基于数字孪生的柔性直流电网纵联保护原理  

Pilot Protection of Flexible DC Grid Based on Digital Twin

作　　者：李猛 聂铭 和敬涵[1] 陈可傲 王小君[1] 许寅 LI Meng;NIE Ming;HE Jinghan;CHEN Ke’ao;WANG Xiaojun;XU Yin(School of Electrical Engineering,Beijing Jiaotong University,Haidian District,Beijing 100044,China)

机构地区：[1]北京交通大学电气工程学院,北京市海淀区100044

出　　处：《中国电机工程学报》2022年第5期1773-1782,共10页Proceedings of the CSEE

基　　金：国家自然科学基金项目(52007003);国家自然科学基金委员会–国家电网公司智能电网联合基金项目(U2066210)。

摘　　要：随着柔性直流输电技术的发展,直流电网越来越受到关注。但是,直流电网故障电流上升速度快,与电力电子的弱过流能力形成突出矛盾。直流线路保护需在数毫秒级完成故障判别,同时还需兼顾选择性、可靠性、灵敏性,极具挑战性。该文提出了基于数字孪生的柔性直流输电系统纵联保护原理,在考虑直流线路参数频变的基础上,建立精确的直流线路数字孪生模型,利用状态估计的冗余特征提升了保护的可靠性,通过比较测量值与估计值之间的差异判别故障。仿真表明,所提保护方法可快速可靠地判别区内、外故障,并具有较好的耐受过渡电阻和抗干扰的能力。With the development of flexible DC transmission technology, DC grid has attracted more and more attention. However, the rapid rise of the fault current of the DC grid has a prominent contradiction with the weak overcurrent capability of power electronics. The DC line protection needs to complete the fault recognition in a few milliseconds with selectivity, reliability, and sensitivity, which is extremely challenging. A pilot protection based on digital twins was proposed for flexible DC transmission systems. On the basis of considering the frequency variation of DC line parameters, an accurate DC line digital twin model was established. The redundancy feature of state estimation was used to improve the reliability of protection, and the fault was judged by comparing the difference between the measured value and the estimated value. The simulation shows that the proposed protection principle can quickly and reliably distinguish the internal and external faults. This principle has the advantages of high fault resistance tolerance and strong anti-interference ability.

关 键 词：柔性直流 数字孪生 纵联保护 动态状态估计 频变参数 

分 类 号：TM77[电气工程—电力系统及自动化]