A repetitive damping lightning suppression line arrester

Abstract

This utility model discloses a repetitive damping lightning suppression line arrester, comprising: a varistor unit for introducing lightning current into the ground; an inductive suppression unit for suppressing sudden changes in lightning current; the varistor unit and the inductive suppression unit are electrically connected and grounded; and a damping suppression unit for adjusting the suppression intensity of the inductive suppression unit according to the intensity of the lightning current, the damping suppression unit being electrically connected to the inductive suppression unit. This solution improves upon the traditional surge arrester based on the nonlinear characteristics of zinc oxide varistors to achieve protection, by setting up an inductive suppression unit to suppress sudden changes in lightning current, and by combining it with a damping suppression unit to adjust the suppression intensity of the inductive suppression unit according to the intensity of the lightning current, effectively suppressing lightning impulse current and protecting power equipment from damage caused by lightning overvoltage.

Description

Technical Field

[0001] This utility model relates to the field of surge arrester design technology, specifically to a repetitive damping lightning suppression line surge arrester. Background Technology

[0002] In the field of power system overvoltage protection, surge arresters are the core devices for preventing damage to electrical equipment from lightning strikes and switching overvoltages. Traditional surge arresters typically achieve their protection function based on the nonlinear characteristics of zinc oxide varistors (MOVs): during normal system operation, the MOV exhibits a high resistance state, allowing only microampere-level leakage current to pass through; however, when the system suffers from lightning overvoltage or switching overvoltage, the resistance of the MOV rapidly decreases, forming a low-impedance path that dissipates the overvoltage energy to the ground, thereby limiting the voltage amplitude across the equipment.

[0003] Although zinc oxide varistors are widely used in AC systems, their technical limitations are becoming increasingly apparent in complex lightning environments and DC systems, specifically manifested in the following problems:

[0004] Insufficient suppression capability for lightning surge steepness: Lightning surge waves have extremely high voltage rise rates (dv / dt). The response speed of traditional MOVs is limited by grain boundary capacitance effects and microstructural characteristics, resulting in conduction delay. During this period, the steep wave front that is not discharged in time will directly affect the protected equipment, causing the risk of insulation breakdown.

[0005] The contradiction between residual voltage and energy absorption: The residual voltage level of zinc oxide varistors is positively correlated with their current carrying capacity, meaning that their residual voltage increases significantly when subjected to large current surges. To reduce the residual voltage, the cross-sectional area of ​​the zinc oxide varistors needs to be increased or the number of varistors connected in parallel needs to be increased, but this will lead to increased size and cost, and may also cause current sharing problems due to the characteristic dispersion of multiple zinc oxide varistors.

[0006] Poor adaptability to DC systems: In DC power systems (such as photovoltaic power generation, rail transit, and energy storage systems), zinc oxide varistors are subjected to continuous unidirectional voltage for extended periods, leading to accelerated degradation of the zinc oxide grain interface barrier, a gradual increase in leakage current, and ultimately thermal collapse. Furthermore, DC systems lack a voltage zero-crossing point; when lightning strikes are superimposed on the DC bus voltage, the conduction threshold of the zinc oxide varistor is difficult to accurately match, easily resulting in a protection blind zone.

[0007] Multi-wave protection failure under complex impacts: Actual lightning impacts often include multiple pulses or subsequent return strokes. Traditional MOVs may experience deterioration of nonlinear characteristics due to temperature rise after the first impact, resulting in a decrease in response capability to subsequent impacts and a reduction in protection performance.

[0008] To address the aforementioned problems, existing technologies attempt to improve the situation by optimizing zinc oxide varistors, improving surge arrester structures (such as series gap design), or introducing auxiliary circuits (such as RC snubber networks). However, these solutions still have the following limitations in DC system applications:

[0009] Although series gap surge arresters can reduce leakage current, the gap breakdown delay will exacerbate the threat of steep waves to equipment.

