CN112670971A - One-way earth fault comprehensive processing system - Google Patents
One-way earth fault comprehensive processing system Download PDFInfo
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- CN112670971A CN112670971A CN202011479504.8A CN202011479504A CN112670971A CN 112670971 A CN112670971 A CN 112670971A CN 202011479504 A CN202011479504 A CN 202011479504A CN 112670971 A CN112670971 A CN 112670971A
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- 238000005070 sampling Methods 0.000 claims abstract description 18
- 238000012544 monitoring process Methods 0.000 claims abstract description 5
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- 238000004458 analytical method Methods 0.000 claims description 6
- 238000004891 communication Methods 0.000 claims description 6
- 239000012212 insulator Substances 0.000 claims description 4
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- 238000009413 insulation Methods 0.000 description 4
- 238000012546 transfer Methods 0.000 description 4
- 230000016507 interphase Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
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- 230000008033 biological extinction Effects 0.000 description 2
- 238000010891 electric arc Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 230000008030 elimination Effects 0.000 description 2
- 238000003379 elimination reaction Methods 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention discloses a one-way grounding fault comprehensive processing system, which is characterized in that: a neutral point is led out of the grounding transformer and is connected with the ground through a monostable switch, a zero sequence current transformer is installed on each branch circuit, an outgoing line loop of each branch circuit is connected with a synchronous sampling unit through a zero sequence current synchronous sampling channel, a one-way vacuum contactor is connected with a high-voltage current-limiting fuse and an arc suppression equipment isolating switch in series and then is communicated with a main circuit, the one-way vacuum contactor is electrically connected with a pulse arc suppression coil and then is connected with the neutral point, a PT fuse is connected with a voltage transformer in series and then is connected with the synchronous sampling unit and the grounding transformer, the synchronous sampling unit is connected with a main controller, and the main controller is connected with a background; the invention utilizes the mutual cooperation of the unidirectional vacuum contactor and the pulse type arc suppression coil for mutual protection, improves the safety and reliability of system power supply, and integrates single-phase grounding arc suppression and harmonic suppression treatment and high-speed synchronous acquisition, monitoring and wave recording of a power grid.
Description
Technical Field
The invention relates to the technical field of safety electricity utilization, in particular to a one-way grounding fault comprehensive processing system.
Background
In 3-35KV medium-voltage power transmission and distribution systems in China, most of the systems adopt a mode that a neutral point is not directly grounded, namely the neutral point is not grounded or is grounded through an arc suppression coil. The neutral point is not directly grounded, and the system line voltage can still keep three-phase symmetry without influencing the normal work of the electric equipment under the single-phase grounding state. Therefore, the power supply reliability of the power transmission and distribution system adopting the neutral point non-direct grounding mode is far higher than that of the power transmission and distribution system adopting the neutral point direct grounding mode, which is the greatest advantage of the neutral point non-direct grounding mode and is the basic reason for the long-standing use of the grounding mode in the medium-voltage power transmission and distribution system in China. However, from years of operational experience and recent development of medium voltage transmission and distribution systems, the way in which the neutral point is not directly grounded also causes some problems to the medium voltage transmission and distribution system: the system with the neutral point not directly grounded is easy to have high-voltage oscillation, so that various overvoltage is caused.
When a single-phase earth fault occurs in a system in which the neutral point is not directly grounded, it is generally in the form of an arc ground. The voltage to ground of the non-faulted phase line can be raised to 3.5 times rated phase voltage at the most. Such overvoltages throughout the system tend to cause flashovers to ground at points of system insulation weakness. Meanwhile, the grounding electric arc easily burns the line insulation at the grounding part, particularly the cable line, the grounding electric arc easily burns the interphase insulation of the cable to cause the interphase short circuit of the cable, and the 'blasting' of the cable is caused, and in addition, in the arc grounding process, the system is caused to generate violent electromagnetic oscillation by the change of the electromagnetic parameters of the system. In the oscillation process, charging and discharging currents of a system ground capacitor can form a loop through a neutral point of a voltage transformer in the system when an arc is extinguished and a fault is eliminated. The current is often far larger than the rated current of the voltage transformer, so that the iron core of the transformer is saturated, the primary side current is increased rapidly, the fuse of the voltage transformer is fused, and even the voltage transformer is burnt; it is difficult to determine the branch in which the single-phase ground fault occurs. In the single-phase earth fault line selection device based on the small current line selection principle in the market, when a system has a single-phase earth fault, the size and the direction of zero-sequence capacitance current flowing through each branch are collected, and the branch with the single-phase earth fault is determined by different analysis methods. When the device is applied to a system with a neutral point grounded through an arc suppression coil, the original line selection device based on the power direction line selection principle cannot be used.
