CN104157433B - A kind of split type no arc load ratio bridging switch of transformer - Google Patents

Abstract

The invention discloses a transformer split type arcless on-load tap changer. The switch of the invention includes a tap selector and a changeover switch; the changeover switch includes a power loop, a control loop and a control power supply; the tap selector To realize the selection of the number of turns of the transformer winding, the moving contact is connected to the static contact of the power loop; each static contact of the power loop is connected to the straight-through contact and the bidirectional switch branch; the bidirectional switch branch is connected by After two power electronic switches are combined and connected, a buffer circuit is connected in parallel, and then connected in series with a fuse; the buffer circuit is connected in parallel between the static contacts of the power circuit; the control circuit includes a communication unit, a trigger unit and a detection unit. A unit; controlling the on-off of the bidirectional switch branch according to the data detected by the detection unit. The invention realizes the arc-free switching of the split type on-load tap changer, prevents accident expansion when the bidirectional switch fails, does not damage devices, has simple structure and reliable operation.

Description

A transformer split type arcless on-load tap changer

technical field

The invention relates to the technical field of voltage regulation of transformers, and more specifically relates to a transformer split-type arcless on-load tap changer.

Background technique

In the prior art, for a distribution transformer in operation, due to changes in the primary side voltage, load size and nature, the secondary side voltage may have a large change. my country's distribution transformers cover a voltage level below 35kV. In order to maintain the load voltage within the specified range and ensure the normal needs of electrical equipment, the distribution transformer must be adjusted.

The basic principle of transformer on-load voltage regulation is to draw several taps from the coil on one side of the transformer, generally the high-voltage side, and switch from one tap to the other through the on-load tap changer without cutting off the load current. A tap to change the number of effective turns to adjust the voltage. The on-load tap changer is composed of two parts, one part is the transformer body, which is different from the usual transformer in that it leads to multiple taps, and the other part is the on-load tap changer, which can be supplied and assembled by different manufacturers.

Commonly used transformer on-load tap-changers are divided into two categories: mechanical type and vacuum type. Mechanical on-load tap-changers have two structures: one-piece and two-piece.

In the integrated mechanical on-load tap-changer, the winding taps directly form a circular body, and each tap constitutes a static contact. The moving contact is composed of a contact with transition resistance and a straight contact, which can be in the form of single transition resistance, double transition resistance or multiple transition resistance.

Split mechanical on-load tap-changers consist of a switch selector and a diverter switch. The switch selector is composed of two rings, which are respectively connected to the odd-numbered and even-numbered taps. The tap selector drives the motor to drive the moving contacts of the tap selector to connect to one tap respectively. The two moving contacts of the tap selector output as The two static contacts of the diverter switch, each static contact is equipped with a transition resistor to form a double resistance structure, and only one contact is connected to the output cable in a steady state. The moving contact of the diverter switch has only one straight-through contact, which is driven by the diverter switch drive motor to switch from one static contact to the other.

Vacuum tap changers generally adopt a split structure, and the taps of the windings are switched by the tap selector. The static contacts of the diverter switch are respectively connected to a vacuum switch, a transitional vacuum switch is installed between the two static contacts, and a transitional resistor is installed between the transitional vacuum switch and one of the static contacts. Three vacuum switch outputs have two structures: fixed connection and mobile connection. In the fixed connection mode, the output of the three vacuum switches can be short-circuited and fixedly connected to the winding, and the current can be transferred between different taps only by controlling the vacuum switch. The mobile connection method adopts a moving contact, and the moving contact has only one straight-through contact, which is driven by the switching switch to switch from one static contact to the other. During the movement, the position of the moving contact is judged in real time to realize the vacuum switch The on-off control of the transformer ensures that the transformer winding is not open circuited and the winding taps are not short-circuited.

The problems existing in the existing technology are: the mechanical tap changer generates an arc during the tap switching process, causing contact ablation; when the vacuum tap changer adopts a fixed structure, the off-state vacuum switch is always under voltage, and it needs to be designed according to the system voltage. When the mobile structure is adopted, due to the slow opening and closing time of the vacuum switch, the moving speed of the moving contact needs to be coordinated with it, which is difficult to control; and the above-mentioned tap changer needs transition resistance, which increases the loss.

