A fully enclosed controllable transformer neutral point protection discharge gap

Abstract

The present invention provides a fully enclosed controllable transformer neutral point protection discharge gap, comprising a housing filled with insulating gas, first and second wall bushings respectively provided at both ends of the housing; first and second discharge gap members respectively fixed to the extending ends of the first and second wall bushings, forming a discharge gap between the first and second discharge gap members; a plasma jet generating device provided at the air outlet of a blower, the plasma jet generating device being used to generate a plasma jet; the present invention utilizes the formation of a plasma jet between the discharge gaps, and when the transformer is subjected to overvoltage and a higher voltage appears at both ends of the discharge gap, the discharge gap is immediately conductive; the two discharge gap members are provided in a sealed housing structure, the breakdown of the discharge gap is not affected by external environmental factors, the dispersion of the breakdown voltage of the discharge gap is eliminated, and malfunction of the discharge gap under overvoltage and damage to the transformer are avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power equipment, and in particular relates to a fully enclosed controllable transformer neutral point protection discharge gap. Background Art

[0002] In 110kV and 220kV voltage level power grids, in order to limit the zero-sequence impedance of the transformer system, a grounding method is generally adopted in which some transformer neutral points are directly grounded and some transformer neutral points are not grounded. Since 110kV and 220kV kilovolt transformers usually adopt graded insulation, when the neutral point is not grounded, in order to protect the neutral point insulation, the transformer neutral point is usually connected to the ground in parallel through a protective gap and a lightning arrester. The coordination principle of the two is: the lightning arrester is responsible for the lightning overvoltage and the operating overvoltage protection under normal operating conditions; due to the formation of a local ungrounded system due to a ground fault, under the steady-state and transient overvoltage of the power frequency The gap should operate to protect the transformer neutral point insulation and lightning arrester; when the system operates in an effective grounding mode and a single-phase grounding fault occurs, the gap should not operate under power frequency steady-state and transient overvoltages; the standard lightning impulse discharge voltage of the gap should be lower than the lightning impulse protection level of the transformer neutral point, the lightning arrester cannot withstand power frequency overvoltages exceeding its rated voltage, and the upper limit of the power frequency discharge voltage of the gap must be less than the rated voltage of the lightning arrester; the principle of this protection is to use the lightning arrester as the main protection against lightning and switching overvoltages under normal operating conditions, and the gap as backup protection. Once abnormal conditions occur, the gap discharges to protect the lightning arrester.

[0003] In the existing technology, the insulating medium of the gap is air, and the breakdown voltage is affected by air humidity, temperature, atmospheric pressure and altitude, and has a large dispersion. If it is not properly matched, the gap will break down under the overvoltage condition that should be protected by the lightning arrester, and the lightning arrester will be short-circuited and fail to play a protective role, causing the protection device to malfunction or the transformer to be damaged. In practice, the single-phase grounding transient voltage of the grounded system is often greater than the single-phase grounding steady-state voltage of the ungrounded system, making it difficult to find a suitable gap distance to match the lightning arrester. Summary of the Invention

[0004] In response to the technical problems existing in the prior art, the present invention provides a fully enclosed controllable transformer neutral point protection discharge gap to solve the technical problems that the insulating medium of the existing gap structure is air, the breakdown voltage is greatly affected by the environment, the dispersion is large, and it is easy to cause malfunction of the protection device or damage to the transformer.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The present invention provides a fully enclosed controllable transformer neutral point protection discharge gap, comprising a housing, a first discharge gap member, a second discharge gap member, a first wall bushing, a second wall bushing, a blower, and a plasma jet generating device; the housing is a sealed shell structure, the interior of the housing is filled with insulating gas, and the first wall bushing and the second wall bushing are respectively provided at both ends of the housing;

[0007] The first discharge gap member is fixedly arranged at the end portion of the first wall sleeve extending therethrough, and the second discharge gap member is fixedly arranged at the end portion of the second wall sleeve extending therethrough, and a discharge gap is formed between the first discharge gap member and the second discharge gap member; the fan is arranged in the middle of the discharge gap, and the air outlet of the fan is arranged toward one side of the discharge gap; the plasma jet generating device is arranged at the air outlet of the fan, and the plasma jet generating device is used to generate a plasma jet.

