Medium voltage direct current distribution panel magnetic field control method, medium voltage direct current distribution panel

Abstract

The application discloses a medium-voltage direct-current distribution board magnetic field control method and a medium-voltage direct-current distribution board. The external magnetic field characteristics of a main busbar and a distribution board complete cabinet in a power-on state are determined through simulation. The magnetic field characteristics of the main busbar in the initial design are determined. Then, the magnetic field characteristics after taking magnetic field shielding measures are determined. Then, the main busbar is optimized. The number and arrangement mode of the main busbar are determined. Then, the size and arrangement interval of the busbar are determined. Then, the magnetic field characteristics of the optimized main busbar are determined. Finally, the optimized scheme of the main busbar capable of greatly reducing the external magnetic field of the medium-voltage direct-current distribution board is determined through simulation result comparison. The application can greatly suppress the magnetic field generated by the busbar when the busbar passes through a normal working current, thereby reducing the influence on the magnetic characteristics of a ship, and ensuring the safe navigation of the ship.

Description

Technical Field

[0001] This invention relates to ship electrical systems, specifically to a magnetic field control method for a medium-voltage DC switchboard and a medium-voltage DC switchboard. Background Technology

[0002] Magnetic stealth is a crucial component of ship stealth, and improving it can effectively defend against magnetic mine attacks. The ultimate goal of ship magnetic stealth design is to reduce the ship's magnetic properties and thus minimize the activation of mine magnetic fuses.

[0003] Ships equipped with integrated power systems are equipped with large-capacity medium-voltage DC switchboards. Under normal operating conditions, the current passing through the main busbar of the switchboard reaches thousands of amperes. The resulting magnetic field will be superimposed on the ship's magnetic field, resulting in increased magnetic characteristics of the ship, poorer magnetic stealth, and a threat to the ship's safety. Summary of the Invention

[0004] To address the issue that medium-voltage DC power distribution boards can easily lead to a decrease in magnetic stealth, the present invention aims to provide a method for controlling the magnetic field of a medium-voltage DC power distribution board and a medium-voltage DC power distribution board that can significantly suppress the magnetic field generated when the busbar carries normal operating current, thereby reducing the impact on the magnetic characteristics of the ship and ensuring the safe navigation of the ship.

[0005] The technical solution adopted in this invention is: A magnetic field control method for a medium-voltage DC switchboard is proposed. The method involves determining the external magnetic field characteristics of the main busbar and the entire switchboard cabinet under energized conditions through simulation. First, the magnetic field characteristics of the main busbar under the initial design are determined. Then, the magnetic field characteristics after implementing magnetic field shielding measures are determined. Next, the main busbar is optimized by first determining the number and arrangement of the main busbars, then determining the busbar dimensions and spacing, and finally determining the optimized magnetic field characteristics. Finally, the optimized main busbar scheme that significantly reduces the external magnetic field of the medium-voltage DC switchboard is determined through simulation result comparison.

[0006] Furthermore, when optimizing the main bus, the size of the bus is determined based on the voltage and current of the distribution board, and the spacing of the bus is determined based on the space of the distribution board and the position of other components.

[0007] Furthermore, the bus parameters used in the simulation are the same as those on the actual ship, including the number of busbars, materials, internal arrangement of the busbars, and the magnitude of the DC current passing through them.

[0008] A medium-voltage DC distribution board has a main busbar divided into two groups, left and right, each group having four copper busbars arranged from front to back: positive, negative, negative, and positive.

[0009] The beneficial effects of this invention are: This invention can significantly suppress the magnetic field generated by the busbar when it carries normal operating current, thereby reducing the impact on the ship's magnetic properties and ensuring the ship's safe navigation. Attached Figure Description Figure 1 This is a schematic diagram of the main busbar under the initial design.

[0010] Figure 2 It is the location for magnetic field assessment.

[0011] Figure 3 It is a simulation model of the medium-voltage DC distribution board under the initial design of the main bus.

[0012] Figure 4 It is a simulation model of a medium-voltage DC distribution board after optimization of the main busbar. Detailed Implementation

[0013] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to specific embodiments.

[0014] This application discloses a magnetic field control method for a medium-voltage DC switchboard. The method uses simulation to determine the external magnetic field characteristics generated by the main busbar and the entire switchboard cabinet under energized conditions. First, the magnetic field characteristics of the main busbar under the initial design are determined. Then, the magnetic field characteristics after implementing magnetic field shielding measures are determined. Next, the main busbar is optimized by first determining the number and arrangement of the main buses, then determining the busbar dimensions and spacing, and finally determining the optimized magnetic field characteristics. Finally, the optimized main busbar scheme that significantly reduces the external magnetic field of the medium-voltage DC switchboard is determined through simulation result comparison. Specifically, when optimizing the main busbar, the busbar dimensions are determined based on the voltage and current of the switchboard, and the busbar spacing is determined based on the space of the switchboard and the positions of other components, ensuring that the dimensions and spacing meet actual installation requirements. The busbar parameters used in the simulation are the same as those used in the actual ship, including the number of buses, materials, cabinet layout, and the magnitude of the DC current, making the simulation more realistic.

