Compound type high-voltage direct current transmission system

Abstract

The invention provides a compound type high-voltage direct current transmission system which comprises at least one rectifier station, a contravariant station and an aerial electric power transmission line. The rectifier station and the contravariant station both comprise positive electrodes and negative electrodes, a thyristor current converter is adopted in the rectifier station, a positive electrode and a negative electrode of the thyristor current converter both comprise at least one twelve-impulse thyristor current converter, a voltage source current converter which has direct current fault processing capacity is adopted in the contravariant station, and a positive electrode and a negative electrode of voltage source current converter both comprise at least one multi-level current converter with two series-wound modules. Connection points of the positive electrodes and negative electrodes of each station are connected with a grounding electrode or a local network according to operation mode, a double electrode ground return wire or a single ground return wire or a single electrode metal return wire, of the direct current transmission system. By means of the compound type high-voltage direct current transmission system, a commutation failure of the contravariant station in the direct current transmission system is avoided, operation mode is flexible, reliability is high, and project cost is reduced. Besides, the advantages of the thyristor current converter and the voltage source current converter are integrated, and thus the compound type high-voltage direct current transmission system has direct current side fault processing capacity.

Description

technical field [0001] The invention is a compound high-voltage direct-current transmission system capable of dealing with direct-current side faults, in particular to a rectifier station using a thyristor converter and an inverter station using a multi-level modular voltage source commutation with direct-current fault handling capability The invention relates to a high-voltage direct current transmission system of a device, belonging to the field of high-voltage direct current transmission. Background technique [0002] The high-voltage direct current transmission system using thyristor converters in both the rectifier station and the inverter station has the advantages of low loss, relatively low cost, and high reliability. However, commutation failures are prone to occur during the inverter operation of thyristor converters. For multiple DC centralized feed-in grids, AC system failures may cause multiple converter stations to fail commutation at the same time, causing a h...

AI Technical Summary

Problems solved by technology

Voltage source converter topologies based on two-level, three-level, and half-H-bridge sub-modules do not have the ability to handle DC faults. For the rectifier circuit, the DC side fault restart method in the thyristor converter HVDC power transmission system cannot be used, and the AC side circuit breaker can only be tripped for fault handling, and the response speed is slow, so it is only suitable for low-failure rate cable lines, not Suitable for power overhead lines prone to temporary faults

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