaft and rotates together with the rotation shaft, a lever arm and a spring arm are attached to the deflection shaft and are rotatable around the deflection shaft, and one end of the spring arm has a contact, which rotates together with the rotation shaft to contact or disengage from a corresponding control switch, thereby opening and closing the corresponding control switch.

[0025] In one embodiment, the control mechanism is realized by a changeover switch driven by a rotating shaft.

[0026] In one embodiment, the two thyristor sub-modules have the same structure.

[0027] In one embodiment, each thyristor auxiliary module includes a pair of thyristors connected in parallel in the opposite direction, and an RC series circuit is connected in parallel to both ends of the thyristors connected in parallel in the opposite direction. A capacitor, a resistor and a diode are sequentially connected between the gate and cathode of each thyristor, the positive pole of the diode is connected to the cathode of the corresponding thyristor, and the negative pole of the diode is connected to the gate of the corresponding thyristor. A control switch is further connected in series between the gates of the two thyristors connected in parallel in the opposite direction via a full bridge rectifier circuit. Two Zener diodes, a resistor and another control switch are further connected in series between the gates of the two thyristors connected in parallel in the opposite direction. The two Zener diodes are connected in series in the opposite direction. The Zener diodes and the resistor are connected in series and then connected to the output terminal of the full bridge rectifier circuit. The negative pole of the Zener diode corresponds to the positive output terminal of the full bridge rectifier circuit, and the positive pole of the Zener diode corresponds to the negative output terminal of the full bridge rectifier circuit.

[0028] The present invention includes at least two master switches, two changeover switches and two thyristor auxiliary modules, each thyristor auxiliary module includes two control switches, the two master switches include one originally turned on master switch and one to be turned on master switch, the master switches are connected to corresponding circuits of voltage regulating coils through corresponding transformer taps, and the two thyristor auxiliary modules are connected to the originally turned on master switch or the to be turned on master switch according to the required timing during the switching process of the master switches; The second arc-less on-load tap changer is characterized in that the master switch and the change-over switch are both rotary switches, the master switch and the corresponding change-over switch are linked and rotate synchronously, and the opening and closing of the corresponding master switch, change-over switch and control switch are controlled according to a predetermined timing, thereby realizing uninterrupted transfer of the load current from the master switch that is originally on to the master switch that should be turned on, and no arc is generated during the opening and closing process of each switch.

[0029] In one embodiment, the control mechanism is a mechanical linkage.

[0030] In one embodiment, the mechanical linkage mechanism includes a deflection shaft, the deflection shaft is fixed to the rotation shaft and rotates together with the rotation shaft, a lever arm and a spring arm are attached to the deflection shaft and are rotatable around the deflection shaft, and one end of the spring arm has a contact, which rotates together with the rotation shaft to contact or disengage from a corresponding control switch, thereby opening and closing the corresponding control switch.

[0031] In one embodiment, the control mechanism is realized by a changeover switch driven by a rotating shaft.

[0032] In one embodiment, the two thyristor sub-modules have the same structure.

[0033] In one embodiment, each thyristor auxiliary module includes a pair of thyristors connected in parallel in the opposite direction, and an RC series circuit is connected in parallel to both ends of the thyristors connected in parallel in the opposite direction. A capacitor, a resistor and a diode are sequentially connected between the gate and cathode of each thyristor, the positive pole of the diode is connected to the cathode of the corresponding thyristor, and the negative pole of the diode is connected to the gate of the corresponding thyristor. A control switch is further connected in series between the gates of the two thyristors connected in parallel in the opposite direction via a full bridge rectifier circuit. Two Zener diodes, a resistor and another control switch are further connected in series between the gates of the two thyristors connected in parallel in the opposite direction. The two Zener diodes are connected in series in the opposite direction. The Zener diodes and the resistor are connected in series and then connected to the output terminal of the full bridge rectifier circuit. The negative pole of the Zener diode corresponds to the positive output terminal of the full bridge rectifier circuit, and the positive pole of the Zener diode corresponds to the negative output terminal of the full bridge rectifier circuit.

[0034] A second aspect of the present invention provides a method for controlling switching of an arc-less on-load tap changer.

[0035] In one or more embodiments, a first method for controlling switching of an arc-less on-load tap changer provided by the present invention includes: controlling the rotation of the rotating shaft to drive the movable contacts to connect to or disconnect from the corresponding fixed contacts; and controlling the opening and closing of the corresponding master switch, changeover switch and control switch according to a predetermined timing, thereby realizing uninterrupted transfer of the load current from the master switch that is originally turned on to the master switch that should be turned on, and no arc is generated during the opening and closing process of each switch.

[0036] In one embodiment, the rotational manner of the rotation shaft includes clockwise rotation and counterclockwise rotation.

[0037] In one embodiment, the process of toggling the master switch once is: Making the movable contact of the corresponding changeover switch contact the corresponding fixed contact to turn on the first control switch of the thyristor auxiliary module connected to the originally turned-on master switch, and turning off the originally turned-on master switch; Turning on the second control switch of the thyristor auxiliary module connected to the master switch to be turned on, and turning off the first control switch of the thyristor auxiliary module connected to the master switch that was originally turned on; When a set time interval has elapsed, turning on a first control switch of a thyristor auxiliary module connected to the master switch to be turned on, and turning on the master switch to be turned on; All the control switches are turned off, and the movable contacts of the corresponding changeover switches are no longer in contact with the corresponding fixed contacts, completing one changeover of the master switch.

[0038] In one embodiment, the voltage across both thyristor auxiliary modules is zeroed out before the master switch switches.

[0039] A second method for controlling switching of an on-load tap changer without arcing provided by the present invention includes the following steps: controlling the opening and closing of corresponding master switches and changeover switches so as to interlock and rotate synchronously; and controlling the opening and closing of the corresponding master switch, changeover switch and control switch according to a predetermined timing, thereby realizing uninterrupted transfer of the load current from the master switch that is originally turned on to the master switch that should be turned on, and no arc is generated during the opening and closing process of each switch.

[0040] A third aspect of the present invention provides an electric device.

[0041] In one or more embodiments, the electrical device comprises: a voltage regulating coil including a plurality of transformer taps; a non-arc on-load tap changer connected to the voltage regulating coil, The arc-less on-load tap changer is the arc-less on-load tap changer according to any one of the preceding claims.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] (1) In the arc-free on-load tap changer provided by the present invention, the movable contacts are attached to a rotating shaft and rotated together with the rotating shaft to connect with the corresponding fixed contacts, thereby solving the problem that the conventional arc-free on-load tap changer is not suitable for use in an oil-filled transformer. The arc-free on-load tap changer of the present invention uses a rotating shaft as a driving force, and finally controls the originally turned-on master switch, the changeover switch, the control switch, and the master switch to be turned on to open and close correspondingly according to a predetermined timing, thereby realizing no arc during the opening and closing process, and switching between master switches, and enabling various switches and contacts to operate in the oil tank of the oil-filled transformer.

