An integrated lightning protection device and method for power collection lines in new energy power plants

Abstract

This invention provides an integrated lightning protection device and method for power line collection lines in new energy power plants. The device includes a lightning protection body with an insulator connected in series. The lightning protection body comprises an external series discharge gap unit and a capacitive impedance adjustment unit. One end of the external series discharge gap unit is electrically connected to the conductor of the protected power line, and the other end is electrically connected in series with the capacitive impedance adjustment unit. The free end of the capacitive impedance adjustment unit is electrically connected to the grounding system through an insulator. This invention achieves differentiated responses between high impedance at power frequency and low impedance at high frequency through the synergistic series connection of the external series discharge gap and the capacitive impedance adjustment unit. This effectively suppresses power frequency leakage current and heat accumulation, while reducing reliance on low grounding resistance. It resolves the technical contradictions of traditional surge arresters, such as poor multi-waveform response capability and difficulty in simultaneously controlling residual voltage and interrupting follow current, thus improving the lightning protection reliability and service life of power line collection lines in complex environments.

Description

Technical Field

[0001] This invention belongs to the field of power system lightning protection technology, specifically relating to an integrated lightning protection device and method suitable for the collection lines of new energy power plants. Background Technology

[0002] New energy power plants are mostly located in open areas, mountainous regions, or coastal areas, where lightning activity is frequent. The collector lines are susceptible to lightning strikes, leading to flashovers, tripping, and even equipment damage. Traditional zinc oxide surge arresters (MOAs) have significant shortcomings in handling multi-waveform lightning currents, power frequency follow current interruption, and high-frequency oscillation suppression. These shortcomings are mainly manifested in the following ways: the nonlinear resistance characteristics of the classic nonlinear resistance model cannot simultaneously match the protection requirements of steep waves, lightning waves, and switching waves, resulting in significant differences in protection margins under different operating conditions, making it difficult to simultaneously address protection characteristics under multiple conditions such as steep waves, lightning waves, and switching waves; traditional equivalent circuit models rely on linear resistors or single nonlinear resistor elements, presenting irreconcilable technical contradictions, and there is a technical contradiction between arc extinguishing performance and residual voltage control; the lack of an effective power frequency isolation structure leads to heat accumulation during long-term operation; furthermore, the absence of an effective power frequency isolation structure in traditional zinc oxide surge arresters results in power frequency leakage current during long-term grid operation. In high soil resistivity environments such as mountainous areas, problems such as grounding corrosion and resistance reduction difficulties can accelerate device failure. Therefore, there is an urgent need for a lightning protection device with optimized structure, fast response, and strong adaptability to improve the lightning protection capability and operational reliability of the power collection lines of new energy power plants. Summary of the Invention

[0003] The purpose of this invention is to provide an integrated lightning protection device and method suitable for the collector lines of new energy power plants. Through the coordinated design of an external series discharge gap and capacitive impedance, it achieves precise triggering, energy dissipation, and follow current interruption under multiple operating conditions, significantly improving lightning protection effectiveness and system stability. This addresses the aforementioned shortcomings of existing lightning protection devices for the collector line areas of new energy power plants.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides an integrated lightning protection device suitable for the power collection lines of new energy power stations, comprising: a lightning protection device body, wherein an insulator is connected in series with the lightning protection device body; The lightning protection device body includes an external series discharge gap unit and a capacitive impedance adjustment unit, wherein: One end of the external series discharge gap unit is electrically connected to the conductor of the protected current collection line, and the other end is electrically connected in series with the capacitive impedance adjustment unit; the free end of the capacitive impedance adjustment unit is electrically connected to the grounding system through an insulator.

[0005] Preferably, the external series discharge gap unit includes a high-voltage end electrode and a lead electrode. The high-voltage end electrode is used to electrically connect with the conductor of the protected current collector line; the lead electrode is electrically connected to the capacitive impedance adjustment unit.

[0006] Preferably, the capacitive impedance adjustment unit includes a surge arrester valve and a capacitor, wherein the surge arrester valve and the capacitor are connected in parallel.

