CN117013506B - Neutral point nonlinear resistor grounding protection system and reliable line selection device - Google Patents
Neutral point nonlinear resistor grounding protection system and reliable line selection device Download PDFInfo
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- CN117013506B CN117013506B CN202311281262.5A CN202311281262A CN117013506B CN 117013506 B CN117013506 B CN 117013506B CN 202311281262 A CN202311281262 A CN 202311281262A CN 117013506 B CN117013506 B CN 117013506B
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- 230000007935 neutral effect Effects 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 claims abstract description 37
- 238000012544 monitoring process Methods 0.000 claims abstract description 19
- 238000002347 injection Methods 0.000 claims abstract description 16
- 239000007924 injection Substances 0.000 claims abstract description 16
- 238000012545 processing Methods 0.000 claims abstract description 13
- 230000005291 magnetic effect Effects 0.000 claims description 11
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
- H02H7/262—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of switching or blocking orders
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00001—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by the display of information or by user interaction, e.g. supervisory control and data acquisition systems [SCADA] or graphical user interfaces [GUI]
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00002—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by monitoring
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00032—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for
- H02J13/00036—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers
- H02J13/0004—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers involved in a protection system
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Human Computer Interaction (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
The invention discloses a neutral point nonlinear resistor grounding protection system and a reliable line selection device, which comprise a high-impedance grounding transformer GJBC, an execution unit, a three-phase control rapid circuit breaker DL2, a zero sequence current transformer LH, a voltage transformer YH, an instantaneous current injection method line selection controller, a fault processing controller and a full-voltage monitoring and fault wave recording controller. The neutral point nonlinear resistor grounding protection system and the reliable line selection device can realize quick line selection and fault loop locking by injecting instantaneous heavy current into a circuit, so that the aim of quick and safe neutral point grounding protection is well achieved, the safety is greatly improved, the grounding fault inquiry is simple and quick, the risk of short circuit accidents is greatly reduced, the probability of two different places or interphase short circuits formed by grounding of the system can be effectively reduced, the accident of the system is avoided, and the system has remarkable economic benefit.
Description
Technical Field
The invention relates to the technical field of electrical engineering, in particular to a neutral point nonlinear resistor grounding protection system and a reliable line selection device.
Background
The neutral point ungrounded system and the neutral point arc suppression coil grounded system are called as small current grounded systems. The small-resistance grounded or neutral-point ungrounded system is called a high-current grounded system, and the operation mode is not compatible at present, so that the problem of the existing system is solved.
The grounding fault point is quickly found by combining the grounding operation mode of small current which is mainly adopted in our country at present, namely, the grounding operation mode of no grounding or through arc suppression coils, the fault point is quickly found by adopting various line selection modes, the 100% accurate requirement of system line selection is not met at present, the current situation of research and application at home and abroad is integrated, and the grounding fault line selection of the small current grounding power grid basically adopts the small current line selection mode.
The existing small-current line selection mode is low in safety, difficult in ground fault inquiry and easy in occurrence of short-circuit accidents, the purposes of quick line selection and locking of a fault loop by injecting instantaneous large current into a circuit cannot be achieved, the purpose of quick and safe neutral point ground protection cannot be achieved, quick short-circuit protection cannot be achieved by matching a quick single-phase vacuum circuit breaker with other controllers, meanwhile, safety protection cannot be achieved on the opening and closing positions of a control switch in the quick single-phase vacuum circuit breaker, the problem of leakage risk existing in the quick single-phase vacuum circuit breaker is solved, and accordingly great inconvenience is brought to people in electric power safety operation.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a neutral point nonlinear resistor grounding protection system and a reliable line selection device, which meet the reliability and economy of system operation, and simultaneously change unconditionally into a high-current grounding mode under the condition of system failure, ensure the safety of the system, and adopt safe protection measures according to the nature of a failure loop.
