Production process of intelligent on-load voltage regulation three-dimensional wound core transformer

Abstract

The invention relates to the technical field of transformers, in particular to a production process of an intelligent on-load voltage regulation three-dimensional wound core transformer, the transformer comprises an oil tank, a three-dimensional wound core, a high-voltage coil, a low-voltage coil and an intelligent on-load voltage regulation switch, the three-dimensional wound core, the high-voltage coil and the low-voltage coil are all arranged in the oil tank, and the three-dimensional wound core is arranged in the three-dimensional wound core. The production process comprises the steps that a three-dimensional wound core is prepared, the three-dimensional wound core is formed by combining three same iron core frames, each iron core frame is formed by stacking multi-stage and multi-layer amorphous alloy belt materials, a core column and a lower iron yoke of each iron core frame are of a closed structure, and an upper iron yoke of each iron core frame is of an open structure; through the arrangement of the opening structure of the three-dimensional wound core, a special three-dimensional wound core winding machine, an argon arc welding machine, a gear mold, a winding framework insulating cylinder and other equipment are not needed in the production process.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and particularly to a production process of an intelligent on-load voltage regulating three-dimensional wound core transformer. Background Art

[0002] As the power grid has increasingly lower energy consumption requirements for power transmission and transformation equipment, the national mandatory standard GB 20052-2024 "Minimum allowable values of energy efficiency and energy efficiency grades for power transformers" will be implemented on February 1, 2025. Due to the characteristics of the core material and the overall structural advantages, when users adopt a transformer with an amorphous alloy three-dimensional wound core, the energy consumption value will reach the lowest and the volume will be the smallest. However, due to the characteristics of the amorphous alloy core strip such as thinness, brittleness, and hardness, if the production process is not good, there will be a risk of high loss and high noise in batches of transformers. Traditional three-dimensional wound cores generally adopt a closed structure, and the production process is complex, requiring special three-dimensional wound core winding machines, argon arc welders, gear molds, etc. A customized insulating cylinder is required as a winding skeleton inside each coil. The low-voltage leads need to be led out by very short soft copper strips and embedded in the gear mold slots, and the slot positions of the three-phase leads are all different. A certain operating space also needs to be reserved between the insulating cylinder skeleton and the gear mold and the core. If this spacing is too small or the operation is improper, there will be a risk of the core generating fragments, increased loss and noise, and due to the characteristic that the core cannot bear force, the short-circuit resistance of the transformer coil is poor. The production and manufacturing cycle of the entire transformer is long and the cost is high. Summary of the Invention

