多端柔性直流输电系统(voltage source converter based multi-terminal direct current system,VSC-MTDC)是在两端直流输电基础上发展而来的直流输电系统,可靠性高、适用于海上风电并网等场景,相应的控制策略更加多样,其潮流模型也更...多端柔性直流输电系统(voltage source converter based multi-terminal direct current system,VSC-MTDC)是在两端直流输电基础上发展而来的直流输电系统,可靠性高、适用于海上风电并网等场景,相应的控制策略更加多样,其潮流模型也更加复杂。该文分析VSC换流站和MTDC的稳态模型,研究可适用于VSC-MTDC的不同拓扑和连接方式的潮流模型;研究多端直流各种控制策略潮流计算模型的不同点并推导出其方程。在此基础上,提出一种兼具统一迭代法和交替迭代法优点的含VSC-MTDC交直流系统潮流算法,给出初值和边界条件求解方法,对于不同直流拓扑和交流系统都能够进行求解。最后通过2个实际算例验证该文潮流模型的有效性和收敛性,对于不同控制方式、不同运行场景和直流拓扑都能够迅速、稳定收敛。展开更多
直流电压稳定是多端柔性直流输电(voltage source converter based multi-terminal high voltage direct current transimisson,VSC-MTDC)系统稳定的前提。相比特征值法,采用阻抗稳定判据分析VSC-MTDC系统的直流稳定性问题具有建模过程...直流电压稳定是多端柔性直流输电(voltage source converter based multi-terminal high voltage direct current transimisson,VSC-MTDC)系统稳定的前提。相比特征值法,采用阻抗稳定判据分析VSC-MTDC系统的直流稳定性问题具有建模过程简单和物理意义清晰等优势。建立了基于通用下垂控制的多端柔性直流输电系统的直流侧小信号阻抗模型,并采用奈奎斯特稳定判据分析了传输功率、下垂系数、线路长度、换流站直流电容对系统的稳定性的影响。根据稳定性分析,设计相应的仿真实验,验证了该分析方法的准确性。展开更多
In recent years,the interconnection of asynchronous power grids through the VSC-MTDC system has been proposed and extensively studied in light of the potential benefits of economical bulk power exchanges and frequency...In recent years,the interconnection of asynchronous power grids through the VSC-MTDC system has been proposed and extensively studied in light of the potential benefits of economical bulk power exchanges and frequency regulation reserves sharing.This paper proposes an optimized allocation method for sharing frequency regulation reserves among the interconnected power systems and the corresponding frequency regulation control of the VSC-MTDC system under emergency frequency deviation events.First,the frequency regulation reserve classification is proposed.In the classification,the available frequency response capacity reserves of each interconnection are divided into commercial reserves and regular reserves.While the commercial reserves are procured through long-term contracts,the regular reserves are purchased based on market prices of frequency regulation services.Secondly,based on the proposed frequency regulation reserve classification,a novel frequency regulation control is then introduced for the VSC-MTDC system.This control method could minimize the costs of the disturbed power grid for the needed frequency response supports from the other power grids.Simulation verifications are performed on a modified IEEE 39 bus system and a highly reduced power system model representing the North American grids.The simulation verification indicates that the developed frequency regulation control significantly reduced ancillary service costs of the disturbed power grid.展开更多
文摘多端柔性直流输电系统(voltage source converter based multi-terminal direct current system,VSC-MTDC)是在两端直流输电基础上发展而来的直流输电系统,可靠性高、适用于海上风电并网等场景,相应的控制策略更加多样,其潮流模型也更加复杂。该文分析VSC换流站和MTDC的稳态模型,研究可适用于VSC-MTDC的不同拓扑和连接方式的潮流模型;研究多端直流各种控制策略潮流计算模型的不同点并推导出其方程。在此基础上,提出一种兼具统一迭代法和交替迭代法优点的含VSC-MTDC交直流系统潮流算法,给出初值和边界条件求解方法,对于不同直流拓扑和交流系统都能够进行求解。最后通过2个实际算例验证该文潮流模型的有效性和收敛性,对于不同控制方式、不同运行场景和直流拓扑都能够迅速、稳定收敛。
文摘直流电压稳定是多端柔性直流输电(voltage source converter based multi-terminal high voltage direct current transimisson,VSC-MTDC)系统稳定的前提。相比特征值法,采用阻抗稳定判据分析VSC-MTDC系统的直流稳定性问题具有建模过程简单和物理意义清晰等优势。建立了基于通用下垂控制的多端柔性直流输电系统的直流侧小信号阻抗模型,并采用奈奎斯特稳定判据分析了传输功率、下垂系数、线路长度、换流站直流电容对系统的稳定性的影响。根据稳定性分析,设计相应的仿真实验,验证了该分析方法的准确性。
基金This work was supported in part by the Young Innovative Talents Project of Universities and Colleges in Guangdong Province under Grant 2021KQNCX002in part by the Talent Team Building Funds of SCUT under Grant D6211230.
文摘In recent years,the interconnection of asynchronous power grids through the VSC-MTDC system has been proposed and extensively studied in light of the potential benefits of economical bulk power exchanges and frequency regulation reserves sharing.This paper proposes an optimized allocation method for sharing frequency regulation reserves among the interconnected power systems and the corresponding frequency regulation control of the VSC-MTDC system under emergency frequency deviation events.First,the frequency regulation reserve classification is proposed.In the classification,the available frequency response capacity reserves of each interconnection are divided into commercial reserves and regular reserves.While the commercial reserves are procured through long-term contracts,the regular reserves are purchased based on market prices of frequency regulation services.Secondly,based on the proposed frequency regulation reserve classification,a novel frequency regulation control is then introduced for the VSC-MTDC system.This control method could minimize the costs of the disturbed power grid for the needed frequency response supports from the other power grids.Simulation verifications are performed on a modified IEEE 39 bus system and a highly reduced power system model representing the North American grids.The simulation verification indicates that the developed frequency regulation control significantly reduced ancillary service costs of the disturbed power grid.