In order to achieve the above purpose, the invention is realized by the following technical scheme: the neutral point nonlinear resistor grounding protection system comprises a high-impedance grounding transformer GJBC, an execution unit, a three-phase control rapid circuit breaker DL2, a zero sequence current transformer LH, a voltage transformer YH, an instantaneous current injection method line selection controller, a fault processing controller and a full-voltage monitoring and fault wave recording controller, wherein the execution unit is one of a rapid single-phase vacuum circuit breaker DL1 and a nonlinear self-control unit FR;
when the execution unit adopts a rapid single-phase vacuum breaker DL1, in the normal operation process of the system, the rapid single-phase vacuum breaker DL1 and a three-phase control rapid breaker DL2 are in a switching-off state, the system operates in a mode that a neutral point is not grounded, a nonlinear resistor carried by a high-impedance grounding transformer GJBC is in a high-impedance state, the device is in an idle running mode, the system is in a low-current grounding system operation mode, the bus voltage is monitored through a voltage transformer YH, and a full-voltage monitoring and fault wave recording controller collects and analyzes zero sequence current of each feeder line loop;
when a single-phase grounding fault occurs, the full-voltage monitoring and fault wave recording controller judges the grounding fault by adopting a U-I double-criterion compound algorithm through the YH signal mutation of a voltage transformer and the acquisition and analysis of zero sequence current signals of each feeder line loop, and sends a closing instruction of a rapid single-phase vacuum circuit breaker DL1, the system is converted into a high-current grounding system, instantaneous current is injected into the zero sequence loop of a fault line, and the fault line is accurately selected by the instantaneous current injection method line selection controller through a maximum increment method and a fusion method;
after the line selection is completed, the fault processing controller sends out a switching-off instruction of a switch of the rapid single-phase vacuum circuit breaker DL1, the grounding is withdrawn and is changed to be restored to the operation of a system which is not grounded, and meanwhile, the fault processing controller sends out a fault phase switching-on instruction of the three-phase control rapid circuit breaker DL2 to forcibly extinguish a fault point arc.
Preferably, when the execution unit adopts the nonlinear self-control unit FR, the three-phase control quick breaker DL2 is in a switching-off state in the normal operation process of the system, the system operates in a neutral point grounding mode, the nonlinear resistance carried by the nonlinear self-control unit FR and the high-impedance grounding transformer GJBC is in a high-impedance state, the device is in no-load operation, the system is in a small-current grounding system operation mode, the bus voltage is monitored through the voltage transformer YH, and meanwhile, the full-voltage monitoring and fault wave recording controller collects and analyzes the zero sequence current of each feeder circuit;
when a single-phase earth fault occurs, the full-voltage monitoring and fault wave recording controller judges the earth fault by adopting a U-I double-criterion compound algorithm through YH signal mutation of a voltage transformer and acquisition and analysis of zero sequence current signals of each feeder line loop, when the current passing through a nonlinear self-control unit FR reaches a preset bearing large current value, the voltage on the nonlinear self-control unit FR is basically constant, instant current is injected into the zero sequence loop of a fault line, and the instant current injection method line selection controller accurately selects the fault line through a maximum increment method and a fusion method;
after the line selection is completed, the fault processing controller sends out a fault phase switching-on instruction of the three-phase control rapid breaker DL2, and the fault point arc is forcibly extinguished.
Preferably, the U-I double-criterion compound algorithm is implemented by comparing the normal working voltage U of the circuit with the abrupt circuit voltageAnd analyzing the collected zero sequence current change condition, and combining the two to comprehensively judge whether the whole power system has the ground fault.
Preferably, the maximum increment method and the fusion method are to detect the maximum increment of the instantaneous current and the line position when the amplitude of the instantaneous current is maximum after the instantaneous current is injected into the line selection controller, and the line position is the fault line.
The invention also provides a reliable line selection device for the neutral point nonlinear resistor grounding, which comprises a cabinet body and is characterized in that: the high-impedance grounding transformer, the execution unit, the band-pass sensor, the zero sequence current transformer and the instantaneous current injection method line selection controller are fixedly installed in the cabinet body, one side of the cabinet body is fixedly provided with a wiring sleeve, the middle part of the cabinet body is fixedly provided with an isolation handcart for installing a fusing protection element, and the quick single-phase vacuum circuit breaker comprises a shell, a vacuum circuit breaker fixedly installed on the shell and a control mechanism which is internally arranged in the shell and used for controlling the opening and closing of the vacuum circuit breaker.