[0007] Preferably, the capacitive impedance adjustment unit is further connected in parallel with a parallel gap unit.

[0008] Preferably, the trigger current threshold of the parallel gap unit is greater than the operating threshold of the surge arrester valve in the capacitive impedance regulating unit.

[0009] Preferably, the volt-ampere characteristic of the capacitive impedance adjustment unit satisfies a nonlinear equation:

[0010] in, For structurally relevant constants, This is the capacitance coefficient.

[0011] Preferably, the capacitive impedance adjustment unit has a high equivalent impedance characteristic state under power frequency and low frequency conditions, and a low equivalent impedance characteristic state under lightning impulse conditions.

[0012] Preferably, the external series discharge gap unit is in an insulating state under rated power frequency voltage and operating overvoltage conditions; and in a breakdown discharge state under lightning impulse overvoltage conditions.

[0013] Secondly, the present invention provides a method for operating an integrated lightning protection device for power collection lines in new energy power plants, which includes the following steps based on the lightning protection device: Under power frequency operating conditions: Under the action of rated power frequency voltage, the external series discharge gap unit remains in an insulating state, and the capacitive impedance adjustment unit exhibits high impedance characteristics, thereby suppressing power frequency leakage current; Lightning strike conditions: When the lightning impulse voltage reaches the impulse discharge voltage threshold of the external series discharge gap unit, the external series discharge gap unit will break down and discharge preferentially. The capacitive impedance adjustment unit will switch to a low impedance state under high frequency conditions, and the lightning current will be discharged to the ground through the integrated lightning protection device. Lightning current discharge completed: After the voltage returns to the power frequency operating level, the voltage across the external series discharge gap unit decreases and the insulation state is restored. Combined with the high impedance characteristics of the capacitive impedance adjustment unit under power frequency conditions, the power frequency follow current in the integrated lightning protection device circuit is cut off.

[0014] Preferably, when the lightning current amplitude exceeds the design threshold of the integrated lightning protection device, the parallel gap unit connected in parallel with the capacitive impedance adjustment unit breaks down, forming a low-impedance discharge channel to divert and discharge the lightning current, thereby reducing the current amplitude and energy density borne by the capacitive impedance adjustment unit.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention provides an integrated lightning protection device for power line collection lines in new energy power plants. Addressing the problems of traditional zinc oxide surge arresters in the background art, such as poor multi-waveform response, technical contradictions between residual voltage control and follow current interruption, lack of power frequency isolation leading to heat accumulation, and weak adaptability in high soil resistivity environments, this invention achieves precise response to lightning current and effective suppression of power frequency follow current under multiple operating conditions by setting up series insulators and a lightning protection device body containing an external series discharge gap unit and a capacitive impedance adjustment unit. One end of the external series discharge gap unit is connected to a conductor, and the other end is connected in series with the capacitive impedance adjustment unit. The free end of the capacitive impedance adjustment unit is grounded through an insulator. This resolves the contradiction between residual voltage control and arc extinguishing performance, reduces the risk of heat accumulation caused by power frequency leakage current, and reduces reliance on low grounding resistance, thereby improving adaptability and operational reliability in complex environments such as high soil resistivity. Attached Figure Description

