A transformer DC-blocking device based on a current-triggered gap component

Abstract

The present invention relates to the field of transformers, and specifically discloses a DC isolation device for a transformer based on a current-triggered gap component, including a DC isolation device body. A first terminal serving as a power transmission terminal and a second terminal serving as a power input terminal are respectively arranged at the top and bottom sides of the DC isolation device body. A protection mechanism is electrically connected between the first terminal and the second terminal, and a detection and feedback system is arranged on the protection mechanism. Through the setting of the detection and feedback system, on the one hand, it can effectively protect the transformer when a three-phase unbalance fault occurs in the system and the remaining protections fail. On the other hand, it can also trigger the vacuum gap faster and more efficiently, improving the protection efficiency and quality of the protection mechanism.

Description

Technical Field

[0001] The present invention relates to a DC isolation device, specifically to a transformer DC isolation device based on a current-triggered gap component, belonging to the field of transformers. Background Art

[0002] When a transformer winding passes through a DC current, a DC magnetic potential is generated, and a DC magnetic flux is generated in the iron core, resulting in a deeper saturation degree of the iron core in half a cycle. This phenomenon is called DC bias. For the DC bias that appears in the system, it is often necessary to install a DC isolation device.

[0003] However, the existing DC isolation devices still have certain disadvantages in use. When a three-phase unbalance fault occurs in the system and the other protections fail, the neutral point voltage and short-circuit current of the transformer will continue to rise at this time. When the short-circuit current exceeds 2 kA and the neutral point voltage exceeds the conduction value of the high-voltage zinc oxide varistor, it often causes the expansion of the fault and damages the equipment. Secondly, since the installation of the DC isolation device requires a sealed environment, and an industrial air conditioner is often installed on the side of the housing where the DC isolation device is installed for heat dissipation, therefore, when it is necessary to open the outer housing of the DC isolation device, the door panel often cannot be opened. For this reason, we propose a transformer DC isolation device based on a current-triggered gap component. Summary of the Invention

[0004] Aiming at the problems in the prior art, the present invention provides a transformer DC isolation device based on a current-triggered gap component.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A transformer DC isolation device based on a current-triggered gap component includes a DC isolation device body. The top and bottom sides of the DC isolation device body are respectively provided with a first terminal as a power transmission end and a second terminal as a power input end. A protection mechanism is electrically connected between the first terminal and the second terminal. A detection and feedback unit is arranged on the protection mechanism. The DC isolation device body is fixedly connected to one side inside the housing. A pressurizing component is arranged on the side inside the housing far from the DC isolation device body. A door panel is hinged to one side of the housing. A sealing ring is arranged at the joint of the housing and the door panel.

[0007] Preferably, the protection mechanism includes a current transformer, a zinc oxide varistor and a vacuum box. The current transformer and the zinc oxide varistor are connected in series between the first terminal and the second terminal. Both ends of the current transformer are connected in parallel with the vacuum box. One end of the current transformer far from the first terminal is electrically connected to the second terminal through an L-shaped wire. One end of the second terminal far from the DC isolation device body is electrically connected to a ground wire.

[0008] Preferably, an input end and an output end are respectively arranged at one ends of the top and bottom of the vacuum box body. The current transformer is connected in parallel with the vacuum box body through a Z-shaped wire. One end of the Z-shaped wire far away from the current transformer is electrically connected to the middle of one side of the vacuum box body. A piston cylinder is fixedly connected to the middle of one side of the vacuum box body far away from the input end and the output end. A through hole for communication is arranged at the connection between the vacuum box body and the piston cylinder. A contact switch is fixedly connected to one end of the piston cylinder far away from the vacuum box body. A boss is arranged at one end of the contact switch far away from the piston cylinder. A T-shaped column is slidably sleeved inside the piston cylinder. A conductive column is fixedly connected to the vertical end of the T-shaped column in the shape of a "T" and is located inside the vacuum box body. The vertical end of the T-shaped column in the shape of a "T" is slidably sleeved in the through hole.

[0009] Preferably, the telescopic ends of a plurality of electric telescopic rods are fixedly connected to the side of the T-shaped column far away from the conductive column. The fixed ends of the electric telescopic rods are fixedly connected to the inner wall of one side of the piston cylinder far away from the vacuum box body. A Y-shaped guide hole is arranged inside the T-shaped column. The two ends of the Y-shaped guide hole are respectively communicated with the inside of the vacuum box body and the piston cylinder. A rotating plate is rotatably connected to the center of the inside of the vacuum box body. An electric rotating shaft is arranged inside one end of the rotating plate. The electric rotating shaft is electrically connected to the contact switch. Air bags are arranged at the connections between the vacuum box body and the input end and the output end respectively. The air bags are communicated with a conduit embedded inside the vacuum box body and the piston cylinder. One end of the conduit far away from the air bag is communicated with the inside of one end of the piston cylinder far away from the vacuum box body. First one-way valves are arranged inside the conduit and the Y-shaped guide hole.