Preferably, the control mechanism comprises a box body fixedly mounted in the shell and a fixed shaft fixedly mounted in the shell, a fixed cylinder is fixedly mounted on the outer surface of the fixed shaft, a U-shaped electromagnet is fixedly mounted on one side of the inner part of the fixed cylinder, an arc-shaped magnetic metal piece matched with the U-shaped electromagnet is slidably arranged on the other side of the inner wall of the fixed cylinder, an eccentric driving wheel is fixedly mounted on one side of the arc-shaped magnetic metal piece through a fixing piece, and a movable rod is hinged on one side of the eccentric driving wheel through a hinge piece.
Preferably, the inside of box body is connected with the wane through rotating the piece rotation, the one end of wane runs through the box body and extends to the outside of box body, and the one end that the wane extends to the outside of box body is articulated through the one end that eccentric drive wheel was kept away from to articulated elements and movable rod, the inside of box body is provided with the protection subassembly that is used for carrying out earth leakage protection to the actuating lever that control vacuum circuit breaker opened and shut, and the opposite side of wane and protection subassembly's bottom contact.
Preferably, the protection component comprises a limiting frame fixedly installed inside the box body and a sliding rod penetrating through the limiting frame and arranged on the limiting frame in a sliding mode, an insulating ball in contact with a seesaw is fixedly installed at the bottom end of the sliding rod, a hemisphere is fixedly installed at the top end of the sliding rod, a groove is formed in the top of the hemisphere, and the bottom end of an actuating rod for controlling opening and closing of the vacuum circuit breaker extends into the groove.
Preferably, the mounting groove has all been seted up to the inner wall both sides of recess, and the inside of mounting groove is connected with the bull stick through rotating the piece rotation, one side of bull stick surface is through connecting rod fixed mounting has the elastic insulation embracing cover with the actuating lever looks adaptation of control vacuum circuit breaker switching, and the opposite side fixed mounting of bull stick surface has the elasticity rope, the inner wall of mounting groove is fixed with one side of connecting rod through the extension spring.
Preferably, one end of the elastic rope far away from the rotating rod penetrates through the hemispheroid and extends to the outer part of the hemispheroid, and one end of the elastic rope extending to the outer part of the hemispheroid is fixedly connected with the top of the limiting frame through the fixing ring.
The invention provides a neutral point nonlinear resistor grounding protection system and a reliable line selection device. Compared with the prior art, the method has the following beneficial effects:
(1) After the system is grounded, the system is converted into a high-current grounding system through the device, the device accurately selects a fault loop, so that the fault point is processed according to the system requirement, and meanwhile, the system is restored to an initial state, so that the purposes of quick line selection and locking of the fault loop by injecting instantaneous high current into the circuit can be realized, the purpose of quick and safe neutral point grounding protection can be well achieved, the quick fault protection by adopting a quick single-phase vacuum circuit breaker and matching with other controllers is realized, the safety is greatly improved, the ground fault inquiry is simple and quick, and the risk of short-circuit accidents is greatly reduced.
(2) The neutral point nonlinear resistor grounding protection system and the reliable line selection device can effectively reduce the probability of two different-place short circuits or inter-phase short circuits formed by the system due to grounding, avoid accidents of the system and have obvious economic benefits.
(3) This neutral point nonlinear resistor ground connection protection system and reliable route selection device through setting up protection component in quick single-phase vacuum circuit breaker, realizes carrying out safety protection to the position that control switch opened and shut in the quick single-phase vacuum circuit breaker, solves the problem of the electric leakage risk that quick single-phase vacuum circuit breaker itself exists, when needs quick single-phase vacuum circuit breaker to close a floodgate, only need go up a protection component, make protection component only wrap vacuum switch's actuating lever, make the more reliable and stable of closing a floodgate, and when quick single-phase vacuum circuit breaker does not need to close a floodgate, protection component resets to protection component does not contact with vacuum switch's actuating lever, avoids from vacuum switch actuating lever to whole quick single-phase vacuum circuit breaker's electric leakage risk, thereby has made things convenient for people to carry out electric power safety operation greatly.