[0016] Figure 1 This is a schematic diagram and equivalent circuit diagram of the integrated lightning protection device of the present invention; Figures 2(a) and (b) show the current waveforms under power frequency and high frequency lightning current conditions, respectively, reflecting the high impedance characteristics of the device of the present invention at power frequency and low impedance at high frequency. Figure 2(c) is a simulation diagram of the current shunting effect of the parallel gap under high current conditions; Figure 3(a) shows the voltage response of a lightning flashover under high-frequency lightning current conditions with a zinc oxide surge arrester installed. Figure 3(b) is a simulation diagram of residual voltage under high-frequency lightning current conditions with zinc oxide surge arrester installed; Figure 4(a) shows the voltage response under high-frequency lightning current conditions without lightning flashover when the integrated lightning protection device of the present invention is installed; Figure 4(b) is a simulation diagram of the residual voltage under high-frequency lightning current conditions in the integrated lightning protection device of the present invention. The residual voltage is significantly reduced compared to Figure 3(b). Figure 5(a) shows the voltage response diagram of a lightning flashover when a conventional zinc oxide surge arrester is installed (lightning current amplitude 48kA, grounding resistance 20Ω). Figure 5(b) shows the voltage response diagram when the integrated lightning protection device of this embodiment of the invention is installed without lightning flashover; (lightning current amplitude 48kA, grounding resistance 20Ω). Figure 5(c) shows the voltage response diagram of a lightning flashover when a conventional zinc oxide surge arrester is installed (lightning current amplitude 39kA, grounding resistance 50Ω). Figure 5(d) shows the voltage response diagram when the integrated lightning protection device of this embodiment of the invention is installed without lightning flashover; (lightning current amplitude 39kA, grounding resistance 50Ω). Figure 5(e) shows the voltage response diagram of a lightning flashover when a conventional zinc oxide surge arrester is installed (lightning current amplitude 21kA, grounding resistance 100Ω). Figure 5(f) shows the voltage response diagram of the integrated lightning protection device of this embodiment of the invention when no lightning flashover occurs; (lightning current amplitude 21kA, grounding resistance 100Ω). Detailed Implementation

[0017] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0018] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0019] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0020] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0021] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0023] Example 1 This embodiment provides an integrated lightning protection device suitable for power collection lines in new energy power plants, comprising: External series discharge gap unit: It consists of high-voltage end electrode and lead electrode. It maintains insulation under the rated power frequency voltage of the system to achieve power frequency isolation; it breaks down first when lightning overvoltage occurs to ensure "discharge before equipment"; it quickly restores insulation after the lightning current is discharged and, combined with the high impedance characteristics of capacitive impedance, cuts off the power frequency follow current.

[0024] Capacitive impedance regulation unit: Features nonlinear frequency characteristics of "high impedance at power frequency and low impedance at high frequency," used for modulating lightning current waveforms, suppressing high-frequency oscillations, and controlling residual voltage amplitude. Its volt-ampere characteristic satisfies the nonlinear equation:

[0025] in, For structurally relevant constants, The capacitance coefficient is approximately 0.2.

[0026] Under power frequency freewheeling conditions, its high impedance characteristics limit the peak freewheeling current to within 150A; under high frequency lightning current conditions, its low impedance characteristics keep the residual voltage within a reasonable range, with a protection ratio of only 2.5, which is far lower than 100 times that of traditional linear resistors.

[0027] Parallel gap unit in the lightning protection section: When it breaks down under high current impact, it forms a low-resistance discharge channel, diverts lightning current, protects the main surge arrester varistors, and extends the service life of the device.

[0028] Support insulation system: Used for overall structural fixation and electrical isolation, ensuring the mechanical and electrical reliability of the device.

[0029] Example 2 This embodiment provides a method for optimizing the parameters of an integrated lightning protection device for power collection lines in new energy power plants, comprising the following steps: Step 1: Component-level electrical characteristic testing and parameter calibration (1) Nonlinear voltage-current characteristic test of zinc oxide varistor in zinc oxide surge arrester: The residual voltage-current characteristic curve of zinc oxide varistor is obtained by 8 / 20μs lightning impulse, 30 / 60μs switching wave and 1 / 5μs steep wave impulse test. The nonlinear coefficient and current capacity are calibrated based on the residual voltage-current characteristic curve.

[0030] (2) Conduct capacitive impedance frequency characteristic test on zinc oxide varistors in zinc oxide surge arresters: measure impedance amplitude and phase characteristics in the frequency range of 50Hz to tens of MHz, verify its "high impedance at power frequency and low impedance at high frequency" characteristics, and determine the equivalent capacitance value or nonlinear impedance index.

[0031] (3) Conduct external series discharge gap discharge and arc extinguishing characteristic tests on the zinc oxide varistors in the zinc oxide surge arrester: test the breakdown voltage under power frequency, switching impulse and lightning impulse, plot the volt-second characteristic curve, verify the arc extinguishing capability, and determine the trigger voltage and arc extinguishing criterion.