[0015] Example This study investigates the magnetic field control of a medium-voltage DC switchboard to be used on a certain ship. Simulations are used to determine the characteristics of the external magnetic field generated by the main busbar and the entire switchboard cabinet under energized conditions. Step 1: Determine the magnetic field characteristics of the main bus under the initial design. The main busbar is divided into left and right groups. In the initial design, each group consisted of two copper busbars, one positive and one negative, with the positive terminal in front and the negative terminal behind, with a spacing of 90mm between the positive and negative terminals. Figure 1As shown; the outer cabinet panel and internal partition of the DC distribution board are made of ordinary steel plate with a thickness of 2.6mm and a magnetic permeability of 218; the unidirectional DC current passing through the main busbar is 5kA; taking a centerline at a certain depth below the plane where the distribution board is located, the parallel lines 8.5m to the left and right of the centerline are the magnetic field evaluation lines, as shown. Figure 2 As shown in the figure, the box represents the top view projection of the switchboard; the numerical model of the medium-voltage DC switchboard is established as follows. Figure 3 As shown, according to Flux software simulation calculations, the maximum magnetic field generated by the medium-voltage DC distribution board at this depth is 129 nT.

[0016] Step 2: Determine the magnetic field characteristics after implementing magnetic field shielding measures. For DC power distribution boards, using a shell made of high magnetic permeability material is a feasible method of magnetic field shielding.

[0017] By replacing the material of the DC distribution board's outer shell with special steel with a magnetic permeability of 1500, the total magnetic field of the distribution board was re-evaluated. When a 5kA DC current passed through the main busbar, the maximum magnetic field generated by the DC distribution board on the evaluation line was 162nT, which was slightly larger than the original distribution board's magnetic field.

[0018] This indicates that using high magnetic permeability materials as the outer shell of the distribution board has limited shielding effect on the magnetic field generated by the busbar.

[0019] The third step is to optimize the main busbar and determine the magnetic field characteristics of the optimized main busbar. Due to the limited internal space of the DC distribution board, and considering the actual situation, each pair of main buses was split from two (positive and negative) into four (positive, negative, negative, and positive) buses, with each bus carrying a current of 2.5kA; for example... Figure 4 As shown, according to Flux software simulation calculations, the maximum magnetic field generated by the medium-voltage DC distribution board on the magnetic field evaluation line is 18nT. That is, the magnetic field generated by the DC distribution board after the main busbar optimization configuration is reduced by about 86% compared with the original distribution board.

[0020] This indicates that, after optimization, the external magnetic field of the DC power distribution board has been effectively controlled.

[0021] Based on the above optimized main bus scheme, this application also provides a medium-voltage DC distribution board, whose main bus is divided into left and right groups, each group having four copper busbars from front to back: positive, negative, negative, and positive. The medium-voltage DC distribution board has been verified by simulation to effectively control the external magnetic field of the medium-voltage DC distribution board and significantly reduce the impact on the overall magnetic field of the ship.

[0022] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for controlling the magnetic field of a medium-voltage DC distribution board, characterized in that, The external magnetic field characteristics generated by the main bus and the entire distribution board cabinet under energized conditions were determined through simulation: First, the magnetic field characteristics of the main bus under the initial design were determined; Then determine the magnetic field characteristics after taking magnetic field shielding measures; Then the main busbar is optimized. First, the number and arrangement of the main busbars are determined, then the size and spacing of the busbars are determined, and finally the magnetic field characteristics of the optimized main busbars are determined. Finally, by comparing simulation results, the optimal main busbar scheme that can significantly reduce the external magnetic field of medium-voltage DC distribution boards was determined. When optimizing the main bus, the size of the bus is determined based on the voltage and current of the distribution board, and the spacing of the bus is determined based on the space of the distribution board and the position of other components.

2. The magnetic field control method for medium-voltage DC distribution boards as described in claim 1, characterized in that: The bus parameters used in the simulation are the same as those on the actual ship, including the number of busbars, materials, internal arrangement of the busbars, and the magnitude of the DC current passing through them.

3. A medium-voltage DC switchboard, characterized in that: The medium-voltage DC distribution board magnetic field control method described in claim 1 or 2 is adopted, wherein the main busbar is divided into two groups, left and right, and each group has four copper busbars arranged from front to back: positive, negative, negative, and positive.

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