[0010] Preferably, the pressurizing assembly includes a slide rail arranged on the inner wall of the housing. An electric slide rod is slidably connected inside the slide rail. The electric slide rod is adapted to the electric telescopic rod. One end of the electric slide rod far away from the slide rail is fixedly connected to a partition plate. A heat pipe for heat dissipation is fixedly connected to the top of the partition plate. A connecting rod is fixedly connected to the bottom of the electric slide rod. One end of the connecting rod far away from the electric slide rod is fixedly connected to a piston plate. The piston plate is slidably sleeved inside a cylinder. An air inlet pipe and an air outlet pipe are respectively communicated with the bottom side of the cylinder. The air inlet pipe is communicated with the outside air and a filter screen is arranged at the communication part. One end of the air outlet pipe far away from the cylinder is communicated with an air box. An electromagnetic valve for exhausting is arranged on one side of the air box. An electromagnetic valve switch is fixedly connected to one side of the top of the housing. The electromagnetic valve switch is electrically connected to the electromagnetic valve. Second one-way valves are arranged inside the air inlet pipe and the air outlet pipe.

[0011] Preferably, the detection and feedback unit includes a current monitoring module, a processing module and a receiving module. The current monitoring module includes current detectors arranged at the output end of the vacuum box body, one end of the L-shaped wire far away from the current transformer and one end of the zinc oxide varistor far away from the current transformer.

[0012] The processing module is electrically connected to the electric telescopic rod. The processing module is configured to receive the current data fed back by the current detector, analyze the current data, and send a target instruction to the electric telescopic rod according to the analysis result. The target instruction is used to instruct the electric telescopic rod to extend or contract.

[0013] Preferably, the current monitoring module further includes a data feedback sub-module. The data feedback sub-module is communicatively connected to the processing module, and is configured to feedback the current data measured by the current monitoring module to the processing module.

[0014] Preferably, the processing module analyzes the current data and sends a target instruction to the electric telescopic rod according to the analysis result, including: calculating the current data of the target node by using a current formula; wherein, the current formula includes:

[0015] In the formula: I is the current data of the target node, K is a correction coefficient, is the average value of the current measured instantaneously n times. The target nodes include: node a at the output end of the vacuum box body, node b at the end of the L-shaped wire far from the current transformer, and node c at the end of the zinc oxide varistor far from the current transformer;

[0016] Using the current analysis formula: Determine the target instruction and send the target instruction to the electric telescopic rod;

[0017] wherein, I 0 is the determination base number, AHQ and W are preset parameters;

[0018] Using the current analysis formula: Determine the target instruction and sending the target instruction to the electric telescopic rod includes:

[0019] If the value of I 0 is, then end; if the value of I 0 is greater than, use the formula: U = RI b , determine the target result; wherein, U is the voltage across the current transformer, R is the rated resistance of the current transformer. If U > 3000V, the processing module sends an extension instruction to the electric telescopic rod. If U ≤ 3000V, the processing module sends a shortening instruction to the electric telescopic rod.

[0020] Preferably, the protection mechanism protects the DC-blocking device body and the transformer electrically connected to the DC-blocking device body by a protection method of a vacuum trigger gap. The protection method includes the following steps:

[0021] Step 1: When there is no three-phase unbalance fault in the circuit, the neutral point voltage and short-circuit current of the transformer will operate stably. At this time, the body of the DC-blocking device forms a path with the current transformer and the zinc oxide varistor through the first terminal and the second terminal; the body of the DC-blocking device and the transformer operate stably.

[0022] Step 2: When a three-phase unbalance fault occurs in the circuit and other protections fail, the neutral point voltage and short-circuit current of the transformer will continue to rise. When the short-circuit current exceeds 2 kA and the neutral point voltage exceeds the conduction value of the zinc oxide varistor, the neutral point of the transformer is grounded through the series branch of the zinc oxide varistor and the current transformer. When the voltage between the neutral point of the transformer and the body of the DC-blocking device is restored, the circuit resumes the operation mode described in Step 1.

[0023] Step 3: When the voltage between the neutral point of the transformer and the body of the DC-blocking device in Step 2 above has not been restored and the instantaneous high voltage generated on both sides of the current transformer is greater than 3 kV, the vacuum gap between the output terminal and the input terminal on the vacuum box body is triggered, so that the current on the output terminal and the input terminal breaks through the vacuum, and then the discharge circuit is turned on to quickly ground the fault short-circuit current, achieving the purpose of backup protection and preventing the fault from expanding and damaging the equipment.

[0024] Preferably, the zinc oxide varistor in Step 2 is prepared by high-voltage zinc oxide, and the outer surface of the zinc oxide varistor is covered with an insulating and heat-conducting protective sleeve.

[0025] Advantages of the present invention:

[0026] 1. Through the setting of the detection and feedback system, on the one hand, it can effectively protect the transformer when a three-phase unbalance fault occurs in the system and other protections fail. On the other hand, it can also trigger the vacuum gap faster and more efficiently, improving the protection efficiency and quality of the protection mechanism. The setting of the detection and feedback system can also promote the air cylinder to supplement air into the air tank through the movement of the electric telescopic rod, so that the door panel can be opened more conveniently when the body of the DC-blocking device is overhauled and maintained.