Drawings
FIG. 1 is a circuit diagram of a neutral point nonlinear resistor ground protection system in embodiment 1 of the present invention;
FIG. 2 is a circuit diagram of a neutral nonlinear resistor ground protection system in embodiment 2 of the present invention;
FIG. 3 is a schematic diagram of the neutral point nonlinear resistor grounding protection system of the present invention when a transient high current is injected;
FIG. 4 is a schematic diagram of the neutral point nonlinear resistor ground protection system of the present invention when arc extinction is performed;
fig. 5 is a front view showing the structure of a wire selecting device in embodiment 1 of the present invention;
fig. 6 is a rear view showing the structure of the wire selecting device in embodiment 1 of the present invention;
FIG. 7 is a side view of the interior of the wire selecting device of embodiment 1 of the present invention;
fig. 8 is a sectional view of a fast single-phase vacuum circuit breaker according to embodiment 1 of the present invention;
FIG. 9 is a schematic view showing the structure of a fixed shaft, a fixed cylinder and an eccentric driving wheel in embodiment 1 of the present invention;
fig. 10 is a schematic structural diagram of a protection component in embodiment 1 of the present invention.
In the figure, 1 cabinet body, 2 high impedance grounding transformers, 3 quick single-phase vacuum circuit breakers, 31 shell, 32 vacuum circuit breakers, 33 control mechanism, 331 box body, 332 fixed shaft, 333 fixed cylinder, 334U shape electromagnet, 335 arc magnetic metal piece, 336 eccentric driving wheel, 337 movable rod, 338 wane, 339 protection component, 3391 limit frame, 3392 slide bar, 3393 insulating ball, 3394 hemisphere, 3395 groove, 3396 mounting groove, 3397 rotating rod, 3398 elastic insulating embracing sleeve, 3399 elastic rope, 33910 tension spring, 4 band electric sensor, 5 zero sequence current transformer, 6 instantaneous current injection method line selection controller, 7 wiring sleeve and 8 isolation handcart.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1-3, the embodiments of the present invention provide two technical solutions, specifically as follows:
a neutral point nonlinear resistor grounding protection system comprises an isolation handcart GL, a high-impedance grounding transformer GJBC, a rapid single-phase vacuum circuit breaker DL1, a three-phase-control rapid circuit breaker DL2, a charged sensor CGQ, a zero sequence current transformer LH, a voltage transformer YH, a first fuse FU, a second fuse RD, a six-column overvoltage protector WH6B, a primary arc suppressor XXQ, an instantaneous current injection method line selection controller, a fault processing controller and a full-voltage monitoring and fault recording controller;
when the system normally operates, the rapid single-phase vacuum circuit breaker DL1 and the three-phase control rapid circuit breaker DL2 are in a switching-off state, the system operates in a mode that a neutral point is not grounded, a nonlinear resistor carried by a high-impedance grounding transformer GJBC is in a high-impedance state, the device is in a no-load operation mode, the system is in a mode that a low-current grounding system operates, bus voltage is monitored through a voltage transformer YH, the functions of a common PT cabinet are met, an alarm function is provided for system voltage out-of-limit faults, and a full-voltage monitoring and fault wave recording controller collects and analyzes zero sequence currents of feeder circuits;
when single-phase earth fault occurs, the full-voltage monitoring and fault wave recording controller accurately judges the earth fault within 20ms by adopting a U-I double-criterion compound algorithm through the YH signal mutation of the voltage transformer and the acquisition and analysis of zero sequence current signals of each feeder circuit, and sends a closing instruction of the rapid single-phase vacuum circuit breaker DL 1. The rapid single-phase vacuum circuit breaker DL1 is switched on and put into the grounding transformer within 10ms, the system is converted into a high-current grounding system, the zero sequence loop of the fault line is injected with instantaneous current, the line selection controller of the instantaneous current injection method accurately selects the fault line within 10ms through a maximum increment method and a fusion method,
after the line selection is completed, the fault processing controller sends out a switching-off instruction of a switch of the rapid single-phase vacuum circuit breaker DL1, the grounding is withdrawn within 10ms to enable the attraction to be restored to the operation of an ungrounded system, meanwhile, the fault processing controller sends out a fault phase switching-on instruction of the three-phase control rapid circuit breaker DL2, the three-phase control rapid circuit breaker DL2 switches on a fault phase within 20ms, an arc of a fault point is forcedly extinguished, arc grounding overvoltage is effectively controlled, and cable blasting and interphase short-circuit tripping accidents are avoided; meanwhile, the intervention type arc extinction function can also avoid the accidents of step voltage or serious human body injury caused by electric shock of a human body due to falling of the lead.
