In multi-infeed DC systems,there exist subsequent commutation failure,excessive reactive power demand and slowDC power recovery after the failure of AC systems,which probably further degrades the stability of the system.In order to solve this problem,the voltage-active power recovery characteristics of both the single-infeed and the multi-infeed DC systems are analyzed,and a progressive staggering recovery index of multi-infeed DC systems is put forward based on the relationship among multi-infeed effective short-circuit ratio,multi-infeed interaction factor and DC power transmission capacity.Afterwards,according to the value of this index,a staggering recovery strategy for the subsystems of multi-infeed DC systems is formulated.The proposed strategy is then realized by setting a first-order lag after the voltage-dependent current order limiter of each DC system and by controlling the time constant.Moreover,by using the dynamic reactive power peak size,the time consumption for 90% of active power recovery and the whole reactive power demand of multi-infeed DC systems,the recovery performance of the multi-infeed DC system is quantized.Finally,a simulation system with seven-infeed DC receiving end is constructed on PSCAD/EMTDC to verify the effectiveness of the proposed multi-infeed DC coordinated and progressive staggering recovery strategy.
XIA Cheng-jun HUANG Hao-yu TU Liang HONG Chao
. Coordinated and Progressive Recovery Strategy for Failure at Receiving End of Multi-Infeed DC Systems[J]. Journal of South China University of Technology(Natural Science), 2016
, 44(4)
: 47
-54
.
DOI: 10.3969/j.issn.1000-565X.2016.04.008