At present, there is an all-electronic tap changer structure. The electronic switch is composed of power electronic devices such as thyristors. Each transformer winding tap is connected to an electronic switch. The tap switching is realized through certain timing control and does not require transition resistors. This solution requires high withstand voltage of the electronic switch, and the structure is complex and expensive.

There is also an electromechanical hybrid tap changer structure, which is equivalent to replacing the double transition resistors of the mechanical tap changer with anti-parallel thyristors, and the tap switching is realized by controlling the opening and closing of the thyristors and the moving position of the straight-through contacts. In this scheme, since the thyristor is a semi-controlled device, it is difficult to realize the timing coordination of the thyristor on and off when the movable contact moves.

In addition, there is another electromechanical hybrid tap-changer mechanism, which is equivalent to replacing the double transition resistance of the mechanical tap-changer with two anti-series power electronic switches. The moving position of the head cooperates to realize tap switching. In this scheme, the power electronic switch adopts fully controlled devices such as IGBT or MOSFET.

During the switching process of the above two electromechanical hybrid structures, if the power electronic switch fails, the winding will be short-circuited when it is in a short-circuit state after the fault. The full voltage of the pressure-side coil is applied to both ends of the power electronic switch, which breaks down and burns the control part.

For this kind of fault, there is another structure that connects transition resistors in parallel at both ends of the power electronic switch on this basis. When the power electronic switch fails and the result is an open circuit, it can still be used as a conventional on-load tap changer. This solution still has an arcing process during the switching process, and cannot realize the arc-free operation of the on-load tap-changer.

Contents of the invention

(1) Technical problems to be solved

The technical problem to be solved by the present invention is how to realize the arc-free switching process of the transformer on load, and at the same time stop the switching process in time without damaging the device when a short circuit or an open circuit occurs during the switching process.

(2) Technical solution

In order to solve the above technical problems, the present invention provides a transformer split type arcless on-load tap-changer, the transformer split type arcless on-load tap-changer includes a tap selector and a diverter switch; the diverter switch Including power loop and control loop;

The moving contact of the tap selector is connected to the static contact of the power circuit; each static contact of the power circuit is connected to the straight-through contact and the bidirectional switch branch; the bidirectional switch branch is composed of two After the power electronic switch combination is connected, a buffer circuit is connected in parallel, and then connected in series with a fuse; the buffer circuit is connected in parallel between the static contacts of the power circuit;

The control loop includes a trigger unit and a detection unit; the detection unit detects the current of the bidirectional switch branch, the voltage drop, the current of the static contact of the power loop, the voltage drop between the two static contacts and the The current of the straight-through contact is calculated, and after the obtained parameters are calculated, a control command is issued to the trigger unit, and the trigger unit provides a trigger signal for the power electronic switch of the bidirectional switch branch.

Preferably, the buffer circuit is a capacitor or a resistance-capacitance circuit.

Preferably, the number of static contacts of the power circuit is two.

Preferably, the changeover switch further includes a control power supply unit, the control power supply unit takes the voltage drop of the two static contacts of the power loop as an input stage voltage, and provides power supply for the control loop.

Preferably, the control loop further includes a communication unit, the communication unit uploads the data detected by the detection unit to the upper computer, and the upper computer controls the drive motor to drive the movable contact of the diverter switch and the tap selector The moving contact action.

Preferably, the control power supply unit converts the input stage voltage into a DC voltage through its internal isolation and transformation circuit.

Preferably, the power electronic switch adopts a half-controlled device of a thyristor or a fully-controlled device of an IGBT or a MOSFET.

Preferably, when the power electronic switch adopts a semi-controlled device of a thyristor, the combined connection form of the two power electronic switches is an anti-parallel connection; The combined connection form is anti-serial connection.

(3) Beneficial effects

The invention provides a transformer split-type arc-free on-load tap-changer. By using a bi-directional switch and controlling the trigger sequence of the bi-directional switch, the arc-free switching of the split-type on-load tap-changer is realized, and the failure of the bi-directional switch is prevented. When the accident is expanded, the device is not damaged, and the structure is simple and the work is reliable.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a circuit diagram of a transformer split type arcless on-load tap changer according to a preferred embodiment of the present invention;

Fig. 2 is a structural schematic diagram of a control circuit of a transformer split type arcless on-load tap-changer according to a preferred embodiment of the present invention;

Fig. 3 is a schematic structural diagram of a control power supply unit of a transformer split type arcless on-load tap changer according to a preferred embodiment of the present invention;

Figures 4a-4e are state diagrams of the process of switching the moving contact from R1 to R2 of a diverter switch of a transformer split-type arcless on-load tap-changer according to a preferred embodiment of the present invention;

Figs. 5a-5d are diagrams of electronic switch timing control state diagrams of a transformer split type arcless on-load tap changer according to a preferred embodiment of the present invention.

