CN111463038A

CN111463038A - Special on-load voltage regulating switch for distribution transformer and on-load voltage regulating distribution transformer

Info

Publication number: CN111463038A
Application number: CN201910056946.2A
Authority: CN
Inventors: 吕云洁; 周甫庆; 叶传海
Original assignee: Jinan Aidi Electric Equipment Co ltd
Current assignee: Jinan Aidi Electric Equipment Co ltd
Priority date: 2019-01-22
Filing date: 2019-01-22
Publication date: 2020-07-28

Abstract

The invention discloses a special on-load voltage regulation switch for a distribution transformer and the on-load voltage regulation distribution transformer, wherein the switch comprises an installation mainboard, an insulation back plate, a driving mechanism assembly, a selection switch assembly, a change-over switch assembly and a transition element, the driving mechanism assembly comprises a stepping motor, a gearbox, a bevel gear, a driving gear and a square shaft, the rotating motion of the stepping motor is transmitted to the driving gear by means of the gearbox and the bevel gear, the driving gear drives the square shaft to rotate, and then the selection switch assembly and the change-over switch assembly are driven to act, so that the conversion of voltage regulation gears is completed. The on-load voltage regulating switch is miniaturized, is installed in a distribution transformer without changing the conventional shape and the conventional volume of the on-load voltage regulating switch, realizes frequent voltage regulation of the distribution transformer under the condition of load, stabilizes the power supply voltage, reduces the loss, realizes wide and multi-gear and refined voltage regulation, simultaneously realizes the same service life of the switch as that of the distribution transformer body, does not need maintenance in the service life, and improves the reliability of on-load voltage regulation of the distribution transformer.

Description

Special on-load voltage regulating switch for distribution transformer and on-load voltage regulating distribution transformer

Technical Field

The device relates to the technical field of electric power products, in particular to a special on-load tap changer for a distribution transformer and the on-load tap changing distribution transformer.

Background

The distribution transformer is the last transformer of a power supply network, is applied to various fields of the national civilization, is distributed in various corners of cities and countryside, and is huge in quantity. The existing distribution transformer is in a non-excitation voltage regulation mode, a power supply is cut off firstly during voltage regulation, then a non-excitation voltage regulation switch is manually adjusted, and power transmission is recovered after adjustment is finished. Because the voltage can be regulated only by power failure and timely voltage regulation cannot be realized, the distribution transformer in an actual power supply network is equal to a distribution transformer without voltage regulation measures, the power supply voltage has low qualification rate and poor stability, and the loss of the distribution transformer and the loss of electric equipment are increased due to abnormal operation of the electric equipment. Along with the continuous promotion and development of social economy and power grids, the requirement on the voltage quality is higher and higher, so that the requirement on the reliability of the on-load voltage-regulating distribution transformer is higher and higher, and the requirements on the voltage-regulating gear number and the wide voltage-regulating range of the on-load voltage-regulating distribution transformer are also increased to meet the requirements of different occasions.

In recent years, there are cases where an on-load tap changer of a main transformer is applied to a distribution transformer to realize on-load tap changing, but the on-load tap changer of the main transformer is large in size, needs to be maintained regularly, cannot meet the reliability requirement of the distribution transformer, and is not suitable for the distribution transformer with large quantity. The on-load tap changer adopting a spring energy storage mode and a permanent magnet and electromagnetic driving mode is also applied to a distribution transformer in the market, although vacuum arc extinguishing is also adopted, the driving mode of the type is adopted, the impact force is large during driving transmission, the service life of relevant parts of the on-load tap changer is influenced, the service life cycle of the on-load tap changer cannot meet the design service life cycle of the distribution transformer, and the on-load tap changer is not suitable for being used in a large number of distribution transformers.

DE19743864C1 describes an on-load tap changer using a reactor transition method, in which both a selector switch assembly and a diverter switch assembly are arranged on the same phase plate, the structural design is complex, the overall switch occupies a large space, and the reactor is used for on-load voltage regulation transition, which greatly increases the cost of the on-load voltage regulation switch and is not suitable for a large number of distribution transformers.

