CN117761409A - Lightning protection early warning device for equipment of hydropower station switching station - Google Patents
Lightning protection early warning device for equipment of hydropower station switching station Download PDFInfo
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- CN117761409A CN117761409A CN202310927821.9A CN202310927821A CN117761409A CN 117761409 A CN117761409 A CN 117761409A CN 202310927821 A CN202310927821 A CN 202310927821A CN 117761409 A CN117761409 A CN 117761409A
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Abstract
The invention discloses an equipment lightning protection early warning device of a hydropower station switching station, which comprises a lightning current detection unit, an optical fiber transmission unit, a signal processing unit and an early warning and indicating unit; the lightning current detection unit comprises a detection coil, a first signal wire and a second signal wire; the optical fiber transmission unit comprises a first light emitting diode, a first resistor, an optical fiber, a phototriode, a second resistor and a first direct current power supply; the signal processing unit comprises a third signal wire, a singlechip and a second direct-current power supply; the early warning indication unit comprises a second light emitting diode and a loudspeaker. The invention can provide monitoring data for operators to analyze the damage condition of the electrical equipment, and can provide rapid early warning for the safety lightning protection of the electrical equipment and the operation and inspection personnel.
Description
Technical Field
The invention belongs to the technical field of electrical engineering, and relates to a lightning protection early warning device for equipment of a hydropower station.
Background
Hydroelectric power generation is low-carbon green power generation of new energy in the world, a large-scale hydroelectric power plant is a power generation hub of an electric power system, and a hydroelectric power plant switching station carries out high-pressure conveying and distribution on electric energy generated by the hydroelectric power plant. Along with the development of modern hydroelectric power generation, a large-scale hydroelectric power plant brings green energy to the life of people, and meanwhile, the large-scale hydroelectric power plant is built nearby a great river and a Chong mountain, so that certain potential safety hazards exist, and particularly lightning affects the safe operation of a hydropower plant switching station. If a lightning strike occurs in a hydropower station, electrical equipment in the hydropower station is seriously damaged, and even safety of operators is guaranteed. Therefore, lightning protection measures of the switching stations of the water power plants are necessary.
In short, as the output electric energy of the hydroelectric power plant increases and the output voltage increases, lightning strike accidents in mountain areas often cause damage to electric equipment of a switching station of the hydroelectric power plant, and lightning strike accidents of the hydroelectric power plant are more serious, which often cause the power plant to stop generating electricity. Secondly, the internal insulation level of the hydropower station switch station is often lower than that of the transmission line, and once the hydropower station switch station is broken down by lightning overvoltage, the result is serious. Therefore, the equipment lightning protection early warning device of the hydropower station is beneficial to protecting electrical equipment and personnel safety and improving the safe operation level of the large hydropower plant.
Disclosure of Invention
Aiming at the problems that the internal insulation level of the existing hydropower station is often lower than the insulation of a power transmission line, once the internal insulation level is broken down by lightning overvoltage, the consequence is serious and the like, the invention provides the equipment lightning protection early warning device of the hydropower station, so as to provide rapid early warning for the safety lightning protection of electrical equipment and operation and inspection personnel.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
an equipment lightning protection early warning device of a hydropower plant switching station comprises a lightning current detection unit, an optical fiber transmission unit, a signal processing unit and an early warning indication unit.
Further, the lightning current detection unit comprises a detection coil, a first signal wire and a second signal wire.
Further, the detection coil is buried in the soil between the grounding body A of the framework lightning rod and the grounding body B of the electrical equipment.
Further, the optical fiber transmission unit comprises a first light emitting diode, a first resistor, an optical fiber, a phototriode, a second resistor and a first direct current power supply.
Further, the first resistor and the second resistor are both current limiting resistors.
Further, the signal processing unit comprises a third signal wire, a singlechip and a second direct-current power supply.
Further, the program for monitoring the potential difference is stored in the memory of the singlechip and is mainly divided into three modules, namely a parameter fitting module, a calculating module and an early warning module.
Further, the singlechip is singlechip 8096.
Further, the early warning indication unit comprises a second light emitting diode and a loudspeaker.