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but should not be used to limit the scope of the present invention.

Fig. 1 is a circuit diagram of a transformer split-type arcless on-load tap-changer according to a preferred embodiment of the present invention; the transformer split-type arcless on-load tap-changer includes a tap selector and a changeover switch; The changeover switch includes a power loop, a control loop, and a control power supply unit.

The tap selector realizes the selection of the number of turns of the transformer winding, it selects the taps at no-load, and then realizes the on-load switching by the changeover switch. The moving contacts of the tap selector are connected to the static contacts of the power circuit, that is, the first static contact R1 and the second static contact R2; the odd-numbered taps of the transformer are J1, J3, etc., and the even-numbered taps are J2 , J4, etc., the tap selector includes two rings, that is, the first tap selector and the second tap selector, the static contacts of the first tap selector are respectively connected to the single taps J1, J3 and so on, the static contacts of the second tap selector are respectively connected to even-numbered taps J2, J4 and so on.

The first static contact R1 of the power circuit is respectively connected to the first straight contact K1 and one end of the first bidirectional switch branch S1, and the second static contact R2 is respectively connected to the second bidirectional switch branch S2, One end of the second through contact K2 is connected, the buffer circuit C3 is connected in parallel between the first static contact R1 and the second static contact R2, and the moving contacts of the first tap selector and the second tap selector The head can be connected to a certain tap of the transformer by being dragged by the drive motor. One end of the moving contact D of the diverter switch is connected to the outlet terminal N, and the other end is sequentially connected to the other end of the first straight-through contact K1 connected to the first static contact R1 through the dragging of the diverter switch motor. The other end of the bidirectional switch branch S1, the other end of the second bidirectional switch branch S2 on the second static contact R2, and the other end of the second through contact K2 are connected.

The bidirectional switch branch is formed by combining two power electronic switches, connecting a buffer circuit in parallel, and connecting in series with a fuse. In Fig. 1, S11, S12, S21, S22 represent power electronic switches, the first bidirectional switch branch S1 is composed of the first unidirectional switch S11, the second unidirectional switch S12, the buffer circuit C1 and the fuse M1, and the third unidirectional switch The directional switch S21, the fourth unidirectional switch S22, the snubber circuit C2 and the fuse M2 form a second bidirectional switch branch S2. The functions of the buffer circuits C1 and C2 are as follows: when the bidirectional switch branch is disconnected, the inductance part in the current loop will form an overvoltage, and the buffer circuit will protect the bidirectional switch branch at this time. The functions of the fuses M1 and M2 are: when the bidirectional switch branch fault results in a short circuit, if the switch continues, the fuse will be blown to avoid the short circuit of the winding. After the switch is completed, the fault signal will be controlled by the control loop The unit is uploaded to the host computer, and operation is prohibited.

When the bidirectional switch branch fault results in an open circuit, it will cause the load to open circuit, and the parameter value detected by the detection unit in the control loop can identify this fault and prohibit further operation. When the power electronic switch adopts full control devices of IGBT and MOSFET, the combined connection form of the two power electronic switches is an anti-series connection. The power switch in this embodiment adopts IGBT. The characteristics of this type of device are that it can withstand high voltage in the forward direction and not withstand the voltage in the reverse direction. Generally, a diode is connected in antiparallel with it to form a unidirectional switch. Two unidirectional switches are connected in reverse series. Constitute a bidirectional switch, taking the first bidirectional switch branch S1 composed of the first unidirectional switch S11 and the second unidirectional switch S12 as an example, when no trigger signal is applied, both unidirectional switches are in the off state, and the The first bidirectional switch branch S1 is in an off state; when the first unidirectional switch S11 bears a positive voltage, a trigger signal is applied to the first unidirectional switch S11, and the diode of the first unidirectional switch S11 and the second unidirectional switch S12 constitutes The path, that is, the first bidirectional switch branch S1 is turned on; when the second unidirectional switch S12 is subjected to a positive voltage, a trigger signal is applied to the second unidirectional switch S12, which constitutes the diode of the first unidirectional switch S11 path, that is, the first bidirectional switch branch S1 is turned on; if the unidirectional switch that bears the positive voltage does not apply a trigger signal, and a trigger signal is applied to the other unidirectional switch in anti-series, the first bidirectional switch branch S1 Cannot conduct; when the trigger signal is applied to the first one-way switch S11 and the second one-way switch S12 at the same time, regardless of the voltage direction, the first two-way switch branch S1 is in the on-state.

