CN113049886B - Lightning invasion switch room monitoring method based on current distribution of ground grid - Google Patents

Lightning invasion switch room monitoring method based on current distribution of ground grid Download PDF

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Publication number
CN113049886B
CN113049886B CN202110397931.XA CN202110397931A CN113049886B CN 113049886 B CN113049886 B CN 113049886B CN 202110397931 A CN202110397931 A CN 202110397931A CN 113049886 B CN113049886 B CN 113049886B
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lightning
bus
current
ground
arrester
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CN113049886A (en
Inventor
项宇锴
叶杰
黄鸿标
叶桂中
陈苏芳
林桥玉
郑茂华
肖荣洋
章日欣
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State Grid Fujian Electric Power Co Ltd
Longyan Power Supply Co of State Grid Fujian Electric Power Co Ltd
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State Grid Fujian Electric Power Co Ltd
Longyan Power Supply Co of State Grid Fujian Electric Power Co Ltd
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R29/00Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
    • G01R29/08Measuring electromagnetic field characteristics
    • G01R29/0807Measuring electromagnetic field characteristics characterised by the application
    • G01R29/0814Field measurements related to measuring influence on or from apparatus, components or humans, e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning
    • G01R29/0842Measurements related to lightning, e.g. measuring electric disturbances, warning systems
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/20Measuring earth resistance; Measuring contact resistance, e.g. of earth connections, e.g. plates
    • G01R27/205Measuring contact resistance of connections, e.g. of earth connections
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/52Testing for short-circuits, leakage current or ground faults

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention provides a lightning intrusion switch room monitoring method based on current distribution of a ground grid, which is characterized by comprising the following steps of: the current on the public convergence ground wire of the bus arrester, the bus PT, the grounding transformer and the primary equipment and the secondary side voltage of the bus PT are respectively collected to judge the source of the lightning invasion and the influence on the primary equipment and the secondary equipment. It can effectively monitor the area where lightning strikes occur and whether lightning waves invade the switch room.