When ferromagnetic resonance occurs, the PTK device connected in parallel with the primary harmonic eliminator LXQ of the nonlinear resistor is disconnected, and the nonlinear resistor is connected in series between the primary neutral point of the voltage transformer and the ground to isolate a resonant circuit; in a normal operation state, the PTK device is connected in parallel to bypass the primary harmonic eliminator LXQ, so that an operation mode of primary neutral point grounding of the voltage transformer is ensured, and unreliable operation of the system caused by rising of the neutral point voltage is avoided.
In the embodiment of the invention, the U-I double-criterion compound algorithm is implemented by comparing the normal working voltage U of a circuit with the abrupt voltage of the circuitAnd analyzing the collected zero sequence current change condition, and combining the two to comprehensively judge whether the whole power system has the ground fault.
In the embodiment of the invention, the maximum increment method and the fusion method are to detect the maximum increment of the instantaneous current and the line position when the amplitude of the instantaneous current is maximum after the instantaneous current is injected into the line selection controller, and the line position is the fault line.
As shown in fig. 4-6, the embodiment of the invention further provides a reliable line selection device, which comprises a cabinet body 1, a high-impedance grounding transformer 2, a rapid single-phase vacuum circuit breaker 3, a band electric sensor 4, a zero sequence current transformer 5 and an instantaneous current injection method line selection controller 6 which are fixedly installed in the cabinet body 1, wherein a wiring sleeve 7 is fixedly installed on one side of the cabinet body 1, an isolation handcart 8 for installing a fusing protection element is fixedly installed in the middle of the cabinet body 1, and the rapid single-phase vacuum circuit breaker 3 comprises a shell 31, a vacuum circuit breaker 32 fixedly installed on the shell 31 and a control mechanism 33 which is internally installed in the shell 31 and used for controlling the opening and closing of the vacuum circuit breaker 32.
As shown in fig. 7 and 8, in the embodiment of the present invention, the control mechanism 33 includes a case 331 fixedly installed in the case 31 and a fixing shaft 332 fixedly installed in the case 31, a fixing cylinder 333 is fixedly installed on an outer surface of the fixing shaft 332, a U-shaped electromagnet 334 is fixedly installed on one side of an inner portion of the fixing cylinder 333, an arc-shaped magnetic metal member 335 adapted to the U-shaped electromagnet 334 is slidably disposed on the other side of an inner wall of the fixing cylinder 333, an eccentric driving wheel 336 is fixedly installed on one side of the arc-shaped magnetic metal member 335, a movable rod 337 is hinged on one side of the eccentric driving wheel 336 through a hinge, a rocker 338 is rotatably connected to an inner portion of the case 331 through a rotating member, one end of the rocker 338 extends through the case 331 and extends to an outer portion of the case 331, one end of the rocker 338 extending to the outer portion of the case 331 is hinged to one end of the movable rod 337 away from the eccentric driving wheel 336 through the hinge, a protection component 339 for protecting an execution rod for opening and closing the vacuum break switch 32 is disposed inside the case 331, and the other side of the rocker 338 contacts with a bottom of the protection component 339.