[0027] 2. The protection mechanism effectively protects the DC-blocking device and the transformer through the protection method of the vacuum-triggered gap. When the voltage between the neutral point of the transformer and the body of the DC-blocking device has not been restored and the instantaneous high voltage generated on both sides of the current transformer is greater than 3 kV, the vacuum gap between the output terminal and the input terminal on the vacuum box body is triggered, so that the current on the output terminal and the input terminal breaks through the vacuum, and then the discharge circuit is turned on to quickly ground the fault short-circuit current, achieving the purpose of backup protection and preventing the fault from expanding and damaging the equipment.

[0028] 3. The electric slide bar will also drive the partition to rise. On the one hand, it can expose the zinc oxide varistor inside the housing, enabling the industrial air conditioner installed on the side of the housing to effectively cool the zinc oxide varistor. On the other hand, a large amount of heat generated by the zinc oxide varistor will also cause the temperature around the zinc oxide varistor to rise rapidly. By driving the partition to rise through the electric slide bar, the partition and the heat pipe can also be moved away from the position of the zinc oxide varistor, enabling the heat pipe and the partition to dissipate heat effectively at other positions inside the housing, greatly improving the heat dissipation function of the zinc oxide varistor.

[0029] 4. Through the setting of the air cylinder, when the electric slide bar descends, the gas in the air cylinder is compressed into the air tank through the air outlet pipe. When it is necessary to open the door panel for maintenance of the internal DC blocking device body, by opening the solenoid valve switch installed on the side of the housing, the solenoid valve is opened, enabling the pressurized gas in the air tank by the air cylinder to flow out, thereby increasing the air pressure inside the housing and enabling the door panel to be opened more quickly and effectively, greatly improving the efficiency during the maintenance of the device. At the same time, through the setting of the filter screen, it can also effectively prevent dust from entering the air cylinder and the air tank. Brief Description of the Drawings

[0030] For the convenience of those skilled in the art to understand, the present invention will be further described below with reference to the accompanying drawings.

[0031] Figure 1 It is a schematic flow diagram of the detection and feedback unit of the present invention.

[0032] Figure 2 It is a schematic diagram of the overall structure of the present invention.

[0033] Figure 3 It is a schematic diagram of the overall structure of the present invention after removing the door panel.

[0034] Figure 4 It is a schematic diagram of the partial cross-sectional structure of the present invention.

[0035] Figure 5 It is a schematic cross-sectional view of the structure of the partition of the present invention.

[0036] Figure 6 It is a schematic cross-sectional view of the structure of the vacuum box of the present invention.

[0037] Figure 7 It is a schematic cross-sectional view of the structure of the T-shaped column of the present invention.

[0038] Figure 8 It is a schematic diagram of the connection structure of the zinc oxide varistor of the present invention.

[0039] Figure 9 It is a schematic diagram of the connection circuit of the zinc oxide varistor of the present invention.

[0040] In the figure: 1. DC-blocking device body; 2. Outer shell; 3. Door panel; 4. First terminal; 5. Current transformer; 6. Second terminal; 7. Partition board; 8. Gas box; 9. Slide rail; 11. Electric slide bar; 12. Air cylinder; 13. Inlet pipe; 14. Outlet pipe; 15. Heat pipe; 16. Vacuum box body; 17. Connecting rod; 18. Piston plate; 21. Zinc oxide varistor; 22. Piston cylinder; 23. Rotating plate; 24. Contact switch; 25. Conductive column; 26. Airbag; 27. Duct; 28. Y-shaped guide hole; 29. T-shaped column; 30. Electric telescopic rod; 31. Current detector. Specific embodiments

[0041] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0042] Please refer to Figures 1-9 As shown, a DC-blocking device for a transformer based on a current-triggered gap assembly includes a DC-blocking device body 1. A first terminal 4 serving as a power transmission end and a second terminal 6 serving as a power input end are respectively arranged at the top and bottom sides of the DC-blocking device body 1. A protection mechanism is electrically connected between the first terminal 4 and the second terminal 6. A detection and feedback unit is arranged on the protection mechanism. The DC-blocking device body 1 is fixedly connected to one side inside the outer shell 2. A pressurizing assembly is arranged on the side of the outer shell 2 away from the DC-blocking device body 1. A door panel 3 is hinged to one side of the outer shell 2. A sealing ring is arranged at the joint of the outer shell 2 and the door panel 3. Through the arrangement of the first terminal 4 and the second terminal 6, the protection mechanism is effectively connected as a bypass to the DC-blocking device body 1, so that the protection mechanism can effectively protect the DC-blocking device body 1.