Description

Lightning invasion switch room monitoring method based on current distribution of ground grid
Technical Field
The invention relates to the field of operation and maintenance management of power systems, in particular to a lightning invasion switch room monitoring method based on ground grid current distribution.
Background
With the continuous development of society, electric power systems are widely used in production and daily life, electric energy has become a main energy and power for modern industrial production, and ensuring high-quality and stable electric energy supply is one of the work key points of electric power companies. However, in areas with frequent lightning, the transformer substation is subjected to a large-area power failure accident caused by lightning attack, the large-area power failure caused by the lightning attack not only causes inconvenience to users, but also often causes damage to the 10-35 kV switch cabinet of the transformer substation, and the economic loss is serious. Therefore, the research on the intrusion of lightning into the substation is not slow.
The main ways of lightning invading the switch cabinet can be divided into four types: 1) the aerial charge directly/indirectly discharges power equipment, and lightning directly strikes/detours. The primary lightning stroke main discharge is generally tens of thousands to hundreds of thousands of amperes, and instantaneous high heat and electric power can be generated; 2) after direct lightning flows into the ground and is dispersed, the potential of the ground network rises, so that the potential difference on each branch line is large, electronic equipment on different positions is damaged, and lightning counterattack is caused. 3) The energy of the direct lightning discharge is radiated to the surroundings through electromagnetic induction and electrostatic induction, resulting in overvoltage of the equipment and the earth screen, and induced lightning overvoltage. 4) The high-voltage power transmission line and the distribution line are invaded into a transformer substation in a remote lightning, direct-hit or electromagnetic induction and electrostatic induction mode, namely, the lightning wave is invaded.
However, under the existing lightning protection measures, the 10-35 kV equipment is still a disaster area of lightning invasion, most of researches on the lightning invasion switch room in the prior art are stopped at the theoretical and qualitative analysis level, and the existing monitoring means in the 10-35 kV switch room cannot effectively monitor the lightning invasion, so that the lightning invasion is effectively monitored. Therefore, on the premise of not influencing the reliable operation of the existing system, the method for effectively monitoring the lightning invasion has important practical value.
Disclosure of Invention
Aiming at the defects and shortcomings in the prior art, the invention provides a lightning invasion switch room monitoring method based on ground grid current distribution, which can effectively monitor the area where lightning stroke occurs and whether lightning waves invade the switch room.
The technical scheme is as follows:
a lightning intrusion switch room monitoring method based on current distribution of a ground grid is characterized by comprising the following steps:
the current on the public convergence ground wire of the bus arrester, the bus PT, the grounding transformer and the primary equipment and the secondary side voltage of the bus PT are respectively collected to judge the source of the lightning invasion and the influence on the primary equipment and the secondary equipment.
Further, the overvoltage area caused by lightning is judged according to the lightning current directions on the public bus grounding wire of the acquired grounding transformer, the bus PT, the bus lightning arrester and the primary equipment:
if the lightning current direction is from the main ground net to the equipment, judging that the outdoor main ground net is struck by lightning;
and if the lightning current direction is that the slave equipment points to the main ground grid, judging that the incoming line of the bus is struck by lightning.
Further, when the outdoor main ground net is judged to be struck by lightning, the sensed lightning wave shape is analyzed, and whether the connection position of the switch room and the outdoor main ground net and the grounding resistance of the main ground net at the connection position are overlarge or not is checked.
Further, when the outdoor main ground net is judged to be struck by lightning, the influence of lightning counterattack on the equipment operating in the switch room is monitored through the numerical value and the waveform of current collected from the bus PT, the grounding transformer and the public bus ground wire of the primary equipment and the voltage change on the bus PT.
Further, when the incoming line of the bus is judged to be struck by lightning, whether the arrangement of the main transformer side arrester and the feeder line arrester is reasonable or not is evaluated through the numerical value and the waveform of current collected at the public confluence ground wire of the bus arrester, the bus PT, the grounding transformer and the primary equipment and the voltage change on the bus PT.
Further, when the secondary side voltage of the bus PT and the current on the bus PT and the grounding transformer are changed due to the fact that lightning waves are collected, the method comprises the following steps: if the current at the bus arrester is smaller than a preset value, and the difference value between the numerical value of the current at the public confluence ground wire of the primary equipment and the sum of the currents collected by the bus PT and the grounding transformer is smaller than the preset value, judging that the arrester at the main transformer side acts correctly, and positioning a lightning overvoltage area as other voltage sides outside the switch chamber;
and if the current value acquired at the public convergence ground wire of the primary equipment is larger than the preset value and the waveform conforms to the breakdown characteristic of the lightning arrester, judging that the lightning arrester on the feeder side acts correctly.
Further, whether fuse damage or damage caused by lightning stroke is obtained by analyzing the current waveform collected at the position of the bus PT.
Further, when the 35kV side of the transformer substation has no grounding transformer, the influence of the grounding transformer on the system under the condition of a grounding fault or a lightning stroke is evaluated by comparing the upper current waveforms of 10kV and 35 kV.
The invention and the preferable scheme thereof can effectively monitor the area where the lightning stroke occurs and whether the lightning wave invades the switch room.
Drawings
The invention is described in further detail below with reference to the following figures and detailed description:
FIG. 1 is a schematic diagram of a lightning intrusion 10kV system according to an embodiment of the invention;
FIG. 2 is a schematic diagram of a lightning current path when lightning current intrudes along a line and a lightning arrester is not broken down according to an embodiment of the invention;
FIG. 3 is a schematic diagram of a lightning current path when lightning current intrudes along a line and a lightning arrester breaks down according to an embodiment of the invention;
