CN112530681A

CN112530681A - Dry-type transformer and production process thereof

Info

Publication number: CN112530681A
Application number: CN202010470926.2A
Authority: CN
Inventors: 潘炳阳; 姚灿林; 潘安基; 曾俊杰
Original assignee: Fujian Yongjia Technology Co ltd
Current assignee: Fujian Yongjia Technology Co ltd
Priority date: 2020-05-28
Filing date: 2020-05-28
Publication date: 2021-03-19

Abstract

A dry-type transformer and its preparation method, this dry-type transformer includes the base, two lower clamp pieces mounted on base, three iron cores mounted on lower clamp piece at intervals, two upper clamp pieces mounted on both sides of top of iron core, three high-low voltage coil groups that are fitted over three iron cores separately and body insulating part and hardware connecting piece used for connecting high-low voltage coil group and iron core to connect, its preparation method includes step one, coiling the high-voltage coil; winding a low-voltage coil; and step three, carrying out general assembly on the high-voltage coil in the step one, the low-voltage coil in the step two, the iron core, the base, the upper clamping piece, the lower clamping piece, the body insulator and the hardware connecting piece. The high-voltage coil of the dry-type transformer is not easy to crack and has longer service life.

Description

Dry-type transformer and production process thereof

Technical Field

The invention relates to the field of transformers, in particular to a dry-type transformer and a production process thereof.

Background

The DMD epoxy prepreg material is prepared by soaking a polyester film and a polyester fiber non-woven fabric soft composite material (F-grade DMD) in heat-resistant modified epoxy resin and baking.

The DMD epoxy prepreg material has the characteristics and the application: the coated epoxy resin contains active groups such as epoxy groups, amino groups and the like, is rapidly cured at medium and high temperature, is firmly bonded with the copper foil, does not generate low-molecular volatile matters during drying and curing, and forms an insulating structure with extremely low shrinkage. The product is widely used for the interlayer insulation of the low-voltage coil of the dry type transformer and can also be used for the slot insulation and the interphase insulation of an F-level motor.

The pre-impregnated DMD is a soft composite material which is prepared by adhering high-melting-point polyester non-woven fabrics on two surfaces of a polyester film, then soaking the three-layer composite material with high-temperature-resistant modified epoxy resin, and drying the three-layer composite material into a semi-solidified state.

The glass fiber mesh fabric is prepared by taking glass fiber woven fabric as a base material and soaking a coating layer by using a high-molecular anti-emulsion. Therefore, the high-strength heat-insulating waterproof paint has good alkali resistance, flexibility and high tensile resistance in the warp and weft directions, and can be widely used for heat insulation, water resistance, fire resistance, crack resistance and the like of inner and outer walls of buildings. The glass fiber mesh cloth is mainly alkali-resistant glass fiber mesh cloth, is formed by twisting medium-alkali-free glass fiber yarns (the main component is silicate and has good chemical stability) through a special tissue structure, namely a gauze tissue, and then is subjected to high-temperature heat setting treatment such as alkali resistance, a reinforcing agent and the like. Curing agent: the curing agent is methyl tetrahydrophthalic anhydride (MTHPA). The molecular formula is as follows: C9H10O 3. Molecular weight 166.17. The light yellow liquid has the relative density of 1.21, the freezing point below 15 ℃, the viscosity (25 ℃) of 50-80 mPa & s, the refractive index of 1.498 and good stability in air. Boiling point: the temperature is 115-155 ℃, crystals are not easy to separate out, and the paint is non-toxic. The product is an anhydride epoxy resin curing agent, and has the excellent performances of long-term storage at room temperature, low freezing point, low volatility, low toxicity and the like. The method is widely applied to impregnation, pouring, winding and the like of motors, dry-type transformers, high-voltage switches, mutual inductors, line output transformers, household electrical appliance capacitors, power capacitor resistors, integrated circuits.

Epoxy resin: the epoxy resin is a generic name of a polymer having two or more epoxy groups in a molecule. It is a polycondensation product of epichlorohydrin and bisphenol A or polyol. Because of the chemical activity of the epoxy group, the epoxy group can be opened by a plurality of compounds containing active hydrogen, and the epoxy group is cured and crosslinked to form a network structure, so that the epoxy group is a thermosetting resin.

The resin-cast dry-type transformer has the advantages of safe and stable operation, no pollution, low noise, no maintenance and the like, and is widely applied to various power utilization places. However, the resin-cast dry-type transformer has the problems that the quality after casting is unstable, the defects of more air gaps, poor resin mechanical and insulating properties, difficult demoulding and the like often occur, and the test indexes of the cast coil such as local discharge capacity, power frequency withstand voltage and the like are unqualified and the process defects are caused.

Disclosure of Invention

The invention provides a dry-type transformer and a production process thereof, and mainly aims to overcome the defects of improving the quality of a resin pouring process and solving the problem of high local discharge capacity.

