WIRE CONNECTING METHOD AND CONVERTER STATION FOR ULTRA-HIGH VOLTAGE DIRECT CURRENT POWER TRANSMISSION, AND ULTRA-HIGH VOLTAGE DIRECT CURRENT POWER TRANSMISSION SYSTEM

摘要

Present invention discloses a connection method for UHVDC transmission, an UHV converter station and an UHVDC transmission system. An UHV LV converter station at rectification side converts a first AC power into a first low voltage DC power and transmits it to an UHV HV converter station at rectification side. The UHV HV converter station at rectification side converts a second AC power into DC power and superimposes it with the first low voltage DC power to generate a first UHV DC power and transmits it to an UHV HV converter station at inversion side. The UHV HV converter station at inversion side outputs a third AC power and a second low voltage DC power, supplies the third AC power to a first load area, and transmits the second low voltage DC power to an UHV LV converter station at inversion side, at which the second low voltage DC power is converted into a fourth AC power, which is supplied to a second load area. One or more UHV MV converter stations can be set between the HV and LV converter stations at both rectification side and inversion side. The respective UHV MV converter stations are cascaded via DC transmission line. The present invention employs a manner of multiple drop points to solve the problem of poor security stability of electric grid caused by feeding a large amount of power via one point.