Low-residual-pressure converter valve arrester

Abstract

The application discloses a low-residual-voltage converter valve lightning arrester, which is developed by using a low-residual-voltage resistor disc, improving a charge rate, increasing the number of parallel columns, increasing the diameter of the resistor disc, improving the gradient of the resistor disc and the like, so as to reduce the insulation level, manufacturing difficulty and cost of the converter valve of an extra-high voltage direct-current converter station in a high-altitude area.

Description

Technical Field

[0001] This invention relates to the field of surge arrester technology, and more specifically, to a low residual voltage converter valve surge arrester. Background Technology

[0002] To promote the development and utilization of hydropower resources in Southwest China and support the economic and social development of the region, especially the Tibetan areas, the State Grid Corporation of China plans to construct ultra-high-voltage direct current (UHVDC) transmission projects in the upper reaches of the Jinsha River. The sites for these converter stations are generally located at high altitudes; for example, the initial site selection on the upper reaches of the Jinsha River is approximately 4000 meters above sea level. High altitudes reduce the external insulation withstand capability of equipment. Furthermore, the high insulation requirements for converter valves in UHVDC converter stations will make manufacturing difficulties and costs significant constraints on the project design and construction.

[0003] Therefore, it is urgent to optimize the insulation level of high-altitude converter stations (mainly by reducing the residual voltage of surge arresters) from aspects such as insulation coordination and surge arrester design, reduce the insulation level, manufacturing difficulty and cost of converter valves, and ensure the smooth progress of the project. Summary of the Invention

[0004] The technical problem to be solved by this invention is how to develop a low residual voltage converter valve surge arrester, thereby reducing the insulation level, manufacturing difficulty and cost of converter valves in UHVDC converter stations in high-altitude areas, and providing a low residual voltage converter valve surge arrester.

[0005] According to the present invention, a low residual voltage converter valve surge arrester is provided, comprising:

[0006] The surge arrester consists of an upper valve surge arrester element 1, a lower valve surge arrester element 2, a first equalizing ring 3, a second equalizing ring 4, a third equalizing ring 5, a first flange 6, and a second flange 7.

[0007] The first equalizing ring 3 is located at the upper end of the upper valve surge arrester element 1;

[0008] The second equalizing ring 4 is located at the connection between the upper valve surge arrester element 1 and the lower valve surge arrester element 2, and the upper valve surge arrester element 1 and the lower valve surge arrester element 2 are connected in series through the second equalizing ring 4.

[0009] The second equalizing ring 4 is fixed to the upper valve surge arrester element 1 via the first flange 6;

[0010] The third equalizing ring 5 is located at the lower end of the lower valve surge arrester element 2, and the third equalizing ring 5 is fixed to the lower valve surge arrester element 2 through the second flange 7;

[0011] Furthermore, the charge rate of the low residual voltage converter valve surge arrester is greater than 84%, the number of parallel columns of the low residual voltage converter valve surge arrester is greater than 3, the diameter of the resistor element of the low residual voltage converter valve surge arrester is greater than 105mm, and the resistor element gradient of the low residual voltage converter valve surge arrester is greater than 250V / mm.

[0012] Optionally, the charge rate of the low residual voltage converter valve arrester is selected to be 92%.

[0013] Optionally, the number of parallel columns of the low residual pressure converter valve surge arrester is selected as 6 columns.

[0014] Optionally, the number of parallel columns of the low residual pressure converter valve arrester is selected as 8 columns.

[0015] Optionally, the diameter of the resistor element in the low residual voltage converter valve surge arrester is selected to be 136mm.

[0016] Optionally, the resistance gradient of the low residual voltage converter valve arrester is selected to be 350V / mm.

[0017] This invention employs methods such as low residual voltage resistors, increasing charge rate, increasing the number of parallel columns, increasing resistor diameter, and improving resistor gradient to develop a low residual voltage converter valve surge arrester, thereby reducing the insulation level, manufacturing difficulty, and cost of converter valves in UHVDC converter stations in high-altitude areas. Attached Figure Description

[0018] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0019] Figure 1 This is a structural diagram of a low residual voltage converter valve surge arrester according to an embodiment of the present invention;

[0020] Figure 2 This is a structural diagram of a parallel column structure with 6 columns according to an embodiment of the present invention;

[0021] Figure 3 This is a structural diagram of an embodiment of the present invention with 8 parallel columns. Detailed Implementation

[0022] Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0023] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0024] like Figure 1As shown, an embodiment of the present invention provides a low residual pressure converter valve surge arrester, comprising an upper valve surge arrester element 1, a lower valve surge arrester element 2, a first equalizing ring 3, a second equalizing ring 4, a third equalizing ring 5, a first flange 6, and a second flange 7, wherein the first equalizing ring 3 is located at the upper end of the upper valve surge arrester element 1; the second equalizing ring 4 is located at the connection between the upper valve surge arrester element 1 and the lower valve surge arrester element 2, and the upper valve surge arrester element 1 and the lower valve surge arrester element 2 are connected in series through the second equalizing ring 4; The second equalizing ring 4 is fixed to the upper valve surge arrester element 1 via the first flange 6; the third equalizing ring 5 is located at the lower end of the lower valve surge arrester element 2, and the third equalizing ring 5 is fixed to the lower valve surge arrester element 2 via the second flange 7; furthermore, the charge rate of the low residual voltage converter valve surge arrester is greater than 84%, the number of parallel columns of the low residual voltage converter valve surge arrester is greater than 3, the diameter of the resistor element of the low residual voltage converter valve surge arrester is greater than 105mm, and the resistor element gradient of the low residual voltage converter valve surge arrester is greater than 250V / mm.