In order to solve the technical problems, the invention adopts the following technical scheme:

a dry-type transformer comprises a base, an iron core installed on the base, three high-low voltage coil groups sleeved on the iron core and three hardware connecting pieces used for connecting the high-low voltage coil groups with the iron core, wherein the high-voltage coil is manufactured by a high-voltage coil mold used for winding the high-voltage coil, a high-voltage coil winding machine used for rotating the high-voltage coil mold, a resin casting machine used for casting the high-voltage coil mold and a pair of curing and drying boxes used for curing and drying the high-voltage coil mold in sequence, the high-voltage coil comprises a plurality of layers of first insulation layers wound by the high-voltage coil winding machine, wires arranged in the first insulation layers and wound by the high-voltage coil winding machine, a plurality of first air passages arranged at intervals in the first insulation layers and six tapping and leading wires connected with the winding wires through tapping leads The distance between adjacent tapping leads is 15-20 mm, the distance between the tapping leads and the unconnected wiring terminal is larger than or equal to 10mm, and the tapping turns of the tapping leads are 16:15:15: 15.

Furthermore, the first insulating layer comprises an inner first insulating layer formed by winding the high-voltage coil die, an interlayer first insulating layer wound on one side of the inner first insulating layer, an outer first insulating layer wound on the other side of the interlayer first insulating layer and an air duct insulating layer wound on the first air duct, and the distance between the tapping lead and the outermost layer of the first insulating layer is 15-20 mm.

Furthermore, the part of the high-voltage coil inner layer insulation which exceeds the conducting wire is covered with an insulating tape.

Furthermore, the low-voltage coil is manufactured by a low-voltage coil mould for winding the low-voltage coil and a low-voltage coil winding machine for rotating the low-voltage coil mould, a plurality of layers of second insulating layers are wound on the low-voltage coil mould by using the low-voltage coil winding machine, and a polypropylene film coating is coated on the contact surface of the low-voltage coil mould and the second insulating layers.

The production process of the dry-type transformer comprises the following steps

Step one, winding a high-voltage coil;

winding a low-voltage coil;

step three, carrying out general assembly on the high-voltage coil in the step one, the low-voltage coil in the step two, the iron core, the base, the upper clamping piece, the lower clamping piece, the body insulator and the hardware connecting piece;

further, the first step is composed of the following procedures in sequence,

step 1a, installing a high-voltage coil mold on a high-voltage coil winding machine for rotation, and preparing the high-voltage coil mold;

step 1b, winding a winding wire and a first insulating layer are wound on a high-voltage coil die, a plurality of air channel rods arranged at intervals are inserted, the winding wire is connected with a wiring terminal, a layer of release agent is brushed between the first insulating layer and the high-voltage coil, a first coil winding procedure is carried out, and finally a first coil is obtained;

step 1c, conveying the first coil in the step 1b into a curing and drying box for drying, keeping the temperature at 120-140 ℃, and keeping the temperature for 9-12 hours;

step 1d, conveying the first coil dried in the step 1c into a resin casting machine for casting;

step 1e, sending the first coil which is cast in the step 1d into a curing and drying box for curing and drying;

step 1f, performing a demoulding, material returning and cooling process on the first coil in the step 1 e;

step 1g, polishing and finishing the outer surface of the high-voltage coil obtained in the step 1f to enable the port of the high-voltage coil to be flat and smooth, and performing a finishing process to obtain the high-voltage coil;

step 1h, after the pouring in the step 1d is finished, cleaning a mixing tank of a resin pouring machine, taking alcohol as a cleaning agent, automatically extracting the cleaning agent into the mixing tank for a pipeline during cleaning, sealing the mixing tank during cleaning, discharging the cleaning agent from the mixing tank through a waste liquid port after the cleaning is finished, discharging and collecting to obtain cleaning waste liquid, standing the cleaning waste liquid to obtain supernatant liquid which is alcohol, taking the precipitate as resin, and secondarily utilizing the supernatant liquid for cleaning the mixing tank to perform a cleaning process,

the use of the cleaning agent can be saved by recycling the supernatant liquid for secondary utilization on one hand, the purchase cost of the cleaning agent is reduced, on the other hand, the resin for recycling the precipitate can be sold to change waste into valuable, the cost for treating waste is saved, and the two purposes are achieved at one stroke.

The second step is composed of the following procedures in sequence,

step 2a, mounting a low-voltage coil mold on a foil winding machine for rotation, and preparing the low-voltage coil mold;

step 2b, winding the second insulating layer and the copper foil on a low-voltage coil die, loading two copper bars arranged at intervals, loading a plurality of drawing pieces arranged at intervals and a temperature control probe tube bound on one drawing piece, and performing a second coil winding process to obtain a second coil;

step 2c, feeding the second coil obtained in the step 2b into a drying box, keeping the temperature at 120-140 ℃, and carrying out heat preservation for 9-11 hours to carry out a second coil drying procedure;

step 2d, taking out the second coil processed in the step 2c, carrying out an end-sealing process by using normal-temperature epoxy resin, standing for 2h and cooling;

step 2e, removing the low-voltage coil mould from the second coil after the end-sealing process, performing a demoulding process to obtain a low-voltage coil,

further, in step 1d,

pouring: feeding epoxy resin and a curing agent into a mixing tank according to the weight ratio of 1:1, heating to 70-80 ℃, vacuumizing and stirring for 1.5-2 h to obtain a mixture A, feeding the mixture A into a vacuum tank through a blanking valve to cast a first coil, and after the first coil is fully cast, adopting the following steps,

step 1d1, vacuumizing the vacuum tank, and standing for 25-45 min;

step 1d2, breaking the vacuum state in the vacuum tank, inflating and pressurizing to 2-3 kPa, and keeping the pressure for 20 min;

step 1d3, vacuumizing the vacuum tank, and standing for 20-30 min;

step 1d4, breaking the vacuum state in the vacuum tank, inflating and pressurizing to 2-3 kPa, keeping the pressure and standing for 20-30 min;

and step 1d5, regulating the pressure to 1kPa, and standing for 30-60 min.

