摘要
特高压混合级联直流输电系统在逆变侧采用了多个模块化多电平换流器(modular multilevel converter,MMC)并联后与电网换相换流器(line commutated converter,LCC)串联的结构,其中定电压控制MMC在系统运行工况改变或发生故障时会产生功率返送现象。为了避免计划之外的功率返送现象,提出了一种简单有效的有功调控策略来改善功率返送现象,其基本原理为通过调节定功率MMC的有功指令来维持MMC换流站功率平衡。基于PSCAD/EMTDC建立了相应的电磁暂态模型,分别在不同工况下对有功调控策略的功率返送改善效果进行对比,电磁暂态仿真结果表明有功调控策略能够有效改善功率返送现象,而且也可以加快故障恢复速度,降低故障过程中及故障后系统主要电气量的波动。
The hybrid cascaded UHVDC transmission system adopts the structure of multiple modular multilevel converter(MMC)connected in parallel with line-commutated-converter in series on the inverter side,in which the constant voltage control MMC will produce power return phenomenon when the system operating conditions change or faults occur.In order to avoid the unplanned power return phenomenon,a simple and effective active power control strategy is proposed to improve the power return phenomenon.The basic principle is to maintain the power balance of the MMC converter station by adjusting the active power instructions of the fixed power control MMC.The corresponding electromagnetic transient model is established based on PSCAD/EMTDC,and the power return improvement effects of the active power control strategy are compared under different working conditions.The electromagnetic transient simulation results show that the active power control strategy can not only effectively improve the power return phenomenon,but also accelerate the fault recovery speed and reduce the fluctuation of the main electrical quantity of the system during and after faults.
作者
樊鑫
郭春义
FAN Xin;GUO Chunyi(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources,North China Electric Power University,Beijing 102206,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2022年第12期5037-5046,共10页
High Voltage Engineering
基金
国家自然科学基金(51877077)。