Further, the second light emitting diode is a two-color light emitting diode.
The beneficial effects of the invention are as follows:
(1) The invention can provide monitoring data for operators to analyze the damage condition of the electrical equipment, and can provide rapid early warning for the safety lightning protection of the electrical equipment and the operation and inspection personnel.
(2) The invention can detect the distributed transient magnetic field synthesized by the three-dimensional space current in the soil between the grounding body of the framework lightning rod and the grounding body of the electrical equipment point by point, and can effectively realize the detection of the whole three-dimensional space transient magnetic field.
Drawings
Fig. 1 is a schematic block diagram of the present invention.
Fig. 2 is a schematic structural diagram of a lightning protection early warning device of a hydropower station switching station.
Fig. 3 is a schematic view of the space between the grounding body a of the lightning rod and the grounding body B of the electrical equipment.
Detailed Description
As shown in figures 1-3, a lightning protection early warning device of a hydropower station switching station is characterized in that a lightning current detection unitThe system comprises a unit 1, an optical fiber transmission unit 2, a signal processing unit 3 and an early warning indication unit 4. The lightning current detection unit 1 consists of a detection coil 5, a first signal wire 6 and a second signal wire 7, and the detection coil 5 is buried in soil between a grounding body A of a framework lightning rod and a grounding body B of electrical equipment so as to capture a transient electromagnetic field generated by lightning impulse current; the optical fiber transmission unit 2 consists of a first light emitting diode 8, a first resistor 9, an optical fiber 10, a phototriode 12, a second resistor 11 and a first direct current power supply 17, wherein the first resistor 9 and the second resistor 11 are current limiting resistors; the signal processing unit 3 consists of a third signal lead 13, a singlechip 14 and a second direct-current power supply 18, wherein the singlechip 14 is a singlechip 8096, and the potential difference U is monitored AB The program of (t) is stored in the memory of the singlechip 14 and is mainly divided into three modules, i.e. parameters (r AB K, E (t)) fitting module, calculating module and early warning module; the early warning indicating unit (4) consists of a second light-emitting diode (15) and a loudspeaker (16), wherein the second light-emitting diode (15) is a double-color light-emitting diode. The optical fiber 10 adopted by the early warning device has the characteristics of electromagnetic interference resistance, water resistance, moisture resistance and strong insulation, and the optical fiber 10 not only can effectively transmit optical signals, but also can protect overvoltage generated by lightning impulse.
The lightning protection early warning device for the hydropower station switching station is characterized in that lightning impulse current can be generated in the ground between the grounding body of the framework lightning rod and the grounding body of the electrical equipment when lightning strikes the lightning rod (the framework lightning rod for short) on the power distribution device framework of the hydropower station switching station, and a transient magnetic field can be generated in the ground between the grounding body of the framework lightning rod and the grounding body of the electrical equipment by the lightning impulse current. The invention relates to a monitoring and early warning device for lightning impulse hydropower station, which aims at overvoltage counterattack accidents of electrical equipment caused by lightning striking a lightning rod (abbreviated as a framework lightning rod) on a framework of the hydropower station. The problem of overvoltage 'counterattack' of electrical equipment is that lightning strikes current is injected into the ground through a lightning rod grounding body when lightning strikes a lightning rod on a framework without directly striking the electrical equipment, so that the potential of the lightning rod grounding body is increased, potential difference (namely overvoltage) is formed between the lightning rod grounding body and the electrical equipment grounding body, and when the overvoltage reaches the soil sufficient for breakdown between the electrical equipment grounding body and the lightning rod grounding body, a 'counterattack' accident of lightning strike overvoltage of a switch station of a hydropower plant can be generated, and finally, insulation damage of the electrical equipment is caused.