[0010] Although the parallel connection of multi-stage zinc oxide varistors can improve the current carrying capacity, it may lead to local overload failure of zinc oxide varistors due to the dispersion of device parameters.

[0011] RC buffer networks have limited suppression of high-frequency steep waves and increase system complexity and maintenance costs.

[0012] Therefore, there is an urgent need to develop a new type of line surge arrester that can effectively suppress voltage steepness and reduce residual voltage levels under complex lightning impact environments, and adapt to the special operating conditions of DC systems, thereby improving the insulation safety and operational reliability of power equipment. Utility Model Content

[0013] The technical problem this invention aims to solve is that traditional surge arresters rely on the nonlinear characteristics of zinc oxide varistors for protection, which is insufficient to effectively suppress voltage steepness and reduce residual voltage levels under complex lightning strike conditions, and is also difficult to adapt to the special operating conditions of DC systems. This invention aims to provide a repetitive damping lightning suppression line arrester. Based on the traditional surge arrester that relies on the nonlinear characteristics of zinc oxide varistors for protection, the circuit principle is improved. By setting an inductive suppression unit, the sudden change in lightning current is suppressed. Simultaneously, combined with a damping suppression unit, the suppression strength of the inductive suppression unit is adjusted according to the intensity of the lightning current, effectively suppressing lightning surge current and protecting power equipment from damage caused by lightning overvoltage.

[0014] This utility model is achieved through the following technical solution:

[0015] This solution provides a repetitive damping lightning suppression line arrester, including:

[0016] A varistor unit is used to introduce lightning current into the ground;

[0017] An inductor suppression unit is used to suppress sudden changes in lightning current; the varistor unit is electrically connected to the inductor suppression unit and then grounded.

[0018] A damping suppression unit is used to adjust the suppression intensity of the inductor suppression unit according to the intensity of the lightning current. The damping suppression unit is electrically connected to the inductor suppression unit.

[0019] A further optimization is that the inductor suppression unit includes a single inductor branch or multiple inductor branches; the multiple inductor branches are composed of multiple inductors connected in series.

[0020] A further optimization is that, for the inductor suppression unit of a single inductor branch, the damping suppression unit is connected in parallel across the single inductor.

[0021] For an inductor suppression unit with multiple inductor series branches, the damping suppression unit is connected in parallel across any one of the inductors.

[0022] A further optimized solution is that the damping suppression unit includes a thyristor branch and a control branch;

[0023] The thyristor branch is composed of bidirectional thyristors. The T1 and T2 terminals of the bidirectional thyristor are connected to both sides of an inductor in a single-inductor branch, or the T1 and T2 terminals of the bidirectional thyristor are connected to both sides of any one inductor in a multi-inductor series branch. The control branch is used to adjust the on-state and off-state voltages of the bidirectional thyristor.

[0024] A further optimized scheme is that the control branch includes a voltage divider resistor and an adjustable resistor. One end of the voltage divider resistor is connected to the T1 terminal of the bidirectional thyristor, and the other end of the voltage divider resistor is connected in series with the adjustable resistor and then connected to the T2 terminal of the bidirectional thyristor. The control terminal of the bidirectional thyristor is connected between the voltage divider resistor and the adjustable resistor.

[0025] A further optimization is that the varistor unit is a zinc oxide varistor.

[0026] A further optimized solution includes a packaging shell; the packaging shell is a passive sealed structure; the varistor unit, the inductor suppression unit, and the damping suppression unit are all encapsulated within the packaging shell.

[0027] A further optimized solution includes an insulating support column, on which the inductor is wound.

[0028] A further optimized solution includes a support component, wherein the insulating support column is encapsulated within the encapsulation shell via the support component; the inductor, the support component, and the insulating support column are cast as a single unit.

[0029] A further optimization is that the surge arrester is applied to a DC system with a lightning current ≥1KA.