[0032] (4) Conduct support insulation and mechanical performance tests on zinc oxide varistors in zinc oxide surge arresters: verify the insulation margin and structural reliability through power frequency dry and wet withstand tests and mechanical strength tests.

[0033] Step 2: Engineering quota parameters and electrical design constraints (1) Design of rated voltage and power frequency freewheeling voltage: Taking a 35kV system as an example, the power frequency freewheeling voltage should not be lower than the highest operating voltage of the system, which is defined as the most critical rated parameter of the device.

[0034] (2) Power frequency discharge voltage design: It must meet the requirements of normal operation without malfunction and reliable interruption of follow current after lightning strike. Considering the overvoltage and arc extinguishing conditions, the lower limit of the power frequency discharge voltage of the 35kV device is taken as approximately 73kV.

[0035] (3) Design of impulse discharge voltage and impulse residual voltage: The impulse discharge voltage should be lower than the impulse flashover voltage of the protected insulator to ensure that it "operates before the equipment". The impulse operating voltage of 35kV collector lines should be designed to be 190-240kV, and the impulse residual voltage should be controlled to be 120-135kV.

[0036] (4) Current capacity design: The current capacity is designed to be 65-100kA using a 4 / 10μs waveform. The proposed scheme is no less than 65kA.

[0037] Step 3: Structural Layer Matching and Overall Response Test (1) Series structure matching test: Apply different waveform impact currents, measure the overall residual voltage, energy distribution and transient response process, and verify the action sequence and voltage distribution characteristics of the external series gap and capacitive impedance.

[0038] (2) Transient residual voltage and waveform response test: Under standard lightning wave and steep wave conditions, test the voltage waveform change characteristics at both ends of the device and verify the simulation accuracy of the model for high-frequency transient processes.

[0039] Step 4: Transient simulation and multi-objective optimization based on ATP / EMTP An electromagnetic transient simulation model including collector lines, towers, insulators, transformers, and lightning protection devices was constructed. The Heidler model was used as the lightning current source to analyze the overvoltage response under different lightning current amplitudes, waveforms, grounding resistances, lightning strike locations, and line topologies. With the optimization objectives of "minimizing residual voltage, fastest follow current interruption, and lowest flashover risk," a multi-objective genetic algorithm was employed to optimize the configuration of gap spacing, capacitive impedance parameters, and parallel gap triggering thresholds.

[0040] Example 3 like Figure 1 As shown in the figure, this embodiment provides an integrated lightning protection device for the collection lines of new energy power stations, the lightning protection device body, and an insulator connected in series with the lightning protection device body; The lightning protection device body includes an external series discharge gap unit 1 and a capacitive impedance adjustment unit 1, wherein: One end of the external series discharge gap unit is electrically connected to the conductor of the protected current collection line, and the other end is electrically connected in series with the capacitive impedance adjustment unit; the free end of the capacitive impedance adjustment unit is electrically connected to the grounding system through an insulator.

[0041] In this embodiment, the external series discharge gap unit 1 includes a high-voltage end electrode and a lead electrode. The high-voltage end electrode is used to electrically connect with the conductor of the protected collector line; the lead electrode is electrically connected to the capacitive impedance adjustment unit.

[0042] A controllable air or composite insulating medium gap is formed between the high-voltage end electrode and the lead electrode. The gap distance and electrode structure are optimized to maintain the insulation state under the rated power frequency voltage and operation overvoltage conditions of the system, while being able to preferentially undergo breakdown discharge under the action of lightning impulse overvoltage.

[0043] The capacitive impedance adjustment unit 2 includes a surge arrester valve and a capacitor, wherein the surge arrester valve and the capacitor are connected in parallel.

[0044] The capacitive impedance adjustment unit 2 is also connected in parallel with a parallel gap unit 3.

[0045] The trigger current threshold of the parallel gap unit is greater than the working threshold of the surge arrester valve in the capacitive impedance adjustment unit 2.