[0008] Furthermore, the plasma jet generating device includes a grounding electrode sheet, a high-voltage electrode sheet, an insulating layer and a polytetrafluoroethylene tube; the polytetrafluoroethylene tube is arranged at the air outlet of the fan, and a gas channel is provided in the polytetrafluoroethylene tube, and the inlet end of the gas channel is connected to the air outlet of the fan; the grounding electrode sheet and the high-voltage electrode sheet are coaxially arranged and are sequentially arranged at the outlet end of the gas channel; the center of the grounding electrode sheet and the high-voltage electrode sheet are both provided with jet holes, and the insulating layer is provided between the grounding electrode sheet and the high-voltage electrode sheet.

[0009] Furthermore, it also includes a radio frequency power supply, a fan power supply and a control module; the output end of the radio frequency power supply is connected to the plasma jet generating device, and the output end of the fan power supply is connected to the fan; the output end of the control module is connected to the radio frequency power supply and the fan power supply respectively.

[0010] Furthermore, the fan power supply is connected to the fan through a fan power line, the fan power supply is arranged on the outside of the housing, one end of the fan power line is connected to the fan power supply, and the other end passes through the sealing hole on the housing and is connected to the fan;

[0011] The radio frequency power supply is connected to the plasma jet generating device through a plasma jet device cable. The radio frequency power supply is arranged on the outside of the shell. One end of the plasma jet device cable is connected to the radio frequency power supply, and the other end passes through the sealing hole on the shell and is connected to the plasma jet generating device.

[0012] Furthermore, the outer shell includes a first end cover, a second end cover and an intermediate straight cylinder. The first end cover and the second end cover are respectively sealed at the two ends of the intermediate straight cylinder. The first end cover, the second end cover and the intermediate straight cylinder constitute a sealed shell structure; the first wall sleeve is sealingly inserted on the first end cover, and the second wall sleeve is sealingly inserted on the second end cover.

[0013] Furthermore, the exposed end of the first wall bushing is connected to the arrester, and the exposed end of the second wall bushing is grounded.

[0014] Furthermore, the first discharge gap member adopts a rod gap or a ball gap, and the second discharge gap member adopts a rod gap or a ball gap.

[0015] Furthermore, the insulating gas is nitrogen or SF6.

[0016] Furthermore, the gas passage adopts a trumpet-shaped gas passage, the inlet end of the trumpet-shaped gas passage is the large end, and the outlet end is the small end.

[0017] Furthermore, the input signals of the control module include the on / off status of the high-voltage side circuit breaker of the grounded main transformer in the station and the voltage amplitude signal of the neutral point of the main transformer.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention provides a fully enclosed controllable transformer neutral point protection discharge gap. A plasma jet generating device and a fan are arranged in the middle of the discharge gap, and a plasma jet is formed between the discharge gap by utilizing the plasma jet generating device and the fan. When the transformer is subjected to overvoltage and a high voltage appears at both ends of the discharge gap, the conductivity of the plasma jet is utilized to immediately conduct the discharge gap. Two discharge gap members are arranged in a sealed housing structure, so that the discharge gap formed by the two discharge gap members is in a sealed environment. The breakdown of the discharge gap is not affected by external environmental factors, thereby eliminating the dispersion of the discharge gap breakdown voltage caused by changes in environmental factors, effectively improving the reliability of the neutral point protection discharge gap, and avoiding malfunction of the discharge gap under overvoltage and damage to the transformer.

[0020] Furthermore, by generating high voltage between the ground electrode sheet and the high-voltage electrode sheet to break down the insulating gas, the gas molecules can be ionized in a short time to form a plasma jet; by arranging the ground electrode sheet, the high-voltage electrode sheet and the insulating layer at the outlet end of the gas channel, only airflow is generated between the discharge gap when only the fan power supply is connected, thereby avoiding the breakdown of the discharge gap and effectively improving the reliability of the gap structure.

[0021] Furthermore, by setting up a control module, connecting the control module with the RF power supply and the fan power supply, and using the control module to control the on and off of the RF power supply and the fan power supply, false operation of the discharge gap is avoided and the safety of the discharge gap is improved.

[0022] Furthermore, the outer shell is composed of two end covers and a middle straight tube, which has a simple structure and is convenient for structural replacement and inspection and maintenance.