[0003] The purpose of the present invention is to provide a production process of an intelligent on-load voltage regulating three-dimensional wound core transformer to solve the problems raised in the above background art.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A production process of an intelligent on-load voltage regulating three-dimensional wound core transformer, the transformer includes an oil tank, a three-dimensional wound core, a high-voltage coil, a low-voltage coil, and an intelligent on-load voltage regulating switch. The three-dimensional wound core, the high-voltage coil, and the low-voltage coil are all arranged in the oil tank. The production process is as follows: S1. Prepare the three-dimensional wound core. The three-dimensional wound core is composed of 3 identical core frames. Each single core frame is stacked by multi-stage and multi-layer amorphous alloy strips. The core column and the lower yoke of the core frame are of a closed structure, and the upper yoke is of an open structure; S2. The cross-section of the core frame is multi-stage amorphous alloy strips stacked in a parallelogram. On the operating table, splice the amorphous alloy strips into a multi-layer parallelogram. The upper yoke has multi-stage joints, and it is required that the joints overlap tightly. After the single core frame is stacked and shaped, remove the excess corner material beyond the circumcircle of the core column. Fill the gaps between the core column and the lower yoke with insulating rods, brush a layer of resin, and after the resin cures, semi-wrap the outside with a layer of fiber tape, and then evenly apply a layer of glass glue on the outside of the core; S3. Wind the high-voltage coil and the low-voltage coil together as a whole. First, use the foil winding process to wind the low-voltage coil on a circular winding form. All the oil ducts inside the low-voltage coil are divided into two parts. The outer part is the long low-voltage oil duct, and the inner part is the short low-voltage oil duct. No oil ducts are placed at the 60° phase-interval angles on both sides of the inner part. After the low-voltage coil is wound, place the main insulation oil duct between the high-voltage coil and the low-voltage coil. All the oil ducts inside the high-voltage coil are also divided into two parts. The outer part is the long high-voltage oil duct, and the inner part is the short high-voltage oil duct. No oil ducts are placed at the 60° phase-interval angles on both sides of the inner part. S4. The high-voltage coil is of multi-layer cylindrical type and is provided with interlayer insulation. The interlayer insulation uses DDP fully-impregnated insulating paper. The starting end of the coil is A(B,C). After multi-layer winding, the e, c, and a tapping leads are completed in turn on the second outermost layer. Then, disconnect the a and b tapping leads during the winding process, and start winding the outermost layer of the coil from the other end of the coil axis. First, add a filling end ring at the starting end of the outermost layer. The width of the filling end ring is equal to the size of the non-full-turn distribution of the outermost layer plus the size of the end insulation. Then, complete the b, d, f tapping leads and the X(Y,Z) end drop in turn on the outermost layer. The tapping leads of the second outermost layer and the outermost layer are symmetrically arranged along the coil axis. All the tapping leads are led to the upper end through axial leads. S5. For transformer assembly, first place the three-phase coils on the horizontal ground in phase sequence, fix the phase spacers, and tie them tightly inside and outside with PET packing straps. Then, place the three-phase coils on the turning table and rotate them 90°. Place the whole on the operating table. Open the upper yoke of the iron core, and tie the yoke sheath. The sheath is made of rolled stainless steel plate, and is in the shape of a half-cone as a whole, with a semi-circular cross-section. The inner diameter of the large end of the cone is equal to the outer diameter of the core column. The large end of the sheath is tied and fixed to the core column, and the other end is tied to the upper yoke, requiring no burrs at the corners and being arc-shaped all around. Then, insert the single iron core frame into the coil one by one, fix the upper yoke connection head, and then place the whole on the turning table and rotate it counterclockwise by 90°. Place all the connection heads at the lower part of the transformer body, and hoist it to the next assembly process. S6. Carry out the general assembly, including lead connection, transformer oil filling, and installation of accessory components. Finally, conduct electrical performance test and detection to complete the production.

[0005] The intelligent on-load tap-changer includes a switch module and a controller module. The switch module is installed inside the oil tank, and the controller module is installed outside the oil tank.

[0006] The switch module is correspondingly connected to the tapping leads on the high-voltage side of the transformer. The tapping leads are switched through the switch module to realize the adjustment of the output voltage of the transformer.

[0007] The controller module includes a voltage sampling sensor, a calculation and processing chip, a communication module, a charge and discharge management circuit, and a reserve battery. The voltage sampling sensor and the charge and discharge management circuit are both connected in parallel to the low-voltage terminal block of the transformer through leads; the voltage sampling sensor monitors the output voltage of the low-voltage terminal of the transformer; the charge and discharge management circuit obtains electrical energy through the low-voltage terminal block of the transformer and charges the reserve battery, so that the power in the reserve battery is always maintained within a certain range; the reserve battery is used to supply power to the calculation and processing chip, the communication module and the switch module, so that after the low-voltage terminal block of the transformer is powered off, the calculation and processing chip, the communication module and the switch module can all maintain operation for a certain period of time.

[0008] An emergency processing program is set in the calculation and processing chip; When the voltage sampling sensor detects that the voltage of the low-voltage terminal block of the transformer disappears, it feeds back a signal to the emergency processing program in the calculation and processing chip, and the emergency processing program controls the operation of the switch module. The switch module makes a step-by-step switching adjustment of the tap changer in the negative direction, so that the number of turns of the high-voltage side coil decreases step by step, thereby attempting to bypass the open circuit point of the high-voltage coil; when the voltage sampling sensor detects that the low-voltage terminal block of the transformer generates voltage, the switching of the tap changer is stopped.

[0009] Compared with the prior art, the beneficial effects of the present invention are: 1. Through the opening structure setting of the three-dimensional wound core, there is no need for special equipment such as a three-dimensional wound core winding machine, argon arc welder, gear mold, and winding skeleton insulating cylinder in the production process.

