提升交流系统暂态稳定性的多端直流最优紧急功率控制  

Optimal control of MTDC for improving rotor angle stability of AC systems

作　　者：章德 田国梁 谭玉东 蒋星 朱思睿 丛凡超 ZHANG De;TIAN Guoliang;TAN Yudong;JIANG Xing;ZHU Sirui;CONG Fanchao(State Grid Hunan Electric Power Co.,Ltd.,Changsha 410004,China;School of Electrical Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]国网湖南省电力有限公司,湖南长沙410004 [2]西安交通大学电气工程学院,陕西西安710049

出　　处：《电力系统保护与控制》2020年第17期37-44,共8页Power System Protection and Control

基　　金：国家电网公司科技项目资助(5216A018000H)。

摘　　要：随着新能源在电力系统中的占比日益增大、系统有效惯量不断降低,交直流系统的暂态稳定性问题变得尤为突出。为解决交直流混联系统有效惯量降低、有效阻尼下降导致的功角稳定性问题,提出一种基于最优控制的多端直流(MTDC)系统的紧急功率调制方案。通过对直流潮流方程在电压平衡点处线性化,建立了含有直流网络功率调制控制的交直流混联系统模型。以发电机转子转速偏差和控制能耗最小为目标,考虑直流母线电压、直流电流、换流器功率等运行约束,得出最优控制律。基于三机九节点的交直流混联系统非线性数值仿真,表明所提控制方案在系统故障和负荷突变情况下均可有效抑制多机系统的第一摇摆,提高交直流系统的暂态稳定性。Transient stability of a meshed AC/DC system when there is decreased effective inertia with high penetration of renewables has become a major challenge.This paper proposes an emergency power modulation scheme of optimal based control of an MTDC grid for improving the rotor angle stability of a power system after considering the reduction of effective inertia and effective damping.First,an AC/DC meshed system model with power modulation control of a DC grid is established by the linearization of power flow equations of the DC grid.Then,the optimal based control rule of an MTDC grid is deduced by the online minimization of the rotor speed deviations of generators and the control energy,when the limits of DC voltage,the DC line current,and the power of converters are satisfied.Finally,the nonlinear numerical simulations of one simple three-generator nine-bus AC/DC meshed system demonstrate the effectiveness of the proposed scheme in three-phase fault and sudden load changes in AC system.The result shows that the proposed scheme stands out for being better able to suppress the first swing damping oscillation performance of a multi-machine system and improving the transient stability of the AC and DC system.

关 键 词：多端直流网络 转子功角稳定 优化控制 电压源型换流器 暂态稳定性 

分 类 号：TM721.3[电气工程—电力系统及自动化]