[0023] Furthermore, the insulating gas is nitrogen or SF6, and the gas channel is a trumpet-shaped gas channel. When the gas passes through the trumpet-shaped gas channel, high voltage electricity is generated between the positive and negative poles, breaking down the insulating gas to form a plasma jet, and the plasma jet is stable.

[0024] Furthermore, the input signal of the control module includes the on-off status of the high-voltage side circuit breaker of the grounded main transformer in the station and the neutral point voltage amplitude signal of the main transformer; when it is detected that the overvoltage duration exceeds the preset number of cycles, and the overvoltage amplitude is greater than the single-phase grounded neutral point steady-state voltage value, and the high-voltage side circuit breakers of the grounded main transformer in the station are all tripped, it is judged that the neutral point has lost ground, and the neutral point has an industrial frequency overvoltage or temporary overvoltage. The control module connects the fan power supply and the radio frequency power supply, and the neutral point is turned on to protect the neutral point lightning arrester and the transformer neutral point insulation; under lightning overvoltage, if the overvoltage duration does not exceed the preset number of cycles; when the neutral point does not lose ground, the high-voltage side circuit breakers of the grounded main transformer in the station are not all tripped, the control module does not connect the radio frequency power supply, and the discharge gap will not malfunction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of the transformer neutral point protection discharge gap according to the present invention;

[0026] Figure 2 It is a partially enlarged schematic diagram of the plasma jet generating device in the present invention;

[0027] Figure 3 This is a schematic diagram of the application structure of the transformer neutral point protection discharge gap according to the present invention.

[0028] Among them, 1 is a shell, 2 is a first discharge gap member, 3 is a second discharge gap member, 4 is a first wall bushing, 5 is a second wall bushing, 6 is a fan, 7 is a plasma jet generating device, 8 is a fixing bracket, 9 is a fan power line, 10 is a plasma jet device cable, 11 is a lightning arrester, 12 isolating switch; 100 is a fully enclosed controllable protective gap; 101 is a first end cover, 102 is an end cover, 103 is an intermediate straight tube; 71 is a grounding electrode sheet, 72 is a high-voltage electrode sheet, 73 is an insulating layer, 74 is a polytetrafluoroethylene tube, and 75 is a gas channel. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail in the following specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] As attached Figure 1-2As shown, the present invention provides a fully enclosed controllable transformer neutral point protection discharge gap, including a shell 1, a first discharge gap member 2, a second discharge gap member 3, a first wall bushing 4, a second wall bushing 5, a fan 6, a plasma jet generating device 7, a fixing bracket 8, a fan power line 9, a plasma jet device cable 10, a radio frequency power supply, a fan power supply and a control module; the shell 1 is installed on the fixing bracket 8, and the shell 1 is fixed to the base by the fixing bracket 8; the shell 1 is a sealed shell structure, and a sealed cavity is provided in the shell 1; the interior of the shell 1 is filled with insulating gas to ensure that the neutral point protection discharge gap is in an insulating gas atmosphere; the first wall bushing 4 and the second wall bushing 5 are respectively inserted into the two sides of the shell 1 end; one end of the first wall bushing 4 extends into the housing 1, and the other end is exposed; the first discharge gap member 2 is fixedly arranged at the end of the first wall bushing 4, and the exposed end of the first wall bushing 4 is connected to the lightning arrester 11; one end of the second wall bushing 5 extends into the housing 1, and the other end is exposed; the second discharge gap member 3 is fixedly arranged at the end of the second wall bushing 5, and the exposed end of the second wall bushing 5 is grounded; a discharge gap is formed between the first discharge gap member 2 and the second discharge gap member 3; the fan 6 is arranged at the lower middle part of the discharge gap, and the air outlet of the fan 6 is arranged toward one side of the discharge gap; the plasma jet generating device 7 is arranged at the air outlet of the fan 6, and the plasma jet generating device 7 is used to generate a plasma jet.

[0031] The output end of the fan power supply is connected to the fan 6, and the fan power supply is connected to the fan 6 through the fan power supply line 9; the fan power supply is arranged on the outside of the outer shell 1, one end of the fan power supply line 9 is connected to the fan power supply, and the other end passes through the sealing hole at the upper end of the outer shell 1 and is connected to the fan 6.