[0044] (2) With regard to the arc-free on-load tap changer provided by the present invention, it is possible to realize the arc-free on-load tap changer of the present invention based on the basic structure of a conventional oil-immersed on-load tap changer, and it is also possible to realize the arc-free on-load tap changer of the present invention based on the basic structure of a conventional oil-immersed non-magnetized tap changer.

[0045] (3) In the arc-free on-load tap changer provided by the present invention, a change-over switch includes multiple fixed contacts, corresponding fixed contacts of the change-over switch are connected to transformer taps, and at least one control switch is mounted on a rotating shaft and driven by the rotating shaft to control opening and closing, thus upgrading the oil-filled vacuum on-load tap changer based on the basic structure of the traditional oil-filled vacuum on-load tap changer, and realizing no arc during the opening and closing process and switching between master switches.

[0046] (4) The arc-free on-load tap changer of the present invention retains the experience gained in the past, and has a simplified structure, small volume, light weight, reduced cost, small operating vibration, low failure rate, and short time for one complete switching process.

[0047] Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. [Brief description of the drawings]

[0048] The drawings in the specification which form a part of the present invention are intended to provide a further understanding of the present invention, and the illustrative embodiments of the present invention and the description thereof are intended to provide an understanding of the present invention and are not intended to unduly limit the present invention. [Figure 1] FIG. 2 is a circuit diagram of a thyristor auxiliary module according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a structural diagram of a rotating shaft of the first non-arc on-load tap changer according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a horizontally expanded structural diagram of a first arc-free on-load tap changer according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the relationship between the arc degrees of fixed contacts according to an embodiment of the present invention. [Diagram 5] 3 is a structural diagram of switches KB1 and KB2 according to an embodiment of the present invention. [Figure 6] FIG. 2 is a structural diagram of a rotating shaft of a second arc-free on-load tap changer according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] The invention will be further explained below in connection with the figures and examples.

[0050] It should be noted that the following detailed description is illustrative and is intended to further illustrate the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs.

[0051] It should be noted that the terminology used herein is merely for the purpose of describing specific embodiments and is not intended to limit the exemplary embodiments according to the present invention. For example, unless the context clearly indicates otherwise, the singular forms used herein are intended to include the plural forms, and it should also be understood that when the terms "comprise" and / or "include" are used in this description, they indicate the presence of features, steps, operations, devices, assemblies, and / or combinations thereof. <Arc-free on-load tap changer and switching control method>

[0052] In the background art, the conventional arc-free on-load tap changer is not suitable for use in oil-filled transformers. Even if it is suitable for oil-filled transformers, various switches are distributed on two or three rotating shafts that are not synchronized with each other, and when one rotating shaft needs to rotate, the other rotating shafts need to be stationary, so the operating structure is still complicated and it lacks a coordinated control mechanism for the rotating shafts, a cooperation means between the movable contacts and fixed contacts of the rotating shafts, and a driving means for the control switches. In order to solve this problem, the present invention provides a arc-free on-load tap changer and a corresponding switching control method. EXAMPLES

[0053] This embodiment includes at least two master switches, two changeover switches, and two thyristor auxiliary modules, each thyristor auxiliary module includes two control switches, the two master switches include one originally turned on master switch and one to be turned on master switch, the master switches are connected to corresponding circuits of the voltage regulating coils through corresponding transformer taps, and the two thyristor auxiliary modules are connected in parallel to the originally turned on master switch or the to be turned on master switch according to the required timing during the switching process of the master switches; The master switch and the changeover switch are both rotary switches, the movable contacts of the master switch and the changeover switch are both mounted on a rotating shaft, the corresponding fixed contacts of the master switch and the changeover switch are connected to corresponding transformer taps, and the movable contacts are connected to the fixed contacts on the same shaft in the process of rotating together with the rotating shaft. The opening and closing of the corresponding master switch, changeover switch and control switch are controlled according to a predetermined timing, thereby realizing uninterrupted transfer of load current from the master switch that is originally on to the master switch that should be turned on, and no arc is generated during the opening and closing process of each switch, thereby providing an arc-free on-load tap changer.

[0054] The arc-free on-load tap changer of this embodiment is a shaft-driven, oil-filled transformer-compatible arc-free on-load tap changer with rotating and sliding contacts, the structure of which is shown in Fig. 2. Oil-filled on-load tap changers are generally three-phase on-load tap changers that are mounted on the same insulated shaft, have the same structure, and are driven synchronously by the shaft, so for convenience of explanation, Fig. 2 takes a three-tap single-phase oil-filled on-load tap changer as an example.

[0055] In this embodiment, the control switch is also a rotary switch, and the movable contact of the control switch is also provided on the rotating shaft.

[0056] All the fixed contacts of both the master switch and the changeover switch are divided into at least two sets in total, and the fixed contacts of each set are attached to a corresponding rail, and the rails are all centered on a rotating shaft and fixed so as not to move, where the rail is a circular insulating frame that does not move with the rotating shaft, and the movable contacts are attached to the rotating shaft and rotate with the rotating shaft.

[0057] Wherein, before the no-arc on-load tap changer switches, one end of the thyristor auxiliary modules is either floating or connected in parallel to the master switch that was originally turned on, and before the no-arc on-load tap changer switches, the voltages across the thyristor auxiliary modules are all zero.

[0058] In the switching process of the arc-free on-load tap changer, the thyristor auxiliary module is connected in parallel to the master switch that is originally turned on, or to the master switch that should be turned on according to the required timing.

[0059] In this embodiment, an example will be described in which the number of sets of fixed contacts is two, that is, there are two rails, each set has three fixed contacts, and the number of movable contacts is three.

[0060] It can be understood herein that in other embodiments, those skilled in the art may specifically set the number of moving contacts and the number of sets of fixed contacts according to the actual situation.

[0061] In this embodiment, the first rail has three fixed contacts arranged in sequence, the radius of the interval between the center positions of the first and second fixed contacts on the first rail is equal to W, and the radius of the interval between the center positions of the second and third fixed contacts on the first rail is also equal to W. The second rail also has fixed contacts, the number of which is equal to the number of the fixed contacts on the first rail. The center lines of the fixed contacts on the first rail overlap with the center lines of one of the fixed contacts on the second rail, and the fixed contacts on the first rail and the fixed contacts on the second rail whose center lines overlap are connected to each other and are sequentially connected to tap I, tap II, and tap III of the transformer coil L1, respectively.

[0062] The arc degrees of the three fixed contacts on the first rail are the same and equal to W1, the arc degrees of the three fixed contacts on the second rail are the same and equal to W2, and the arc degrees of the gaps between the fixed contacts on the second rail are the same; ΔW is equal to (W - W2). For convenience of explanation, the structural diagram of the rotating shaft of the tap changer under no-arc load in FIG. 2 is horizontally unfolded as shown in FIGS. 3 and 4. It is required that 0 < ΔW < W1 < 0.5W < W2.