[0030] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0031] 1. The purpose of this utility model is to provide a repetitive damping lightning suppression line arrester. Based on the traditional surge arrester that realizes protection function based on the nonlinear characteristics of zinc oxide varistors, the circuit principle is improved. By setting an inductive suppression unit, the sudden change of lightning current is suppressed. At the same time, combined with the damping suppression unit, the suppression intensity of the inductive suppression unit can be adjusted according to the intensity of the lightning current, so as to effectively suppress the lightning impulse current and protect the power equipment from damage by lightning overvoltage.

[0032] 2. The purpose of this utility model is to provide a repetitive damping lightning suppression line arrester, which integrates the inductor, support components and insulating support column into a single unit, ensuring normal operation under high lightning current conditions, and is applicable to DC systems with lightning current ≥1KA. Attached Figure Description

[0033] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0034] Figure 1 Schematic diagram of the circuit frame for a repetitive damped lightning suppression line arrester;

[0035] Figure 2 Schematic diagram of the circuit principle of a repetitive damping lightning suppression line arrester;

[0036] Figure 3 A schematic diagram illustrating the working principle of a repetitive damping lightning suppression line arrester.

[0037] Figure 4 This is a schematic diagram of the terminal voltage of a traditional surge arrester;

[0038] Figure 5 A schematic diagram comparing the voltage at the end of the inductor under different inductance values ​​when adjusting the surge arrester of the repetitive damping lightning suppression line;

[0039] Figure 6 A schematic diagram comparing the voltage at the end of the surge arrester under different inductances when adjusting the surge arrester for repetitive damping lightning suppression lines.

[0040] Figure 7 A schematic diagram comparing the loop current waveforms of a traditional surge arrester and a repetitive damping lightning suppression line surge arrester;

[0041] Figure 8 A schematic diagram comparing the energy absorbed by traditional surge arresters and repetitive damping lightning suppression line surge arresters.

[0042] In the attached diagram:

[0043] 1-High voltage electrode of equipment, 2-Zinc oxide varistor, 3-High voltage electrode of inductor, 4-Epoxy insulating board, 5-Inductor suppression unit, 6-Low voltage electrode of inductor, 7-Low voltage electrode of equipment. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0045] Traditional surge arresters rely on the nonlinear characteristics of zinc oxide varistors to achieve protection functions. However, they struggle to effectively suppress voltage steepness and reduce residual voltage levels under complex lightning strike conditions, and are also ill-suited to the special operating conditions of DC systems. Therefore, this solution provides the following embodiments to address the aforementioned technical problems:

[0046] Example 1

[0047] This embodiment provides a repetitive damping lightning suppression line arrester, such as... Figures 1-3 As shown, it includes:

[0048] A varistor unit is used to introduce lightning current into the ground; in this embodiment, the varistor unit is a zinc oxide varistor (MOV).

[0049] Inductor suppression unit 5 is used to suppress sudden lightning current changes; the varistor unit is electrically connected to the inductor suppression unit and then grounded.

[0050] A damping suppression unit is used to adjust the suppression intensity of the inductor suppression unit according to the intensity of the lightning current. The damping suppression unit is electrically connected to the inductor suppression unit.

[0051] The inductor suppression unit includes a single inductor branch or multiple inductor branches; the multiple inductor branches are composed of multiple inductors connected in series; as a preferred embodiment, the inductor suppression unit in this embodiment is a multiple inductor branch, composed of inductors L1 and L2 connected in series; during the conduction of lightning impulse current, a large voltage drop will be generated between the inductors connected in series, which is equivalent to reducing the lightning impulse voltage borne by the protected equipment, thereby further improving the protection level of the equipment; according to experimental data, this voltage drop can reduce the lightning impulse voltage borne by the protected equipment by about 20%.

[0052] For the inductance suppression unit of a single inductor branch, the damping suppression unit is connected in parallel across the single inductor.