The existing fault voltage monitoring device can not truly record and analyze transient overvoltage of arc light, electricity, operation and the like suffered by a system.
In order to solve the problems, the application group develops an earth fault comprehensive processing system, when a single-phase earth fault occurs in a system which is not directly earthed at a neutral point, the earth fault comprehensive processing system has 100% accuracy of rapid line selection, single-phase earth comprehensive arc extinction and resonance elimination processing and high-speed synchronous acquisition, monitoring and wave recording of a power grid.
Disclosure of Invention
The invention mainly aims to provide a one-way grounding fault comprehensive processing system which can effectively solve the problems in the background technology.
In order to achieve the purpose, the invention adopts the technical scheme that: a one-way earth fault integrated processing system is characterized in that: the grounding transformer is led out a neutral point and is connected with the ground through the monostable switch, the zero sequence current transformer is arranged on each branch, an outlet loop of each branch is connected with the synchronous sampling unit through a zero sequence current synchronous sampling channel, the one-way vacuum contactor is connected with the main trunk after being connected with the high voltage current limiting fuse and the arc suppression device isolating switch in series and is connected with the neutral point after being electrically connected with the pulse type arc suppression coil, the grounding transformer is connected with the main transformer through the grounding transformer isolating switch, and the PT fuse is connected with the synchronous sampling unit and the grounding transformer after being connected with the voltage transformer in series, the synchronous sampling unit is connected with a main controller, the main controller is connected with a background monitor and a mobile terminal, and the main controller is connected with the established cloud database.
Preferably, main control unit is equipped with RS485 communication interface, is equipped with standard MODBUS communication protocol and is connected with monitored control system, realizes data transfer.
Preferably, the main controller adopts a 32-bit high-performance double CPU, a 7-inch wide-screen industrial color liquid crystal touch display screen and a windowed voltage fault recording analysis system.
Preferably, the main controller can synchronously acquire 24 channel currents and voltages at a high speed at a rate of 12.8 k.
Preferably, the pulse type arc suppression coil can supplement system electric capacitance current and suppress system overvoltage.
Preferably, the monostable switch includes an insulating shell and an external shell, a vacuum arc extinguish chamber is installed in the insulating shell, a movable conducting rod and a fixed conducting rod are installed in the vacuum arc extinguish chamber respectively, the ends of the movable conducting rod and the fixed conducting rod are connected with a movable contact and a fixed contact respectively, the end of the movable conducting rod, which is located outside the vacuum arc extinguish chamber, is fixedly connected with a connecting rod through an insulator, the lower end of the connecting rod is fixedly connected with an eddy current disc, the end face of the eddy current disc is close to a closing coil, the closing coil is installed on the external shell, the outer ring of the connecting rod is fixedly connected with a tension plate, the tension plate is connected with a support plate through a reset spring, the support plate is fixedly connected with the external shell, and the side wall of the movable conducting rod is electrically.
Compared with the prior art, the invention has the following beneficial effects: according to the invention, the neutral point is led out through the grounding transformer and is grounded through the monostable switch, when a single-phase grounding fault occurs, the main controller can rapidly trigger the monostable switch to carry out current conversion, rapidly judge a fault branch circuit, mutually cooperate and protect by utilizing the one-way vacuum contactor and the pulse type arc suppression coil, the safety and reliability of system power supply are improved, and single-phase grounding comprehensive arc suppression and harmonic elimination processing and high-speed synchronous acquisition, monitoring and wave recording of a power grid are realized.
Drawings
FIG. 1 is an overall system schematic of the present invention;
FIG. 2 is a schematic diagram of the overall system data delivery of the present invention;
fig. 3 is a schematic cross-sectional view of a monostable switch of the invention.