[0063] In this embodiment, there are three movable contacts on the rotating shaft, namely the movable contact J3, the movable contact Q1, and the movable contact Q2. The movable contacts are attached to the rotating shaft and rotate with the rotating shaft. Here, the movable contact Q1 and the movable contact Q2 are respectively provided on both sides of the movable contact J3.

[0064] While the movable contact J3 rotates with the rotating shaft, it is respectively connected to or disconnected from the three fixed contacts on the first rail in sequence to realize the on and off of the master switch. While the movable contact Q1 and the movable contact Q2 rotate with the rotating shaft, they are respectively connected to or disconnected from the three fixed contacts on the second rail in sequence to realize the conversion of the changeover switch. The center position of the movable contact Q1 is on the second rail on the left side of the center of the movable contact J3, and the included angle between the two is 0.5W. The center position of the movable contact Q2 is on the second rail on the right side of the center of the movable contact J3, and the included angle between the two is 0.5W.

[0065] The normal operating state before switching of the tap changer under no-arc load in this embodiment is that the movable contact J3 on the rotating shaft is on the center line of the fixed contact W1, and the movable contact Q1 and the movable contact Q2 are respectively on the center lines of the gaps.

[0066] In this embodiment, the thyristor auxiliary module M1 and the thyristor auxiliary module M2 have the same circuit, and the main circuit of each thyristor auxiliary module includes a pair of thyristors connected in parallel in the opposite directions. An RC series circuit is connected in parallel to both ends of the thyristors connected in parallel in the opposite directions. A capacitor, a resistor and a diode are connected between the gate and cathode of each thyristor. The positive electrode of the diode is connected to the cathode of the corresponding thyristor, and the negative electrode of the diode is connected to the gate of the corresponding thyristor. The two thyristors connected in parallel in the opposite directions are connected to each other. A control switch is further connected in series between the gates of the thyristors via a full-bridge rectifier circuit, and two Zener diodes connected in series in the opposite direction, a resistor, and another control switch are further connected in series between the gates of the two thyristors connected in parallel in the opposite direction. The Zener diodes and the resistor are connected in series and then connected to the output terminal of the full-bridge rectifier circuit, with the negative electrode of the Zener diode corresponding to the positive output terminal of the full-bridge rectifier circuit and the positive electrode of the Zener diode corresponding to the negative output terminal of the full-bridge rectifier circuit.

[0067] Specifically, as shown in FIG. 1, the main circuit of each thyristor auxiliary module includes a pair of thyristors D1, D2 connected in parallel in the opposite direction; a resistor R1 and a capacitor C1 are connected in series and then connected in parallel to both ends of the thyristors D1, D2 connected in parallel in the opposite direction; capacitors C3, C4, resistors R3, R4, and diodes D3, D4 are connected in parallel to the gates and cathodes of the two thyristors D1, D2, respectively; the positive electrodes of the diodes D3, D4 are connected to the cathodes of the thyristors D1, D2, respectively; the negative electrodes of the diodes D3, D4 are connected to the gates of the thyristors D1, D2, respectively; Zener diodes D10, D11 are connected in series in the opposite direction and then connected in series to a resistor R5, which is further connected in series to a control switch KA, and then connected between the gates of the two thyristors D1, D2. The input terminal of the full-bridge rectifier circuit consisting of diodes D5, D6, D7, and D8 is connected in series with the control switch KB, and then connected between the gates of the two thyristors D1 and D2. The Zener diode D9 is connected in series with the resistor R6, and then connected to the output terminal of the full-bridge rectifier circuit. The negative pole of the Zener diode D9 corresponds to the positive output terminal of the full-bridge rectifier circuit, and the positive pole of the Zener diode D9 corresponds to the negative output terminal of the full-bridge rectifier circuit. The stable voltage of the Zener diode D9 is U1=k1U2, where k1 is the reliability coefficient and has a value of 1.2-2, and U2 is the peak of the regulation interval voltage of the voltage regulating transformer. It is recommended that the stable voltage of the Zener diodes D10 and D11 be 1-3 volts.

[0068] It should be noted that the specific operation process of the thyristor auxiliary module is disclosed in the patent document having application number CN201810290470.4, and detailed description thereof is omitted here.

[0069] In this embodiment, the thyristor auxiliary module M1 is connected to the control switches KA1 and KB1, and the thyristor auxiliary module M2 is connected to the control switches KA2 and KB2.

[0070] The movable contact J3 is connected to the common terminal, both ends of the main circuit of the thyristor auxiliary module M1 are connected to the movable contact Q1 and the common terminal, and both ends of the main circuit of the thyristor auxiliary module M2 are connected to the movable contact Q2 and the common terminal.

[0071] In a specific implementation process, the control switches KA1 and KA2 are mounted on a rotating shaft, and each of the control switches KA1 and KA2 can form two concentric rails, respectively called the third rail and the fourth rail, when rotating with the rotating shaft. In the third rail between the center line of the first fixed contact on the first rail and the center line of the second fixed contact on the first rail, there is a fixed contact W3, and in the fourth rail, there is a fixed contact W4. Similarly, in the third rail and the fourth rail between the center line of the second fixed contact on the first rail and the center line of the third fixed contact on the first rail, there are also fixed contacts W3 and W4 that appear repeatedly, as shown in FIG.

[0072] The control switch KA1 rotates with the rotating shaft, turns on when it encounters the fixed contact W3, and turns off when it separates from the fixed contact W3, and the control switch KA2 rotates with the rotating shaft, turns on when it encounters the fixed contact W4, and turns off when it separates from the fixed contact W4. This shows that the fixed contacts W3 and W4 are not necessarily made of metal materials as long as they can trigger the control switch KA1 or the control switch KA2 to be turned on.

[0073] When the rotating shaft rotates clockwise, before the movable contact J3 leaves the fixed contact W1, the control switch KA1 must contact the fixed contact W3, and only after the movable contact J3 leaves the fixed contact W1 can the control switch KA1 leave the fixed contact W3; before the movable contact J3 comes into contact with another fixed contact W1, the control switch KA2 must contact the fixed contact W4, and only after the movable contact J3 comes into contact with the other fixed contact W1 can the control switch KA2 leave the fixed contact W4; and after the control switch KA1 leaves the fixed contact W3, the control switch KA2 can only contact the fixed contact W4 after at least a time interval t1 has elapsed.