The processing technology of secondary vacuum pumping and secondary vacuum breaking pressurization is adopted to enable the filling of the epoxy resin to be more compact and reduce the existence of air bubbles in the resin, so that the sealing degree of the resin in the high-voltage coil is improved, the insulation effect of the high-voltage coil is improved, the high-voltage coil is not easy to crack, the service life of the high-voltage coil is prolonged, and the compression strength and the external impact strength of the high-voltage coil are improved.

Further, in the step 1e, a curing and drying process is carried out in a curing and drying oven at 80-140 ℃, and the curing and drying process comprises the following four stages in sequence, wherein (1) the temperature of the first stage is 80-95 ℃, the temperature is kept for 3-5 h, and (2) the temperature of the second stage is 100-110 ℃, and the temperature is kept for 2-3 h; (3) the temperature of the third stage is 120-140 ℃, and the temperature is kept for 3-5 h; (4) and cooling to 90-110 ℃ in the fourth stage, and keeping the temperature for 2-3 h.

Resin in the high-voltage coil is solidified more uniformly and compactly by adopting the four-section type temperature rise, so that the insulativity of the high-voltage coil is improved, the electric shielding effect of the high-voltage coil is improved, the high-voltage coil is not easy to crack, the service life of the high-voltage coil is prolonged, and the two purposes are achieved by one stroke.

Furthermore, the iron core in the third step is composed by the following procedures in sequence,

step 3a, longitudinally shearing the iron core raw material;

step 3b, transversely shearing the iron core raw material longitudinally sheared in the step 3 a;

step 3d, stacking the iron core raw materials subjected to transverse shearing in the step 3 b;

step 3e, carrying out end sealing on the iron core raw material stacked in the step 3d to obtain an iron core;

and 3e, end sealing is carried out on the iron core raw material: coating a normal-temperature epoxy resin coating on the end part of the iron core, standing for 2h, and waiting for solidification;

in step 1b, winding wire: winding the electromagnetic wire, finishing and prepressing the wound electromagnetic wire, wrapping the electromagnetic wire by using an insulating tape to obtain a winding wire, injecting epoxy resin mixture to permeate into each layer of the winding, and curing and molding the winding to integrate the electromagnetic wire and the second insulating layer into a whole to obtain a winding wire; the winding wire is wrapped by the insulating tape, so that the winding wire and the epoxy resin are separated from each other, the epoxy resin cannot penetrate into the winding wire from a gap during pouring, and the insulating tape plays a role in fixing the winding wire so as to facilitate the positioning of the winding wire.

The copper foil is wound on the low-voltage coil mould for 14 turns in total, and the method comprises the following steps of (1) winding 4 turns firstly to place a plurality of spaced drawing pieces, (2) winding 4 turns secondly to place a plurality of spaced drawing pieces, (3) winding the remaining 6 turns finally, wherein the second insulating layer comprises an inner second insulating layer wound on the low-voltage coil mould, an interlayer second insulating layer wound on two sides of the middle-layer copper foil, an outer insulating layer wound on the outer side surface of the outer-layer copper foil and a reinforced second insulating layer, the outer surface of the low-voltage coil is wrapped by the second insulating layer for three layers and then is wrapped by a heat-drying shrinkage tape for one layer in a half-overlapping mode, the reinforced second insulating layer is respectively arranged at the starting end and the tail end between the copper bar and the inner second insulating layer, the reinforced second insulating layer is additionally arranged between the lead bar in the low-voltage coil and the adjacent turns, the lower end parts of the two lead bars, The lower end is 15-20 mm higher than the low-voltage copper foil.

Drawings

Fig. 1 is a flow chart of a dry type transformer production process.

Fig. 2 is a schematic structural diagram of the dry-type transformer in a top view.

Fig. 3 is a schematic structural diagram of a dry-type transformer.

Fig. 4 is a diagram of boss tap lead routing and a high voltage coil schematic.

Fig. 5 is a top view of the high voltage coil.

Fig. 6 is a schematic structural diagram of the outlet panel.

Fig. 7 is a schematic diagram of a winding structure of a high-voltage coil.

Fig. 8 is a top view of the low voltage coil.

Fig. 9 is a schematic structural diagram of the low voltage coil.

Fig. 10 is a schematic view of the installation of the body insulation assembly.

Detailed Description

The following describes embodiments of the present invention with reference to the drawings.

Referring to fig. 1-10, a dry-type transformer includes a base 21, three high-low voltage coil sets respectively sleeved on three iron cores 25, a body insulator disposed on the high-low voltage coil sets, a hardware connector for connecting the high-low voltage coil sets and the iron cores 25, a fan 43 mounted on the base 21, a fan bracket for mounting the fan 43, and a dry-type transformer temperature controller (model BWD-KRE or BWD-K3) for controlling the fan, wherein the three high-low voltage coil sets are arranged at a transverse interval.