In the figure: 1. a main controller; 2. a synchronous sampling unit; 3. a zero sequence current transformer; 4. a grounding transformer; 5. a main transformer; 6. a grounding transformer isolating switch; 7. an arc extinction device isolating switch; 8. a high voltage current limiting fuse; 9. a one-way vacuum contactor; 10. a pulse type arc suppression coil; 11. a monostable switch; 111. an insulating case; 112. a vacuum arc-extinguishing chamber; 113. a movable conductive rod; 114. fixing a conducting rod; 115. a moving contact; 116. fixing a contact; 117. a vortex disk; 118. a closing coil; 119. a connecting rod; 1110. a return spring; 1111. a support plate; 1112. an external connection shell; 1113. an insulator; 1114. a tension plate; 1115. a soft conductive wire; 12. a PT fuse; 13. a voltage transformer; 14. a background monitor; 15. a mobile terminal; 16. and (4) a cloud database.
Detailed Description
In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.
As shown in fig. 1 to 3, a unidirectional ground fault comprehensive processing system is characterized in that: the grounding transformer 4 is led out a neutral point and is connected with the ground through the monostable switch 11, the zero sequence current transformer 3 is arranged on each branch, an outgoing line loop of each branch is connected with the synchronous sampling unit 2 through a synchronous sampling channel of the pulse type arc suppression coil, the one-way vacuum contactor 9 is connected with the main trunk circuit after being connected with the high voltage current limiting fuse and the arc suppression device isolation switch in series, the one-way vacuum contactor 9 is connected with the neutral point after being electrically connected with the pulse type arc suppression coil 10, and the grounding transformer 4 is connected with the main transformer 5 through the zero sequence grounding isolation switch 6, PT fuse is connected with synchronous sampling unit 2 and grounding transformer 4 after establishing ties with voltage transformer 13, synchronous sampling unit 2 is connected with main control unit 1, main control unit 1 is connected with backstage monitoring machine 14 and removal end 15 to main control unit 1 is connected with the cloud database 16 of establishing.
When a certain branch of the system has a ground fault, the main controller 1 detects a ground signal and then rapidly triggers the monostable switch 11, a half-wave current with controllable same phase with the system flows through a fault branch, the main controller 1 collects and compares current waveforms of zero sequence current transformers 3 of all branch outgoing line loops through the synchronous sampling unit 2, judges fault branches, fault types and fault time, adopts different working modes according to the property of the ground fault, mutually cooperates and protects the pulse arc suppression coil 10 and the one-way vacuum contactor 9 to improve the reliability and the safety of system power supply, when the one-way ground fault occurs, the main controller 1 rapidly starts the fault phase vacuum contactor after completing line selection, the vacuum contactor transfers the high-frequency ground capacitance current flowing through a fault point, eliminates the system arc light overvoltage, and then tunes the pulse arc suppression coil 10, the vacuum contactor of the fault phase is disconnected, and in the opening process of the vacuum contactor, the pulse type arc suppression coil 10 supplements system grounding capacitance current, so that the system grounding capacitance current is prevented from flowing through a fault point again, the fault branch is prevented from being converted into an interphase short circuit accident from a one-way grounding fault, and the operation overvoltage generated when the vacuum contactor is opened can be effectively prevented; if the insulation of the fault point is recovered, the system normally operates, the whole system quits the pulse type arc suppression coil 10, if the fault point is not recovered, the whole system rapidly starts the fault phase vacuum contactor again to transfer the current of the fault point, then the pulse type arc suppression coil 10 is discharged, and the system is ensured to continuously supply power for 2 hours. Simultaneously main control unit 1 record ripples, analysis, processing are carried out to the fault condition of electric power system and the voltage waveform when suffering the impact such as thunder and lightning, operation, earth fault, the current waveform in all return circuits is complete, uploads to high in the clouds database and removes end 15, and convenience of customers in time seeks when the trouble takes place, handles the fault recovery power supply, and further analysis electric power system's operating condition after the trouble takes place avoids the trouble to take place once more.
In this embodiment, main control unit 1 is equipped with RS485 communication interface, is equipped with standard MODBUS communication protocol and is connected with monitored control system, realizes data transfer.
In this embodiment, the main controller 1 adopts a 32-bit high-performance dual CPU, a 7-inch wide-screen industrial color liquid crystal touch display screen, and has a windowed voltage fault recording analysis system.
In this embodiment, the main controller 1 can synchronously acquire 24 channel currents and voltages at a high speed at a rate of 12.8 k.
In this embodiment, the pulse arc suppression coil 10 can supplement system power capacitor current and suppress system overvoltage.