[0074] When the rotating shaft rotates counterclockwise, before the movable contact J3 leaves the fixed contact W1, the control switch KA2 must contact the fixed contact W4, and only after the movable contact J3 leaves the fixed contact W1 can the control switch KA2 leave the fixed contact W4; before the movable contact J3 comes into contact with another fixed contact W1, the control switch KA1 must contact the fixed contact W3, and only after the movable contact J3 comes into contact with the other fixed contact W1 can the control switch KA1 leave the fixed contact W3; and after the control switch KA2 leaves the fixed contact W4, the control switch KA1 can only contact the fixed contact W3 after at least a time interval t1 has elapsed.

[0075] To ensure that the time interval t1 is greater than the set time (for example, 0.015 seconds), the rotation of the rotating shaft should not be too fast. If the time it takes for the rotating shaft to rotate once is T seconds, T>((0.015×2π) / (W2-W3-W4)).

[0076] where W2 is the radian of each fixed contact in the second rail, and W3 and W4 are the radians of each fixed contact in the third and fourth rails, respectively.

[0077] In this embodiment, the rotating shaft further includes a control mechanism. When the rotating shaft rotates clockwise, before KA1 leaves the fixed contact W3, the control mechanism must ensure that the control switch KB1 is turned off and the control switch KB2 is turned on. When the rotating shaft rotates counterclockwise, before KA2 leaves the fixed contact W3, the control mechanism must ensure that the control switch KB1 is turned on and the control switch KB2 is turned off.

[0078] The principle of control of the arc-free on-load tap changer of this embodiment is as follows: Controlling the rotation of the rotary shaft to rotate and driving the movable contact to connect or disconnect with the corresponding fixed contact; By controlling the opening and closing of the corresponding master switches, changeover switches and control switches according to a predetermined timing, an uninterrupted transfer of the load current from the master switch that is originally on to the master switch that is to be turned on is realized, and no electric arc occurs during the opening and closing process of each switch.

[0079] Here, the rotation manner of the rotation shaft includes clockwise rotation and counterclockwise rotation.

[0080] In this embodiment, the process of switching the master switch once is as follows: Bringing the movable contacts of the two changeover switches into contact with the fixed contacts, respectively connecting the two thyristor auxiliary modules in parallel to the master switch that was originally turned on or the master switch that should be turned on, turning on the first control switch connected to the thyristor auxiliary module that is connected in parallel to the master switch that was originally turned on, and turning off the master switch that was originally turned on; Turning on a second control switch connected to a thyristor auxiliary module connected in parallel to the master switch to be turned on, and turning off a first control switch connected to a thyristor auxiliary module connected in parallel to the master switch that was originally turned on; When a set time interval has elapsed, turning on a first control switch connected to a thyristor auxiliary module connected in parallel to the master switch to be turned on, and turning on the master switch to be turned on; This includes turning off all the control switches, and the movable contacts of the two changeover switches no longer contacting the fixed contacts, completing one changeover of the master switch.

[0081] Referring to FIG. 2, in this embodiment, the process of switching the master switch once is as follows.

[0082] (1) The movable contacts Q1 and Q2 are brought into contact with the two fixed contacts W2, respectively, to turn on the control switch KA of the auxiliary thyristor module connected in parallel to the master switch that was originally turned on; (2) Turn off the master switch that was originally on, (3) turning on the control switch KB of another thyristor auxiliary module connected in parallel to the master switch to be turned on; (4) Turn off the control switch KA of the auxiliary thyristor module connected in parallel to the master switch that was originally turned on; (5) after a time interval t1 (wherein the time interval t1 is greater than 0.015 seconds), turning on a control switch KA of a thyristor auxiliary circuit connected in parallel with the master switch to be turned on; (6) Turn on the master switch that should be turned on. (7) Turn off all control switches of the thyristor auxiliary module; (8) The movable contacts Q1 and Q2 no longer come into contact with the fixed contact W2. (9) One master switch change is completed.

[0083] The process of switching the master switch of this embodiment once will be described below with reference to FIG. 2, with reference to clockwise and counterclockwise rotation of the rotary shaft.

[0084] The switching control process of the arc-free on-load tap changer of this embodiment during clockwise rotation is as follows.

[0085] (1) The movable contact J3 starts to rotate clockwise from the center line position of the fixed contact W1 with which it is in contact, the movable contact Q1 contacts the fixed contact W2 connected to the fixed contact W1 with which the movable contact J3 is in contact, the movable contact Q2 contacts the fixed contact W2 connected to the fixed contact W1 with which the movable contact J3 should be in contact, the control switch KA1 of the thyristor auxiliary module M1 contacts the fixed contact W3, the control switch KA1 is turned on, the flow path of the load current does not change, and the load current flows from the fixed contact W1 with which the movable contact J3 is still in contact to the common end point through the movable contact J3, (2) The movable contact J3 separates from the fixed contact W1 with which it was originally in contact, and the load current flows from the fixed contact W2, which is connected to the original fixed contact W1, through the movable contact Q1 and the thyristor auxiliary module M1 to the common terminal point. (3) The control switch KB2 of the thyristor auxiliary module M2 is turned on, and the flow path of the load current does not change. (4) The control switch KA1 of the thyristor auxiliary module M1 is separated from the fixed contact W3, and the control switch KA1 is turned off. Each zero-cross point of the load current triggers the thyristor auxiliary module M2 once, so that the load current flows from the fixed contact W2 connected to the fixed contact W1 to the movable contact Q2 through the thyristor auxiliary module M2 to the common end point; (5) After the time interval t1 has elapsed, the control switch KA2 of the thyristor auxiliary module M2 contacts the fixed contact W4, the control switch KA2 is turned on, and the flow path of the load current does not change; (6) The movable contact J3 comes into contact with the fixed contact W1 that it is supposed to contact, and the load current flows from the fixed contact W1 that the movable contact J3 comes into contact with to the common end point through the movable contact J3. (7) The movable contacts Q1 and Q2 are no longer in contact with the fixed contact W2, the control switch KA2 of the thyristor auxiliary module M2 is separated from the fixed contact W4, the control switch KA2 is turned off, and the control switch KB2 of the thyristor auxiliary module M2 is turned off. (8) When the movable contact J3 rotates to the center line position of the new fixed contact W1, it stops rotating and one master switch switching is completed. The time interval t1 is greater than 0.015 seconds.

[0086] The switching control process of the no-arc on-load tap changer of this embodiment during counterclockwise rotation is as follows.

