Lightning protection circuit of direct-current system

Abstract

The invention belongs to the design field of lightning protection circuits, and provides a lightning protection circuit of a direct-current system. The circuit comprises a primary lightning protection circuit which is in parallel connection with to-be-protected direct-current equipment in the direct-current system. A lightning current suppression circuit is in parallel connection between the primary lightning protection circuit and the to-be-protected direct-current equipment. When lightning currents are introduced through a power wire, and a part of lightning currents pass a primary lightning protection discharging place. Then, transient high impedance is formed as for remained lightning current waveforms by the lightning current suppression circuit, so that the primary lightning protection circuit can be connected quickly to discharge more lightning current energy, the lightning currents are prevented from spreading along the power wire and lightning protection effect is optimized. Meanwhile, discharging distribution of the lightning currents no longer only depends on resistance of a grounding grid and characteristic impedance of the to-be-protected equipment, so that resistance requirements on the grounding grid can be relaxed, construction and maintenance costs of the grounding grid are remarkably reduced and construction period of the grounding grid is shortened.

Description

technical field [0001] The invention belongs to the field of lightning protection circuit design, in particular to a lightning protection circuit applied in a direct current system. Background technique [0002] In the prior art, the lightning protection method of the DC system is to provide a grounding network with a small grounding resistance. If the DC equipment and AC equipment of the DC system are together, it is only necessary to connect the grounding point of the DC equipment with the grounding grid; if the DC equipment and AC equipment of the DC system are not The base stations of the AC power supply are far apart, and the long overhead lines are likely to be invaded by direct lightning or induced lightning again. In this case, a special grounding network must be built to cooperate with the surge protector to discharge the lightning current. [0003] In the lightning protection method of the above-mentioned DC system, the smaller the resistance value of the groundin...

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Problems solved by technology

[0006] The purpose of the embodiments of the present invention is to provide a lightning protection circuit for a DC system, which aims to solve the problem that in the current lightning protection mode of a DC system, there is only one level of surge protector, and the surge protector cannot fully protect the DC equipment. If it is short-circuited, part of the lightning strike current flows through the protected load equipment, and the lightning protection effect is uncontrollable. At the same time, due to the limitation of the resistance value of the grounding grid, the construction cost of the grounding grid is high.

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