The principle of a PT100 linear platinum resistance sensor for transformer temperature protection is that an LED displays temperature, the temperature setting is realized, the highest temperature value is stored, an alarm tripping signal is automatically sent, a fan is automatically/manually started and stopped, and the fan adopts an axial flow fan, so that the linear platinum resistance sensor has the advantages of large air quantity, good heat dissipation effect and silence.

The high-low voltage coil set comprises a low voltage coil 54 sleeved on the middle part of the iron core 25 and a high voltage coil 36 sleeved on the outer side of the low voltage coil 54.

Referring to fig. 1 to 10, the body insulator includes an insulating cylinder 53 disposed between the low voltage coil 54 and the high voltage coil 36, and a plurality of insulating pads disposed on upper and lower sides of the insulating cylinder 53 at intervals, wherein the high voltage coil 36 is disposed on an outer side of the insulating cylinder 53.

The insulating spacer block comprises an upper spacer block 51 arranged above the insulating cylinder 53 and a lower spacer block 55 arranged below the insulating cylinder 53,

go up cushion 51 and lower cushion 55 on same vertical line, the contained angle is 90 degrees between two last cushions 51 towards high-voltage lead 32 direction, and the contained angle is 90 degrees between two lower cushions 55 towards high-voltage lead 32 direction, and the contained angle is 90 degrees between two last cushions 51 towards low-voltage lead direction, and the contained angle is 90 degrees between two lower cushions 55 towards low-voltage lead direction. The insulating cushion block is formed by resin in a mould in a casting mode, and the cushion block is iron red. The resin cushion block is arranged to have impact resistance and electric insulation resistance, so that the stability of the high-voltage and low-voltage coil assembly is protected, and the loss of electric power is reduced.

Referring to fig. 1 to 10, the hardware connector includes a high voltage lead 32 connected to a high voltage coil 36, a low voltage lead connected to a low voltage coil 54, a zero phase copper bar installed on the low voltage lead, a tab installed on the outer side of the high voltage coil 36, a conductive rod installed on the outer side of the high voltage coil 36, two lower clamping pieces 31 installed on a base 21, three iron cores 25 installed on the lower clamping pieces 31 at intervals, and two upper clamping pieces 22 installed on the left and right sides of the top of the iron core 25.

This lower folder 31 is located on the left and right sides of iron core 25 bottom, and it is U type channel-section steel to go up folder 22, and lower folder 31 is the U type channel-section steel, goes up folder 22 and all is provided with six spacing holes that are used for assembling iron core 25 on the folder 31 down, and detachable inserts and is equipped with the screw rod 24 that is used for installing iron core 25 on the spacing hole for iron core 25 installs on last folder 22 and lower folder 31.

The hardware connecting piece also comprises a plurality of assembling parts of the known dry-type transformer, such as a buffer cushion, an insulator, a high-pressure heat-shrinkable tube, a low-pressure heat-shrinkable tube, a high-pressure U-shaped plate 45, a wiring copper pipe, a gasket, a screw rod, a nut and the like.

The high voltage lead 32 includes three insulators 26, a plurality of washers, a plurality of spring washers, three high voltage U-shaped plates, a plurality of copper tubes, a wiring board, and a plurality of bolts.

The low-voltage lead comprises a copper bar specification of 8X60, six insulating terminals, a plurality of bolts, a plurality of gaskets, a plurality of nuts and a plurality of double-headed screws.

The high-voltage coil 36 is manufactured by sequentially processing a high-voltage coil mold for winding the high-voltage coil 36, a high-voltage coil winding machine for rotating the high-voltage coil mold, a resin casting machine for casting the high-voltage coil mold, and a curing and drying oven for curing and drying the high-voltage coil mold.

Referring to fig. 1 to 10, the high-voltage coil 36 includes a first insulating layer wound by a high-voltage coil winding machine, a winding wire 72 wound by the high-voltage coil winding machine and disposed in the first insulating layer, a plurality of first air ducts 76 disposed at intervals in the first insulating layer, six tapping terminals 80 connected to the winding wire 72 through tapping leads, a wire inlet terminal 79 disposed at one end of the winding wire 72, a wire outlet terminal 81 disposed at the other end of the winding wire 72, and a boss for mounting the wire inlet terminal 79, the wire outlet terminal 81, and the tapping terminals 80, wherein the distance between adjacent tapping leads is 15-20 mm, the preferred tapping lead is 17mm when running in the boss, the distance between the tapping lead and an unconnected terminal is equal to or greater than 10mm, the preferred distance is 12mm, and the tapping turns of the tapping lead are 16:15: 15.

The first insulating layer comprises an inner first insulating layer formed by winding a high-voltage coil die, an interlayer first insulating layer 73 wound on one side of the inner first insulating layer, an outer first insulating layer 75 wound on the other side of the interlayer first insulating layer 73 and an air duct insulating layer wound on the first air duct 76, and the distance between the tapping lead and the outermost layer of the first insulating layer is 15-20 mm.

The part of the high-voltage coil 36, which is insulated and exceeds the wire, is covered with an insulating tape, each side of the specific interlayer first insulating layer 73 exceeds the wire by 5mm, each side of the insulating tape for the tapping lead is wrapped by 3mm, and the insulating tape is glass fiber mesh cloth and is used for protecting the tapping lead from being damaged due to overhigh temperature in the high-voltage coil 36.