[0046] The capacitive impedance adjustment unit is made of a ceramic-like functional material with significant nonlinear frequency characteristics. Its structural parameters include effective height, equivalent cross-sectional area, and dielectric parameters, which, together with the intrinsic properties of the material, determine its electrical behavior.

[0047] The capacitive impedance regulation unit exhibits the following electrical characteristics: high equivalent impedance under power frequency and low frequency conditions; and low equivalent impedance under high frequency conditions such as lightning impulses. These characteristics enable differentiated modulation of lightning current and power frequency follow current.

[0048] The parallel gap unit 3 is connected in parallel with the surge arrester valve in the capacitive impedance regulating unit and is located in the downstream circuit of the capacitive impedance regulating unit. The breakdown voltage or triggering current threshold of this parallel gap unit is higher than the operating threshold of the main surge arrester under normal lightning current conditions. It only breaks down when subjected to extremely high amplitude lightning current impact, thereby forming a low impedance bypass channel to divert and discharge the lightning current.

[0049] This parallel gap structure effectively limits the energy absorption ratio of the main surge arrester valve plate, reduces its thermal stress level, and improves the overall withstand capability and service life of the device.

[0050] In this embodiment, the integrated lightning protection device further includes a support insulation system 4, which is used to provide mechanical support and electrical isolation for the above-mentioned electrical units. Its insulation level and mechanical strength meet the safety requirements of the operating environment of the power collection line and under lightning impact conditions.

[0051] The supporting insulation system not only ensures the structural stability of the device during long-term operation, but also provides reliable electrical boundary conditions for the external series gap unit.

[0052] Example 4 This embodiment provides a method for operating an integrated lightning protection device for power collection lines in new energy power plants, including the following steps: Under power frequency operating conditions: Under the action of rated power frequency voltage, the external series discharge gap unit remains in an insulating state, and the capacitive impedance adjustment unit exhibits high impedance characteristics, thereby suppressing power frequency leakage current; Lightning strike conditions: When the lightning impulse voltage reaches the impulse discharge voltage threshold of the external series discharge gap unit, the external series discharge gap unit will break down and discharge preferentially. The capacitive impedance adjustment unit will switch to a low impedance state under high frequency conditions, and the lightning current will be discharged to the ground through the integrated lightning protection device. Lightning current discharge completed: After the voltage returns to the power frequency operating level, the voltage across the external series discharge gap unit decreases and the insulation state is restored. Combined with the high impedance characteristics of the capacitive impedance adjustment unit under power frequency conditions, the power frequency follow current in the integrated lightning protection device circuit is cut off.

[0053] Example 5 Based on Example 4, this example provides a method for operating an integrated lightning protection device for power collection lines in new energy power plants, the method further including: When the lightning current amplitude exceeds the design threshold of the integrated lightning protection device, the parallel gap unit connected in parallel with the capacitive impedance adjustment unit breaks down, forming a low-impedance discharge channel to divert and discharge the lightning current, thereby reducing the current amplitude and energy density borne by the capacitive impedance adjustment unit.

[0054] Example 6 This embodiment provides a method for operating an integrated lightning protection device for power collection lines in new energy power plants, including the following steps: 1) Power frequency operation condition Under normal power frequency voltage, as shown in Figure 2(a), the surge current of the lightning protection device in this embodiment is extremely small, and the current amplitude is stably maintained within the range of 0 to 0.2 A without significant fluctuations. This is because: the external series discharge gap remains insulated under power frequency conditions and does not break down; the capacitive impedance unit exhibits high impedance characteristics under power frequency, effectively suppressing the power frequency current.

[0055] The aforementioned structure and parameter matching enable the device to effectively limit power frequency leakage current when subjected to long-term power frequency operating voltage, avoiding heat accumulation and material aging problems caused by continuous current flow, thereby ensuring the long-term stability and reliability of the lightning protection device under normal operating conditions.