[0010] 2. The iron core is simple to manufacture, the specifications and models of the amorphous alloy strips are few and can be combined arbitrarily, there is no need for an iron core mold, the coil can be easily sleeved, no debris is generated during the process, the overall structure is compact, the iron core is made of amorphous alloy material, which can reduce the no-load loss of the transformer to below the first-level energy efficiency, and the entire production process of the transformer is simple, which can greatly reduce the production and manufacturing cycle of the transformer.

[0011] 3. The iron core adopts good shock absorption measures, the upper yoke joint is tightly overlapped and not affected by external forces, the transformer has low noise, no matter which high-voltage tap position the user uses, the ampere-turn unbalance rate can be minimized to the greatest extent, the short-circuit resistance ability is strong, while reducing the distance between the iron cores, the main insulation can be ensured to be safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is the three-dimensional general drawing of the transformer of the present invention.

[0013] Figure 2 It is the front view of the transformer of the present invention.

[0014] Figure 3 It is the structural schematic diagram of the iron core frame of the present invention.

[0015] Figure 4 It is the cross-sectional schematic diagram of the iron core frame of the present invention.

[0016] Figure 5 This is the sectional layout diagram of the oil ducts of the high- and low-voltage coils of the present invention.

[0017] Figure 6 This is the winding diagram of the high-voltage coil of the present invention.

[0018] Figure 7 This is the sectional diagram of the transformer assembly of the present invention.

[0019] Figure 8 This is the schematic diagram of the intelligent on-load tap-changer module of the present invention.

[0020] In the figure: 1. Oil tank; 2. Intelligent on-load tap-changer; 101. Tank cover; 102. High-voltage bushing; 103. Low-voltage bushing; 3. Iron core frame; 4. Amorphous alloy strip; 5. Corner material; 6. Insulating rod; 7. Glass glue; 8. Main insulation oil duct; 9. Low-voltage long oil duct; 10. High-voltage long oil duct; 11. Low-voltage short oil duct; 12. High-voltage short oil duct; 13. High-voltage electromagnetic wire; 14. Interlayer insulation; 15. Filling end ring; 16. Tap-off tap; 17. PET packing belt; 18. Phase spacer. Specific embodiments

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] Please refer to Figures 1 to 8 , the present invention provides a technical solution: a production process of an intelligent on-load tap-changing three-dimensional wound core transformer, the transformer includes an oil tank 1, a three-dimensional wound core, a high-voltage coil, a low-voltage coil and an intelligent on-load tap-changer 2. The three-dimensional wound core, the high-voltage coil and the low-voltage coil are all arranged in the oil tank 1. A tank cover 101 is arranged above the oil tank 1 to seal the oil tank 1. A high-voltage bushing 102 and a low-voltage bushing 103 are installed on the tank cover 101, as Figure 1 and Figure 2 shown in.