[0032] The output end of the RF power supply is connected to the plasma jet generating device 7. The RF power supply is arranged on the outside of the shell 1. The RF power supply is connected to the plasma jet generating device 7 through a plasma jet device cable 10. One end of the plasma jet device cable 10 is connected to the RF power supply, and the other end passes through the sealing hole on the shell 1 and is connected to the plasma jet generating device 7.

[0033] The output end of the control module is connected to the RF power supply and the fan power supply respectively, and the input end of the control module is connected to the high-voltage side circuit breaker of the grounded main transformer in the station and the neutral point of the main transformer. The input signal of the control module includes the on-off status of the high-voltage side circuit breaker of the grounded main transformer in the station and the voltage amplitude signal of the neutral point of the main transformer.

[0034] The outer shell 1 includes a first end cover 101, a second end cover 102 and an intermediate straight tube 103. The first end cover 101 and the second end cover 102 are respectively sealed at the two ends of the intermediate straight tube 103. The first end cover 101, the second end cover 102 and the intermediate straight tube 103 constitute a sealed shell structure; the first wall bushing 4 is sealed and penetrated on the first end cover 101, and the second wall bushing 5 is sealed and penetrated on the second end cover 102; the insulating gas in the outer shell 1 is nitrogen or SF6.

[0035] In the present invention, the first discharge gap member 2 is a rod gap or a ball gap, and the second discharge gap member 3 is a rod gap or a ball gap.

[0036] The plasma jet generating device 7 includes a ground electrode sheet 71, a high-voltage electrode sheet 72, an insulating layer 73 and a polytetrafluoroethylene tube 74; the polytetrafluoroethylene tube 74 is arranged at the air outlet of the fan 6, and a gas channel 75 is provided in the polytetrafluoroethylene tube 74, and the inlet end of the gas channel 75 is connected to the air outlet; the ground electrode sheet 71 and the high-voltage electrode sheet 72 are coaxially arranged and arranged in sequence at the outlet end of the gas channel 75; the center of the ground electrode sheet 71 and the high-voltage electrode sheet 72 are both provided with a jet hole, and the insulating layer 73 is provided between the ground electrode sheet 71 and the high-voltage electrode sheet 72; preferably, the outer structure of the plasma jet generating device 7 is a hyperbolic structure; the gas channel 75 adopts a trumpet-shaped gas channel, the inlet end of the trumpet-shaped gas channel is the large end, and the outlet end is the small end; wherein, a high voltage is generated between the ground electrode sheet 71 and the high-voltage electrode sheet 72 by a radio frequency power supply, breaking down the insulating gas, and ionizing the gas molecules in a short time to form a plasma jet.

[0037] Working principle and usage

[0038] As attached Figure 3 As shown, when the present invention is used, the fully enclosed controllable protection gap 100 is connected in parallel with the lightning arrester 11. The fully enclosed controllable protection gap 100 is the fully enclosed controllable transformer neutral point protection discharge gap described in the present invention; the fully enclosed protection gap 100 is connected between the neutral point of the transformer and the ground, and the isolating switch is set on the base and placed on the other side of the lightning arrester 11; the isolating switch is connected to the insulating support of the isolating knife switch 12, and the knife switch of the isolating knife switch 12 is connected to the static contact of the isolating switch, and the top of the lightning arrester 11 is connected to the isolating switch through the connecting busbar to protect the neutral point insulation of the transformer and the neutral point lightning arrester.

[0039] In the present invention, when the on / off state of the high-voltage side circuit breaker of the grounded main transformer in the station and the voltage amplitude signal of the neutral point of the main transformer are used as input signals of the control module, when the control module detects that the overvoltage duration exceeds a preset number of cycles, the overvoltage amplitude is greater than the single-phase grounded neutral point steady-state voltage value, and all the high-voltage side circuit breakers of the grounded main transformer in the station are tripped, it is determined that the neutral point is lost, and a power frequency overvoltage or a temporary overvoltage occurs at the neutral point. The control module connects the fan power supply and the radio frequency power supply, uses the plasma jet generating device and the fan to form a plasma jet between the discharge gap, and uses the conductivity of the plasma jet to immediately conduct the discharge gap and the neutral point, thereby protecting the neutral point arrester and the neutral point insulation of the transformer. Under the lightning overvoltage, if the overvoltage duration does not exceed the preset number of cycles and the neutral point does not lose ground, and if the high-voltage side circuit breakers of the grounded main transformer in the station are not tripped, the control module does not connect the radio frequency power supply, and the discharge gap does not malfunction.