Fig. 2 is a schematic structural diagram of a control circuit of a transformer split type arcless on-load tap-changer according to a preferred embodiment of the present invention; the control circuit includes a communication unit, a trigger unit and a detection unit; the detection unit detects The current iS1, iS2 flowing through the bidirectional switch branch, the voltage drop uS1, uS2 of the bidirectional switch branch, the current iK1 of the first through contact K1, the current iK2 of the second through contact K2 and the static state of the power circuit The current i1, i2 of the contacts R1, R2 and the voltage drop between the two static contacts are the stage voltage U ₀ . The function of the current i1 and i2 of the static contact is that the addition of the two is equivalent to the load current i of the transformer outlet terminal at any time, which is used for judging the sequence. Since the control circuit is installed on the static contact, and The load current i is on the side of the moving contact, so it is not convenient to collect, so collect i1 and i2; the voltage drop U ₀ between the two static contacts is used to compare with uS1, uS2 to detect whether the bidirectional switch withstands the stage voltage. iS1, uS1, iS2, and uS2 are all used when judging the timing during switching.

The detection unit calculates the obtained parameters and sends a control command to the trigger unit, and the trigger unit provides a trigger voltage for the power electronic switch of the bidirectional switch branch; the communication unit includes a first communication unit, The second communication unit and the third communication unit, the third communication unit uploads the information detected by the detection unit to the upper computer through the second communication unit and the first communication unit, and the upper computer controls the drive motor control unit to drive The motor controls the action of the moving contact of the diverter switch and the moving contact of the tap selector.

Fig. 3 is a schematic structural diagram of a control power supply unit of a transformer split type arcless on-load tap changer according to a preferred embodiment of the present invention; The head R1 and the second static contact R2 are connected, which is a step voltage U ₀ , and the output terminal U _DCV is a 24V DC voltage, which supplies power for the control circuit. The isolation and conversion circuit inside the control power supply converts the stage voltage into direct current that can be used by the control circuit. Since the voltage value of the stage voltage varies from hundreds to thousands depending on the transformer model, considering the insulation requirements, the The above-mentioned voltage conversion can adopt power frequency isolation or high frequency isolation power technology, wherein, compared with power frequency isolation, the high frequency isolation technology has a smaller volume and is easier to install.

The following describes the switching process of the moving contact of the diverter switch:

The moving contact D of the diverter switch can be switched from the first static contact R1 to the second static contact R2, or from the second static contact R2 to the first static contact R1. When the steady state is set, the moving contact D of the diverter switch is connected to the first through contact K1 connected to the first static contact R1, the load current flows through the winding input terminal L, and the first tap selector A certain static contact, the first static contact R1, the first through contact K1, the switch moving contact D to the outlet terminal N, thus forming a current path. Assuming that the command from the host computer is received at this time, the moving contact D of the diverter switch is switched from the first static contact R1 to the second static contact R2, and the process of moving the diverter switch moving contact D is shown in Figure 4a-4e. Here, for simplicity, only the switch part is shown.

When the moving contact D of the diverter switch moves from the first direct contact K1 to the second direct contact K2, the mechanical action is a continuous process, and the time taken is on the order of milliseconds. During this movement, the first two-way The first one-way switch S11 and the second one-way switch S12 of the switch branch S1, the third one-way switch S21 and the fourth one-way switch S22 of the second two-way switch branch S2 are realized by the first For arc-free switching from the through contact K1 to the second through contact K2, the switching time of the electronic switch is on the order of microseconds, and the switching can be completely completed during the mechanical movement. The key to realizing arcless switching in the present invention is that the electrical switching process must control the breaking and closing of the first two-way switch branch S1 and the second two-way switch branch S2 at different moving positions of the mechanical process, and must According to a certain sequence, to avoid load open circuit or winding short circuit.