[0043] As a technical optimization scheme of the present invention, the protection mechanism includes a current transformer 5, a zinc oxide varistor 21 and a vacuum box body 16. The current transformer 5 and the zinc oxide varistor 21 are connected in series between the first terminal 4 and the second terminal 6. Both ends of the current transformer 5 are connected in parallel with the vacuum box body 16. One end of the current transformer 5 away from the first terminal 4 is electrically connected to the second terminal 6 through an L-shaped wire. One end of the second terminal 6 away from the DC-blocking device body 1 is electrically connected to a ground wire. The setting of the zinc oxide varistor 21, through the good volt-ampere characteristic curve of the zinc oxide varistor 21, can effectively enable the protection mechanism to form three paths under different conditions, so as to effectively protect the DC-blocking device body 1 and the transformer.

[0044] As a technical optimization solution of the present invention, an input end and an output end are respectively arranged at one end of the top and bottom of the vacuum box body 16. The current transformer 5 is connected in parallel with the vacuum box body 16 through a Z-shaped wire. One end of the Z-shaped wire far away from the current transformer 5 is electrically connected to the middle part of one side of the vacuum box body 16. A piston cylinder 22 is fixedly connected to the middle part of one side of the vacuum box body 16 far away from the input end and the output end. A through hole for communication is arranged at the connection part of the vacuum box body 16 and the piston cylinder 22. A contact switch 24 is fixedly connected to one end of the piston cylinder 22 far away from the vacuum box body 16. A boss is arranged at one end of the contact switch 24 far away from the piston cylinder 22. A T-shaped column 29 is slidably sleeved inside the piston cylinder 22. A conductive column 25 is fixedly connected to the vertical end of the T-shaped column 29 with respect to the "T shape", and the conductive column 25 is located inside the vacuum box body 16. The vertical end of the T-shaped column 29 with respect to the "T shape" is slidably sleeved in the through hole. The setting of the boss enables the boss to effectively block the Y-shaped guide hole 28 when the T-shaped column 29 abuts against the contact switch 24, further preventing the possibility of the gas in the piston cylinder 22 from entering the vacuum box body 16.

[0045] As a technical optimization solution of the present invention, the telescopic ends of a plurality of electric telescopic rods 30 are fixedly connected to the side of one end of the T-shaped column 29 far away from the conductive column 25. The fixed ends of the electric telescopic rods 30 are fixedly connected to the inner wall of one side of the piston cylinder 22 far away from the vacuum box body 16. A Y-shaped guide hole 28 is opened inside the T-shaped column 29. The two ends of the Y-shaped guide hole 28 are respectively communicated with the inside of the vacuum box body 16 and the piston cylinder 22. A rotating plate 23 is rotatably connected to the center of the inside of the vacuum box body 16. An electric rotating shaft is arranged inside one end of the rotating plate 23, and the electric rotating shaft is electrically connected to the contact switch 24. Air bags 26 are arranged at the connection parts of the vacuum box body 16 with the input end and the output end respectively. The air bags 26 are communicated with a conduit 27 embedded inside the vacuum box body 16 and the piston cylinder 22. One end of the conduit 27 far away from the air bag 26 is communicated with the inside of one end of the piston cylinder 22 far away from the vacuum box body 16. First one-way valves are arranged inside both the conduit 27 and the Y-shaped guide hole 28. The first one-way valve inside the conduit 27 only enables the gas to enter the air bag 26 through the conduit 27, and the first one-way valve arranged inside the Y-shaped guide hole 28 only enables the gas to enter the piston cylinder 22 through the Y-shaped guide hole 28.

[0046] As a technical optimization solution of the present invention, the pressurizing assembly includes a slide rail 9 provided on the inner wall of the outer shell 2. An electric slide rod 11 is slidably connected in the slide rail 9. The electric slide rod 11 is adapted to the electric telescopic rod 30. One end of the electric slide rod 11 away from the slide rail 9 is fixedly connected to a partition plate 7. A heat pipe 15 for heat dissipation is fixedly connected to the top of the partition plate 7. A connecting rod 17 is fixedly connected to the bottom of the electric slide rod 11. One end of the connecting rod 17 away from the electric slide rod 11 is fixedly connected to a piston plate 18. The piston plate 18 is slidably sleeved in the air cylinder 12. An air inlet pipe 13 and an air outlet pipe 14 are respectively communicated with the bottom side of the air cylinder 12. The air inlet pipe 13 is communicated with the outside air and a filter screen is provided at the communicating place. One end of the air outlet pipe 14 away from the air cylinder 12 is communicated with an air box 8. An electromagnetic valve for exhausting is provided on one side of the air box 8. An electromagnetic valve switch is fixedly connected to one side of the top of the outer shell 2. The electromagnetic valve switch is electrically connected to the electromagnetic valve. Second one-way valves are provided inside both the air inlet pipe 13 and the air outlet pipe 14. The second one-way valve provided in the air inlet pipe 13 can only allow the outside air to enter the air cylinder 12, and the second one-way valve provided in the air outlet pipe 14 can only allow the gas to enter the air box 8. The electric slide rod 11 is adapted to the electric telescopic rod 30. When the electric telescopic rod 30 extends, the electric slide rod 11 slides upward. When the electric telescopic rod 30 contracts, the electric slide rod 11 slides downward. Thus, when the electric telescopic rod 30 contracts to the shortest state, the electric slide rod 11 can effectively drive the partition plate 7 to block beside the zinc oxide varistor 21, which can further promote the function of the insulating and heat-conducting protective sleeve covering the surface of the zinc oxide varistor 21, preventing the situation that when the insulating and heat-conducting protective sleeve is damaged, the current breaks through the air through the zinc oxide varistor 21 when the resistance of the zinc oxide varistor 21 is low, and preventing the situation that the current damages other electrical components inside the outer shell 2.