[0040] The transformer neutral point protection discharge gap described in the present invention comprises a shell comprising two end covers and a middle straight cylinder, the two end covers and the middle straight cylinder together forming a sealed shell structure, the interior of the sealed shell structure being filled with insulating gas; when in use, the volume of the cavity can be effectively reduced by increasing the pressure of the insulating gas; wall bushings are respectively installed at both ends of the shell, one end of the wall bushings extends into the shell and the other end is exposed; a discharge gap member is installed at the end of the extending end of the wall bushing; the discharge gap members at both ends together form a discharge gap, which can adopt a rod-rod gap or a ball-ball gap; a fan and a plasma jet generating device are installed in the middle and lower part of the discharge gap; the present invention arranges the discharge gap in a sealed shell structure, so that the breakdown of the discharge gap is not affected by external environmental factors, thereby eliminating the dispersion of the breakdown voltage of the protective discharge gap due to changes in environmental factors, as well as the risk of malfunction under lightning and operational overvoltage, thereby improving the reliability of the neutral point protection gap, and is applicable to various complex and harsh environments such as plateaus and seas.

[0041] Example

[0042] This embodiment provides a fully enclosed controllable transformer neutral point protection discharge gap, including a housing 1, a first discharge gap member 2, a second discharge gap member 3, a first wall bushing 4, a second wall bushing 5, a fan 6, a plasma jet generating device 7, a fixing bracket 8, a fan power cord 9, a plasma jet device power supply, a radio frequency power supply, a fan power supply, and a control module.

[0043] The outer shell 1 includes two end covers and an intermediate straight tube. The two end covers are respectively sealed at both ends of the intermediate straight tube. The end covers and the intermediate straight tube are spliced ​​together to form a sealed shell structure. The inner cavity of the sealed shell structure is filled with insulating gas; the insulating gas is nitrogen or SF6; by increasing the insulating gas pressure in the shell 1, the volume of the cavity can be reduced.

[0044] The first wall bushing 4 and the second wall bushing 5 are respectively sealed and penetrated on the end covers on both sides of the shell 1. The end of the first wall bushing 4 in the shell is provided with a first discharge gap member 2, and the end of the second wall bushing 5 in the shell is provided with a second discharge gap member 3; a discharge gap is formed between the first discharge gap member 2 and the second discharge gap member 3, and the discharge gap can be a rod-rod gap or a copper ball gap.

[0045] A fan 6 and a plasma jet generating device 7 are installed below the middle of the discharge gap. The fan 6 is installed at the bottom inner side of the shell in the middle of the discharge gap, and an air intake channel is reserved between the fan 6 and the inner wall of the shell; the plasma jet generating device 7 is arranged above the fan 6, and the air outlet of the fan 6 is arranged vertically toward one side of the discharge gap; the plasma jet generating device 7 is installed above the air outlet of the fan 6, and the outer structure of the plasma jet generating device 7 is a hyperbolic structure, which effectively improves the strength and stability of the structure.

[0046] The plasma jet generating device 7 includes a ground electrode sheet 71, a high-voltage electrode sheet 72, an insulating layer 73 and a polytetrafluoroethylene tube 74; the polytetrafluoroethylene tube 74 is arranged at the air outlet of the fan 6, and a gas channel 75 is provided in the polytetrafluoroethylene tube 74, the inlet end of the gas channel 75 is connected to the air outlet; the ground electrode sheet 71 and the high-voltage electrode sheet 72 are coaxially arranged and sequentially arranged at the outlet end of the gas channel 75; preferably, the ground electrode sheet 71 and the high-voltage electrode sheet 72 are both metal electrode sheets; the center of the ground electrode sheet 71 and the high-voltage electrode sheet 72 are both provided with a jet hole, and the insulating layer 73 is provided between the ground electrode sheet 71 and the high-voltage electrode sheet 72; preferably, the outer structure of the plasma jet generating device 7 is a hyperbolic structure; the gas channel 75 is a trumpet-shaped gas channel, the inlet end of the trumpet-shaped gas channel is the large end, and the outlet end is the small end; wherein, a high voltage is generated between the ground electrode sheet 71 and the high-voltage electrode sheet 72 by a radio frequency power supply, breaking down the insulating gas, and ionizing the gas molecules in a short time to form a plasma jet.