[0087] (1) The movable contact J3 starts to rotate counterclockwise from the center line position of the fixed contact W1 with which it is in contact, the movable contact Q2 contacts the fixed contact W2 connected to the fixed contact W1 with which the movable contact J3 is in contact, the movable contact Q1 contacts the fixed contact W2 connected to the fixed contact W1 with which the movable contact J3 should be in contact, the control switch KA2 of the thyristor auxiliary module M2 contacts the fixed contact W4, the control switch KA2 is turned on, the flow path of the load current does not change, and the load current flows from the fixed contact W1 with which the movable contact J3 is still in contact to the common end point through the movable contact J3, (2) The movable contact J3 separates from the fixed contact W1 with which it was originally in contact, and the load current flows from the fixed contact W2, which is connected to the original fixed contact W1, through the movable contact Q2 and the thyristor auxiliary module M2 to the common terminal point. (3) The control switch KB2 of the thyristor auxiliary module M1 is turned on, and the flow path of the load current does not change. (4) The control switch KA2 of the thyristor auxiliary module M2 is separated from the fixed contact W4, and the control switch KA2 is turned off. Each zero-cross point of the load current triggers the thyristor auxiliary module M1 once, so that the load current flows from the fixed contact W2 connected to the fixed contact W1 to be contacted through the movable contact Q1 and the thyristor auxiliary module M1 to the common end point; (5) After the time interval t1 has elapsed, the control switch KA1 of the thyristor auxiliary module M1 contacts the fixed contact W3, the control switch KA1 is turned on, and the flow path of the load current does not change; (6) The movable contact J3 comes into contact with the fixed contact W1 that it is supposed to contact, and the load current flows from the fixed contact W1 that the movable contact J3 comes into contact with through the movable contact J3 to the common end point. (7) The movable contacts Q1 and Q2 are no longer in contact with the fixed contact W2, the control switch KA1 of the thyristor auxiliary module M1 is separated from the fixed contact W3, the control switch KA1 is turned off, and the control switch KB1 of the thyristor auxiliary module M1 is turned off. (8) When the movable contact J3 rotates to the center line position of the new fixed contact W1, it stops rotating and one master switch switching operation is completed.

[0088] The arc-free on-load tap changer of the present embodiment uses a rotating shaft as a driving force, similar to the conventional oil-immersed on-load tap changer, and can operate various switches and contacts in the oil tank of the oil-immersed transformer. Therefore, the arc-free on-load tap changer of the present invention can be modified based on the basic structure of the conventional oil-immersed on-load tap changer.

[0089] The driving force of the conventional oil-immersed on-load tap changer comes from an AC motor. In order to prevent the switch-changing process from being interrupted due to power loss, the conventional on-load tap changer is equipped with a spring energy release mechanism, and when the power is lost during the switch-changing process, the spring energy release mechanism can ensure one complete switching process of the on-load tap changer. However, the spring energy storage time is long, and the spring energy storage is only performed after receiving the switching command, so one complete switching process of the conventional on-load tap changer is long. The spring energy storage mechanism and the spring energy release mechanism of the on-load tap changer have a complex structure, large operating vibration, and a high failure rate.

[0090] The arc-free on-load tap changer of this embodiment can adopt DC motor drive and electrical energy storage, so the spring energy storage mechanism and the spring energy release mechanism may be omitted.

[0091] It should be noted here that the driving motor of the oil-immersed on-load tap changer of this embodiment may adopt a DC motor. The AC power source that originally supplies power to the AC motor supplies power to the DC motor through a bridge rectifier circuit and a voltage stabilizing circuit, and a capacitor energy storage circuit is connected in parallel to the output of the bridge rectifier circuit, and the electrical energy stored in the capacitor energy storage circuit is at least sufficient for the on-load tap changer to complete one complete operation. Since the electrical energy storage can be performed before receiving a switching command, the time for the no-arc on-load tap changer of this embodiment to complete one complete switching process is actually shorter. Thus, the spring energy storage mechanism and the spring energy release mechanism may be omitted in the no-arc on-load tap changer of this embodiment.

[0092] In the arc-free on-load tap changer of this embodiment, there is no transition resistor, and no heat generating components are involved in the switch changing process. In this way, the changing process does not need a high speed mechanism (ensuring that the current flow time of the transition resistor does not exceed 40 milliseconds) which is essential in the conventional on-load tap changer. The changing process of the arc-free on-load tap changer of this embodiment may be completed in tens of seconds. Therefore, the arc-free on-load tap changer of the present invention can be modified based on the basic structure of the conventional oil-immersed non-magnetized tap changer.

[0093] The arc-free on-load tap changer of the present embodiment has a simple structure, small operating vibration, and low failure rate. The arc-free on-load tap changer of the structure of FIG. 2 is a combined arc-free on-load tap changer. The combined arc-free on-load tap changer is a combination of a selector and a switching device, which simplifies the structure of the on-load tap changer and is low in cost, but can only be applied when the selector is simple. If the selector of the on-load tap changer is complex and not suitable for use as a combined on-load tap changer, a combined structure in which the selector and the switching device are connected in series may be adopted. If the fixed contacts of the first rail in the structure of FIG. 2 are reduced to two, it actually becomes the structure of a switching device. If a switching device of such a structure is connected in series to a conventional selector, a combined arc-free on-load tap changer can be constructed. EXAMPLES

[0094] This embodiment provides an arc-free on-load tap changer having the same structure as that of embodiment 1. This embodiment differs from embodiment 1 in that the control switches KB1 and KB2 are controlled by a mechanical interlocking mechanism.

[0095] As shown in FIG. 5, the mechanical linkage mechanism of this embodiment includes a deflection shaft 6, which is fixed to the rotating shaft 4 and rotates together with the rotating shaft 4, and a lever arm 7 and a spring arm 8 are attached to the deflection shaft 6, which are rotatable around the deflection shaft 6. One end of the spring arm 8 has a contact, which rotates together with the rotating shaft 4 and comes into contact with or separates from a corresponding control switch to open or close the corresponding control switch.

[0096] Here, the working process of the mechanical interlocking mechanism of this embodiment is as follows.

[0097] The rotating shaft 4 can drive and rotate the fixed plate 5, which further includes a deflection shaft 6, to which a lever arm 7 and a spring arm 8 are attached. The lever arm 7 and the spring arm 8 can rotate around the deflection shaft 6, and one end of the spring arm 8 has a contact. The stationary insulating frame has a hoop with the rotating shaft 4 as its center, the hoop has gaps at the center line of the fixed contact W1, the hoop is divided into a number of segments, and the number of hoop gaps is the same as the number of the fixed contacts W1, for example, when there are three fixed contacts W1, there are three hoop gaps, and the three hoop gaps divide the hoop into a first hoop 9 and a second hoop 10. The normal operating state of the first arc-free on-load tap changer before switching is that the lever arm 7 is at the center line of the hoop gap.

[0098] When the rotating shaft 4 rotates clockwise, the lever arm 7 encounters the second hoop 10, which propels the lever arm 7 to rotate counterclockwise around the deflection shaft 6, and the lever arm 7 drives the spring arm 8 to rotate counterclockwise, so that the contact of the spring arm 8 contacts the contact of the switch KB2, which turns on. When the lever arm 7 moves away from the second hoop 10 and encounters the next hoop gap, the lever arm 7 returns to the center line of the hoop gap, and the spring arm 8 also returns to the center line of the hoop gap, so that the contact of the spring arm 8 moves away from the contact of the switch KB2, which turns off the switch KB2.

