A liquid metal current limiting device and method based on an insulating baffle

Abstract

The invention provides a liquid metal current limiting device based on an insulating baffle plate and a liquid metal current limiting method thereof. According to the device, a fast transfer switch and a liquid metal current limiting unit are combined through a mechanical connecting rod so as to enhance the rated current and the current limiting efficiency of a current limiter. The rated current flows through the fast transfer switch and almost has no loss of conduction under the normal working condition; when a short circuit fault occurs, the fast transfer switch is driven to be fast turned on by a metal repulsion plate so that fault current is enabled to be completely transferred to the liquid metal current limiting unit, the metal repulsion plate drives the insulating baffle plate in the current limiting device to move and thus the throughflow hole fluid column in the current limiting unit is enabled to rapidly reduce and contract and strike arc. The arc column in the current limiting unit can be rapidly extruded by the method through mutual staggering of the baffle plate and insulating separating plates so that high-efficiency current limiting can be realized. The liquid metal current limiting device based on the insulating baffle plate is simple in structure and particularly suitable for limiting fault current of the AC / DC system of the field of median and low voltage so as to reduce the burden of circuit breakers and other electrical equipment.

Description

technical field [0001] The invention belongs to the technical field of limiting fault current in high-voltage, medium-voltage or low-voltage switchgear, and in particular relates to a liquid metal current limiting device and method based on an insulating baffle. Background technique [0002] With the increase of power system capacity year by year, the short-circuit capacity and short-circuit current level of the power grid are also increasing, which has become an important problem restricting the operation and development of the power grid. Therefore, research on effective short-circuit current limiting devices to limit the short-circuit capacity of the power system and improve the reliability of the power system has become an urgent issue for the safe and stable operation of the power system and the construction and development of power systems in my country. So far, the technologies applied to short-circuit current limiting mainly include: series current-limiting reactance...

AI Technical Summary

Problems solved by technology

[0003] Series current-limiting reactance is a conventional method for current limiting in the past, but it will inevitably consume electric energy and cause unnecessary economic losses when the power grid is working normally.

[0004] The solid-state short-circuit fault current limiting technology is a current limiting method with the rapid development of power electronics technology. It is mainly composed of conventional reactors, power electronic devices (controllable power semiconductor devices) and controllers. problem, making it limited in application

[0005] The superconducting fault current limiter has attracted much attention after the discovery of high-temperature superconductors in the 1980s, but the application technology of superconducting materials for high-power applications is still immature and the reliability is poor. It is generally difficult to meet the requirements of automatic reclosing and other aspects, and there are also problems such as the need for auxiliary refrigerants such as liquid nitrogen and refrigeration equipment during recovery, and the additional loss is large.

[0006] The current-limiting fuse is currently the only commercial fault current limiter. The short-circuit current can be forcibly limited before reaching the first peak value by using the rapidity of the fuse. However, the fuse is a single action, which reduces the automation of system operation. At the same time, due to its long arcing time, it sacrifices the selectivity of protection for the grid with complex structure

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