FIG. 4 is a schematic diagram of a lightning current path in case of primary equipment insulation problems according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a lightning current path when insulation between secondary devices is a problem according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a lightning current path when the ground resistance is too large according to the embodiment of the present invention;
FIG. 7 is a schematic diagram of a lightning current path when a secondary earth grid is too close to a grounding point of a lightning tower according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a lightning intrusion switch room monitoring method based on distribution of current in the earth grid according to an embodiment of the invention.
Detailed Description
In order to make the features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail as follows:
as shown in fig. 1, which is a 10kv system diagram, the present embodiment analyzes the situation of lightning invasion.
As shown in fig. 2, when lightning induced overvoltage and direct lightning overvoltage of the overhead line form lightning waves and intrude along the line or lightning induced overvoltage along the line of the main transformer 10kV side (when the lightning induced overvoltage does not satisfy the breakdown voltage of the lightning arrester), the 10kV is connected in a triangle, and the lightning current enters the primary earth screen through the path shown in the first drawing and then flows into the ground.
As shown in fig. 3, when lightning induced overvoltage and direct lightning overvoltage of the overhead line intrude along the line (when lightning overvoltage satisfies breakdown voltage of the lightning arrester), most of lightning current flows into the ground through the lightning arrester and then enters the primary ground grid along the path shown in fig. two, and the rest of current flows into the ground through the bus PT and the ground along the blackened path and then enters the primary ground grid.
As shown in fig. 4, when lightning induced overvoltage of the overhead line and lightning direct overvoltage form lightning wave which invades along the line and when insulation of the primary equipment to the ground is problematic, the lightning current flows into the primary earth screen through a thickened black path in the switch cabinet and then flows into the ground.
As shown in fig. 5, when lightning induced overvoltage of the overhead line and lightning induced overvoltage of the direct lightning form a lightning wave to intrude along the line and when insulation between primary and secondary devices is problematic (i.e., when primary and secondary insulation of the current transformer is problematic), the lightning flows through the current transformer into the protection measurement and control device and then flows into the ground after flowing into the secondary earth screen.
As shown in fig. 6, in the conventional switch room, there are two cases of grounding after the primary and secondary grounding nets are shorted and separately grounding. When the primary and secondary grounding grids are grounded after short circuit, lightning current caused by overlarge grounding resistance cannot flow into the ground, so that the primary grounding grid flows into the secondary grounding grid, and secondary equipment is damaged.
As shown in fig. 7, when a primary ground potential of the primary ground network is increased due to the fact that a primary ground network grounding point of a secondary ground network is too close to a lightning conductor grounding point of an outdoor lightning tower or due to the fact that lightning directly strikes a primary device, lightning counterattack causes the situation that the primary ground network is coupled with the secondary ground network to enter a voltage or breakdown is caused due to insulation damage, and therefore voltage and current of the primary ground network are changed.
Based on the above analysis, to achieve the purpose of the present invention, the embodiment of the present invention proposes a technical solution as shown in fig. 8:
by collecting the current on the bus arrester (node 1), the bus PT (node 2), the grounding transformer (node 3), the common confluence ground wire (node 4) of the primary equipment, and the secondary side voltage of the bus PT, as shown in fig. 8, the lightning invasion source and the influence on the primary and secondary equipment are determined by measuring the current value of the grounding point at 4 and the secondary side voltage value of the bus PT respectively. The specific method comprises the following steps:
judging overvoltage area (10 kV bus (incoming line) or outdoor main ground net) caused by thunder according to lightning current direction collected at 4
And secondly, if the lightning current direction points to the equipment from the main ground net, judging that the outdoor main ground net is struck by lightning. At this time, the waveform of the sensed lightning wave can be analyzed, and whether the connection position of the switch room and the outdoor main ground network is proper or not and whether the grounding resistance of the main ground network is overlarge or not can be researched. In addition, the influence of lightning counterattack on the running equipment in the switch room can be researched by researching the values and waveforms of the collected currents at 2, 3 and 4 and the voltage change on the bus PT.
And thirdly, if the lightning current direction is that the slave equipment points to the main grounding grid, the lightning current direction is judged to be 10kV bus (incoming line), and whether the setting of the main transformer side arrester and the feeder line (incoming line) arrester is reasonable or not can be evaluated through the numerical values and waveforms of the current collected at the positions 1, 2, 3 and 4 and the voltage change on the bus PT. (when the variation condition caused by collecting lightning waves on the bus PT, the bus 2 and the bus 3 is generated, the position 1 has almost no current, and the numerical value of the current at the position 4 is almost equal to the sum of the bus 2 and the bus 3, the lightning arrester at the main transformer side can be judged to act correctly, at the moment, the lightning overvoltage area can be positioned to be the other voltage sides outside the switch chamber, the numerical value of the current collected at the position 4 is very large, the waveform accords with the breakdown characteristic of the lightning arrester, and the lightning arrester at the feeder line (incoming line) side can be judged to act correctly.)
And fourthly, considering the condition that the fuse on the conventional bus PT is easy to fuse, the condition that the fuse is damaged due to ground fault or damaged due to lightning stroke is expected to be obtained by analyzing the current waveform acquired at the position 2. (lightning current and fault current can be judged by the direct current high-frequency component monitored by the sensor.)
Considering that no grounding transformer exists at the 35kV side of the transformer substation, the influence of the grounding transformer on a system under the condition of ground fault or lightning stroke can be evaluated by comparing the upper current waveforms of 10kV and 35 kV.
And considering the influence of the lightning invasion wave on 10kV, the reliability of the line lightning protection measure close to the transformer substation side can be evaluated through the lightning current monitoring device.
The present invention is not limited to the above preferred embodiments, and any other various types of monitoring methods for lightning intrusion switch rooms based on distribution of current in the earth grid can be obtained from the teaching of the present invention.

