AC Filterless Flexible LCC HVDC with Reduced Voltage Rating of Controllable Capacitors

Research output: Contribution to journalArticlepeer-review

Colleges, School and Institutes


This paper presents a further significant development to the developed Flexible LCC HVDC system with controllable capacitors [1], which can provide AC
voltage/reactive power control [2]. The development involves the installations of fixed parallel capacitors at the valve side of converter transformer, which brings the following significant benefits: 1) AC filter banks at the AC side of converter
transformer are not needed as a better harmonic filtering performance can be achieved; 2) significant reduction of the HVDC station land requirement (compared with traditional LCC HVDC), as the AC filters together with the switchgear can occupy over 50% of the HVDC station footprint; 3) up to 50%
reduction of the required voltage rating and more than 60% reduction of the capacitance of controllable capacitors for commutation failure elimination can be achieved while similar power system dynamic performance (AC voltage/reactive power control) compared with that in [1] can be demonstrated. Detailed
analyses are presented to illustrate the effective commutation process and superb harmonic filtering performance. Selections of the component values are presented. Simulation results in RTDS are presented to verify the effectiveness of commutation failure elimination, power system dynamic performance, harmonic
filtering performance and show voltage/current stress of the fixed parallel capacitors.


Original languageEnglish
JournalIEEE Transactions on Power Systems
Early online date23 Feb 2018
Publication statusE-pub ahead of print - 23 Feb 2018


  • HVDC , LCC HVDC , flexible LCC HVDC , AC filterless flexible LCC HVDC , AC filter , communication failure , communication failure elimination , controllable capacitor , energy storage , energy storage by capacitor , energy storage by controllable capacitor