After the tap selector completes the no-load shift under the drive of the motor, the moving contact D of the diverter switch is driven to move, and it is assumed that the first static contact R1 moves to the second static contact R2. When the movable contact D moves to the position shown in Figure 4b according to the sequence, the movable contact D of the diverter switch is connected to the first through contact K1 and the first bidirectional switch branch S1. At this time, the first bidirectional switch is not subjected to positive Voltage, the detection unit detects the current iK1 of the first straight-through contact K1, when iK1>0, triggers the first one-way switch S11, and makes the first two-way switch branch S1 conduct; when iK1<0 , triggering the second one-way switch S12 to turn on the first two-way switch branch S1. At this time, since the resistance of the first through contact K1 is small, although the first one-way switch S11 and the second one-way switch S12 have been turned on, the load current still flows through the first through contact K1.

As the diverter switch moving contact D continues to move and reaches the position shown in Figure 4c, the diverter switch moving contact D is connected to both the first bidirectional switch branch S1 and the second bidirectional switch branch S2, from the state in Figure 4b to Figure 4c During the moving process of the state, when the moving contact D of the diverter switch is not connected with the second bidirectional switch branch S2, because the second two-wire switch branch S2 is in a floating state, the voltage drop is zero; when the moving contact of the diverter switch When D moves to connect with both the first bidirectional switch branch S1 and the second bidirectional switch branch S2, since the second bidirectional switch branch S2 is in the off state, it must bear the first static contact R1 and the second static contact R2 The level voltage U _o between the windings, the level voltage detected by the control loop detection unit changes from 0 to U _o , which is the basis for the connection between the moving contact D of the diverter switch and the second bidirectional switch branch S2, eliminating the need for mechanical The position judging mechanism starts the switching sequence at this time and needs the direction data of the load current. Let the current flow from the first static contact R1 to the movable contact D be positive, that is, the load current i>0, otherwise i<0. According to the direction of the load current and the direction of the switch, there are four working conditions, as shown in Fig. 5a-5d. Among them, Fig. 5a and Fig. 5b both represent the process of switching from the first bidirectional switch branch S1 to the second bidirectional switch branch S2, the load current i>0 in Fig. 5a; the load current i<0 in Fig. 5b; Fig. 5c and 5d Both represent the process of switching from the second bidirectional switch S2 to the first bidirectional switch S1, the load current i>0 in FIG. 5c; the load current i<0 in FIG. 5d.

The switching process is explained below by taking Fig. 5a as an example. The working condition is i>0, the first unidirectional switch S11 and the second unidirectional switch S12 are turned on, and the second bidirectional switch branch S2 bears the stage voltage U ₀ , the load current flows through the switch tube of the first one-way switch S11 and the diode of the second one-way switch S12, that is, the state before time t1 in Figure 5a; turning off the second one-way switch S12 at time t1 does not affect The circulation of the load current is delayed for a certain time to t2, for example, 3 microseconds to ensure the reliable shutdown of the second one-way switch S12; the third one-way switch S21 is turned on at the time t2, and the load current flows through two branches at this time , including the switch tube of the first one-way switch S11 and the diode of the second one-way switch S12 as a branch, the switch tube of the third one-way switch S21 and the diode of the fourth one-way switch S22 as another branch, ensuring In order to ensure that the winding is not short-circuited and the load is not open-circuited during the switching process, a certain time is delayed until t3 to ensure that the current i drops to zero; at the time t3, the first one-way switch S11 is turned off, and the load current is completely transferred to the second two-way switch branch S2 , delay to t4 to ensure that the first one-way switch S11 is turned off reliably, at this time the load current flows through the switch tube of the third one-way switch S21 and the diode of the fourth one-way switch S22; the fourth one-way switch S22 is turned on at time t4 To the switch S22, so far, the first bidirectional switch branch S1 is completely turned off, and the second bidirectional switch branch S2 is completely turned on. When the load current is all transferred to the second bidirectional switch branch S2, the moving contact D of the diverter switch continues to move, and when the first bidirectional switch branch S1 is disconnected from the diverter switch movable contact D, it will not cause the load to open, and play a role in eliminating function of the arc.

In the switching process of Figure 4c, when the first bidirectional switch branch S1 is turned off, because the current in the inductor cannot change suddenly, an overvoltage will be formed in the winding of the transformer cut off part. At this time, the snubber circuit C3 forms a path, and the bidirectional The switch acts as a protection.