The german MR company has filed chinese invention patents with the following application numbers in china: 1. application number 201780005054.9 entitled "on-load tap changer"; 2. application No. 201780007088.1 entitled "on-load tap changer, adjustable transformer with on-load tap changer and method for switching on-load tap changer". The two patents only describe the structure and action condition of the selection component and the switching component of the on-load tap-changer, and the driving transmission mechanism is not illustrated, the driving part of the on-load tap-changer is one of the core components, if the driving mechanism adopts a spring energy storage or permanent magnet driving mode, the impact force is large in the switching process, the performance of the on-load tap-changer is greatly reduced, and the service life of the on-load tap-changer is influenced. The design life of the distribution transformer is at least 30 years, the requirement on the reliability of an on-load tap changer is higher, the two patents realize the function of voltage regulation of the transformer without interruption, but the reliability of the transformer is not described, each phase switching component part of the on-load tap changer of the two patents adopts a single vacuum arc-extinguishing chamber and the matching switching of a mechanical mechanism thereof, the tap is switched from an N tap to an N +1 tap, the vacuum arc-extinguishing chamber needs to be disconnected and closed twice, the current is switched and disconnected in the vacuum arc-extinguishing chamber, the requirement on a contact of the vacuum arc-extinguishing chamber is higher, and the reliability is relatively lower compared with the condition that the vacuum arc-extinguishing chamber is only connected and disconnected once in the gear shifting process. The invention relates to an on-load tap-changer, an adjustable transformer with the on-load tap-changer and a method for switching the on-load tap-changer, wherein a preselector is arranged on the basis of the on-load tap-changer, a set of maltese wheels are additionally arranged to increase the voltage regulating gear number, the structure design is complex, the length of the switch is increased, each part of a fixed switch is two adopted rods or bars which are cylindrical, the integral height of the switch is increased, the specification and the attached drawings show that the invention and the creation are not carried out on a miniaturized on-load tap-changer in the structure design, the volume size of the on-load tap-changer affects the volume size, the production cost and the installation space of a distribution transformer, and the miniaturized and high-reliability on-load tap-changer is needed for the huge distribution transformer.

Disclosure of Invention

The invention aims to provide an on-load tap changer special for a distribution transformer and an on-load tap changing distribution transformer, which solve the problem that the on-load tap changing distribution transformer in the prior art needs regular maintenance due to on-load tap changing, solve the problems that the on-load tap changer in the prior art is large in size and inconvenient to install, realize the miniaturization of the on-load tap changer, enable the on-load tap changer to be installed without changing the size and the shape of a conventional distribution transformer, realize the characteristics of long service life and maintenance-free of the on-load tap changer and enable the service life cycle of the on-load tap changer to be equal to the service life of a.

In order to achieve the purpose, the invention adopts the following technical scheme:

the utility model provides a special on-load tap changer of distribution transformer which characterized in that: the device comprises a mounting main board, an insulating back board, a driving mechanism assembly, a selection switch assembly, a change-over switch assembly and a transition element;

the driving mechanism assembly comprises a stepping motor, a gearbox, a bevel gear, a driving gear and a square shaft;

a motor protective shell is arranged outside the stepping motor, a socket of a connector is arranged on the motor protective shell, the socket of the connector is positioned on the lower shell of the motor protective shell, an external control cable is connected with a plug of the connector, and a plug of the connector is upwards connected with the socket of the connector;

the gearbox comprises a box body, a box cover, an electronic circuit board, a position sensor and a gear set;

the position sensor transmits the motion information of the gear set to the electronic circuit board, and the electronic circuit board analyzes and processes the motion information and outputs the gear position of the on-load tap changer;

the selection switch assembly, the change-over switch assembly and the transition element are respectively provided with three groups to respectively complete the selection and the switching of three-phase voltage regulating gears;

the stepping motor is installed on the gear box, and the gear box is installed on the installation main board;

the selector switch assembly and the selector switch assembly are fixedly arranged on the installation main board;

the insulating back plate is fixedly connected with one ends of the selector switch assembly and the selector switch assembly;

the transition element is fixedly arranged on one side of a change-over switch main board in the change-over switch assembly;

the square shaft penetrates through the selection switch assembly and the change-over switch assembly;

the driving gear is sleeved on the square shaft;

the rotating motion of the stepping motor is transmitted to the driving gear by means of the gearbox and the bevel gear, the driving gear drives the square shaft to rotate, and then the selection switch assembly and the change-over switch assembly are driven to act, and the conversion of the pressure regulating gears is completed.

According to a preferred embodiment of the present invention, the positioning of the voltage-regulating gear is controlled and positioned by using the stepping motor.