[0025] Optionally, the charge rate of the low residual voltage converter valve arrester is selected to be 92%.

[0026] Optionally, such as Figure 2 As shown, the number of parallel columns of the low residual voltage converter valve surge arrester is selected as 6 columns. Each parallel column consists of a resistor element, a shorting element, and a resistor element column.

[0027] Optionally, such as Figure 3 As shown, the number of parallel columns of the low residual pressure converter valve surge arrester is selected as 8 columns.

[0028] Optionally, the diameter of the resistor element in the low residual voltage converter valve surge arrester is selected to be 136mm.

[0029] Optionally, the resistance gradient of the low residual voltage converter valve arrester is selected to be 350V / mm.

[0030] In this embodiment of the invention, the reference voltage of the surge arrester is primarily determined by the allowable charge rate. The charge rate of surge arresters in my country's DC systems largely follows data from the early stages of DC engineering construction in the 1980s, with the charge rate of converter valve surge arresters being approximately 84%. This invention proposes that, by reducing the leakage current of the surge arrester and improving its aging performance, the charge rate of the converter valve surge arrester be selected at 92%. By increasing the charge rate, the residual voltage of the converter valve surge arrester can be reduced by approximately 8%.

[0031] In this embodiment of the invention, the conventional converter valve surge arrester has 2 or 3 parallel columns. Research has shown that increasing the number of parallel columns reduces the current flowing through the resistor during an impulse action, thus lowering the residual voltage of the surge arrester. Therefore, this invention proposes a converter valve surge arrester designed with 6 or 8 parallel columns, resulting in a reduction of approximately 2% in the residual voltage of the surge arrester.

[0032] In this embodiment of the invention, the diameter of the resistor element used in traditional converter valve surge arresters is generally between 100mm and 105mm. Research has shown that increasing the resistor element diameter can reduce the residual voltage ratio of the surge arrester. Therefore, this invention proposes using a resistor element with a diameter of approximately 136mm for the converter valve surge arrester, which will reduce the residual voltage of the surge arrester by approximately 2%.

[0033] In this embodiment of the invention, it was found that changing the resistor sheet formulation and process can reduce the residual voltage ratio of the surge arrester. Therefore, this invention improves grain growth, reduces the scattering effect of internal grain defects on electrons, increases grain conductivity, reduces the residual voltage ratio of the resistor sheet, and increases the breakdown field strength of individual grain boundaries by changing the resistor sheet formulation and process, thereby increasing the resistor sheet gradient to 350V / mm or even higher, and reducing the residual voltage of the surge arrester by about 2%.

[0034] Therefore, the low residual voltage converter valve surge arrester proposed in this invention reduces the residual voltage of the surge arrester by about 14% compared with the traditional design.

[0035] In summary, this invention employs methods such as low residual voltage resistors, increasing charge rate, increasing the number of parallel columns, increasing resistor diameter, and improving resistor gradient to develop a low residual voltage converter valve surge arrester, thereby reducing the insulation level, manufacturing difficulty, and cost of converter valves in UHVDC converter stations in high-altitude areas.

[0036] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A low-residual-voltage surge arrester for a converter valve, characterized in that Comprise: The upper valve arrester element (1), the lower valve arrester element (2), the first grading ring (3), the second grading ring (4), the third grading ring (5), the first flange (6) and the second flange (7), wherein The first grading ring (3) is located at the upper end of the upper valve arrester element (1); The second grading ring (4) is located at the connection of the upper valve arrester element (1) and the lower valve arrester element (2), and the upper valve arrester element (1) and the lower valve arrester element (2) are connected in series through the second grading ring (4); The second grading ring (4) is fixed with the upper valve arrester element (1) through the first flange (6); The third grading ring (5) is located at the lower end of the lower valve arrester element (2), and the third grading ring (5) is fixed with the lower valve arrester element (2) through the second flange (7); And, the charge rate of the low residual voltage converter valve arrester is greater than 84%, the number of parallel columns of the low residual voltage converter valve arrester is greater than 3 columns, the diameter of the resistor sheet of the low residual voltage converter valve arrester is greater than 105mm, and the resistor sheet gradient of the low residual voltage converter valve arrester is greater than 250V / mm.

2. A low residual voltage surge arrester for a commutator according to claim 1, characterized in that The charge rate of the low residual voltage converter valve arrester is selected as 92%.

3. A low residual voltage surge arrester for a commutator according to claim 1, characterized in that The number of parallel columns of the low residual voltage converter valve arrester is selected as 6 columns.

4. A low residual voltage surge arrester for a commutator according to claim 1, characterized in that The number of parallel columns of the low residual voltage converter valve arrester is selected as 8 columns.

5. A low residual voltage converter valve arrester according to claim 1, characterized in that The diameter of the resistor sheet of the low residual voltage converter valve arrester is selected as 136mm.

6. A low residual voltage converter valve arrester according to claim 1, characterized in that The resistor sheet gradient of the low residual voltage converter valve arrester is selected as 350V / mm.

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