When the diverter switch movable contact D moves to the position shown in Figure 4d, the diverter switch movable contact D is connected to the second bidirectional switch branch S2 and the second through contact K2, because the resistance of the second through contact K2 is much smaller than the second In the bidirectional switch branch S2, the current is transferred to the second through contact K2. When the control loop detection unit detects that the current iS2 of the second bidirectional switch branch S2 suddenly decreases to close to zero, it can be judged that the switch movable contact D has It communicates with the second straight-through contact K2, and at this moment, the second bidirectional switch branch S2 can be turned off. When the diverter switch movable contact D moves to the position shown in Fig. 4e, the diverter switch movable contact D is only connected to the second through contact K2, so far, a switching process is completely completed.

The working principles of the other three working conditions are basically the same, which can be understood by referring to Figures 5b-5d, and will not be repeated here.

According to the working sequence when using the full-control device as shown in Fig. 5b-5d of the above embodiment, the control sequence when using the half-control device can be designed by analogy, and will not be repeated.

The foregoing embodiments have explained the working principle and basic constitution of the present invention by taking a single-phase winding as an example. The structure shown in Fig. 1 can be used in a three-phase structure through simple expansion. Structures such as a neutral point tap, an angled connection end tap, and an angled connection center tap, no matter which structure is used, does not affect the use of the present invention.

The invention provides a transformer split-type arc-free on-load tap-changer, through the use of a bidirectional switch and the trigger sequence control of the bidirectional switch, the arc-free switching of the split-type on-load tap-changer is realized, and the failure of the bidirectional switch is prevented. When the accident is expanded, the device is not damaged, and the structure is simple and the work is reliable.

The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications or equivalent replacements of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all should cover Within the scope of the claims of the present invention.

Claims (8)

1. A transformer split-type arcless on-load tap-changer, comprising a moving contact of a diverter switch connected to a transformer outlet terminal, characterized in that the transformer split-type arcless on-load tap-changer includes a tap A selector, a switch; the switch includes a power loop and a control loop; The moving contact of the tap selector is connected to the static contact of the power circuit; each static contact of the power circuit is connected with a straight contact and a two-way switch branch; the two-way switch branch is connected by After the two power electronic switches are combined and connected, a buffer circuit is connected in parallel, and then connected in series with a fuse; the buffer circuit is connected in parallel between the static contacts of the power circuit; the moving process of the moving contact of the switch is sequentially connected with the The straight-through contact and the bidirectional switch branch are connected; The control loop includes a trigger unit and a detection unit; the detection unit detects the current of the bidirectional switch branch, the voltage drop, the current of the static contact of the power loop, the voltage drop between the two static contacts and the the current of the straight-through contact, and after calculating the obtained parameters, send a control command to the trigger unit, and the trigger unit provides a trigger signal for the power electronic switch of the bidirectional switch branch; When the parameter value detected by the detection unit identifies the fault result of the bidirectional switch branch as an open circuit, it is forbidden to continue to operate. 2. A transformer split type arcless on-load tap-changer according to claim 1, wherein the buffer circuit is a capacitor or a resistance-capacitance circuit. 3 . The transformer split type arcless on-load tap changer according to claim 1 , wherein the number of static contacts of the power circuit is two. 4 . 4. A transformer split type arcless on-load tap-changer according to claim 1, characterized in that, the transfer switch also includes a control power supply unit, and the control power supply unit uses two static power circuits of the power circuit The voltage drop of the contact is the input stage voltage, and provides the power supply for the control circuit. 5. A transformer split type arcless on-load tap-changer according to claim 1, characterized in that the control loop also includes a communication unit, and the communication unit uploads the data detected by the detection unit to the upper machine, and the host computer controls the driving motor to drive the moving contacts of the diverter switch and the moving contacts of the tap selector. 6. A transformer split type arcless on-load tap changer according to claim 4, characterized in that the control power supply unit converts the input stage voltage into a DC voltage through its internal isolation and conversion circuit. 7. A transformer split-type arcless on-load tap-changer according to claim 1, characterized in that the power electronic switch adopts a semi-controlled device of a thyristor or a fully-controlled device of an IGBT or a MOSFET. 8. A transformer split-type arc-free on-load tap-changer according to claim 7, characterized in that, when the power switch adopts a thyristor semi-controlled device, the combined connection form of the two power electronic switches is inverted. Parallel connection; when the power electronic switch adopts full control devices of IGBT and MOSFET, the combined connection form of the two power electronic switches is an anti-series connection.