According to a preferred embodiment of the present invention, each set of the switch components includes a switch main board, a vacuum interrupter, a cam, a roller, a transmission arm, a support shaft, an interrupter lever, an interrupter contact pressure spring, a lever bracket, and an interrupter mounting base, two components are provided except for the switch main board, each component is located on the same side of the switch main board, and the transition element is mounted on the other side of the switch main board.

According to a preferred embodiment of the invention, the square shaft drives the two cams to rotate, the two cams respectively drive the roller to move in a time sequence, and the roller drives the arc extinguish chamber pull rod to move up and down through the transmission arm, so as to drive the arc extinguish chamber contact pressure spring to move, and control the on-off of the vacuum arc extinguish chamber.

According to a preferred embodiment of the present invention, each set of the selection switch assembly includes a selection switch main board, two sets of sheave mechanisms, a fine selection contact assembly, a rough selection driving tooth, an incomplete gear mechanism, and a rough selection contact assembly, the sheave mechanisms include a dial plate and a sheave, the two sets of sheave mechanisms are respectively installed on two sides of the selection switch main board, the rough selection driving tooth is installed and fixed on the sheave of one of the sheave mechanisms, the incomplete gear mechanism is installed and fixed on one side of the selection switch main board, and the rough selection contact assembly is fixed on one side of the selection switch main board through a fixing column.

According to a preferred embodiment of the invention, the roughing driving gear, the incomplete gear mechanism and the roughing contact assembly are on the same side of the main board of the selector switch.

According to a preferred embodiment of the present invention, the fine selection contact assembly includes two moving contacts and a static contact group, the two moving contacts are respectively and fixedly installed on two grooved wheels of the selection switch assembly, a static contact of the static contact group is fixedly installed in grooves on two sides of the selection switch main board through a conductive bolt, and the static contact is flush with a surface of the selection switch main board after being installed; the number of the static contacts is the same as the tooth number of the grooved pulley, and when gear selection is carried out, the grooved pulley drives the moving contact to rotate, so that the corresponding static contact in the static contact group is selected.

According to a preferred embodiment of the present invention, the rough selection contact assembly includes a moving contact, two fixed contacts, and a contact fixing plate, where the moving contact and the two fixed contacts are both mounted on the contact fixing plate, and when a voltage regulation gear shift is performed, and the sheave drives the rough selection driving tooth to move to engage with a corresponding gear on the incomplete gear mechanism, the rough selection driving tooth drives the incomplete gear mechanism to move, and the incomplete gear mechanism drives the moving contact in the rough selection contact assembly to select the fixed contact in the rough selection contact assembly without current.

An on-load tap changing distribution transformer, characterized in that the on-load tap changing distribution transformer of the on-load tap changing switch special for the distribution transformer with the structure of any one of the preceding claims is adopted.

Compared with the prior art, the on-load tap changer special for the distribution transformer is arranged on a distribution transformer box cover, a switch body is arranged below the box cover, a stepping motor of a drive part of the switch is arranged above the box cover, the stepping motor is provided with a fully-protective motor protective shell, a connector is arranged below the motor protective shell, the on-load tap changer is unique in waterproof and dustproof design and high in protective performance, the on-load tap changer is arranged in the distribution transformer, the shape and the size of a conventional distribution transformer are not changed as much as possible, the production cost greatly increased by the switch size is greatly reduced, the fault-free and maintenance-free continuous voltage regulation action is realized for more than 60 ten thousand times, the maintenance-free operation can be realized in the service life cycle of the distribution transformer, the reliability of the on-load tap regulation of the distribution transformer is improved, the wide range of the distribution transformer is realized, the 17 +/-8 × 2.5.5% wide range voltage regulation can be realized, the frequent voltage regulation under the condition of a load is realized, the.

