DC control protection method for line ice melting of extra-high voltage DC transmission system

Abstract

The invention relates to a direct-current controlling and protecting method for the ice-melting of an ultra high voltage direct current transmission line. For an once connection mode for the ice-melting of two parallel current converters, the control strategies and methods that two current converters at the rectification side are used for setting the electric current, and one of two current converters at the inversion side is used for setting the electric current, and the other one thereof is used for setting the voltage are adopted so as to ensure that an ultra high voltage direct current system can continuously and stably operates in an ice-melting operating mode. The currentration of each current converter at the rectification side is one half of the input ice-melting current instruction value and is one half of the currentration tracing line current measured value of the current converter used for setting the electric current at the inversion side, thereby the even distribution of the direct current between two current converters at the inversion side can be ensured, and the current converter used for setting the voltage at the inversion side is used for controlling the direct-current voltage of the parallel current converters.

Description

technical field [0001] The invention relates to a DC control and protection method for melting ice of UHV DC transmission system lines. More specifically, the present invention combines the characteristics of parallel connection of UHV DC converters to melt ice, and relates to a UHV DC control and protection system to meet the requirements of line melting ice Control and protection strategies and methods adopted. Background technique [0002] Icing of transmission lines in winter seriously threatens the safe operation of the power system. The increase of ice load on the conductors will cause certain mechanical and electrical damage to the conductors, iron towers and fittings. When the ice is severe, it will cause tripping, disconnection, and tower collapse, leading to power outages and causing great losses to the national economy. [0003] Heating and melting ice technology is to inject DC current into the transmission line to achieve the effect of melting ice by heating th...

AI Technical Summary

Problems solved by technology

[0006] At present, the research on deicing of UHVDC transmission lines mainly focuses on primary system design such as the series-parallel connection of converters, and the research on its DC control and protection strategies and methods is still in its infancy.

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