含柔性直流电网的交直流混联系统潮流优化控制  

Optimal Control for Power Flow of AC/DC Hybrid System with Flexible DC Grid

作　　者：苗丹[1] 刘天琪[1] 王顺亮[1] 彭乔[1] 

机构地区：[1]四川大学电气信息学院,四川省成都市610065

出　　处：《电力系统自动化》2017年第12期70-76,共7页Automation of Electric Power Systems

基　　金：国家电网公司科技项目(SGRIZLKJ[2015]457)~~

摘　　要：含柔性直流电网的交直流混联系统中换流站功率参考值和下垂系数分别决定了换流站功率分配以及直流电压与直流功率间的斜率控制关系,进而决定了整个交直流混联系统的潮流分布,因此功率参考值和下垂系数的选取至关重要。为此,提出一种含柔性直流电网的交直流混联系统潮流优化控制策略,对功率参考值和下垂系数进行优化,以实现系统网络损耗和直流电压偏差率综合最小的目标。首先,针对含柔性直流电网的交直流混联系统建立了换流站模型、交流系统模型和直流电网模型,并建立了直流电网在主从运行方式或下垂运行方式下的控制方程统一表达式。然后,基于含柔性直流电网的交直流混联系统最优潮流,在线自适应修正换流站功率参考值和下垂系数。最后,对不同运行方式下含五端柔性直流电网的修正IEEE 39和IEEE 118节点交直流混联系统进行计算分析,其结果验证了所述方法的有效性。The power reference value and the droop coefficient determine power distribution of converter stations and the specific relationship between DC voltage and DC power,and then the power flow of the AC/DC hybrid system with flexible DC grid.So it is very important to select the power reference value and the droop coefficient.A power flow optimal control method for AC/DC hybrid system with flexible DC grid is proposed to minimize the network loss and DC voltage deviation rate.Firstly,the models of converter stations,AC system and DC grid for AC/DC hybrid system with flexible DC grid are built,and a unified expression for the governing equations of DC grid in master-slave control and droop control operation modes is put forward.Then,based on the optimal power flow of AC/DC hybrid system with flexible DC grid,the power reference value and the droop coefficient are corrected continuously in the system running process.Finally,the modified IEEE 39-bus system and IEEE 118-bus system containing five ends of flexible DC grid in different operating modes are simulated and analyzed,with the calculation results showing the effectiveness of the proposed method.

关 键 词：电压源换流器 直流电网 交直流混联系统 下垂系数 最优潮流 

分 类 号：TM721.3[电气工程—电力系统及自动化]