[0099] When the rotating shaft 4 rotates counterclockwise, the lever arm 7 encounters the first hoop 9, which propels the lever arm 7 to rotate clockwise around the deflection shaft 6, and the lever arm 7 drives the spring arm 8 to rotate clockwise, so that the contact of the spring arm 8 contacts the contact of the switch KB1, turning on the switch KB1. When the lever arm 7 moves away from the first hoop 9 and encounters the next hoop gap, the lever arm 7 returns to the center line of the hoop gap, and the spring arm 8 also returns to the center line of the hoop gap, so that the contact of the spring arm 8 moves away from the contact of the switch KB1, turning off the switch KB1.

[0100] It is understood that a person skilled in the art can specifically design the structure of the mechanical interlocking mechanism according to the actual situation, and a detailed description thereof will be omitted here.

[0101] It should be noted that the switching control process of the no-arc on-load tap changer of this embodiment is the same as that of the no-arc on-load tap changer of embodiment 1, and detailed description thereof will be omitted here. EXAMPLES

[0102] This embodiment provides an arc-free on-load tap changer having the same structure as that of embodiment 1. This embodiment differs from embodiment 1 in that the control mechanism for controlling the control switches KB1 and KB2 is realized by a changeover switch driven by a rotating shaft.

[0103] According to the description on pages 63-66 of "Electrical Mechanism of On-Load Tap Changer" edited by Zhu Yinghao et al. and published by China Electricity Press in 2012, the changeover switch MTF driven by the rotating shaft can constitute the control switches KB1 and KB2. In this book, the four fixed contacts of the changeover switch MTF are MTF1, MTF2, MTF3, and MTF4, respectively, and the changeover switch can switch between two states: (1) the first and third contacts are conductive and the second and fourth contacts are cut off, and (2) the first and third contacts are cut off and the second and fourth contacts are conductive. The contacts MTF1 and MTF3 can be both ends of the control switch KB1, and the contacts MTF2 and MTF4 can be both ends of the control switch KB2.

[0104] It should be pointed out that the changeover switch MTF described in "Electrical Mechanism of On-Load Tap Changer" is a large current switch, while the control switches KB1 and KB2 are small current switches, so according to the working principle of the changeover switch MTF, it is necessary to reduce the size and realize the function of the control switches KB1 and KB2. Detailed analysis is omitted.

[0105] It should be noted that the switching control process of the no-arc on-load tap changer of this embodiment is the same as that of the no-arc on-load tap changer of embodiment 1, and detailed description thereof will be omitted here. EXAMPLES

[0106] In the arc-free on-load tap changer shown in Figure 2, the arc degree of the fixed contacts is large and the arc degree of the movable contacts is small. As can be seen from this, the magnitude of the arc degree of the contacts is intended to control the length of contact time between the fixed contacts and the movable contacts and the contact sequence.

[0107] As shown in FIG. 6, this embodiment differs from the first embodiment in that the arc degree of the fixed contact is small and the arc degree of the movable contact is large.

[0108] The structure of the rotating shaft of the arc-free on-load tap changer of this embodiment is as shown in Figure 6. In this embodiment, there are three fixed contacts arranged in sequence on the first rail, the arc degree of the interval between the center positions of the first and second fixed contacts on the first rail is equal to W, and the arc degree of the interval between the center positions of the second and third fixed contacts on the first rail is also equal to W. There are also fixed contacts on the second rail, and the number of fixed contacts on the second rail is equal to the number of fixed contacts on the first rail. The center line of each fixed contact on the first rail overlaps with the center line of one fixed contact on the second rail, and the fixed contact on the first rail whose center line overlaps with the fixed contact on the second rail is connected and sequentially connected to the three taps of the transformer coil L1, respectively.

[0109] In this embodiment, the rotating shaft has at least three movable contacts, namely, movable contact J3, movable contact Q1, and movable contact Q2. The movable contacts are attached to the rotating shaft and rotate together with the rotating shaft. As the movable contact J3 rotates with the rotating shaft, it is sequentially connected to the three fixed contacts on the first rail. As the movable contact Q1 and the movable contact Q2 rotate with the rotating shaft, they are sequentially connected to the three fixed contacts on the second rail. The center position of the movable contact Q1 is on the second rail to the left of the center position of the movable contact J3, and the included angle between them is 0.5W. The center position of the movable contact Q2 is on the second rail to the right of the center position of the movable contact J3, and the included angle between them is 0.5W.

[0110] The arc of the contact of the moving contact J3 is W 1可動 The arc of the contacts of the movable contact Q1 and the movable contact Q2 is W 2可動 The arc of the gap between the movable contact Q1 and the movable contact Q2 is ΔW 可動 =(WW 2可動 ) As shown in Figure 6, 0 < ΔW <W 1可動 <0.5W <W 2可動 where W is the arc between the center positions of the fixed contacts on the first rail.

[0111] It should be further noted here that the opening and closing of the control switch in this embodiment is controlled by a control mechanism, which may be realized by the control mechanism in embodiment 2 or embodiment 3 or other conventional control mechanisms, and those skilled in the art can make a specific selection according to the actual situation, and detailed description is omitted here.

[0112] The switching control method of the no-arc on-load tap changer of this embodiment is the same as the switching control method of the no-arc on-load tap changer of embodiment 1, and detailed description thereof will be omitted here. The content of the no-arc on-load tap changer of this embodiment is the same as the no-arc on-load tap changer of embodiment 1, and detailed description thereof will be omitted.

[0113] Comparing Figures 2 and 6, the arc-free on-load tap changer of this embodiment has a small arc degree for each fixed contact on the first rail and the second rail, a large arc degree for the movable contact, and there are only three movable contacts and the number of fixed contacts can be large, so the manufacturing cost of the arc-free on-load tap changer of this embodiment is lower than that of the arc-free on-load tap changer of embodiment 1. EXAMPLES

[0114] This embodiment includes at least two master switches, two changeover switches, and two thyristor auxiliary modules, each thyristor auxiliary module includes two control switches, the two master switches include one originally turned on master switch and one to be turned on master switch, the master switches are connected to corresponding circuits of the voltage regulating coils through corresponding transformer taps, and the two thyristor auxiliary modules are connected in parallel to the originally turned on master switch or the to be turned on master switch according to the required timing during the switching process of the master switches; The master switch and the changeover switch are both rotary switches, and the master switch and the corresponding changeover switch are linked and rotate synchronously. By controlling the opening and closing of the corresponding master switch, changeover switch and control switch according to a predetermined timing, an uninterrupted transfer of load current from the master switch that is originally on to the master switch that should be turned on is achieved, and no arc is generated during the opening and closing process of each switch, thereby providing an arc-less on-load tap changer.

