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1. (WO2017190291) POWER CONVERSION CIRCUIT, POWER SYSTEM AND METHOD THEREFOR

Pub. No.:    WO/2017/190291    International Application No.:    PCT/CN2016/080981
Publication Date: Fri Nov 10 00:59:59 CET 2017 International Filing Date: Thu May 05 01:59:59 CEST 2016
IPC: H02J 3/18
H02J 3/36
Applicants: ABB SCHWEIZ AG
ANDERSSON, Mats
CAI, Rong
XIE, Hailian
ZHANG, Lidong
Inventors: ANDERSSON, Mats
CAI, Rong
XIE, Hailian
ZHANG, Lidong
Title: POWER CONVERSION CIRCUIT, POWER SYSTEM AND METHOD THEREFOR
Abstract:
It provides a power conversion circuit for interfacing an AC grid to an HVDC transmission line in islanding condition, a power system and the method thereof. The power conversion circuit includes: a current source conversion circuit configured to supply a power output from the AC grid to a load through the HVDC transmission line; a voltage source conversion circuit configured to compensate a reactive AC power of the AC grid; a measurement unit configured to provide a voltage magnitude measurement and a voltage frequency measurement indicative of the AC grid voltage magnitude and the AC grid voltage frequency; and a controller configured to control the current source conversion circuit to adjust an active power balance between the AC grid and the load based on a voltage magnitude deviation of the voltage magnitude measurement from a predetermined voltage magnitude command and control the voltage source conversion circuit to adjust a reactive power balance between the AC grid and the load based on a voltage frequency deviation of the voltage frequency measurement from a predetermined voltage frequency command. This makes it possible for reducing the complexity of the control for distributed system and thus increasing the power system stability.