Taking specifications of CB 10-630/10, 10 +/-2X 2.5%/4V, Dyn11 and UK =6% as examples, 637 turns of the high-voltage coil 36 and the winding wire 72 are counted, the rated capacity is 630kVA, the number of main connecting turns of the high-voltage coil 36 is 606 turns, the winding inner diameter is 340mm, and the connection mode is as follows: d, the inner first insulating layer, the interlayer first insulating layer 73, the first air duct 76, the first insulating layer and the outer first insulating layer 75 are all made of glass fiber mesh cloth with the specification of 2X340X1290mm, the winding wire 72 is made of double-glass-fiber-covered flat copper wire with the specification of 2.12X3.65mm, the reactance height is 310mm, the phase current 21A, the length of a single lead wire is 918m, the length of the inner first insulating layer is 2.5mm, the thickness of the interlayer first insulating layer 73 is 0.4mm, the thickness of the interlayer first insulating layer 73 is made of glass fiber mesh cloth with the specification of 0.4X75mm, the thickness of the outer first insulating layer is 75mm, the outer diameter of the air duct is 376mm, the inner diameter of the air duct is 360 mm.

Referring to fig. 1 to 10, the six tap terminals 80 include a fourth tap terminal 80, a second tap terminal 80 provided on the left side of the fourth tap terminal 80, a sixth tap terminal 80 provided on the right side of the fourth tap terminal 80, a fifth tap terminal 80 provided below the fourth tap terminal 80, a third tap terminal 80 provided on the left side of the fifth tap terminal 80, and a seventh tap terminal 80 provided on the right side of the fifth tap terminal 80.

The number of tap turns between sixth tap terminal 80 and fourth tap terminal 80 is 15 turns, the number of turns between fourth tap terminal 80 and second tap terminal 80 is 16 turns, the number of turns between third tap terminal 80 and fifth tap terminal 80 is 15 turns, the number of turns between fifth tap terminal 80 and seventh tap terminal 80 is 15 turns, the number of turns between outlet terminal 81 and sixth tap terminal 80 is 288 turns (the number of turns remaining half the total number of turns), and the number of turns between seventh tap terminal 80 and inlet terminal 79 is 288 turns (the number of turns remaining half the total number of turns).

Referring to fig. 1 to 10, the low voltage coil 54 is wound on the low voltage coil mold by using a low voltage coil winding machine for winding a plurality of second insulating layers through a low voltage coil mold for winding the low voltage coil and a low voltage coil winding machine for rotating the low voltage coil mold, and a polypropylene film coating is coated on a contact surface of the low voltage coil mold and the second insulating layers.

The low-voltage coil 54 comprises a low-voltage coil body, a plurality of layers of second insulating layers arranged in the low-voltage coil body, a plurality of drawing pieces 83 arranged in the second insulating layers at intervals, a second air passage 88 formed by the drawing pieces 83 and the second insulating layers in a surrounding manner, two copper bars arranged in the second insulating layers at intervals and copper foils 86 arranged on the copper bars, the second insulating layer comprises an inner second insulating layer 91, an outer second insulating layer 92, an interlayer second insulating layer arranged between the inner second insulating layer 91 and the outer second insulating layer 92, and a reinforced second insulating layer 94, the reinforced second insulating layer 94 is respectively arranged at the starting end and the tail end between the copper bar and the inner second insulating layer 91, the copper bar comprises an inner copper bar 85 and an outer copper bar 84, the inner second insulating layer 91 is provided with a plurality of turns of copper foil 86 and inner copper bars 85, the interlayer second insulating layer is provided with a plurality of turns of copper foil 86, and the outer second insulating layer 92 is provided with a plurality of turns of copper foil 86 and outer copper bars 84.

Six tapping terminals 80 are connected to the winding wires 72 of the second layer and the third layer, after welding of the conducting wires and the binding posts is completed, all carbon black is removed completely, the welding positions are polished without sharp corners, and the section distance between the winding wires 72 is 11: 26: 11, the number of tap turns for the six tap terminals 80 is 16:15:15:15, positioning and mounting an incoming terminal 79, an outgoing terminal 81 and a tapping terminal 80 on the outgoing panel 78 on the boss.

The low-voltage coil 54 and the high-voltage coil 36 are provided with the first air passage 76, the second air passage 88, the first insulating layer and the second insulating layer, so that the coils have good insulating property, the electric field intensity between layers and between sections is reduced, the partial discharge performance of the transformer is easy to control, the process winding method is simple, the heat dissipation of the high-voltage coil 36 is easy, the high-voltage coil is not easy to crack, the coil works more stably, and the maintenance cost of the transformer is reduced.