[0056] (2) High-frequency lightning impact conditions When a lightning strike occurs, the external series gap breaks down rapidly, and the capacitive impedance exhibits low impedance characteristics under high-frequency conditions. The lightning protection device quickly conducts, and the simulation results shown in Figure 2(b) indicate that the lightning current rapidly rises to its peak value in a very short time, with a peak current of approximately 12 kA, and decays within a microsecond timescale. This process demonstrates that the lightning protection device of this invention can respond quickly in the early stages of a lightning strike, achieving rapid discharge of lightning energy and effectively suppressing overvoltage levels at the equipment end, thus fully realizing the protection mechanism of "rapid conduction—energy discharge—overvoltage suppression".

[0057] (3) High current impact condition Under high-current impact conditions such as large-amplitude lightning currents or repeated lightning strikes, as shown in Figure 2(c), the parallel gap unit of the lightning protection device is reliably broken down, forming a low-impedance discharge path. At this time, most of the lightning current is preferentially discharged through the gap discharge path, and the current flowing through the arrester varistor is significantly reduced, effectively alleviating the electrothermal stress on the arrester varistor.

[0058] Through the above-mentioned diversion mechanism, the lightning protection device in this embodiment can effectively protect the surge arrester varistor under high current impact conditions, preventing it from being damaged due to overcurrent or energy accumulation, thereby significantly improving the overall lightning protection system's tolerance and operational reliability under strong lightning strikes and multiple impact conditions.

[0059] In summary, the novel lightning protection device of this embodiment achieves adaptive current control under various operating conditions such as power frequency, low-energy lightning strikes, and high-current impacts through the synergistic effect of the external series discharge gap, capacitive impedance adjustment unit, and parallel gap. It takes into account low power frequency leakage, high lightning strike response speed, and strong current shunting capability, and can provide stable, efficient, and long-life lightning protection under complex lightning strike conditions of new energy power station collection lines.

[0060] Example 7 A simulation model of a 35kV wind farm collector line was built based on the ATP-EMTP platform. The lightning current adopted the Heidler model with an amplitude of 36.65kA and a waveform of 2.6 / 50μs. The lightning protection effect of the new lightning protection device was analyzed, and the voltage response of the insulators before and after the installation of the device of this invention was compared.

[0061] As shown in Figure 3, when a conventional zinc oxide surge arrester is installed, flashover occurs at both ends of the insulator. After installing the device of the present invention, the voltage peak at both ends of the insulator in Figures 4(a) and 4(b) is limited to within its insulation withstand level, and there is no high-frequency oscillation, so no flashover occurs.

[0062] As shown in Figure 5, under the conditions of grounding resistance of 20Ω, 50Ω, and 100Ω, the voltage response characteristics of the insulator ends of the traditional lightning protection device and the device of the present invention are compared. Under the same grounding resistance and lightning current amplitude, the conventional lightning arresters in Figures 5(a), 5(c), and 5(e) all exhibit flashover phenomena of varying degrees. The voltage peak at the insulator ends of Figure 5(a) with the conventional lightning arrester installed exceeds 500kV, and the residual voltage is relatively high. After installing the device of the present invention, the voltage peak in Figure 5(b) drops to below 250kV, no flashover occurs, and there is no high-frequency oscillation. At the same time, the residual voltage is significantly reduced.

[0063] In Figures 5(b), 5(d), and 5(f), the device of the present invention was configured in all cases, and no insulation flashover occurred.

[0064] (1) The lightning current amplitude is 48.0 kA and the grounding resistance is 20 Ω. (2) The lightning current amplitude is 39.0 kA and the grounding resistance is 50 Ω. (3) The lightning current amplitude is 21.0 kA and the grounding resistance is 100 Ω. The new integrated lightning protection device exhibits superior lightning protection performance and stronger environmental adaptability, providing an effective technical approach for lightning protection configuration of wind farm collection lines in areas with high soil resistivity.

[0065] Example 8 Taking a 35kV system as an example, the key parameters were determined through component-level testing and simulation optimization as follows: power frequency follow current interruption voltage ≥40.5kV; power frequency discharge voltage 73kV; lightning impulse action voltage 210kV; impulse residual voltage 128kV; current carrying capacity 65kA (4 / 10μs); capacitive coefficient α=0.22; gap spacing 25mm.