[0047] As a technical optimization solution of the present invention, the detection and feedback unit includes a current monitoring module, a processing module and a receiving module. The current monitoring module includes current detectors 31 provided at the output end of the vacuum box 16, one end of the L-shaped wire away from the current transformer 5 and one end of the zinc oxide varistor 21 away from the current transformer 5;

[0048] The processing module is electrically connected to the electric telescopic rod 30. The processing module is used to receive the current data fed back by the current detector 31, analyze the current data, and send a target instruction to the electric telescopic rod 30 according to the analysis result. The target instruction is used to instruct the electric telescopic rod 30 to extend or contract.

[0049] As a technical optimization solution of the present invention, the current monitoring module further includes a data feedback sub-module. The data feedback sub-module is communicatively connected to the processing module. The data feedback sub-module is used to feedback the current data measured by the current monitoring module to the processing module.

[0050] By detecting the settings of the feedback system, on the one hand, it can effectively protect the transformer when a three-phase unbalance fault occurs in the system and the other protections fail. On the other hand, it can also trigger the vacuum gap faster and more efficiently, improving the protection efficiency and quality of the protection mechanism. The settings of the detection feedback system can also promote the air cylinder 12 to replenish air into the air tank 8 through the movement of the electric telescopic rod 30, so that the door panel 3 can be opened more conveniently when maintaining the DC isolation device body 1.

[0051] As a technical optimization scheme of the present invention, the processing module analyzes the current data. According to the analysis result, a target instruction is sent to the electric telescopic rod 30, including: calculating the current data of the target node by using the current formula; where the current formula includes:

[0052] In the formula: I is the current data of the target node, K is the correction coefficient, is the mean value of the current measured instantaneously n times. The target nodes include: node a at the output end of the vacuum box body 16, node b at one end of the L-shaped wire away from the current transformer 5, and node c at one end of the zinc oxide varistor 21 away from the current transformer 5;

[0053] Using the current analysis formula: Determine the target instruction and send the target instruction to the electric telescopic rod 30;

[0054] where, I 0 is the judgment base number, AHQ and W are preset parameters;

[0055] Using the current analysis formula: Determine the target instruction and send the target instruction to the electric telescopic rod 30, including:

[0056] If the value of I 0 is 0, then end; if the value of I 0 is greater than 0, use the formula: U = RI b to determine the target result; where U is the voltage across the current transformer 5, R is the rated resistance of the current transformer 5. If U > 3000V, the processing module sends an elongation instruction to the electric telescopic rod 30. If U ≤ 3000V, the processing module sends a shortening instruction to the electric telescopic rod 30.

[0057] As a technical optimization scheme of the present invention, the protection mechanism protects the DC isolation device body 1 and the transformer electrically connected to the DC isolation device body 1 through the protection method of the vacuum trigger gap. The protection method includes the following steps:

[0058] Step 1: When there is no three-phase unbalance fault in the circuit, the neutral point voltage and short-circuit current of the transformer will operate stably. At this time, the body 1 of the DC-blocking device forms a path with the current transformer 5 and the zinc oxide varistor 21 through the first terminal 4 and the second terminal 6; the body 1 of the DC-blocking device and the transformer operate stably.

[0059] Step 2: When a three-phase unbalance fault occurs in the circuit and the other protections fail, the neutral point voltage and short-circuit current of the transformer will continue to rise. When the short-circuit current exceeds 2 kA and the neutral point voltage exceeds the conduction value of the zinc oxide varistor 21, the neutral point of the transformer is grounded through the series branch of the zinc oxide varistor 21 and the current transformer 5. When the voltage between the neutral point of the transformer and the body 1 of the DC-blocking device is restored, the circuit resumes the operation mode of Step 1.

[0060] Step 3: When the voltage between the neutral point of the transformer and the body 1 of the DC-blocking device in Step 2 above is not restored and the instantaneous high voltage generated on both sides of the current transformer 5 is greater than 3 kV, the vacuum gap between the output terminal and the input terminal on the vacuum box body 16 is triggered, so that the current on the output terminal and the input terminal breaks through the vacuum, and then the discharge circuit is turned on to quickly ground the fault short-circuit current, achieving the purpose of backup protection and preventing the fault from expanding and damaging the equipment.