The dry-type transformer adopts the following production process, and the production process comprises the following steps

Step one, winding a high-voltage coil 36;

step two, winding the low-voltage coil 54;

step three, the high-voltage coil 36 in the step one, the low-voltage coil 54 in the step two, the iron core 25, the base 21, the upper clamping piece 22, the lower clamping piece 31, the insulator of the transformer body and the hardware connecting piece are assembled in a general way;

in this embodiment, a specific step may be sequentially composed of the following processes,

step 1b, winding the winding wire 72 and a first insulating layer on a high-voltage coil die, inserting a plurality of air channel rods arranged at intervals, connecting the winding wire 72 with a wiring terminal, brushing a layer of release agent (the release agent is polysiloxane with a reticular structure of which the organic silicon resin is highly crosslinked and has thermal stability) between the first insulating layer and the high-voltage coil 36, and performing a first coil winding process to obtain a first coil;

step 1c, sending the first coil obtained in the step 1b into a curing and drying oven for drying, keeping the temperature at 120-140 ℃, preferably 130 ℃, for 9-12 hours, preferably 10 hours;

specifically, step 1d may be performed in this embodiment,

pouring: feeding epoxy resin and a curing agent into a mixing tank according to the weight ratio of 1:1, wherein the preferred epoxy resin is bisphenol A epoxy resin, and the curing agent is isomerized methyl tetrahydrophthalic anhydride; heating to 70-80 ℃, preferably 80 ℃, vacuumizing and stirring for 1.5-2 hours, preferably 2 hours to obtain a mixture A, feeding the mixture A into a vacuum tank through a blanking valve to cast a first coil, and after the first coil is fully cast, adopting the following steps,

step 1d1, vacuumizing the vacuum tank, and standing for 25-45 min, preferably 30 min;

step 1d2, breaking the vacuum state in the vacuum tank, inflating and pressurizing to 2-3 kPa, preferably 3kPa, and keeping the pressure for 20 min;

step 1d3, vacuumizing the vacuum tank, and standing for 20-30 min, preferably 20 min;

step 1d4, breaking the vacuum state in the vacuum tank, inflating and pressurizing to 2-3 kPa, preferably 2kPa, keeping the pressure and standing for 20-30 min;

and step 1d5, regulating the pressure to 1kPa, and standing for 30-60 min, preferably 60 min.

step 1g, polishing and finishing the outer surface of the high-voltage coil 36 obtained in the step 1f to enable the port of the high-voltage coil to be flat and smooth, and performing a finishing process to obtain the high-voltage coil 36;

step 1h, after the pouring of step 1d is finished, cleaning a mixing tank of a resin pouring machine, taking alcohol as a cleaning agent, automatically extracting the cleaning agent into the mixing tank for a pipeline during cleaning, sealing the mixing tank during cleaning, discharging the cleaning agent from the mixing tank through a waste liquid port after cleaning, discharging and collecting to obtain cleaning waste liquid, standing the cleaning waste liquid to obtain supernatant which is alcohol, using the precipitate as resin, and using the supernatant for secondary use to clean the mixing tank to perform a cleaning process.

In the step 1e of the present embodiment, the curing and drying process may specifically be performed by performing curing and drying in a curing and drying oven at 80-140 ℃, and sequentially including four stages, wherein (1) the first stage is at 80-95 ℃, preferably 80 ℃, and the temperature is maintained for 3-5 h, preferably 4h, and (2) the second stage is at 100-110 ℃, preferably 110 ℃, and the temperature is maintained for 2-3 h, preferably 3 h; (3) the temperature of the third stage is 120-140 ℃, preferably 130 ℃, and the temperature is kept for 3-5 h, preferably 4 h; (4) and cooling to 90-110 ℃, preferably 100 ℃, at the fourth stage, and keeping the temperature for 2-3 h, preferably 2 h.

The cross section of the air passage rod is rectangular, the length is 25mm, the width is 8mm, the transverse dimension of the straight line part of the upper positioning ring and the lower positioning ring of the high-voltage coil 36 is unilateral enlarged by 2mm, the lower end plate hole on the high-voltage coil mold is a through hole with the diameter of 9X25.5mm, the upper end plate hole is a through hole with the diameter of 10X27mm, the central shaft is provided with a hole with the diameter of 40.5X40.5mm, the height of the support leg of the pouring bottom plate is 90mm, the distance between the welding position and the outer edge is more than or equal to 20mm, the inner film of the high-voltage coil mold is a hard mold with the taper and.

The winding wires 72 of the high-voltage coil 36 are wound in a wave-shaped manner, and are four segments, which account for eleven layers, and the segment spacing between the winding wires 72 is 11: 26: 11, the cylindrical surfaces of the same layer in the winding process are smooth, the initial turn and the final turn of each layer in the winding wire 72 are bound by insulating cloth for a plurality of layers (the insulating cloth is an alkali-free and wax-free insulating tape for binding more than four points), the winding wire 72 is in a segmented cylindrical mode, the winding wire 72 is wound in the right direction, the heights of the upper end and the lower end of the inner first insulating layer and the upper end and the lower end of the outer first insulating layer 75 are both higher than the winding wire 72, and the height size of the winding wire is 20 mm.

Six tapping terminals 80 are connected to the winding wires 72 of the second layer and the third layer, after welding of the wires and the binding posts is finished, all carbon black is removed, the welding positions are polished without sharp points, and specifically, the incoming wire terminal 79, the outgoing wire terminal 81 and the tapping terminals 80 are positioned and installed on the outgoing wire panel 78 on the boss.