[0053] For an inductor suppression unit with multiple inductor series branches, the damping suppression unit is connected in parallel across any one of the inductors. In this embodiment, a zinc oxide varistor 2 is connected to the inductor suppression unit between the high-voltage electrode 1 and the low-voltage electrode 7 of the equipment. The damping suppression unit is connected in parallel across inductor L1. When the voltage at the beginning of the surge arrester's line (on the high-voltage electrode 1 side) rapidly increases to a certain intensity due to lightning strikes, the zinc oxide varistor 2 automatically conducts. At this time, the zinc oxide varistor is in a resistive state, allowing the lightning current to flow and form a path. Then, the inductor suppression unit 5, composed of inductors L1 and L2 connected in series in the circuit, begins to function. Since the current in the inductor cannot change abruptly, its change follows an exponential function law, thus effectively suppressing abrupt changes in the lightning current and reducing the steepness and amplitude of the lightning wave.

[0054] Through the synergistic effect of zinc oxide varistor 2 and inductor suppression unit 5, this solution can effectively suppress the steepness and amplitude of lightning impulse current, reduce the voltage stress borne by the protected equipment, and significantly improve the lightning protection capability of power equipment.

[0055] Zinc oxide varistors can dynamically adjust the series inductance value according to the lightning current intensity to achieve the best current limiting effect, adapt to lightning impulses of different intensities, and improve the flexibility and reliability of protection.

[0056] The damping suppression unit includes a thyristor branch and a control branch;

[0057] The thyristor branch is composed of bidirectional thyristors. The T1 and T2 terminals of the bidirectional thyristor are connected to both sides of an inductor in a single-inductor branch, or the T1 and T2 terminals of the bidirectional thyristor are connected to both sides of any one inductor in a multi-inductor series branch. The control branch is used to adjust the on-state and off-state voltages of the bidirectional thyristor.

[0058] The control branch includes a voltage divider resistor R1 and an adjustable resistor R2. One end of the voltage divider resistor R1 is connected to the T1 terminal of the bidirectional thyristor, and the other end of the voltage divider resistor R1 is connected in series with the adjustable resistor and then connected to the T2 terminal of the bidirectional thyristor. The control terminal of the bidirectional thyristor is connected between the voltage divider resistor R1 and the adjustable resistor R2.

[0059] The on-state and off-state voltages of the bidirectional thyristor can be controlled by adjusting the value of the adjustable resistor R2 to meet different practical needs.

[0060] It also includes a packaging shell; the packaging shell is a passive sealed structure; the varistor unit, the inductor suppression unit and the damping suppression unit are all encapsulated in the packaging shell.

[0061] It also includes an insulating support column, on which the inductor is wound. Figure 2 The epoxy insulation board in the middle is equivalent to an insulating support column used to support the inductor coil;

[0062] It also includes a support member, and the insulating support column is encapsulated in the encapsulation shell by the support member; the inductor, the support member and the insulating support column are cast into one piece.

[0063] The surge arrester is applied to DC systems with lightning current ≥ 1kA. The line surge arrester in this embodiment uses a passive, sealed enclosure, ensuring high reliability and suitability for long-term operation in complex environments.