As shown in fig. 9, in the embodiment of the present invention, the protection component 339 includes a limiting frame 3391 fixedly installed inside the box 331 and a sliding rod 3392 penetrating through and slidably disposed on the limiting frame 3391, an insulating ball 3393 contacting with a rocker 338 is fixedly installed at the bottom end of the sliding rod 3392, a hemisphere 3394 is fixedly installed at the top end of the sliding rod 3392, a groove 3395 is provided at the top of the hemisphere 3394, the bottom end of an actuating rod controlling opening and closing of the vacuum break switch 32 extends into the groove 3395, both sides of the inner wall of the groove 3395 are provided with mounting grooves 3396, the inside of the mounting grooves 3396 is rotatably connected with a rotating rod 3397 through a rotating member, one side of the outer surface of the rotating rod 3397 is fixedly installed with an elastic insulating sleeve 3398 adapted to the actuating rod controlling opening and closing of the vacuum break switch 32 through a connecting rod, an elastic rope 3399 is fixedly installed at the other side of the outer surface of the rotating rod 3397, the position of the elastic rope 3399 fixed on the rotating rod 3397 is located at a symmetrical position of the fixed connecting rod, and accordingly the connecting rod can rotate by pulling the elastic rope 3399, the inner wall of the mounting grooves 3396 extends to one end of the hemisphere 3394 far from the outer end of the connecting rod 3394 through the elastic sleeve 3397, which extends to one end of the elastic rope 3394 through the fixed end of the connecting rod 3394.
In an initial state, namely, the rapid single-phase vacuum circuit breaker 3 is in a switching-off state, the U-shaped electromagnet 334 generates repulsive force to the arc-shaped magnetic metal part 335, the arc-shaped magnetic metal part 335 is in a static state in the fixed cylinder 333, at the moment, the protruding part of the eccentric driving wheel 336 is at the highest point, when the rapid single-phase vacuum circuit breaker 3 is ready to switch on, the U-shaped electromagnet 334 is controlled to generate attractive force to the arc-shaped magnetic metal part 335, the arc-shaped magnetic metal part 335 is rapidly adsorbed in the fixed cylinder 333, meanwhile, the protruding part of the eccentric driving wheel 336 rapidly rotates to the lowest point from the highest point under the action of self gravity and the attractive force of the U-shaped electromagnet 334, the eccentric driving wheel 336 pushes the insulating ball 3393 up through the movable rod 337 and the rocker 338, the insulating ball 3393 drives the hemispherical 3394 to move upwards through the sliding rod 3392, and the elastic rope 3399 is pulled in the hemispherical 3394 moving upwards process, so that the rotating rod 3397 rotates, and the elastic insulating sleeve 3398 is tightly closes to the actuating rod at the bottom end of the vacuum circuit breaker 32 until the actuating rod is tightly wrapped, and the actuating rod moves upwards along with the whole protection assembly, so that the vacuum circuit breaker 339 is switched on the vacuum circuit breaker 32.
The neutral point nonlinear resistor grounding protection system shown in fig. 2 comprises a high-impedance grounding transformer GJBC, a nonlinear self-control unit FR, a three-phase control rapid circuit breaker DL2, a zero sequence current transformer LH, a voltage transformer YH, an instantaneous current injection method line selection controller and a full-voltage monitoring and fault wave recording controller.
When the system normally operates, the three-phase control quick breaker DL2 is in a switching-off state, the system operates in a neutral point grounding mode, the nonlinear resistance carried by the nonlinear self-control unit FR and the high-impedance grounding transformer GJBC is in a high-impedance state, the device is in an idle running mode, the system is in a small-current grounding system operating mode, the voltage of a bus is monitored through a voltage transformer YH, and meanwhile, the full-voltage monitoring and fault wave recording controller collects and analyzes zero sequence currents of feeder circuits;
when a single-phase earth fault occurs, the full-voltage monitoring and fault wave recording controller judges the earth fault by adopting a U-I double-criterion compound algorithm through YH signal mutation of a voltage transformer and acquisition and analysis of zero sequence current signals of each feeder line loop, when the current passing through a nonlinear self-control unit FR reaches a preset bearing large current value, the voltage on the nonlinear self-control unit FR is basically constant, instant current is injected into the zero sequence loop of a fault line, and the instant current injection method line selection controller accurately selects the fault line through a maximum increment method and a fusion method;
after the line selection is completed, the fault processing controller sends out a fault phase switching-on instruction of the three-phase control rapid breaker DL2, and the fault point arc is forcibly extinguished.
In the embodiment of the invention, the U-I double-criterion compound algorithm is implemented by comparing the normal working voltage U of a circuit with the abrupt voltage of the circuitAnd analyzing the collected zero sequence current change condition, and combining the two to comprehensively judge whether the whole power system has the ground fault.
