针对换流站采用传统下垂控制消纳不平衡功率时引起的直流电压偏差问题,提出一种改进的多点直流电压优化协调控制策略。将不平衡功率作为前馈补偿量注入传统下垂控制中,通过平移下垂曲线来实现直流电压的准无差调节;根据换流站功率裕度,...针对换流站采用传统下垂控制消纳不平衡功率时引起的直流电压偏差问题,提出一种改进的多点直流电压优化协调控制策略。将不平衡功率作为前馈补偿量注入传统下垂控制中,通过平移下垂曲线来实现直流电压的准无差调节;根据换流站功率裕度,来合理设定各换流站的前馈补偿量;为避免不平衡功率过大而导致下垂控制换流站满载运行,将偏差控制引入定有功功率换流站,协同下垂控制换流站消纳余下的不平衡功率。最后,基于PSCAD/EMTDC建立五端基于电压源换流器的多端柔性直流输电系统(voltage source converter based multi-terminal high voltage direct current,VSC-MTDC)系统模型进行仿真,仿真结果表明,所提控制策略可以实现直流电压的准无差调节,优化了系统的潮流分布,提升了系统的运行稳定性。展开更多
The demand of electricity and environmental issues associated with conventional power generation plants are increasing significantly.Modern technology has transformed the conventional power system through the integrat...The demand of electricity and environmental issues associated with conventional power generation plants are increasing significantly.Modern technology has transformed the conventional power system through the integration of distributed generation(DG).With the help of modern power electronic technology,the conventional power system is able to support the integration of DGs based on renewable energy sources(RESs).The systematic combination of DGs with energy storage system forms a microgrid(MG),which can operate in islanded mode or grid-connected mode.The intermittent nature of RES and varying load pose substantial obstacles such as voltage and frequency instability,and the unreliability of RES.Unequal feeder impedances and non-linear loads are considered as present challenges in MG control.Hierarchical control has been useful in undertaking solutions to these issues.This paper covers the deep insight of different control methods applied at the primary and secondary control levels in hierarchical control.In primary control,the classification based on droop and non-droop controls is discussed.The virtual synchronization machine(VSM)based control method is reviewed.Voltage and frequency restoration control and economical operations at decentralized and centralized secondary control are analyzed in detail.Based on the existing literature,critical discussion on MG control and future trends are also presented to provide future research perspectives.展开更多
文摘针对换流站采用传统下垂控制消纳不平衡功率时引起的直流电压偏差问题,提出一种改进的多点直流电压优化协调控制策略。将不平衡功率作为前馈补偿量注入传统下垂控制中,通过平移下垂曲线来实现直流电压的准无差调节;根据换流站功率裕度,来合理设定各换流站的前馈补偿量;为避免不平衡功率过大而导致下垂控制换流站满载运行,将偏差控制引入定有功功率换流站,协同下垂控制换流站消纳余下的不平衡功率。最后,基于PSCAD/EMTDC建立五端基于电压源换流器的多端柔性直流输电系统(voltage source converter based multi-terminal high voltage direct current,VSC-MTDC)系统模型进行仿真,仿真结果表明,所提控制策略可以实现直流电压的准无差调节,优化了系统的潮流分布,提升了系统的运行稳定性。
文摘The demand of electricity and environmental issues associated with conventional power generation plants are increasing significantly.Modern technology has transformed the conventional power system through the integration of distributed generation(DG).With the help of modern power electronic technology,the conventional power system is able to support the integration of DGs based on renewable energy sources(RESs).The systematic combination of DGs with energy storage system forms a microgrid(MG),which can operate in islanded mode or grid-connected mode.The intermittent nature of RES and varying load pose substantial obstacles such as voltage and frequency instability,and the unreliability of RES.Unequal feeder impedances and non-linear loads are considered as present challenges in MG control.Hierarchical control has been useful in undertaking solutions to these issues.This paper covers the deep insight of different control methods applied at the primary and secondary control levels in hierarchical control.In primary control,the classification based on droop and non-droop controls is discussed.The virtual synchronization machine(VSM)based control method is reviewed.Voltage and frequency restoration control and economical operations at decentralized and centralized secondary control are analyzed in detail.Based on the existing literature,critical discussion on MG control and future trends are also presented to provide future research perspectives.