Drawings

Fig. 1 is a schematic diagram a of the overall structure of an on-load tap changer dedicated for a distribution transformer according to the present invention;

fig. 2 is a schematic diagram B of the overall structure of the on-load tap changer dedicated for the distribution transformer of the present invention;

FIG. 3 is a schematic view of the fully protective housing of the stepping motor of the on-load tap changer for distribution transformers according to the present invention;

FIG. 4 is a schematic diagram of the internal mechanism of the transmission case of the on-load tap changer dedicated to the distribution transformer of the present invention;

fig. 5 is a schematic diagram of a diverter switch assembly (one side of a diverter switch main board) of the on-load tap changer dedicated to the distribution transformer of the present invention;

fig. 6 is a schematic diagram of a transition element on the other side of a main board of a diverter switch of an on-load tap changer dedicated to a distribution transformer according to the present invention;

fig. 7 is a general schematic diagram of a selector switch assembly of the on-load tap changer specific to the distribution transformer of the present invention;

fig. 8 is a schematic diagram a of the disassembly of the selector switch assembly of the on-load tap changer dedicated to the distribution transformer of the present invention;

fig. 9 is a schematic diagram B of the disassembled selective switch assembly of the on-load tap changer dedicated to the distribution transformer of the present invention;

fig. 10 is a schematic structural diagram of a selective switch assembly of an on-load tap changer dedicated for a distribution transformer, in which a sheave and other components are removed from one side of the selective switch assembly;

fig. 11 is a schematic diagram of a timing sequence for fine-selection gear selection and switching of the on-load tap changer dedicated to the distribution transformer according to the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The embodiments described below are merely intended to more clearly illustrate the technical solutions of the present invention, are selected embodiments of the present invention, not all embodiments, and thus the scope of the present invention is not limited thereto. All other embodiments obtained by a person skilled in the art without making any inventive step are within the scope of protection of the present invention.

Fig. 1 to 10 are schematic diagrams of a preferred on-load tap changer special for a distribution transformer capable of realizing 17-gear tap changing positions according to the present invention, and referring to fig. 1 and 2, the on-load tap changer special for a distribution transformer comprises an installation main board 1, an insulation back board 2, a driving mechanism assembly 3, a selection switch assembly 4, a change-over switch assembly 5, and a transition element 6; the driving mechanism assembly comprises a stepping motor 31, a gearbox 32, a bevel gear 33, a driving gear 34 and a square shaft 35, and the selector switch assembly 4, the selector switch assembly 5 and the transition element 6 are respectively provided with three groups to respectively complete the selection and the switching of three-phase voltage regulating gears.

Referring to fig. 3, the invention adds a full protection design for the stepping motor, a motor protection shell is arranged outside the stepping motor 31, the motor protection shell is fixedly mounted on the gearbox through fastening screws, the motor protection shell is divided into an upper shell 311 and a lower shell 312, a socket of a connector 313 is arranged on the lower shell 312, the socket of the connector 313 is designed downwards, and the design position and direction of the socket effectively play roles of water prevention and dust prevention; the feedback line of the relevant gear information of the on-load tap changer and the control line 314 of the stepping motor are connected to the socket of the connector 313, the plug of the connector 313 is connected with the external control cable, and the plug of the connector 313 faces upwards to be connected with the socket of the connector 313, as shown in fig. 3.

Referring to fig. 4, the transmission case 32 includes a case 321, a case cover 322, an electronic circuit board 323, a position sensor 324, and a gear set 325, wherein the position sensor 324 transmits the motion information of the gear set 325 to the electronic circuit board 323, and the electronic circuit board 323 performs analysis processing to output the gear position of the on-load tap changer.

Referring to fig. 5 and 6, each set of the diverter switch assembly 5 includes a diverter switch main board 51,

vacuum interrupters

521 and 522,

cams

531 and 532,

rollers

541 and 542, driving

arms

551 and 552, supporting

shafts

561 and 562,

interrupter tie rods

571 and 572, interrupter

contact pressure springs

581 and 582, tie rod supports 591 and 592, and

interrupter mounting bases

5101 and 5102, all of which are located on the same side of the diverter switch main board 51, and a transition element 6 is mounted on the other side of the diverter switch main board 51; the square shaft 35 drives the

cams

531 and 532 to rotate, the

cams

531 and 532 respectively drive the

rollers

541 and 542 to move in a time sequence, and the

rollers

541 and 542 drive the arc extinguish

chamber pull rods

571 and 572 to move up and down through the

transmission arms

551 and 552, so that the arc extinguish chamber

contact pressure springs

581 and 582 are driven to move, and the on-off of the vacuum

arc extinguish chambers

521 and 522 is controlled.