[0061] As a technical optimization scheme of the present invention, the zinc oxide varistor 21 in Step 2 is prepared by high-voltage zinc oxide, and a layer of insulating and heat-conducting protective sleeve is covered on the outer surface of the zinc oxide varistor 21. The insulating and heat-conducting protective sleeve is prepared by organosilicon heat-conducting glue, and the model of the organosilicon heat-conducting glue is: Ausbond 160 heat-conducting silicone glue.

[0062] When the present invention is in use, after the body 1 of the DC-blocking device and the protection mechanism are installed, by closing the door panel 3, a sealed space is formed between the outer shell 2 and the door panel 3, so that the body 1 of the DC-blocking device operates effectively inside the outer shell 2. At the same time, an industrial air conditioner is often installed on the outer shell 2 outside the body 1 of the DC-blocking device to effectively dissipate heat for the operation of the body 1 of the DC-blocking device inside the outer shell 2.

[0063] When a trigger voltage is instantaneously generated on both sides of the current transformer 5, the discharge circuit is turned on to quickly ground the fault short-circuit current, achieving the purpose of backup protection and preventing the fault from expanding and damaging the equipment. At this time, the electric telescopic rod 30 is controlled by the controller to extend, thereby pushing the T-shaped column 29 to move into the position of the vacuum box 16. At this time, the movement of the T-shaped column 29 will, on the one hand, move the conductive column 25 towards the input end and the output end of the vacuum box 16, and on the other hand, also cause the piston cylinder 22 to absorb the residual gas in the vacuum box 16, thereby effectively ensuring the vacuum of the vacuum box 16. When the conductive column 25 moves towards the input end and the output end of the vacuum box 16, there is a conductive column 25 between the input end and the output end, making it easier to break down the vacuum between the input end and the output end, thus more effectively achieving the purpose of backup protection and preventing the airtightness of the vacuum box 16 from decreasing with use, and the difficulty of breaking down the vacuum between the input end and the output end due to a small amount of air mixed into the interior of the vacuum box 16 increases, resulting in the vacuum box 16 not being easily broken down, and preventing the situation where the vacuum box 16 cannot be easily broken down and thus cannot be effectively and timely protected.

[0064] When the piston cylinder 22 absorbs the residual gas in the vacuum box 16, the gas in the vacuum box 16 will enter the piston cylinder 22 through the Y-shaped guide hole 28, thereby making the air in the vacuum box 16 approach zero, and making it easier for the input end and the output end to break down the air. At the same time, in this process, the first one-way valve provided in the Y-shaped guide hole 28 can effectively prevent the gas inside the piston cylinder 22 from entering the vacuum box 16. When the electric telescopic rod 30 contracts, the T-shaped column 29 can effectively squeeze the gas inside the piston cylinder 22, so that the gas inside the piston cylinder 22 can effectively enter the airbag 26 through the conduit 27, making the seal between the input end and the output end and the vacuum box 16 more compact, and thus effectively ensuring the airtightness of the vacuum box 16.

[0065] As the electric telescopic rod 30 contracts, the T-shaped column 29 will abut against the contact switch 24. When the T-shaped column 29 abuts against the contact switch 24, the electric rotating shaft will drive the rotating plate 23 to rotate, thereby causing the rotating plate 23 to divide the vacuum box 16 into two chambers, effectively isolating the input end and the output end from the conductive column 25, and preventing the situation where the current breaks down the air when the transformer has no fault, greatly improving the operating stability of the device. During the process of the electric telescopic rod 30 extending, the electric telescopic rod 30 will drive the T-shaped column 29 to separate from the contact switch 24, thereby causing the electric rotating shaft to drive the rotating plate 23 to rotate, and causing the two chambers divided by the rotating plate 23 of the vacuum box 16 to be effectively connected, preventing the rotating plate 23 from hindering the movement of the conductive column 25.

[0066] When the electric telescopic rod 30 extends, the electric slide rod 11 will slide upward. When the resistance value of the zinc oxide varistor 21 increases, a large amount of heat will also be generated. Part of the heat is absorbed by the partition plate 7 and then effectively dissipated through the heat pipe 15. When the electric telescopic rod 30 extends, the electric slide rod 11 will also drive the partition plate 7 to rise. On the one hand, it can make the zinc oxide varistor 21 exposed inside the housing 2, so that the industrial air conditioner installed on the side of the housing 2 can effectively cool the zinc oxide varistor 21. On the other hand, the large amount of heat generated by the zinc oxide varistor 21 will also cause the temperature around the zinc oxide varistor 21 to rise rapidly. By driving the partition plate 7 to rise through the electric slide rod 11, it can also make the partition plate 7 and the heat pipe 15 move away from the position of the zinc oxide varistor 21, so that the heat pipe 15 and the partition plate 7 can dissipate heat effectively at other positions inside the housing 2, greatly improving the heat dissipation function of the zinc oxide varistor 21.