The lightning impulse current is injected into the ground through the lightning rod grounding body to be diffused, then a transient magnetic field is formed in the soil between the framework lightning rod grounding body and the grounding body of the electrical equipment, the lightning impulse current injected into the ground is a dispersed current, the dispersed current is distributed in the soil around the framework lightning rod grounding body, and a three-dimensional space-distributed transient magnetic field is formed in the soil of the grounding body. According to the electromagnetic induction principle, the transient magnetic field can generate induction potential e (t) on the detection coil buried in the soil between the grounding body of the framework lightning rod and the grounding body of the electrical equipment, and by measuring the induction potential e (t), the lightning impulse current i between the grounding body of the framework lightning rod and the grounding body of the electrical equipment can be rapidly detected AB (t) and potential difference U AB (t) wherein the potential difference is
U AB (t)＝ r AB × i AB (t)≈ k×r AB × E(t) (1)
Wherein k is the induced potential E (t) generated on the detection coil and the lightning impulse current i between the grounding body of the framework lightning rod and the grounding body of the electrical equipment AB (t) an associated conversion factor. r is (r) AB Is the ground resistance value between the grounding body of the framework lightning rod and the grounding body of the electrical equipment, r AB The values are accurately transformed according to the change of the environment, so that the detection precision is ensured.
Definition of ground in the national Standard DL/T621-1997 ground for alternating-current Electrical devices: some conductive parts of electrical devices, facilities in an electrical power system or building are connected to a ground body (pole) via a ground wire. The earth is an integral part of the operation of the grounding body (pole) because lightning impulse current is injected into the earth through the grounding body of the lightning rod to spread. Influence type (1) potential difference U AB (t) the main factor in the calculation is the spatial distribution of the soil resistivity due to the injection of ground lightning through the ground body of the lightning rodElectric impulse current i AB (t) diffusion heats the nearby soil and evaporates water, thereby changing the soil resistivity between the ground body of the frame lightning rod and the ground body of the electrical equipment. Therefore, firstly, a soil grounding calculation model related to the soil resistivity, the lightning impulse current I (t) and the induced potential E (t) between the grounding body of the framework lightning rod and the grounding body of the electrical equipment is established:
wherein epsilon is soil resistivity, phi is soil potential, rho is soil electrostatic charge, lambda is soil magnetic permeability, omega is angular frequency, eta is soil medium conductivity, I (t) is lightning impulse current,is vector magnetic bit. The induction potential E (t) calculation can be carried out according to the physical conditions such as the actual soil structure between the grounding body of the lightning rod of the hydropower station switching station framework and the grounding body of the electrical equipment, which are the boundary value conditions of the soil grounding calculation model, and the finite element ANSOFT calculation program is adopted to carry out pretreatment calculation on the soil grounding calculation model of the actual hydropower station switching station.
When vector magnetic potential is calculated, because the electromagnetic parameters between the grounding body A of the lightning rod and the grounding body B of the electrical equipment are different, different current excitation settings are difficult. For this purpose, a field path coupling analysis model is used to calculate the electrical characteristics between the grounding body a of the lightning rod and the grounding body B of the electrical equipment. Fig. 3 is a schematic view of the space between the grounding body a of the lightning rod and the grounding body B of the electrical equipment.
H in FIG. 3 1 The phase difference height between the grounding body A of the lightning rod and the grounding body B of the electrical equipment is equal to the space radius between the grounding body A of the lightning rod and the grounding body B of the electrical equipment. Taking any point P (r) on the grounding body B of the electric equipment 0 ，z 0 ) The center point of the grounding body A of the lightning rod is the origin of coordinates, and the vector magnetic potential strength of the point P is shown in formula (1):
then, the electric equipment induction can be obtained by carrying out integral once according to the length of the grounding body B to obtain the vector magnetic positionIn actual monitoring, the potential difference U between the grounding body of the framework lightning rod and the grounding body of the electrical equipment under the lightning impulse is evaluated by fast calculation of the formula (1) AB And (t) a change rule, so that the frame lightning protection is prevented from counterattack accidents aiming at electrical equipment, and quick early warning is performed.