In this embodiment, the second step may be composed of the following steps in sequence,

step 2a, mounting the low-voltage coil 54 mould on a foil winding machine (foil winding machine model number RJB 1400) for rotation, and preparing a low-voltage coil mould;

step 2b, winding a second insulating layer and a copper foil 86 on a low-voltage coil 54 die, loading two copper bars arranged at intervals, loading a plurality of drawing pieces arranged at intervals and a temperature control probe tube 87 bound on one drawing piece (3240 epoxy tubes are wrapped on the outer surface of the temperature control probe tube 87, and the second insulating layer at the end part and one drawing piece 83 are bound together and arranged in a second air passage 88), and performing a second coil winding process to obtain a second coil;

step 2c, conveying the second coil obtained in the step 2b into a drying box, keeping the temperature at 120-140 ℃, preferably 130 ℃, keeping the temperature for 9-11 hours, preferably 10 hours, and performing a second coil drying process;

and 2e, removing the mold of the low-voltage coil 54 from the second coil after the end sealing process, and performing a demolding process to obtain the low-voltage coil 54.

In the third step, the iron core 25 is formed by the following procedures in sequence,

step 3a, performing a longitudinal shearing process on the iron core raw material;

step 3b, performing a transverse shearing process on the iron core raw material subjected to the longitudinal shearing process in the step 3 a;

step 3d, performing a stacking process on the iron core raw materials subjected to the transverse shearing process in the step 3 b;

step 3e, carrying out end sealing on the iron core 25 raw material stacked in the step 3d to obtain an iron core 25;

and 3e, end capping the raw material of the iron core 25: coating a normal-temperature epoxy resin coating on the end part of the iron core 25, standing for 2h, and waiting for solidification;

in step 1b, the winding wire 72: winding the electromagnetic wire, finishing and prepressing the wound electromagnetic wire, wrapping the electromagnetic wire by using an insulating tape to obtain a winding wire 72, injecting epoxy resin mixture to permeate into each layer of the winding, and curing and molding the winding to integrate the electromagnetic wire and the second insulating layer into a whole to obtain the winding wire 72; the insulating tape is preferably a maraging tape.

The low-voltage coil 54 is of a foil winding structure, the left winding direction and the copper foil 86 are wound on the low-voltage coil 54 die for 14 turns in total, and the method comprises the following steps

(1) Firstly, winding 4 turns (inner layer copper foil 86 is connected with the inner conductive bar, and the auxiliary thickness of the inner layer copper foil 86 is 5.75 mm) to place a plurality of drawing pieces at intervals;

(2) winding 4 turns (a middle layer copper foil 86, the spoke thickness of the middle layer copper foil 86 is 5.75 mm) to place a plurality of drawing pieces at intervals;

(3) and finally winding the remaining 6 turns (outer copper foil 86 connected with the outer conductive bar, the spoke thickness of the outer copper foil 86 is 8.5 mm).

The second insulating layer includes an inner second insulating layer wound around the die of the low voltage coil 54, an interlayer second insulating layer wound around both sides of the middle copper foil 86, and an outer insulating layer wound around the outer side of the outer copper foil 86 and a reinforcing second insulating layer.

The outer surface of low-voltage coil 54 is wrapped up the three-layer back with the second insulating layer (preferably thickness is 0.2mm preimpregnation MDM) and is wrapped up the one deck with hot shrink area half-lap, be equipped with respectively on the initiating terminal between copper bar and the interior second insulating layer and the end and strengthen the second insulating layer, add the pad between lead row and adjacent circle in low-voltage coil 54 and strengthen the second insulating layer, two lead row lower extreme and copper foil 86 parallel and level in low-voltage coil 54, the second insulating layer upper and lower extreme is higher than low-voltage copper foil 8615 ~ 20 mm.

The foil winding structure is adopted to improve the space utilization rate in the low-voltage coil 54, so that the iron cores 2525 are symmetrically distributed, the electric field distribution is more uniform, the structure is more compact, and the manufacturing and the use are simple.

A second insulation layer 94 is additionally padded between the lead rows and the adjacent turns in the low-voltage coil 54 (the reinforced second insulation layer 94 is pre-soaked with two layers of DMD), so that the insulation effect of the starting end and the tail end of the copper bar is increased, the lower end parts of the two lead rows in the low-voltage coil 54 are flush with the copper foil 86, and the upper end and the lower end of the second insulation layer are higher than the copper foil 8615-20 mm. The low voltage coil 54 has an inner diameter of 194mm and the low voltage coil 54 has an outer diameter of 266 mm. The epoxy resin can be 8855A/B epoxy resin with filler

In the second embodiment, referring to fig. 1, the difference between the second embodiment and the first embodiment is: in step 1d, the raw materials adopted in the casting process comprise epoxy resin, a curing agent and a plasticizer,

pouring: epoxy resin, a curing agent and a plasticizer are mixed according to the weight ratio of 1: 0.5, feeding into a mixing tank, wherein the preferred epoxy resin is bisphenol A epoxy resin, and the curing agent is isomerized methyl tetrahydrophthalic anhydride; plasticizer: the side chain type epoxy resin has the effects that the high-voltage coil 36 is prevented from cracking, the high-voltage coil is heated to 70-80 ℃, preferably 80 ℃, the mixture B is obtained after vacuumizing and stirring for 1.5-3 h, preferably 3h, and the mixture B is sent into a vacuum tank through a blanking valve to pour the first coil.

The above description is only an embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any insubstantial modifications made by using the design concept should fall within the scope of infringing the present invention.