[0067] During the upward movement of the electric slide rod 11, it will also drive the piston plate 18 to rise through the connecting rod 17. As a result, the piston plate 18 absorbs air from the outside through the intake pipe 13, allowing the air in the outside atmosphere to enter the air cylinder 12 through the intake pipe 13. When the electric slide rod 11 descends, the gas in the air cylinder 12 is compressed into the air tank 8 through the outlet pipe 14. When it is necessary to open the door panel 3 for maintenance of the internal DC isolation device body 1, by opening the solenoid valve switch installed on the side of the housing 2, the solenoid valve is opened, so that the gas pressurized by the air cylinder 12 in the air tank 8 flows out, increasing the air pressure inside the housing 2, and enabling the door panel 3 to be opened more quickly and effectively, greatly improving the efficiency of the device during maintenance. At the same time, through the setting of the filter screen, it can also effectively prevent dust from entering the air cylinder 12 and the air tank 8. Through the setting of the piston plate 18, every time the electric telescopic rod 30 moves up and down, the device will fill the air tank 8 with corresponding air, effectively pressurizing the gas inside the air tank 8, making it easier to open the door panel 3.

[0068] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments to better explain the principle and practical application of the present invention, so that those skilled in the relevant technical field can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A DC isolation device for a transformer based on a current-triggered gap component, comprising a DC isolation device body (1). Characterized in that at the top and bottom sides of the DC isolation device body (1), a first terminal (4) serving as a power transmission terminal and a second terminal (6) serving as a power input terminal are respectively provided. A protection mechanism is electrically connected between the first terminal (4) and the second terminal (6). A detection and feedback unit is provided on the protection mechanism. The DC isolation device body (1) is fixedly connected to one side inside the housing (2). A pressurizing component is provided on the side of the housing (2) away from the DC isolation device body (1). A door panel (3) is hinged to one side of the housing (2), and a sealing ring is provided at the joint of the housing (2) and the door panel (3). The protection mechanism includes a current transformer (5), a zinc oxide varistor (21) and a vacuum box body (16). The current transformer (5) and the zinc oxide varistor (21) are connected in series between the first terminal (4) and the second terminal (6). Both ends of the current transformer (5) are connected in parallel with the vacuum box body (16). One end of the current transformer (5) away from the first terminal (4) is electrically connected to the second terminal (6) through an L-shaped wire. One end of the second terminal (6) away from the DC isolation device body (1) is electrically connected to a ground wire. One end of the top and bottom of the vacuum box body (16) is respectively provided with an input end and an output end. The current transformer (5) is connected in parallel with the vacuum box body (16) through a Z-shaped wire. One end of the Z-shaped wire away from the current transformer (5) is electrically connected to the middle of one side of the vacuum box body (16). In the middle of one side of the vacuum box body (16) away from the input end and the output end, a piston cylinder (22) is fixedly connected. A through hole for communication is provided at the joint of the vacuum box body (16) and the piston cylinder (22). At one end of the piston cylinder (22) away from the vacuum box body (16), a contact switch (24) is fixedly connected. A boss is provided at one end of the contact switch (24) away from the piston cylinder (22). A T-shaped column (29) is slidably sleeved inside the piston cylinder (22). A conductive column (25) is fixedly connected to the vertical end of the T-shaped column (29) with respect to the "T shape" and the conductive column (25) is located inside the vacuum box body (16). The vertical end of the T-shaped column (29) with respect to the "T shape" is slidably sleeved inside the through hole.

2. The DC isolation device for a transformer based on a current-triggered gap component according to claim 1. Characterized in that One end side of the T-shaped column (29) far from the conductive column (25) is fixedly connected to the telescopic ends of a plurality of electric telescopic rods (30). The fixed ends of the electric telescopic rods (30) are fixedly connected to the inner wall of the piston cylinder (22) on the side far from the vacuum box body (16). A Y-shaped guide hole (28) is formed inside the T-shaped column (29). The two ends of the Y-shaped guide hole (28) are respectively communicated with the inside of the vacuum box body (16) and the piston cylinder (22). A rotating plate (23) is rotatably connected to the center inside the vacuum box body (16). An electric rotating shaft is arranged inside one end of the rotating plate (23), and the electric rotating shaft is electrically connected to the contact switch (24). Air bags (26) are arranged at the joints of the vacuum box body (16) with the input end and the output end respectively. The air bags (26) are communicated with a conduit (27) embedded inside the vacuum box body (16) and the piston cylinder (22). One end of the conduit (27) far from the air bag (26) is communicated with the inside of the piston cylinder (22) on the side far from the vacuum box body (16). First one-way valves are arranged inside both the conduit (27) and the Y-shaped guide hole (28).