[0047] The output end of the fan power supply is connected to the fan 6, and the fan power supply is connected to the fan 6 through a fan power line 9; the fan power supply is arranged on the outside of the shell 1, one section of the fan power line 9 is connected to the fan power supply, and the other end is connected to the fan 6 after passing through the sealing hole at the upper end of the shell 1; the output end of the radio frequency power supply is connected to the plasma jet generating device 7, the radio frequency power supply is arranged on the outside of the shell 1, and the radio frequency power supply is connected to the plasma jet generating device 7 through a plasma jet device cable 10, one end of the plasma jet device cable 10 is connected to the radio frequency power supply, and the other end is connected to the plasma jet generating device 7 after passing through the sealing hole on the shell 1; the output end of the control module is connected to the radio frequency power supply and the fan power supply respectively, and the input end of the control module is connected to the high-voltage side circuit breaker of the grounded main transformer in the station and the neutral point of the main transformer, and the input signal of the control module includes the on-off state of the high-voltage side circuit breaker of the grounded main transformer in the station and the voltage amplitude signal of the neutral point of the main transformer; wherein, the control module includes a timing unit and a comparison unit.

[0048] In this embodiment, the fan power line 9 and the plasma jet device cable 10 both pass through the sealing hole at the bottom of the shell and are connected to the fan power supply and the radio frequency power supply respectively; the fan power supply and the radio frequency power supply are controlled by the control module; when the control module is connected to the radio frequency power supply and the fan power supply, the insulating gas flow passes through the gas channel at high speed after the fan is started, and the radio frequency high voltage is applied between the grounding electrode plate and the high-voltage electrode plate at the same time, so that the plasma jet can be ejected along with the insulating gas flow; with the appropriate discharge gap distance, when the transformer is subjected to overvoltage and a higher voltage appears at both ends of the discharge gap, the conductivity of the plasma can immediately cause the gap to break down; if the radio frequency power supply is disconnected and only the fan power supply is connected, only airflow is generated, and the gap will not be broken down.

[0049] In this embodiment, the input signal of the control module includes the on-off status of the high-voltage side circuit breaker of the grounded main transformer in the station and the neutral point voltage amplitude signal of the main transformer; when the overvoltage duration is detected to exceed 2 cycles, and the overvoltage amplitude is greater than the single-phase grounded neutral point steady-state voltage value, and the high-voltage side circuit breakers of the grounded main transformer in the station are all tripped, it is determined that the neutral point has lost ground, and the neutral point has a power frequency overvoltage or temporary overvoltage; at this time, the control module is connected to the fan power supply and the radio frequency power supply, the neutral point is turned on, and the neutral point lightning arrester and the transformer neutral point insulation are protected; under lightning overvoltage, if the overvoltage duration does not exceed 2 cycles; if the neutral point is not lost, the high-voltage side circuit breakers of the grounded main transformer in the station are not all tripped, the control module will not be connected to the radio frequency power supply, and the discharge gap will not malfunction.

[0050] The neutral point protection discharge gap described in the present invention can overcome the influence of climate and environmental factors on the gap discharge voltage, and can intelligently control the breakdown of the neutral point protection gap of the transformer according to the type of system overvoltage; the discharge gap is set in the shell, and the breakdown of the neutral point protection gap of the transformer is not affected by environmental factors, thereby eliminating the dispersion of the protection gap breakdown voltage due to changes in environmental factors and the risk of malfunction under lightning and operational overvoltage, thereby improving the reliability of the neutral point protection gap and being applicable to various complex and harsh environments such as plateaus and seas.

[0051] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention.