[0023] The production process of the intelligent on-load tap-changing three-dimensional wound core transformer is as follows: S1. Prepare the three-dimensional wound core. The three-dimensional wound core is composed of 3 identical iron core frames 3. Each iron core frame 3 is stacked by multi-stage and multi-layer amorphous alloy strips 4. The core column and the lower yoke of the iron core frame 3 are of a closed structure, and the upper yoke is of an open structure, specifically as Figure 3 shown in. S2. Refer toFigure 4 The cross-section of the iron core frame 3 is composed of multi-stage amorphous alloy strips 4 stacked in a parallelogram shape. The amorphous alloy strips 4 are spliced into a multi-layer parallelogram on the operating table. The upper yoke has multi-stage joints, and it is required that the joints are closely overlapped. After the individual iron core frame 3 is stacked and shaped, the excess corner material 5 beyond the circumcircle of the core column is removed. Insulating rods 6 are filled in the gaps of the core column and the lower yoke. A layer of resin is brushed. After the resin is cured, a fiber tape is semi-overlapped and wrapped around the outside, and then a layer of glass glue 7 is evenly applied to the outside of the iron core; S3, wind the high-voltage coil and the low-voltage coil integrally. First, use the foil winding process to wind the low-voltage coil on a circular winding mold, as Figure 5 shown in the figure. All the oil channels inside the low-voltage coil are divided into two parts. The outer side is the low-voltage long oil channel 9, and the inner side is the low-voltage short oil channel 11. No oil channels are placed at the 60° alternating angles on both inner sides. After the low-voltage coil is wound, a main insulation oil channel 8 is placed between the high-voltage coil and the low-voltage coil. All the oil channels inside the high-voltage coil are also divided into two parts. The outer side is the high-voltage long oil channel 10, and the inner side is the high-voltage short oil channel 12. No oil channels are placed at the 60° alternating angles on both inner sides; S4, as Figure 6 shown in the figure. The high-voltage coil is a multi-layer cylindrical type, composed of high-voltage electromagnetic wires 13, and is provided with interlayer insulation 14. The interlayer insulation 14 uses DDP fully laminated insulating paper. The starting end of the coil is A(B,C). After multi-layer winding, the e, c, and a tapping leads are completed in turn on the second outermost layer. Then, the a and b tapping leads are disconnected during the winding process, and the winding of the outermost layer of the coil starts from the other end of the coil axis. First, a filling end ring 15 is padded at the starting end of the outermost layer. The width of the filling end ring 15 is equal to the size of the non-full turn distribution of the outermost layer plus the size of the end insulation. Then, the b, d, f tapping leads and the X(Y,Z) drop head are completed in turn on the outermost layer; The tapping leads of the second outermost layer and the outermost layer are symmetrically arranged in the coil axis direction, and all the tapping leads are led to the upper end through axial leads; S5, as Figure 7 shown in the figure. For transformer assembly, first place the three-phase coils on the horizontal ground in phase sequence, fix the phase spacer 18, and tie them tightly with PET packing belts 17 inside and outside. Then, place the three-phase coils on the flipping table and rotate them 90°. Place them on the operating table as a whole. Open the upper yoke of the iron core and tie the yoke sheath. The sheath is rolled from a stainless steel plate, and is in the shape of a half cone as a whole, with a semi-circular cross-section. The inner diameter of the large end of the cone is equal to the outer diameter of the core column. The large end of the sheath is tied and fixed to the core column, and the other end is tied to the upper yoke, requiring no burrs at the corners and an arc shape all around; Then, insert the individual iron core frames 3 into the coil interior in turn, fix the upper yoke joint, and then place the whole on the flipping table and rotate it counterclockwise by 90°. Place all the joints at the lower part of the transformer body and hoist it to the next assembly process; S6, general assembly, including lead connection, transformer oil filling, accessory component installation, and finally electrical performance test. When connecting the lead, connect the lead wire of the winding to the terminal of the transformer. The connection should be firm and the contact should be good to ensure the smooth transmission of current. At the same time, the lead wire should be insulated to prevent leakage accidents. Inject the treated transformer oil into the transformer oil tank. The oil filling process should be carried out slowly to prevent the oil flow from impacting the winding and the core. Install other accessories on the transformer, such as oil pillow, radiator, gas relay, etc. Perform various electrical performance tests on the transformer, such as winding DC resistance measurement, insulation resistance measurement, dielectric loss factor measurement, power frequency withstand voltage test, induction withstand voltage test, etc. Through these tests, it can be detected whether the transformer winding has defects such as short circuit and open circuit, and whether the insulation performance is good. The general assembly here is the same as the process in the prior art, and will not be described in detail.

[0024] When the transformer is actually used, the high-voltage side coil has a thinner diameter and more turns than the low-voltage side coil, so the probability of short circuit failure is higher under factors such as thermal expansion and contraction, vibration, etc. When the high-voltage coil of the transformer is short-circuited, the short circuit on the high-voltage side causes the primary current to be interrupted, the magnetic flux of the iron core disappears, and the low-voltage side cannot sense the voltage. At this time, the low-voltage output side of the transformer will be completely powered off. The on-load voltage regulator in traditional technology monitors and controls the voltage of the transformer by connecting to the low-voltage terminal block, and uses the low-voltage terminal block to power the on-load voltage regulator itself. When the above-mentioned high-voltage side coil short circuit failure occurs, the low-voltage output side of the transformer is completely powered off, and the on-load voltage regulator in traditional technology will be completely powered off and stop running, and does not have the function of trying to bypass the high-voltage coil short circuit point to restore power supply in an emergency.