In the embodiment of the invention, the maximum increment method and the fusion method are to detect the maximum increment of the instantaneous current and the line position when the amplitude of the instantaneous current is maximum after the instantaneous current is injected into the line selection controller, and the line position is the fault line.
In the embodiment of the present invention, the nonlinear self-control unit FR is a nonlinear variable resistor, and is in a high-resistance state in a certain voltage range, and is in a low-resistance state when the voltage on the nonlinear self-control unit FR is preset, and the current on the nonlinear self-control unit FR is kept substantially constant, which is the characteristic of the nonlinear self-control unit FR.
And all that is not described in detail in this specification is well known to those skilled in the art.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (7)
1. A neutral point nonlinear resistor ground protection system is characterized in that: the device comprises a high-impedance grounding transformer GJBC, an execution unit, a three-phase control rapid circuit breaker DL2, a zero sequence current transformer LH, a voltage transformer YH, an instantaneous current injection method line selection controller, a fault processing controller and a full-voltage monitoring and fault wave recording controller, wherein the execution unit is one of a rapid single-phase vacuum circuit breaker DL1 or a nonlinear self-control unit FR;
when the execution unit adopts a rapid single-phase vacuum breaker DL1, in the normal operation process of the system, the rapid single-phase vacuum breaker DL1 and a three-phase control rapid breaker DL2 are in a switching-off state, the system operates in a mode that a neutral point is not grounded, a nonlinear resistor carried by a high-impedance grounding transformer GJBC is in a high-impedance state, the device is in an idle running mode, the system is in a low-current grounding system operation mode, the bus voltage is monitored through a voltage transformer YH, and a full-voltage monitoring and fault wave recording controller collects and analyzes zero sequence current of each feeder line loop;
when a single-phase grounding fault occurs, the full-voltage monitoring and fault wave recording controller judges the grounding fault by adopting a U-I double-criterion compound algorithm through voltage transformer YH signal mutation and acquisition and analysis of zero sequence current signals of each feeder circuit, and sends a closing instruction of a rapid single-phase vacuum circuit breaker DL1, so that the system is converted into a high-current grounding system, instantaneous current is injected into the zero sequence circuit of a fault circuit, and the fault circuit is accurately selected by an instantaneous current injection method line selection controller through a maximum increment method and an injection current amplitude maximum method;
after the line selection is completed, the fault processing controller sends out a switching-off instruction of a switch of the rapid single-phase vacuum circuit breaker DL1, the grounding is withdrawn and is changed to be restored to the operation of a non-grounding system, and meanwhile, the fault processing controller sends out a fault phase switching-on instruction of the three-phase control rapid circuit breaker DL2 to forcibly extinguish a fault point arc;
meanwhile, the full-voltage monitoring and fault wave recording controller monitors the voltage states before and after faults occur in the whole process, and data are provided for fault analysis;
when the execution unit adopts the nonlinear self-control unit FR, the three-phase control rapid circuit breaker DL2 is in a switching-off state in the normal operation process of the system, the system operates in a neutral point grounding mode, the nonlinear resistance carried by the nonlinear self-control unit FR and the high-impedance grounding transformer GJBC is in a high-resistance state, the device is in no-load operation, the system is in a small-current grounding system operation mode, the bus voltage is monitored through the voltage transformer YH, and the full-voltage monitoring and fault wave recording controller collects and analyzes the zero sequence current of each feeder circuit;
when a single-phase earth fault occurs, the full-voltage monitoring and fault wave recording controller judges the earth fault by adopting a U-I double-criterion compound algorithm through YH signal mutation of a voltage transformer and acquisition and analysis of zero sequence current signals of each feeder line loop, when the current passing through a nonlinear self-control unit FR reaches a preset bearing large current value, the voltage on the nonlinear self-control unit FR keeps constant along with the increase of the current, the instantaneous current is injected into the zero sequence loop of a fault line, and the instantaneous current injection method line selection controller accurately selects the fault line by a maximum increment method and a fusion method;
after the line selection is completed, the fault processing controller sends out a fault phase switching-on instruction of the three-phase control rapid breaker DL2, and the arc at the fault point is forcedly extinguished;
meanwhile, the full-voltage monitoring and fault wave recording controller monitors the voltage states before and after faults occur in the whole process, and data are provided for fault analysis;
the U-I double-criterion compound algorithm is implemented by comparing the normal working voltage U of a circuit with the abrupt circuit voltage U Variable Analyzing the acquired zero sequence current variation condition, and combining the two to comprehensively judge whether the whole power system has a ground fault or not;
the maximum increment method and the fusion method are to detect the maximum increment of the instantaneous current and the line position when the amplitude of the instantaneous current is maximum after the instantaneous current is injected into the line selection controller, and the line position is the fault line.