Claims

1. A fully enclosed controllable transformer neutral point protection discharge gap, characterized in that: The invention comprises a shell (1), a first discharge gap member (2), a second discharge gap member (3), a first wall bushing (4), a second wall bushing (5), a fan (6) and a plasma jet generating device (7); the shell (1) is a sealed shell structure, the interior of the shell (1) is filled with insulating gas, and the first wall bushing (4) and the second wall bushing (5) are respectively provided at both ends of the shell (1); The first discharge gap member (2) is fixedly arranged at the end of the insertion end of the first wall bushing (4), and the second discharge gap member (3) is fixedly arranged at the end of the insertion end of the second wall bushing (5), and a discharge gap is formed between the first discharge gap member (2) and the second discharge gap member (3); the fan (6) is arranged in the middle of the discharge gap, and the air outlet of the fan (6) is arranged toward one side of the discharge gap; the plasma jet generating device (7) is arranged at the air outlet of the fan (6), and the plasma jet generating device (7) is used to generate a plasma jet; The plasma jet generating device (7) comprises a grounding electrode sheet (71), a high-voltage electrode sheet (72), an insulating layer (73) and a polytetrafluoroethylene tube (74); the polytetrafluoroethylene tube (74) is arranged at the air outlet of the fan (6), a gas channel (75) is arranged in the polytetrafluoroethylene tube (74), and the inlet end of the gas channel (75) is communicated with the air outlet of the fan (6); the grounding electrode sheet (71) and the high-voltage electrode sheet (72) are coaxially arranged and are sequentially arranged at the outlet end of the gas channel (75); the centers of the grounding electrode sheet (71) and the high-voltage electrode sheet (72) are both provided with jet holes, and the insulating layer (73) is arranged between the grounding electrode sheet (71) and the high-voltage electrode sheet (72); The insulating gas used is nitrogen or SF6.

2. The fully enclosed controllable transformer neutral point protection discharge gap according to claim 1, characterized in that: It also includes a radio frequency power supply, a fan power supply and a control module; the output end of the radio frequency power supply is connected to the plasma jet generating device (7), and the output end of the fan power supply is connected to the fan (6); the output end of the control module is connected to the radio frequency power supply and the fan power supply respectively.

3. The fully enclosed controllable transformer neutral point protection discharge gap according to claim 2, characterized in that: The fan power supply is connected to the fan (6) via a fan power supply line (9), and the fan power supply is arranged outside the housing (1). One end of the fan power supply line (9) is connected to the fan power supply, and the other end passes through the sealing hole on the housing (1) and is connected to the fan (6). The radio frequency power supply is connected to the plasma jet generating device (7) via a plasma jet device cable (10). The radio frequency power supply is arranged outside the housing (1). One end of the plasma jet device cable (10) is connected to the radio frequency power supply, and the other end passes through a sealing hole on the housing (1) and is connected to the plasma jet generating device (7).

4. The fully enclosed controllable transformer neutral point protection discharge gap according to claim 1, characterized in that: The housing (1) comprises a first end cover (101), a second end cover (102) and an intermediate straight tube (103); the first end cover (101) and the second end cover (102) are respectively and sealingly arranged at the two ends of the intermediate straight tube (103); the first end cover (101), the second end cover (102) and the intermediate straight tube (103) constitute a sealed shell structure; the first wall bushing (4) is sealedly arranged on the first end cover (101), and the second wall bushing (5) is sealedly arranged on the second end cover (102).

5. The fully enclosed controllable transformer neutral point protection discharge gap according to claim 1, characterized in that: The exposed end of the first wall bushing (4) is connected to the lightning arrester (11), and the exposed end of the second wall bushing (5) is grounded.

6. The fully enclosed controllable transformer neutral point protection discharge gap according to claim 1, characterized in that: The first discharge gap member (2) adopts a rod gap or a ball gap, and the second discharge gap member (3) adopts a rod gap or a ball gap.

7. The fully enclosed controllable transformer neutral point protection discharge gap according to claim 1, characterized in that: The gas passage (75) is a trumpet-shaped gas passage, the inlet end of the trumpet-shaped gas passage is a large end, and the outlet end is a small end.

8. The fully enclosed controllable transformer neutral point protection discharge gap according to claim 2, characterized in that: The input signals of the control module include the on / off status of the high-voltage side circuit breaker of the grounded main transformer in the station and the voltage amplitude signal of the neutral point of the main transformer.

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