[0025] The intelligent on-load voltage regulating switch 2 provided in the present invention has the above functions, and includes a switch module and a controller module. The switch module is installed inside the oil tank 1, and the controller module is installed outside the oil tank 1. The switch module is connected to the tap 16 on the high-voltage side of the transformer, and the tap 16 is switched by the switch module to adjust the output voltage of the transformer. The controller module includes a voltage sampling sensor, a computing and processing chip, a communication module, a charge and discharge management circuit, and a reserve battery; The voltage sampling sensor and the charge and discharge management circuit are both arranged in parallel on the low-voltage terminal block of the transformer through leads; the output voltage of the low-voltage end of the transformer is monitored by the voltage sampling sensor; the charge and discharge management circuit obtains electrical energy through the low-voltage terminal block of the transformer and charges the reserve battery, so that the power in the reserve battery is always kept within a certain range; the reserve battery is used to power the computing and processing chip, the communication module and the switch module, so that after the low-voltage terminal block of the transformer is powered off, the computing and processing chip, the communication module and the switch module can all maintain operation for a certain period of time.

[0026] The communication module can be a WIFI communication or Internet of Things remote communication technology. Through the communication module, the intelligent on-load tap-changer 2 can be set, or the intelligent on-load tap-changer 2 can send a fault alarm through the communication module.

[0027] An emergency handling program is set in the calculation and processing chip; the calculation and processing chip can be a single-chip microcomputer chip or other microprocessor devices, and the functions are realized through programming settings.

[0028] When the voltage sampling sensor detects the disappearance of the voltage at the low-voltage connection terminal of the transformer, a feedback signal is sent to the emergency handling program in the calculation and processing chip. The emergency handling program controls the operation of the switch module, and the tap changer 16 is switched step by step in the negative direction through the switch module, so that the number of turns of the high-voltage side coil is gradually reduced, thereby attempting to bypass the open-circuit point of the high-voltage coil; when the voltage sampling sensor detects the generation of voltage at the low-voltage connection terminal of the transformer, the switching of the tap changer 16 is stopped. The above principle is: assuming that the tap distribution of the high-voltage coil is the main tap, -5% tap, -10% tap, -15% tap... When the open-circuit point of the high-voltage side coil is between the main tap and the -5% tap, by switching the tap changer 16 step by step in the negative direction and switching to the -10% tap, the current path becomes: winding head → -10% tap → winding end to form a connection loop, thereby skipping the open-circuit point, so that when a high-voltage coil open-circuit fault occurs, there is a certain probability that emergency power supply can be restored. After the above-mentioned tap is adjusted downward, the voltage at the low-voltage output side of the transformer will increase. Therefore, it is necessary to preset a safety range for restricting the step-by-step switching adjustment of the tap changer 16 in the negative direction, so that the voltage at the low-voltage output side of the transformer can ensure the safety of downstream equipment after increasing.