Referring to fig. 7 to 10, each set of selection switch assembly 4 includes a selection switch main plate 41, two sets of sheave mechanisms 42, 43, a fine selection contact assembly 44, a roughing drive tooth 45, an incomplete gear mechanism 46, a roughing contact assembly 47, and the sheave mechanisms 42, 43 include

dials

421, 431,

sheaves

422, 432; the fine selection contact assembly 44 includes two moving contacts 441, 442 and a stationary contact group 443, the stationary contact group 443 includes a plurality of stationary contacts, the number of the stationary contacts in the stationary contact group 443 is the same as the number of teeth of the sheave 422 or the sheave 432, and the stationary contact group shown in fig. 10 includes 9 stationary contacts; the roughing contact assembly 47 includes a moving contact 471, two

stationary contacts

472, 473, and a contact fixing plate 474; the two groups of sheave mechanisms 42 and 43 are respectively installed on two sides of the option switch main board 41, the moving contacts 441 and 442 are respectively and fixedly installed on the

sheaves

422 and 432, the static contact in the static contact group 443 is fixedly installed in the grooves on two sides of the option switch main board 41 through the conductive bolt 445, and the static contact in the static contact group 443 is flush with the surface of the option switch main board 41 after installation; the roughing driving gear 45 is fixedly arranged on a grooved wheel 422 of one grooved wheel mechanism 42, the incomplete gear mechanism 46 is fixedly arranged on one side of the selection switch main board 41, and the roughing contact assembly 47 is fixedly arranged on one side of the selection switch main board 41 through a fixing column; the roughing driving gear 45, the incomplete gear mechanism 46 and the roughing contact assembly 47 are arranged on the same side of the main board 41 of the selector switch; fig. 10 shows the internal structure of the

sheave

422 or 432 with the sheave mechanism 42 or 43 removed, and it can be clearly seen that the fixed contact in the fixed contact group 443 is fixed in the groove of the selector switch main board 41, and it can be seen that the movable contact 441 in the thin selector contact assembly 44 is connected with one fixed contact in the fixed contact group 443.

The stepping motor 31 is installed on the gear box 32, the option switch main board 41 and the change-over switch main board 51 are fixed on the installation main board 1, the insulation back board 2 is fixedly connected with one end of the option switch main board 41 and one end of the change-over switch main board 51, the square shaft 35 penetrates through the option switch main board 41 and the change-over switch main board 51, and the driving gear 34, the cams 54 and 55, the

dial

421 and 431 are sleeved on the square shaft 35.

The rotating motion of the stepping motor 31 is transmitted to the driving gear 34 by means of the gearbox 32 and the bevel gear 33, the driving gear 34 drives the square shaft 35 to rotate, and further drives the cams 54 and 55 and the

dial plates

421 and 431 to rotate, the cams 54 and 55 push the vacuum arc-extinguishing chambers 52 and 53 to be switched on and off through the

rollers

541 and 542, the

transmission arms

551 and 552, the arc-extinguishing

chamber pull rods

571 and 572 and the arc-extinguishing chamber

contact pressure springs

581 and 582, and the live switching of the voltage-adjusting gears is completed; the

dial

421 and 431 pushes the

grooved wheels

422 and 432 to move, the

grooved wheels

422 and 432 drive the moving contacts 441 and 442 in the fine selection contact assembly 44 and the rough selection driving tooth 45 to move, the moving contacts 441 and 442 select corresponding static contacts in the static contact set 443, when the rough selection driving tooth 45 moves to be engaged with corresponding gears on the incomplete gear mechanism 46 during corresponding gear shifting, the rough selection driving tooth 45 drives the incomplete gear mechanism 46 to move, and then drives the moving contact 471 in the rough selection contact assembly 47 to select the corresponding static contact 472 or the static contact 473, so that the uncharged selection of the voltage regulating gear is completed, and the voltage regulation is completed.

Referring to fig. 11, there are 7 steps of the fine gear selection switching process performed by the on-load tap changer dedicated to the distribution transformer of the present invention, wherein N, N +1 represents two adjacent coil taps of the tap winding, A, B represents two moving contacts 441, 442 in the fine gear selection contact assembly 44 in the selector switch assembly 4, R represents the transition element 6, and D1, D2 represent two

vacuum interrupters

521, 522 in the selector switch assembly 5.

Timing of switching from N +1 tap to N tap of the regulating winding:

step 1: the moving contacts A, B are all connected with the N +1 tap, and the vacuum arc-extinguishing chambers D1 and D2 are all connected. The current flows through the N +1 tap through the moving contact A and the vacuum arc-extinguishing chamber D2.