The invention relates to a lightning protection early warning device of a hydropower station switching station, which is characterized in that a monitoring potential difference U of a signal processing unit AB The calculation program of (t) is mainly composed of three modules, i.e. parameters (r) AB K, E (t)) fitting module, calculating module and early warning module, wherein r AB The ground resistance between the grounding body of the frame lightning rod and the grounding body of the electrical equipment is k is the induced potential E (t) generated on the detection coil and the lightning impulse current i between the grounding body of the frame lightning rod and the grounding body of the electrical equipment AB (t) a related conversion factor and is closely related to the three-dimensional spatially distributed transient magnetic field strength in the soil. These two parameters (r AB K) is obtained by electromagnetic simulation calculation of actual ground conditions of a hydropower station switching station, r AB The value is continuously adjusted according to the actual state of the soil and is pre-stored in the memory of the signal processing unit 3.
The detecting coil 5 is buried in the soil between the grounding body of the frame lightning rod and the grounding body of the electrical equipment, and the entire detecting coil is impacted by lightning current in the soilThe generated transient magnetic field is surrounded by the magnetic field. Because the transient magnetic field around the detection coil is influenced by the actual soil structure condition (soil conductivity, soil humidity and soil temperature) of the switching station, the calculation mode is to perform electromagnetic simulation calculation according to the actual soil structure condition of the soil conductivity, the soil humidity and the soil temperature, and obtain two important parameters (r) AB K) and the resistance between the grounding body A and the grounding body B is nonlinear due to the influence of the soil structure ground condition (soil conductivity, soil humidity and soil temperature), r AB The actual average resistance between the grounding body A and the grounding body B is that the change of the resistance value is influenced by parameters in the formula (2) and the formula (3), and the value is continuously adjusted according to the actual soil state. And i AB (t) is the average lightning impulse current between the ground body A and the ground body B, which is in fact a diffusion current between the ground body A and the ground body B, which diffusion current i AB (t) is obtained by capturing the transient magnetic field intensity in the soil between the grounding body of the framework lightning rod and the grounding body of the electrical equipment through a plurality of detection coils 5 placed between the grounding body A and the grounding body B, and then averaging through series calculation, wherein the correlation is represented by a corresponding parameter k and is pre-stored in the memory of the signal processing unit 3, and finally, the effect of 'counterattack' overvoltage U on the electrical equipment caused by lightning hitting the framework lightning rod is realized AB And (3) calculating and early warning. Therefore, monitoring data is provided for operators to analyze damage conditions of the electrical equipment, and quick early warning can be provided for safety lightning protection of the electrical equipment and operation and inspection personnel.
The sensor of the lightning current detection unit of the lightning protection early warning device of the hydropower station switch station consists of a detection coil. As can be seen from fig. 1 and 2, the detection unit structure of the present invention is a detection coil, and the coil structure is integral, has a small number of turns, and has a small volume, and the signal is obtained by embedding the sensor detection coil 5 of the lightning current detection unit 1 in the soil between the grounding body a of the frame lightning rod and the grounding body B of the protected electrical equipment, so that the detection coil 5 can be in a three-dimensional spatially distributed transient magnetic field between the grounding body of the frame lightning rod and the grounding body of the electrical equipment, and is subjected to the action of the transient magnetic field to generate an induced voltage signal in the detection coil 5. In order to detect the distributed transient magnetic field between the soils point by point, the detection coil 5 is designed to have a tiny volume and is placed in the soil with the three-dimensional space dispersed current and is surrounded by the dispersed current, so that the distributed transient magnetic field synthesized by the three-dimensional space current in the soil between the grounding body of the framework lightning rod and the grounding body of the electrical equipment can be detected point by point, and the detection of the whole three-dimensional space transient magnetic field can be effectively realized.
The aim of the invention is achieved by the following technical measures:
firstly, according to the physical conditions such as the actual soil structure between the grounding body of the framework lightning rod of the hydropower station and the grounding body of the electrical equipment, which are the boundary conditions of the soil grounding calculation model (formula (2), formula (3) and formula (4)), a finite element ANSOFT calculation program is adopted to perform pretreatment calculation on the soil grounding calculation model of the actual hydropower station. Wherein the vector magnetic potential is calculated by adopting a numerical calculation mode of a formula (5).
