摘要
多馈入直流系统在交流故障后可能发生后续换相失败、无功功率需求过大及直流有功功率恢复缓慢等问题,严重时甚至会影响系统稳定性.文中分析了单回直流电压功率的恢复特性,并进一步分析了多馈入直流电压功率的恢复特性,基于多馈入有效短路比、多馈入相互作用因子及直流功率输送容量的相互联系,提出了多馈入直流系统渐进错峰有序电压功率恢复指标,并依据此指标的大小制定了各回直流先后错峰恢复的策略.提出在直流控制系统的低压限流单元设置一阶延时取小环节,并通过控制时间常数实现了此恢复策略;然后利用各回直流系统的动态无功功率峰值大小、有功功率恢复至额定值90%时所需的时间、多馈入直流系统整体动态无功功率需求,量化评估了多馈入直流恢复性能.最后在PSCAD/EMTDC上搭建受端七馈入直流模型,验证了多馈入直流协调渐进错峰恢复策略的有效性.
In multi-infeed DC systems,there exist subsequent commutation failure,excessive reactive power demand and slow DC 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.
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2016年第4期47-54,共8页
Journal of South China University of Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(51577071)
广东省自然科学资金资助项目(2015A030313202)~~
关键词
多馈入直流系统
错峰恢复
恢复指标
评估指标
multi-infeed DC system
staggering recovery
recovery index
evaluation index