Step 2: the vacuum arc extinguish chamber D2 is disconnected, the moving contact A is disconnected with the tap N +1, the moving contact B is still connected with the tap N +1, and current flows through the moving contact B, the transition element 6 and the vacuum arc extinguish chamber D1 from the tap N + 1.

And step 3: the moving contact B is still connected with the N +1 tap, the moving contact A is switched to the N tap from the N +1 tap without current, and the current flows through the moving contact B, the transition element 6 and the arc extinguishing chamber D1 from the N +1 tap.

And 4, step 4: the moving contact B is still communicated with the N +1 tap, the vacuum arc extinguish chamber D2 is closed, the moving contact A is communicated with the N tap, current flows through the moving contact B, the transition element 6 and the vacuum arc extinguish chamber D1 from the N +1 tap, the current flows through the moving contact A and the vacuum arc extinguish chamber D2 from the N tap, and at the moment, short-time circulation is generated between the N +1 tap and the N tap.

And 5: the vacuum arc extinguish chamber D1 is disconnected, the moving contact B is disconnected with the tap N +1, the moving contact A is still connected with the tap N, and current flows through the moving contact A and the vacuum arc extinguish chamber D2 from the tap N.

Step 6: the moving contact A is still connected with the N taps, the moving contact B is switched to the N taps from the N +1 taps without current, and the current flows through the moving contact A and the vacuum arc-extinguishing chamber D2 from the N taps.

And 7: the moving contact A is still communicated with the N tap, the vacuum arc extinguish chamber D1 is communicated, the moving contact B is communicated with the N tap, and current flows through the moving contact A and the vacuum arc extinguish chamber D2 from the N tap.

The above description is made for the fine-selection gear shifting process of the on-load tap changer, and the rough selection part in the selection switch assembly is according to the conventional on-load tap changing mode: the thickness voltage regulation principle and the positive and negative voltage regulation principle are designed, and no matter the fine selection part or the rough selection part in the selection switch assembly moves or selects the corresponding contact in a current-free state, which is well known by the person skilled in the art and is not described. Above whole selection switching process, electric arc only produces in the vacuum arc extinguishing chamber, can not produce the pollution to transformer oil, does not need regularly to carry out the oil strain maintenance or change the filter core, has saved the operation maintenance cost greatly.

When the on-load tap changer special for the distribution transformer is designed, the on-load tap changer is developed from the aspects of miniaturization, maintenance-free property and equal service life to the design service life of the transformer. The invention adopts the flexible driving and precise positioning characteristics of the stepping motor 31 to carry out the driving conversion and the control positioning of the voltage regulating gears, thereby greatly reducing the impact force on relevant parts (a change-over switch assembly and a selection switch assembly) in the driving and transmission process of the on-load voltage regulating switch and improving the actual service life and the reliability of each part of the switch; the stepping motor 31 drives the gear set 325 in the gearbox 32 to rotate, the position sensor 324 transmits the rotation information of the gear set 325 to the electronic circuit board 323, the electronic circuit board 323 analyzes and processes the gear position of the on-load tap changer to be directly output, the position information of the tap position is directly output in the gearbox 32, a conventional high-fault-rate and unreliable position switch feedback device is omitted, and the service life and the operation reliability of the on-load tap changer are greatly improved; a motor protective shell is arranged outside the stepping motor 31, belongs to a full-protection design structure, and is provided with a connector below the motor protective shell, so that the design position has optimal waterproof and dustproof effects; two vacuum arc-extinguishing chambers 521 and 522 are arranged in the change-over switch component 5, when the voltage-regulating gear is switched, the two vacuum arc-extinguishing chambers 521 and 522 only act once, and compared with the other vacuum arc-extinguishing chambers which only need to act twice during gear switching each time and need to be matched by a more complicated mechanical mechanism, if the same type of vacuum arc-extinguishing chamber is selected, the service life of the invention is prolonged by one time compared with the other vacuum arc-extinguishing chambers, and the reliability of the switch is improved; the invention adopts a mounting main board with enough tolerance strength to fixedly mount each component so as to reduce the overall height of the on-load tap changer; meanwhile, related parts of rough selection and fine selection of the on-load voltage regulating switch are arranged on the same selection switch mainboard, compared with switches arranged on different installation mainboards, the structure of the on-load voltage regulating switch is simple and compact in design, the length of the switch is reduced, and the overall design of the switch is miniaturized. By selecting the scheme, the on-load tap changer has the characteristics of miniaturization, maintenance-free and high reliability, and is suitable for a proper amount of large distribution transformers. It is within the scope of the present invention to modify the present invention according to the preferred embodiment, for example, to use a motor mechanism such as a servo motor or a linear motor instead of a stepping motor in conjunction with a control program.

