基于最优潮流理论的MMC-MTDC直接功率控制策略  

Direct power control strategy of MMC-MTDC based on optimal power flow

作　　者：宋平岗 董辉 周振邦 罗剑 SONG Pinggang;DONG Hui;ZHOU Zhenbang;LUO Jian(School of Electrical and Automation Engineering,East China Jiaotong University, Nanchang 330013 ,China)

机构地区：[1]华东交通大学电气与自动化工程学院,江西南昌330013

出　　处：《电力自动化设备》2018年第6期183-189,共7页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(51367008)~~

摘　　要：为了降低多端直流输电系统中电网三相不平衡故障对系统直流电压、功率调节的准确性和快速性的不良影响,基于最优潮流控制理论提出一种直接功率控制策略。首先分析系统损耗对网络潮流的影响,提出无需知道网络参数的最优潮流优化方法,得出期望功率参考指令;然后在对模块化多电平换流器瞬时功率特性分析的基础上,以消除电网不平衡时直流电压波动为目标设计直接功率控制器,针对故障电压降落和交流侧负序电流对功率参考指令进行修正,并采用前馈解耦控制直接建立功率与电压的关系。最后在PSCAD仿真平台上搭建四端直流输电系统,结果表明该控制策略在稳态和暂态故障情况下都可实现系统潮流最优分配和直流电压稳定的目的。In order to reduce the effects of the unbalanced grid fault on the accuracy and rapidity of DC voltage and power regulation in multi-terminal DC transmission systems,a direct power control strategy based on optimal power flow is proposed.The impact of system loss on the power flow of network is analyzed,the power flow optimization method without knowing the network parameters is proposed,and the desired power reference instruction is obtained.Based on analyzing the instantaneous power characteristics of modular multilevel converter,the direct power controller is designed to eliminate the DC voltage fluctuation when the grid is unbalanced.The power reference instruction is modified according to the fault voltage drop and AC side negative sequence current,and the relationship between power and voltage is established directly by feedforward decoupling control.Four-terminal DC transmission system is built on PSCAD simulation platform.Simulative results show that the proposed control strategy can achieve the optimal distribution of power flow and the stability of DC voltage under both steady and transient faults.

关 键 词：模块化多电平换流器 多端直流输电系统 直接功率控制 功率最优分配 系统损耗最小 

分 类 号：TM46[电气工程—电器] TM721.1