In this embodiment, the monostable switch 11 includes an insulating housing 111 and an outer housing 1112, a vacuum arc-extinguishing chamber 112 is arranged in the insulating shell 111, a movable conducting rod 113 and a fixed conducting rod 114 are respectively arranged in the vacuum arc-extinguishing chamber 112, the ends of the moving conductive rod 113 and the fixed conductive rod 114 are respectively connected with a moving contact 115 and a fixed contact 116, the end of the movable conducting rod 113 outside the vacuum interrupter 112 is fixedly connected to a connecting rod 119 through an insulator 1113, the end part of the lower end of the connecting rod 119 is fixedly connected with an eddy disk 117, the end surface of the eddy disk 117 is close to a closing coil 118, the closing coil 118 is mounted on the outer shell 1112, the outer ring of the connecting rod 119 is fixedly connected with the tension plate 1114, the tension plate 1114 is connected with a support 1111 through a return spring 1110, the support 1111 is fixedly connected with an external casing 1112, and the side wall of the movable conducting rod 113 is electrically connected with a flexible conducting wire 1115.
While certain exemplary embodiments of the present invention have been described above by way of illustration only, it will be apparent to those of ordinary skill in the art that the described embodiments may be modified in various different ways without departing from the spirit and scope of the invention. Accordingly, the drawings and description are illustrative in nature and should not be construed as limiting the scope of the invention.
Claims (6)
1. A one-way earth fault integrated processing system is characterized in that: the grounding transformer is led out a neutral point and is connected with the ground through the monostable switch, the zero sequence current transformer is arranged on each branch, an outlet loop of each branch is connected with the synchronous sampling unit through a zero sequence current synchronous sampling channel, the one-way vacuum contactor is connected with the main trunk after being connected with the high voltage current limiting fuse and the arc suppression device isolating switch in series and is connected with the neutral point after being electrically connected with the pulse type arc suppression coil, the grounding transformer is connected with the main transformer through the grounding transformer isolating switch, and the PT fuse is connected with the synchronous sampling unit and the grounding transformer after being connected with the voltage transformer in series, the synchronous sampling unit is connected with a main controller, the main controller is connected with a background monitor and a mobile terminal, and the main controller is connected with the established cloud database.
2. A unidirectional ground fault integrated processing system according to claim 1, wherein: the main control unit is provided with an RS485 communication interface and is provided with a standard MODBUS communication protocol to be connected with a monitoring system, and data transmission is achieved.
3. A unidirectional ground fault integrated processing system according to claim 1, wherein: the main controller adopts 32-bit high-performance double CPUs and a 7-inch wide-screen industrial color liquid crystal touch display screen, and is provided with a windowing voltage fault recording analysis system.
4. A unidirectional ground fault integrated processing system according to claim 1, wherein: the main controller can synchronously acquire 24 channel currents and voltages at a high speed at a rate of 12.8 k.
5. A unidirectional ground fault integrated processing system according to claim 1, wherein: the pulse arc suppression coil can supplement system power capacitor current and suppress system overvoltage.
6. A unidirectional ground fault integrated processing system according to claim 1, wherein: the monostable switch comprises an insulating shell and an external shell, a vacuum arc extinguish chamber is installed in the insulating shell, a movable conducting rod and a fixed conducting rod are installed in the vacuum arc extinguish chamber respectively, the ends of the movable conducting rod and the fixed conducting rod are connected with a movable contact and a fixed contact respectively, the end, located outside the vacuum arc extinguish chamber, of the movable conducting rod is fixedly connected with a connecting rod through an insulator, the lower end of the connecting rod is fixedly connected with an eddy current disc, the end face of the eddy current disc is close to a closing coil, the closing coil is installed on the external shell, the outer ring of the connecting rod is fixedly connected with a tension plate, the tension plate is connected with a support plate through a reset spring, the support plate is fixedly connected with the external shell, and the side wall of the movable conducting rod is electrically connected.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011479504.8A CN112670971B (en) | 2020-12-15 | 2020-12-15 | Single-phase earth fault comprehensive treatment system |
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| CN202011479504.8A CN112670971B (en) | 2020-12-15 | 2020-12-15 | Single-phase earth fault comprehensive treatment system |
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| CN112670971A true CN112670971A (en) | 2021-04-16 |
| CN112670971B CN112670971B (en) | 2023-12-08 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116073345A (en) * | 2023-04-06 | 2023-05-05 | 安徽凯民电力技术有限公司 | Intelligent comprehensive grounding management system |
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