[0029] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A production process for an intelligent on-load voltage-regulating three-dimensional wound core transformer, characterized in that: The transformer comprises an oil tank, a three-dimensional wound core, a high-voltage coil, a low-voltage coil and an intelligent on-load voltage regulating switch. The three-dimensional wound core, the high-voltage coil and the low-voltage coil are all arranged in the oil tank. The production process is as follows: S1, preparing a three-dimensional wound core, the three-dimensional wound core is composed of three identical core frames, a single core frame is formed by stacking multi-level and multi-layer amorphous alloy strips, the core column and the lower iron yoke of the core frame are closed structures, and the upper iron yoke is an open structure; S2, the cross section of the core frame is a multi-level parallelogram-shaped amorphous alloy strip. The amorphous alloy strip is spliced ​​into a multi-layer parallelogram on the operating table. The upper iron yoke is a multi-level joint, and the joints are required to be tightly overlapped. After the single core frame is stacked and shaped, the part of the corner material that exceeds the circumscribed circle of the core column is removed, and the gap between the core column and the lower iron yoke is filled with an insulating rod, and a layer of resin is applied. After the resin is cured, a layer of fiber tape is wrapped on the outside of the half-fold, and then a layer of glass glue is evenly applied to the outside of the core; S3, the high-voltage coil and the low-voltage coil are wound together as a whole, and the low-voltage coil is first wound on the circular winding mold by using the foil winding process. All the oil passages inside the low-voltage coil are divided into two parts, the outer side is the low-voltage long oil passage, and the inner side is the low-voltage short oil passage. No oil passages are placed at the 60° phase angle on both sides of the inner side; after the low-voltage coil is wound, the main insulating oil passage is placed between the high-voltage coil and the low-voltage coil, and all the oil passages inside the high-voltage coil are also divided into two parts, the outer side is the high-voltage long oil passage, and the inner side is the high-voltage short oil passage. No oil passages are placed at the 60° phase angle on both sides of the inner side; S4, the high-voltage coil is a multi-layer cylindrical type with interlayer insulation. The interlayer insulation adopts DDP full-glue insulation paper. The coil starts with A (B, C). After multiple layers of winding, the e, c, and a taps are completed in sequence on the second outer layer, and then the a and b taps are disconnected during the winding process, and the winding of the outermost coil is started from the other end of the coil axis. First, a pad is added to the starting end of the outermost layer. The width of the filled end ring is equal to the size of the outermost layer without full turns plus the size of the end insulation. Then, the b, d, f taps and X (Y, Z) taps are completed in sequence on the outermost layer; the second outer layer and the outermost layer taps are arranged symmetrically in the axial direction of the coil, and all taps are led to the upper end through axial leads; S5, assemble the transformer. First, place the three-phase coils on the horizontal ground in phase sequence, fix the phase partition, and use PET packing tape to tie the inside and outside. Then, place the three-phase coils on the turning table and rotate them 90 degrees. Place the whole on the operating table, open the yoke on the core, and tie the iron yoke sheath. The sheath is made of stainless steel plate and is half a cone in shape. The cross section is semicircular. The inner diameter of the big end of the cone is equal to the outer diameter of the core column. The big end of the sheath is tied and fixed to the core column, and the other end is tied to the iron yoke. The corners are required to be free of burrs and the surroundings are arc-shaped. Then insert the single core frame into the coil one by one, fix the upper iron choke lap joint, and then put the whole on the turning table and rotate it 90° in the opposite direction, put all the lap joints under the transformer body, and lift it to the next assembly process; S6, general assembly, including lead connection, transformer oil filling, accessory component installation, and finally electrical performance test, thus completing the production; The intelligent on-load voltage regulating switch comprises a switch module and a controller module; the controller module comprises a voltage sampling sensor, a computing and processing chip, a communication module, a charge and discharge management circuit and a reserve battery; the computing and processing chip is provided with an emergency processing program; When the voltage sampling sensor detects that the voltage of the transformer low-voltage terminal block disappears, a feedback signal is sent to the emergency processing program in the computing and processing chip. The emergency processing program controls the operation of the switch module, and the switch module switches the tap to the negative direction step by step, so that the number of turns of the high-voltage side coil is reduced step by step, thereby trying to bypass the high-voltage coil break point; when the voltage sampling sensor detects that the transformer low-voltage terminal block generates voltage, the switching of the tap is stopped.

2. The production process of an intelligent on-load voltage-regulating three-dimensional wound core transformer according to claim 1 is characterized in that: The switch module is installed inside the oil tank, and the controller module is installed outside the oil tank.

3. The production process of an intelligent on-load voltage-adjusting three-dimensional wound core transformer according to claim 2 is characterized in that: The switch module is correspondingly connected to the tapping tap on the high-voltage side of the transformer, and the tapping tap is switched by the switch module, thereby achieving output voltage regulation of the transformer.

4. The production process of an intelligent on-load voltage-adjusting three-dimensional wound core transformer according to claim 2 is characterized in that: The voltage sampling sensor and the charge and discharge management circuit are both arranged in parallel on the low-voltage terminal block of the transformer through leads; the output voltage of the low-voltage end of the transformer is monitored by the voltage sampling sensor; the charge and discharge management circuit obtains electric energy through the low-voltage terminal block of the transformer and charges the reserve battery, so that the amount of electricity in the reserve battery is always kept within a certain range; the reserve battery is used to power the computing and processing chip, the communication module and the switch module, so that after the low-voltage terminal block of the transformer is powered off, the computing and processing chip, the communication module and the switch module can all maintain operation for a certain period of time.

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