[0115] What should be explained here is that the control mechanism is a mechanical interlocking mechanism, and the structure thereof may adopt the specific structure of the mechanical interlocking mechanism described in Example 2, or may adopt the control mechanism described in Example 3, and a person skilled in the art can specifically set it according to the actual situation. Detailed explanation will be omitted here.

[0116] In this embodiment, the two thyristor auxiliary modules have the same structure, and the specific structure is as shown in FIG. 1. The specific description is the same as that of the first embodiment, and the detailed description is omitted here.

[0117] The method for controlling the switching of the non-arc on-load tap changer of this embodiment is as follows: controlling the opening and closing of corresponding master switches and changeover switches so as to interlock and rotate synchronously; and controlling the opening and closing of the corresponding master switch, changeover switch and control switch according to a predetermined timing, thereby realizing uninterrupted transfer of the load current from the master switch that is originally turned on to the master switch that should be turned on, and no arc is generated during the opening and closing process of each switch.

[0118] <Electrical equipment> In one or more embodiments, a voltage regulating coil including a plurality of transformer taps; a non-arc on-load tap changer connected to the voltage regulating coil, The present invention provides an electric device, wherein the non-arc-on-load tap changer is the non-arc-on-load tap changer according to any one of the first to fifth embodiments.

[0119] The transformer in this embodiment is an oil-immersed transformer or a transformer equipped with an oil-immersed vacuum on-load tap changer.

[0120] The electrical equipment can be configured in any way and manner depending on the needs, for example as a compensation choke coil for influencing reactive power in an AC grid or as a local grid transformer or a power transformer or a variable transformer or a phase shifting transformer or a rectifier transformer or a reactive power compensator, and / or the equipment may or may not include at least one additional regulating winding and / or may or may not include at least one additional arc-free on-load tap changer and / or may include at least one main winding.

[0121] Each of the proposed on-load tap changers and each of the proposed devices can be used, for example, to implement one of the proposed methods.

[0122] Preferably, each on-load tap changer in the proposed arcless on-load tap changers is configured and / or used and / or applied such that each of the proposed arcless on-load tap changers performs and / or is capable of performing one of the proposed methods. Preferably, each of the proposed devices is configured and / or used and / or applied such that each of the proposed devices performs and / or is capable of performing one of the proposed methods.

[0123] The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Those skilled in the art can make various modifications and changes to the present invention. All modifications, equivalent replacements, improvements, etc. made without departing from the spirit and principle of the present invention shall be included within the protection scope of the present invention. [Explanation of symbols]

[0124] 1 Tap I 2 Tap II 3. Tap III 4 Rotation Axis 5 Fixed plate 6 Deflection axis 7 Lever Arm 8 Spring Arm 9. First Hoop 10. 2nd Hoop 11 Switch KB1 12 Switch KB2

Claims

1. The power supply includes at least two master switches, two changeover switches, and two thyristor auxiliary modules, each thyristor auxiliary module includes two control switches, the two master switches including one originally turned on master switch and one to be turned on master switch, the master switches are connected to corresponding circuits of a voltage regulating coil through corresponding transformer taps, and the two thyristor auxiliary modules are connected in parallel to the originally turned on master switch or the to be turned on master switch according to required timing during the switching process of the master switches; the master switch and the changeover switch are both rotary switches, the movable contacts of the master switch and the changeover switch are both mounted on a rotating shaft, the corresponding fixed contacts of the master switch and the changeover switch are connected to corresponding transformer taps, and the movable contacts are connected to the fixed contacts of the same shaft in the process of rotating together with the rotating shaft; the opening and closing of the corresponding master switch, changeover switch and control switch are controlled according to a predetermined timing, thereby realizing uninterrupted transfer of load current from the master switch that is originally on to the master switch that should be turned on, and no arc is generated during the opening and closing process of each switch.

2. 2. The arc-free on-load tap changer of claim 1, wherein one end of each of the two auxiliary thyristor modules is floating before the master switch is switched or is connected in parallel to the master switch that is originally turned on, and the voltages across the two auxiliary thyristor modules are both zero.

3. 2. The arc-free on-load tap changer according to claim 1, wherein the control switch is also a rotary switch, and the movable contact of the control switch is also provided on a rotating shaft.

4. 2. The arc-free on-load tap changer as claimed in claim 1, characterized in that all the fixed contacts of both the master switch and the changeover switch are divided into at least two sets in total, the fixed contacts of each set are mounted on a corresponding rail, and the rails are all centered on a rotation axis and fixed so as not to move.

5. 5. An arc-free on-load tap changer as claimed in claim 4, characterized in that the number of fixed contacts in each set is the same.

6. 5. An arc-free on-load tap changer as claimed in claim 4, characterized in that each set of fixed contacts is mounted on a corresponding rail with equal arc degrees.

7. When all the fixed contacts of both the master switch and the changeover switch are divided into two sets in total, the relationship of the arc degree of the fixed contacts on the two corresponding rails is as follows: 0<ΔW<W1<0.5W<W2 ΔW=(W−W2) 5. The arc-less on-load tap changer according to claim 4, wherein W and W1 are the arc degrees between the centers of the fixed contacts and the arc degrees of the fixed contacts on the first rail, respectively, and W2 and ΔW are the arc degrees of the fixed contacts and the gap between the fixed contacts on the second rail, respectively.

8. Prior to the change of the master switch, the normal operating condition of the arc-free on-load tap changer is:

2. The arc-free on-load tap changer according to claim 1, characterized in that one movable contact on the rotating shaft is on the center line of one fixed contact, and the remaining movable contacts are respectively on the center lines of the gaps between the fixed contacts.

9. When there are three movable contacts on the rotating shaft, the first and second movable contacts are arranged on both sides of the third movable contact, and the arc degree relationship of the three movable contacts is as follows: 0<ΔW<W １可動 <0.5W<W ２可動 ΔW 可動 =(W-W ２可動 ) where W is the arc between the center positions of each fixed contact on the first rail, and W １可動 , W ２可動 is the arc of the first movable contact and the second movable contact, and ΔW 可動 9. An arc-free on-load tap changer as claimed in claim 8, characterized in that: ∑ i = 1 i ∑ t ...

10. 10. An arc-free on-load tap changer according to claim 4 or 9, characterized in that the arc degree of the fixed contact is greater than the arc degree of the movable contact.

11. 10. An arc-free on-load tap changer as claimed in claim 4 or 9, characterized in that the arc degree of the fixed contact is equal to or less than the arc degree of the movable contact.

12. 2. The arc-free on-load tap changer according to claim 1, wherein the opening and closing of the control switch is controlled by a control mechanism.

13. 13. An arc-free on-load tap changer as claimed in claim 12, characterised in that the control mechanism is a mechanical linkage.