The voltage regulation modes of the on-load tap changer mainly comprise three modes, namely linear voltage regulation, positive and negative voltage regulation and coarse and fine voltage regulation, the on-load tap changer special for the distribution transformer is applicable, the positive and negative voltage regulation and the coarse and fine voltage regulation are only different in winding mode and wiring mode of a voltage regulation winding, and the linear voltage regulation mode is adopted, and only related parts selected and switched by fine voltage regulation gears of the on-load tap changer are adopted.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several changes and modifications may be made without departing from the technical principle of the present invention, and these changes and modifications should also be construed as the protection scope of the present invention.

Claims

1. The utility model provides a special on-load tap changer of distribution transformer which characterized in that: the device comprises a mounting main board, an insulating back board, a driving mechanism assembly, a selection switch assembly, a change-over switch assembly and a transition element;

the driving gear is sleeved on the square shaft;

2. The on-load tap changer of claim 1, wherein the positioning of the tap position is controlled by the stepper motor.

3. The on-load tap changer special for the distribution transformer according to claim 1, wherein each group of the switching switch assembly comprises a switching switch main board, a vacuum arc extinguish chamber, a cam, two rollers, a transmission arm, a support shaft, an arc extinguish chamber pull rod, an arc extinguish chamber contact pressure spring, a pull rod bracket and an arc extinguish chamber mounting base, and except that the switching switch main board comprises two other components, each component is located on the same side of the switching switch main board, and the transition element is installed on the other side of the switching switch main board.

4. The on-load tap changer special for the distribution transformer according to claim 3, wherein the square shaft drives two cams to rotate, the two cams drive the roller to move in a time sequence, and the roller drives the arc extinguish chamber pull rod to move up and down through the transmission arm, so as to drive the arc extinguish chamber contact pressure spring to move and control the on-off of the vacuum arc extinguish chamber.

5. The on-load tap changer special for the distribution transformer as claimed in claim 1, wherein each group of the selection switch assembly comprises a selection switch main board, two groups of sheave mechanisms, a fine selection contact assembly, a coarse selection driving tooth, an incomplete gear mechanism and a coarse selection contact assembly, the sheave mechanisms comprise a driving plate and a sheave, the two groups of the sheave mechanisms are respectively installed on two sides of the selection switch main board, the coarse selection driving tooth is installed and fixed on the sheave of one of the sheave mechanisms, the incomplete gear mechanism is installed and fixed on one side of the selection switch main board, and the coarse selection contact assembly is fixed on one side of the selection switch main board through a fixing column.

6. The on-load tap changer special for distribution transformers according to claim 5, characterized in that the roughing drive teeth, the incomplete gear mechanism and the roughing contact assembly are on the same side of the main board of the selector switch.

7. The on-load tap changer special for the distribution transformer according to claim 5, wherein the fine selection contact assembly comprises two movable contacts and a static contact group, the two movable contacts are respectively and fixedly installed on the two grooved wheels of the selection switch assembly, the static contact of the static contact group is fixedly installed in the grooves at two sides of the selection switch main board through a conductive bolt, and the static contact is flush with the surface of the selection switch main board after being installed; the number of the static contacts is the same as the tooth number of the grooved pulley, and when gear selection is carried out, the grooved pulley drives the moving contact to rotate, so that the corresponding static contact in the static contact group is selected.

8. The on-load tap changer special for a distribution transformer according to claim 5, wherein the roughing contact assembly comprises a moving contact, two fixed contacts, and a contact fixing plate, the moving contact and the two fixed contacts are both mounted on the contact fixing plate, when a voltage regulation gear shift is performed, when the sheave drives the roughing drive tooth to move to engage with a corresponding gear on the incomplete gear mechanism, the roughing drive tooth drives the incomplete gear mechanism to move, and the incomplete gear mechanism drives the moving contact in the roughing contact assembly to select the fixed contact in the corresponding roughing contact assembly without current.

9. An on-load tap changing distribution transformer, characterized in that the on-load tap changing distribution transformer of the on-load tap changing switch special for the distribution transformer with the structure of any one of the preceding claims is adopted.