[0064] Example 2

[0065] This embodiment compares the designed repetitive damping lightning suppression line arrester with a traditional arrester in an experimental test, observing and comparing the operating states of the two arresters. Figure 4 As shown, the terminal voltage of traditional surge arresters reaches over 10KV; while the repetitive damping lightning suppression line arrester of this scheme is equipped with an inductor suppression unit for suppressing current surges, and the suppression intensity of current surges is adjustable; when the inductor suppression unit in the repetitive damping lightning suppression line arrester is adjusted to 2uH and 5uH, the inductor terminal voltage diagram is compared as follows. Figure 5 As shown (blue represents 2uH, red represents 5uH), compare the voltage diagram at the arrester terminals as follows: Figure 6 As shown (green represents the corresponding state of a conventional surge arrester, blue represents the state of a surge arrester with a 2uH inductor suppression unit in a repetitive damping surge arrester, and red represents the state of a surge arrester with a 5uH inductor suppression unit in a repetitive damping surge arrester), compare the circuit current waveforms of the surge arresters as follows: Figure 7 As shown (where green represents the corresponding state of a conventional surge arrester, blue represents the state corresponding to a surge arrester with a 2uH inductor suppression unit in a repetitive damping surge arrester, and red represents the state corresponding to a surge arrester with a 5uH inductor suppression unit in a repetitive damping surge arrester), compare the energy absorbed by the surge arrester as follows: Figure 8 As shown in the figure, compared with traditional surge arresters, the repetitive damping lightning suppression line surge arrester provided by this solution is equipped with an inductive suppression unit for suppressing current surges, realizing dynamic control of the suppression intensity of current surges. This solves the problem of insulation mismatch between the transformer and the surge arrester caused by the static characteristics of the surge arrester. It realizes the adjustment of the suppression intensity of the inductive suppression unit according to the intensity of the lightning current, effectively suppressing the lightning impulse current and protecting power equipment from damage by lightning overvoltage.

[0066] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A repeated damped lightning arrestor for a lightning suppression line, characterized by, include: A varistor unit is used to introduce lightning current into the ground; Inductor suppression unit, used to suppress sudden changes in lightning current; The varistor unit is electrically connected to the inductor suppression unit and then grounded; A damping suppression unit is used to adjust the suppression intensity of the inductor suppression unit according to the intensity of the lightning current. The damping suppression unit is electrically connected to the inductor suppression unit.

2. The repetitive damping lightning suppression line arrester according to claim 1, characterized in that, The inductor suppression unit includes a single inductor branch or multiple inductor branches; the multiple inductor branches are composed of multiple inductors connected in series.

3. A repetitive damping lightning suppression line arrester according to claim 2, characterized in that, For the inductance suppression unit of a single inductor branch, the damping suppression unit is connected in parallel across the single inductor. For an inductor suppression unit with multiple inductor series branches, the damping suppression unit is connected in parallel across any one of the inductors.

4. A repetitive damping lightning suppression line arrester according to claim 3, characterized in that, The damping suppression unit includes a thyristor branch and a control branch; The thyristor branch is composed of bidirectional thyristors. The T1 and T2 terminals of the bidirectional thyristor are connected to both sides of an inductor in a single-inductor branch, or the T1 and T2 terminals of the bidirectional thyristor are connected to both sides of any one inductor in a multi-inductor series branch. The control branch is used to adjust the on-state and off-state voltages of the bidirectional thyristor.

5. A repetitive damping lightning suppression line arrester according to claim 4, characterized in that, The control branch includes a voltage divider resistor and an adjustable resistor. One end of the voltage divider resistor is connected to the T1 terminal of the bidirectional thyristor, and the other end of the voltage divider resistor is connected in series with the adjustable resistor and then connected to the T2 terminal of the bidirectional thyristor. The control terminal of the bidirectional thyristor is connected between the voltage divider resistor and the adjustable resistor.

6. A repetitive damping lightning suppression line arrester according to claim 2, characterized in that, The varistor unit is a zinc oxide varistor.

7. A repetitive damping lightning suppression line arrester according to claim 2, characterized in that, It also includes a packaging shell; the packaging shell is a passive sealed structure; the varistor unit, the inductor suppression unit and the damping suppression unit are all encapsulated in the packaging shell.

8. A repetitive damping lightning suppression line arrester according to claim 7, characterized in that, It also includes an insulating support column, on which the inductor is wound.

9. A repetitive damping lightning suppression line arrester according to claim 8, characterized in that, It also includes a support member, and the insulating support column is encapsulated in the encapsulation shell by the support member; the inductor, the support member and the insulating support column are cast into one piece.

10. A repetitive damping lightning suppression line arrester according to claim 2, characterized in that, The surge arrester is used in DC systems with a lightning current ≥ 1KA.

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