14. 14. The arc-free on-load tap changer as claimed in claim 13, characterized in that the mechanical linkage mechanism includes a deflection shaft, the deflection shaft is fixed to the rotating shaft and rotates together with the rotating shaft, the deflection shaft is provided with a lever arm and a spring arm which are rotatable around the deflection shaft, one end of the spring arm has a contact, the contact rotates together with the rotating shaft to contact or separate from a corresponding control switch to open or close the corresponding control switch.

15. 13. An arc-free on-load tap changer as claimed in claim 12, characterized in that the control mechanism is realised by a change-over switch driven by a rotating shaft.

16. 2. An arc-free on-load tap changer as claimed in claim 1, characterized in that the structures of the two thyristor auxiliary modules are the same.

17. Each thyristor sub-module includes a pair of thyristors connected in parallel in the opposite direction, an RC series circuit is connected in parallel to both ends of the thyristors connected in parallel in the opposite direction, a capacitor, a resistor and a diode are connected in sequence between the gate and cathode of each thyristor, the positive electrode of the diode is connected to the cathode of the corresponding thyristor, and the negative electrode of the diode is connected to the gate of the corresponding thyristor. A control switch is further connected in series between the gates of the two thyristors connected in parallel in the opposite direction via a full-bridge rectifier circuit.

17. The arc-free on-load tap changer as claimed in claim 16, further comprising: two Zener diodes and a resistor connected in series between the gates of the two thyristors connected in parallel in the opposite direction and another control switch; the two Zener diodes are connected in series in the opposite direction; the Zener diode and the resistor are connected in series to an output terminal of the full-bridge rectifier circuit, the negative pole of the Zener diode corresponds to the positive output terminal of the full-bridge rectifier circuit, and the positive pole of the Zener diode corresponds to the negative output terminal of the full-bridge rectifier circuit.

18. A method for controlling switching of an arc-less on-load tap changer according to any one of claims 1 to 17, comprising the steps of: controlling the rotation of the rotating shaft to drive the movable contacts to connect to or disconnect from the corresponding fixed contacts; and controlling the opening and closing of corresponding master switches, changeover switches and control switches according to a predetermined timing, thereby realizing uninterrupted transfer of load current from the master switch that is originally turned on to the master switch that is to be turned on, and no arc is generated during the process of opening and closing each switch.

19. 20. The method of claim 18, wherein the rotating shaft includes a clockwise rotation and a counterclockwise rotation.

20. The process of toggling the master switch once is as follows: Making the movable contact of the corresponding changeover switch contact the corresponding fixed contact, turning on the first control switch of the thyristor auxiliary module connected to the originally turned-on master switch, and turning off the originally turned-on master switch; Turning on the second control switch of the thyristor auxiliary module connected to the master switch to be turned on and turning off the first control switch of the thyristor auxiliary module connected to the master switch that was originally turned on; When a set time interval has elapsed, turning on a first control switch of a thyristor auxiliary module connected to the master switch to be turned on, and turning on the master switch to be turned on; turning off all the control switches, and the movable contacts of the corresponding changeover switches are no longer in contact with the corresponding fixed contacts, completing one changeover of the master switch.

21. The method for controlling switching of an arc-free on-load tap changer as claimed in claim 18, characterized in that before switching of the master switch, the voltages across both ends of the two auxiliary thyristor modules are both set to zero.

22. The power supply includes at least two master switches, two changeover switches, and two thyristor auxiliary modules, each thyristor auxiliary module includes two control switches, the two master switches include one originally turned on master switch and one to be turned on master switch, the master switches are connected to corresponding circuits of a voltage regulating coil through corresponding transformer taps, and the two thyristor auxiliary modules are connected to the originally turned on master switch or the to be turned on master switch according to required timing during the switching process of the master switches; the master switch and the changeover switch are both rotary switches, the master switch and the corresponding changeover switch are linked and rotate synchronously, and the opening and closing of the corresponding master switch, changeover switch and control switch are controlled according to a predetermined timing, thereby realizing uninterrupted transfer of the load current from the master switch that is originally on to the master switch that should be turned on, and no arc is generated during the opening and closing process of each switch.

23. 23. An arc-less on-load tap changer as claimed in claim 22, characterised in that the control mechanism is a mechanical linkage.

24. 24. The arc-free on-load tap changer as claimed in claim 23, characterized in that the mechanical linkage mechanism includes a deflection shaft, the deflection shaft is fixed to the rotating shaft and rotates together with the rotating shaft, the deflection shaft is provided with a lever arm and a spring arm which are rotatable around the deflection shaft, one end of the spring arm has a contact, the contact rotates together with the rotating shaft to contact or separate from a corresponding control switch to open or close the corresponding control switch.

25. 23. An arc-free on-load tap changer as claimed in claim 22, characterized in that the control mechanism is realised by a change-over switch driven by a rotating shaft.

26. 23. An arc-free on-load tap changer according to claim 22, characterized in that the structures of the two thyristor auxiliary modules are the same.

27. Each thyristor sub-module includes a pair of thyristors connected in parallel in the opposite direction, an RC series circuit is connected in parallel to both ends of the thyristors connected in parallel in the opposite direction, a capacitor, a resistor and a diode are connected in sequence between the gate and cathode of each thyristor, the positive electrode of the diode is connected to the cathode of the corresponding thyristor, and the negative electrode of the diode is connected to the gate of the corresponding thyristor. A control switch is further connected in series between the gates of the two thyristors connected in parallel in the opposite direction via a full-bridge rectifier circuit.

27. The arc-free on-load tap changer as claimed in claim 26, further comprising: two Zener diodes and a resistor connected in series between the gates of the two thyristors connected in parallel in the opposite direction and another control switch; the two Zener diodes are connected in series in the opposite direction; the Zener diode and the resistor are connected in series to an output terminal of the full-bridge rectifier circuit, the negative pole of the Zener diode corresponds to the positive output terminal of the full-bridge rectifier circuit, and the positive pole of the Zener diode corresponds to the negative output terminal of the full-bridge rectifier circuit.

28. A method for controlling switching of an arc-less on-load tap changer according to any one of claims 22 to 27, comprising the steps of: controlling the opening and closing of corresponding master switches and changeover switches so as to interlock and rotate synchronously; and controlling the opening and closing of corresponding master switches, changeover switches and control switches according to a predetermined timing, thereby realizing uninterrupted transfer of load current from the master switch that is originally turned on to the master switch that is to be turned on, and no arc is generated during the process of opening and closing each switch.

29. a voltage regulating coil including a plurality of transformer taps; a non-arc on-load tap changer connected to the voltage regulating coil, The arc-less on-load tap changer is an arc-less on-load tap changer according to any one of claims 1 to 17, or 28. An electrical appliance, characterized in that the arc-less on-load tap changer is an arc-less on-load tap changer according to any one of claims 22 to 27.

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