Claims (5)

1. A lightning intrusion switch room monitoring method based on current distribution of a ground grid is characterized by comprising the following steps:
respectively collecting currents on a bus arrester, a bus PT, a grounding transformer and a public bus earth wire of primary equipment, and secondary side voltage of the bus PT so as to judge the source of lightning invasion and the influence on the primary equipment and the secondary equipment;
the overvoltage area caused by thunder is judged according to the thunder current directions on the public bus earth wires of the grounding transformer, the bus PT, the bus arrester and the primary equipment which are acquired:
if the lightning current direction points to the equipment from the main ground network, judging that the outdoor main ground network is struck by lightning;
if the lightning current direction is that the slave equipment points to the main ground grid, the incoming line of the bus is judged to be struck by lightning;
when the incoming line of the bus is judged to be struck by lightning, evaluating whether the arrangement of a main transformer side arrester and a feeder line arrester is reasonable or not through the numerical value and the waveform of current collected at the public confluence ground wire of the bus arrester, the bus PT, a grounding transformer and primary equipment and the voltage change on the bus PT;
if the current at the bus arrester is smaller than a preset value, and the difference value between the numerical value of the current at the public confluence ground wire of the primary equipment and the sum of the currents collected by the bus PT and the grounding transformer is smaller than the preset value, judging that the arrester at the main transformer side acts correctly, and positioning a lightning overvoltage area as other voltage sides outside the switch chamber;
and if the current value acquired at the public convergence ground wire of the primary equipment is greater than the preset value and the waveform accords with the breakdown characteristic of the arrester, judging that the arrester on the feeder side acts correctly.
2. The lightning intrusion switch room monitoring method based on distribution of current in the earth grid according to claim 1, characterized in that: and when the outdoor main ground net is judged to be struck by lightning, analyzing the waveform of the sensed lightning wave, and checking whether the connection part of the switch room and the outdoor main ground net and the grounding resistance of the main ground net at the connection part are overlarge or not.
3. The lightning intrusion switchhouse monitoring method based on distribution of current in a ground grid according to claim 1, characterized in that: when the outdoor main ground net is judged to be struck by lightning, the influence of lightning counterattack on the equipment operating in the switch room is monitored through the numerical value and waveform of current collected from the bus PT, the grounding transformer and the public bus ground wire of the primary equipment and the voltage change on the bus PT.
4. The lightning intrusion switchhouse monitoring method based on distribution of current in a ground grid according to claim 1, characterized in that: the fuse damage caused by the ground fault or the damage caused by the lightning stroke is obtained by analyzing the current waveform collected at the position of the bus PT.
5. The lightning intrusion switchhouse monitoring method based on distribution of current in a ground grid according to claim 1, characterized in that: when the 35kV side of the transformer substation is not provided with the grounding transformer, the influence of the grounding transformer on a system under the condition of ground fault or lightning stroke is evaluated by comparing the upper current waveforms of 10kV and 35 kV.
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CN114217170B (en) * 2021-12-15 2024-01-23 国网福建省电力有限公司 Lightning invasion switch room positioning device and method based on ground network current distribution

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Publication number Priority date Publication date Assignee Title
CN103454480A (en) * 2013-08-09 2013-12-18 国家电网公司 Method for measuring and calculating transformer invading lightning voltage waveforms with transformer bushing

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JPH073451B2 (en) * 1987-11-10 1995-01-18 東京電力株式会社 Method of detecting lightning strike position in power transmission tower
CN103278709B (en) * 2013-04-27 2015-09-02 国家电网公司 A kind of lightning travelling wave in transmission line characteristic test system
CN105093079B (en) * 2015-08-26 2018-06-15 广东电网有限责任公司电力科学研究院 The determining method and system of substation equipment dielectric level
CN108120870A (en) * 2016-11-29 2018-06-05 沈阳铁路信号有限责任公司 railway station machine room lightning monitoring system
CN111239499A (en) * 2019-12-28 2020-06-05 沈阳铁路信号有限责任公司 CLT type railway station thunder and lightning information acquisition system

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Publication number Priority date Publication date Assignee Title
CN103454480A (en) * 2013-08-09 2013-12-18 国家电网公司 Method for measuring and calculating transformer invading lightning voltage waveforms with transformer bushing

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