Claims

1. The utility model provides a dry-type transformer, includes the base, installs iron core, three on the base are established respectively and are established threely high-low voltage coil group on the iron core and locate ware body insulating part on the high-low voltage coil group and be used for connecting high-low voltage coil group with the five metals connecting piece of iron core, its characterized in that: the high-voltage coil is manufactured by sequentially processing a high-voltage coil mould for winding the high-voltage coil, a high-voltage coil winding machine for rotating the high-voltage coil mould, a resin casting machine for casting the high-voltage coil mould and a curing and drying box for curing and drying the high-voltage coil mould, the high-voltage coil comprises a plurality of first insulating layers wound by the high-voltage coil winding machine, a winding wire arranged in the first insulating layers and wound by the high-voltage coil winding machine, a plurality of first air passages arranged at intervals in the first insulating layers and six tapping terminals connected with the winding wire through tapping leads, the distance between every two adjacent tapping leads is 15-20 mm, the distance between the tap lead and the unconnected wiring terminal is more than or equal to 10mm, and the tapping turns of the tap lead are 16:15:15: 15.

2. A dry-type transformer as claimed in claim 1, wherein: the first insulating layer comprises an inner first insulating layer formed by winding the high-voltage coil die, an interlayer first insulating layer wound on one side of the inner first insulating layer, an outer first insulating layer wound on the other side of the interlayer first insulating layer and an air duct insulating layer wound on the first air duct, and the distance between the tapping lead and the outermost layer of the first insulating layer is 15-20 mm.

3. A dry-type transformer as claimed in claim 1, wherein: and the part of the inner layer insulation of the high-voltage coil, which exceeds the conducting wire, is covered with an insulating tape.

4. A dry-type transformer as claimed in claim 1, wherein: the low-voltage coil is manufactured by a low-voltage coil mould for winding the low-voltage coil and a low-voltage coil winding machine for rotating the low-voltage coil mould, a plurality of layers of second insulating layers are wound on the low-voltage coil mould by using the low-voltage coil winding machine, and a polypropylene film coating is coated on the contact surface of the low-voltage coil mould and the second insulating layers.

5. A production process of a dry-type transformer is characterized by comprising the following steps: the manufacturing process for manufacturing a dry-type transformer according to claims 1-4, comprising the steps of,

step one, winding a high-voltage coil;

winding a low-voltage coil;

and step three, carrying out general assembly on the high-voltage coil in the step one, the low-voltage coil in the step two, the iron core, the base, the upper clamping piece, the lower clamping piece, the body insulator and the hardware connecting piece.

6. A dry-type transformer production process as claimed in claim 5, wherein:

the first step is composed of the following procedures in sequence,

the second step is composed of the following procedures in sequence,

and 2e, removing the low-voltage coil mold from the second coil subjected to the end sealing process, and performing a demolding process to obtain the low-voltage coil.

7. A dry-type transformer production process as claimed in claim 6, wherein: in the step 1d, the process is carried out,

step 1d1, vacuumizing the vacuum tank, and standing for 25-45 min;

step 1d3, vacuumizing the vacuum tank, and standing for 20-30 min;

and step 1d5, regulating the pressure to 1kPa, and standing for 30-60 min.

8. A dry-type transformer production process as claimed in claim 6, wherein: the step 1e is a curing and drying process, wherein curing and drying are carried out in a curing and drying box at the temperature of 80-140 ℃, and the curing and drying process sequentially comprises the following four stages of (1) the temperature of the first stage is 80-95 ℃ and the temperature is kept for 3-5 hours, and (2) the temperature of the second stage is 100-110 ℃ and the temperature is kept for 2-3 hours; (3) the temperature of the third stage is 120-140 ℃, and the temperature is kept for 3-5 h; (4) and cooling to 90-110 ℃ in the fourth stage, and keeping the temperature for 2-3 h.

9. A dry-type transformer production process as claimed in claim 6, wherein:

the iron core in the third step is composed of the following procedures in sequence,

step 3e, carrying out end sealing on the iron core raw material subjected to the stacking procedure in the step 3d to obtain an iron core;

in step 1b, winding wire: the electromagnetic wire is wound, the wound electromagnetic wire is subjected to finishing and prepressing, then the electromagnetic wire is wrapped by the insulating adhesive tape to obtain a winding wire, epoxy resin mixture is injected to permeate into layers of the winding, and the winding is cured and molded, so that the electromagnetic wire and the second insulating layer are combined into a whole to obtain the winding wire.

10. A dry-type transformer production process as claimed in claim 6, wherein: the copper foil is wound on the low-voltage coil mould for 14 turns in total, and the method comprises the following steps of (1) winding 4 turns to place a plurality of spaced drawing pieces, (2) winding 4 turns to place a plurality of spaced drawing pieces, (3) winding the remaining 6 turns, wherein the second insulating layer comprises an inner second insulating layer wound on the low-voltage coil mould, interlayer second insulating layers wound on two sides of the middle-layer copper foil, an outer insulating layer wound on the outer side surface of the outer-layer copper foil and a reinforcing second insulating layer, the outer surface of the low-voltage coil is wrapped by three layers of second insulating layers and then wrapped by a half-lap layer of hot-baking shrinkage belt, the starting end and the tail end between the copper bar and the inner second insulating layer are respectively provided with a reinforced second insulating layer, and a second insulating layer is additionally cushioned between the lead rows and the adjacent turns in the low-voltage coil, the lower end parts of the two lead rows in the low-voltage coil are flush with the copper foil, and the upper end and the lower end of the second insulating layer are higher than the low-voltage copper foil by 15-20 mm.