3. The transformer DC isolation device based on a current-triggered gap assembly according to claim 2, characterized in that, the pressurizing assembly includes a slide rail (9) arranged on the inner wall of the housing (2). An electric slide rod (11) is slidably connected inside the slide rail (9). The electric slide rod (11) is adapted to the electric telescopic rod (30). One end of the electric slide rod (11) far from the slide rail (9) is fixedly connected to a partition plate (7). A heat pipe (15) for heat dissipation is fixedly connected to the top of the partition plate (7). A connecting rod (17) is fixedly connected to the bottom of the electric slide rod (11). One end of the connecting rod (17) far from the electric slide rod (11) is fixedly connected to a piston plate (18). The piston plate (18) is slidably sleeved inside a cylinder (12). An air inlet pipe (13) and an air outlet pipe (14) are respectively communicated with the bottom side of the cylinder (12). The air inlet pipe (13) is communicated with the outside air and a filter screen is arranged at the communication part. One end of the air outlet pipe (14) far from the cylinder (12) is communicated with an air box (8). An electromagnetic valve for exhausting air is arranged on one side of the air box (8). An electromagnetic valve switch is fixedly connected to one side of the top of the housing (2). The electromagnetic valve switch is electrically connected to the electromagnetic valve. Second one-way valves are arranged inside both the air inlet pipe (13) and the air outlet pipe (14).

4. The transformer DC isolation device based on a current-triggered gap assembly according to claim 3, characterized in that, the detection and feedback unit includes a current monitoring module, a processing module and a receiving module. The current monitoring module includes current detectors (31) arranged at the output end of the vacuum box body (16), at one end of the L-shaped wire far from the current transformer (5) and at one end of the zinc oxide varistor (21) far from the current transformer (5); The processing module is electrically connected to the electric telescopic rod (30). The processing module is configured to receive the current data fed back by the current detector (31), analyze the current data, and send a target instruction to the electric telescopic rod (30) according to the analysis result. The target instruction is used to instruct the electric telescopic rod (30) to extend or shorten.

5. A transformer DC isolation device based on a current-triggered gap component according to claim 4, wherein, the current monitoring module further includes a data feedback sub-module, and the data feedback sub-module is communicatively connected to the processing module. The data feedback sub-module is configured to feed back the current data measured by the current monitoring module to the processing module.

6. A transformer DC isolation device based on a current-triggered gap component according to claim 5, wherein, The processing module analyzes the current data and sends a target instruction to the electric telescopic rod (30) according to the analysis result, including: calculating the current data of the target node by using a current formula; wherein, the current formula includes: , where: is the current data of the target node, K is a correction coefficient, is the mean value of the current measured instantaneously for n times, and the target nodes include: node a at the output end of the vacuum box body (16), node b at one end of the L-shaped wire far from the current transformer (5), and node c at one end of the zinc oxide varistor (21) far from the current transformer (5); Using the current analysis formula: , determine the target instruction and send the target instruction to the electric telescopic rod (30); Among them, is the determination base number, and AHQ and W are preset parameters; Using the current analysis formula: , determining the target instruction, and sending the target instruction to the electric telescopic rod (30) includes: If has a value of 0, end; if has a value greater than 0, use the formula: to determine the target instruction; where U is the voltage across the current transformer (5), R is the rated resistance of the current transformer (5), if , the processing module sends an elongation instruction to the electric telescopic rod (30), if , the processing module sends a shortening instruction to the electric telescopic rod (30).

7. A transformer DC isolation device based on a current-triggered gap component according to claim 6, wherein, the protection mechanism protects the DC isolation device body (1) and the transformer electrically connected to the DC isolation device body (1) through a protection method of a vacuum-triggered gap. The protection method includes the following steps: Step 1: When there is no three-phase unbalance fault in the circuit, at this time, the neutral point voltage and short-circuit current of the transformer will operate stably. At this time, the DC isolation device body (1) forms a path with the current transformer (5) and the zinc oxide varistor (21) through the first terminal (4) and the second terminal (6); the DC isolation device body (1) and the transformer operate stably. Step 2: When a three-phase unbalance fault occurs in the circuit and the other protections fail, at this time, the neutral point voltage and short-circuit current of the transformer will continue to rise. When the short-circuit current exceeds 2 kA and the neutral point voltage exceeds the conduction value of the zinc oxide varistor (21), the neutral point of the transformer is grounded through the series branch of the zinc oxide varistor (21) and the current transformer (5). When the voltage between the neutral point of the transformer and the DC isolation device body (1) is restored, the circuit resumes the operation mode described in Step 1. Step 3: When the voltage between the neutral point of the transformer and the DC isolation device body (1) in Step 2 is not restored and the voltage across both sides of the current transformer (5) instantaneously generates a high voltage greater than 3 kV, the vacuum gap between the output terminal and the input terminal on the vacuum box body (16) is triggered, so that the current on the output terminal and the input terminal breaks through the vacuum, and then the discharge circuit is turned on to quickly ground the fault short-circuit current, achieving the purpose of backup protection and preventing the fault from expanding and damaging the equipment.

8. A transformer DC isolation device based on a current-triggered gap component according to claim 7, wherein, the zinc oxide varistor (21) in Step 2 is prepared by high-voltage zinc oxide, and an insulating and heat-conducting protective sleeve is covered on the outer surface of the zinc oxide varistor (21).

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