2. A reliable line selection device for the neutral point nonlinear resistor ground protection system recited in claim 1, comprising a cabinet, characterized in that: the high-impedance grounding transformer, the quick single-phase vacuum circuit breaker, the band-pass sensor, the zero sequence current transformer and the instantaneous current injection method line selection controller are fixedly arranged in the cabinet body, one side of the cabinet body is fixedly provided with a wiring sleeve, the middle part of the cabinet body is fixedly provided with an isolation handcart for installing a fusing protection element, and the quick single-phase vacuum circuit breaker comprises a shell, a vacuum circuit breaker fixedly arranged on the shell and a control mechanism which is arranged in the shell and used for controlling the opening and closing of the vacuum circuit breaker.
3. A reliable line selection device for neutral point nonlinear resistor grounding according to claim 2, characterized in that: the control mechanism comprises a box body fixedly installed in the shell and a fixed shaft fixedly installed in the shell, a fixed cylinder is fixedly installed on the outer surface of the fixed shaft, a U-shaped electromagnet is fixedly installed on one side of the inner portion of the fixed cylinder, an arc-shaped magnetic metal piece matched with the U-shaped electromagnet is slidably arranged on the other side of the inner wall of the fixed cylinder, an eccentric driving wheel is fixedly installed on one side of the arc-shaped magnetic metal piece through the fixed piece, and a movable rod is hinged to one side of the eccentric driving wheel through a hinge piece.
4. A reliable line selection device for neutral point nonlinear resistor grounding according to claim 3, characterized in that: the inside of box body is connected with the wane through rotating the piece rotation, the one end of wane runs through the box body and extends to the outside of box body, and the wane extends to the outside one end of box body and keep away from eccentric drive wheel through articulated elements and movable rod and articulate, the inside of box body is provided with the protection subassembly that is used for carrying out earth leakage protection to the actuating lever that control vacuum circuit breaker opened and shut, and the opposite side of wane and the bottom contact of protection subassembly.
5. The reliable line selection device with neutral point nonlinear resistor grounding according to claim 4, wherein: the protection component comprises a limiting frame fixedly installed inside the box body and a sliding rod penetrating through the limiting frame, wherein the sliding rod is arranged on the limiting frame in a sliding mode, an insulating ball in contact with a rocker is fixedly installed at the bottom end of the sliding rod, a hemisphere is fixedly installed at the top end of the sliding rod, a groove is formed in the top of the hemisphere, and the bottom end of an actuating rod for controlling opening and closing of the vacuum circuit breaker extends into the groove.
6. The reliable line selection device with neutral point nonlinear resistor grounding according to claim 5, wherein: the installation groove has all been seted up to the inner wall both sides of recess, and the inside of installation groove is connected with the bull stick through rotating the piece rotation, one side of bull stick surface is through connecting rod fixed mounting have with the elastic insulation of the actuating lever looks adaptation of control vacuum circuit breaker switching, and the opposite side fixed mounting of bull stick surface has the elastic rope, the inner wall of installation groove is fixed with one side of connecting rod through the extension spring.
7. The reliable line selection device for neutral point nonlinear resistor grounding of claim 6, wherein: one end of the elastic rope far away from the rotating rod penetrates through the hemispheroid and extends to the outer part of the hemispheroid, and one end of the elastic rope extending to the outer part of the hemispheroid is fixedly connected with the top of the limiting frame through the fixing ring.
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