[0066] Simulation results show that under this parameter combination, the residual voltage of the device is lower than the insulator's withstand level under lightning impulse, switching wave, and steep wave conditions, and the follow current interruption time is <0.5ms, which meets the requirements of engineering applications.

[0067] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A lightning protection device for a new energy station power collection line, characterized in that, include: The lightning protection device body, wherein an insulator is connected in series with the lightning protection device body; The lightning protection device body includes an external series discharge gap unit (1) and a capacitive impedance adjustment unit (2), wherein: One end of the external series discharge gap unit is electrically connected to the conductor of the protected current collection line, and the other end is electrically connected in series with the capacitive impedance adjustment unit; the free end of the capacitive impedance adjustment unit is electrically connected to the grounding system through an insulator.

2. The integrated lightning protection device for the power collection line of the new energy station according to claim 1, characterized in that, The external series discharge gap unit (1) includes a high-voltage end electrode and a lead electrode. The high-voltage end electrode is used to electrically connect with the conductor of the protected collector line; the lead electrode is electrically connected to the capacitive impedance adjustment unit.

3. The integrated lightning protection device for the power collection line of the new energy station according to claim 1, characterized in that, The capacitive impedance adjustment unit (2) includes a surge arrester valve and a capacitor, wherein the surge arrester valve and the capacitor are connected in parallel.

4. The integrated lightning protection device for the power collection line of the new energy station according to claim 1, characterized in that, The capacitive impedance adjustment unit (2) is also connected in parallel with a parallel gap unit (3).

5. The integrated lightning protection device for the power collection line of the new energy station according to claim 4, characterized in that, The trigger current threshold of the parallel gap unit is greater than the working threshold of the surge arrester valve in the capacitive impedance adjustment unit (2).

6. An integrated lightning protection device for power collection lines in new energy power plants according to claim 1, characterized in that, The volt-ampere characteristic of the capacitive impedance adjustment unit (2) satisfies the nonlinear equation: wherein is a structure dependent constant, is a capacitance coefficient.

7. The integrated lightning protection device for the power collection line of the new energy station according to claim 1, characterized in that, The capacitive impedance adjustment unit exhibits high equivalent impedance characteristics under power frequency and low frequency conditions, and low equivalent impedance characteristics under lightning impulse conditions.

8. The integrated lightning protection device for the power collection line of the new energy station according to claim 1, characterized in that, The external series discharge gap unit is in an insulating state under rated power frequency voltage and operating overvoltage conditions; and in a breakdown discharge state under lightning impulse overvoltage conditions.

9. A working method of an integrated lightning protection device for a power collection line of a new energy station, characterized in that, The lightning protection device according to claim 1 includes the following steps: Under power frequency operating conditions: Under the action of rated power frequency voltage, the external series discharge gap unit remains in an insulating state, and the capacitive impedance adjustment unit exhibits high impedance characteristics, thereby suppressing power frequency leakage current; Lightning strike conditions: When the lightning impulse voltage reaches the impulse discharge voltage threshold of the external series discharge gap unit, the external series discharge gap unit will break down and discharge preferentially. The capacitive impedance adjustment unit will switch to a low impedance state under high frequency conditions, and the lightning current will be discharged to the ground through the integrated lightning protection device. Lightning current discharge completed: After the voltage returns to the power frequency operating level, the voltage across the external series discharge gap unit decreases and the insulation state is restored. Combined with the high impedance characteristics of the capacitive impedance adjustment unit under power frequency conditions, the power frequency follow current in the integrated lightning protection device circuit is cut off.

10. The working method of the integrated lightning protection device for the power collection line of the new energy station according to claim 9, characterized in that, When the lightning current amplitude exceeds the design threshold of the integrated lightning protection device, the parallel gap unit connected in parallel with the capacitive impedance adjustment unit breaks down, forming a low-impedance discharge channel to divert and discharge the lightning current, thereby reducing the current amplitude and energy density borne by the capacitive impedance adjustment unit.

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