Obtaining the ground resistance r between the grounding body of the frame lightning rod and the grounding body of the electrical equipment AB And for detecting the induced potential E (t) generated on the coil and the lightning impulse current i between the grounding body of the frame lightning rod and the grounding body of the electrical equipment AB (t) the associated conversion factor k, where r is then pre-stored in the memory of the signal processing unit 3 AB The value is continuously adjusted according to the actual state of the soil.
In actual operation, after the frame lightning rod is struck by lightning, lightning impulse current is generated in the ground between the grounding body A of the frame lightning rod and the grounding body B of the electrical equipment, a transient magnetic field generated by the lightning impulse current in the ground induces a potential E (t) on the detection coil 5, the potential E (t) is limited by the first resistor 9 and drives the first light emitting diode 8 to emit light, the light emitted by the first light emitting diode 8 is transmitted to the base electrode of the phototriode 12 through the optical fiber 10, the phototriode 12 is conducted, the potential signal of the second resistor 11 changes, the singlechip 14 acquires the potential signal of the second resistor 11 through the third signal wire 13, and then the potential difference U stored in the memory of the singlechip 14 is used according to the formula (1) AB The calculation program of (t) processes and calculates rapidly when the potential difference U AB When the value (t) exceeds the safety value, the singlechip 14 controls the bicolor light-emitting diode 15 to emit red light to flash and the loudspeaker 16 to emit alarm sound for early warning, and conversely, when the potential difference U is generated AB When the value (t) does not exceed the safety value, the two-color led 15 emits green light to flash and the horn 16 is silent. Therefore, the device provides quick early warning for the safety lightning protection of electrical equipment and operation and inspection personnel.
Claims (10)
1. The lightning protection early warning device for the equipment of the hydropower station switching station is characterized by comprising a lightning current detection unit, an optical fiber transmission unit, a signal processing unit and an early warning and indicating unit.
2. The lightning protection and early warning device for equipment of a hydropower station switching station according to claim 1, wherein the lightning current detection unit comprises a detection coil, a first signal wire and a second signal wire.
3. The lightning protection early warning device for equipment of a hydropower station switching station according to claim 2, wherein the detection coil is buried in the soil between the grounding body A of the framework lightning rod and the grounding body B of the electrical equipment.
4. The lightning protection and early warning device for equipment of a hydropower station switching station according to claim 1, wherein the optical fiber transmission unit comprises a first light emitting diode, a first resistor, an optical fiber, a phototriode, a second resistor and a first direct current power supply.
5. The lightning protection and early warning device for equipment of a hydropower station according to claim 4, wherein the first resistor and the second resistor are current limiting resistors.
6. The lightning protection and early warning device for equipment of a hydropower station switching station according to claim 1, wherein the signal processing unit comprises a third signal wire, a singlechip and a second direct current power supply.
7. The lightning protection and early warning device for equipment of a hydropower station according to claim 6, wherein the program for monitoring potential difference is stored in a memory of a single chip microcomputer and is mainly divided into three modules, namely a parameter fitting module, a calculating module and an early warning module.
8. The lightning protection early warning device for equipment of a hydropower station switching station according to claim 6 or 7, wherein the single-chip microcomputer is a single-chip microcomputer 8096.
9. The lightning protection and early warning device for equipment of a hydropower station switching station according to claim 1, wherein the early warning and indicating unit comprises a second light emitting diode and a loudspeaker.
10. The lightning protection and early warning device for equipment of a hydropower station according to claim 9, wherein the second light emitting diode is a two-color light emitting diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310927821.9A CN117761409A (en) | 2023-07-26 | 2023-07-26 | Lightning protection early warning device for equipment of hydropower station switching station |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310927821.9A CN117761409A (en) | 2023-07-26 | 2023-07-26 | Lightning protection early warning device for equipment of hydropower station switching station |
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| CN117761409A true CN117761409A (en) | 2024-03-26 |
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| CN202310927821.9A Pending CN117761409A (en) | 2023-07-26 | 2023-07-26 | Lightning protection early warning device for equipment of hydropower station switching station |
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- 2023-07-26 CN CN202310927821.9A patent/CN117761409A/en active Pending
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