基于参考电压二次积分值的柔性直流配电网纵联保护方法  

Pilot Protection Method for Flexible DC Distribution Network Based on Quadratic Integration Value of Reference Voltage

作　　者：王泽乾 丛伟[1] 胡选正 胡谅平 古千硕 王瑞梅[1] WANG Zeqian;CONG Wei;HU Xuanzheng;HU Liangping;GU Qianshuo;WANG Ruimei(Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education(Shandong University),Jinan 250061,China)

机构地区：[1]电网智能化调度与控制教育部重点实验室(山东大学),山东省济南市250061

出　　处：《电力系统自动化》2023年第4期153-162,共10页Automation of Electric Power Systems

基　　金：国家自然科学基金资助项目(51877126)。

摘　　要：柔性直流配电网具有良好的新能源消纳能力,是未来配电网的重要发展方向。电力电子器件的控制响应速度快,使得故障后各阶段切换较快且故障特性都不相同,对保护方法的快速性和适应性提出挑战。在分析柔性直流配电线路故障后各阶段故障特性的基础上,文中提出了一种适用于故障全过程的柔性直流配电网纵联比较保护方法。该方法利用测量点电气量计算相应参考点的电压二次积分值,根据二次积分值的正负极性判断故障点是否位于测量点与参考点之间,以此作为保护单元的故障判断结果。纵联保护通过比较两侧保护单元的故障判断结果对被保护线路发生区内还是区外故障做出判断。利用PSCAD/EMTDC搭建了柔性直流配电网故障仿真模型,通过设置不同位置故障对所提方法的正确性进行验证。仿真结果表明,所提方法可以在故障全过程准确判断出区内还是区外故障,具有较高的可靠性、良好的适用性和较强的抗过渡电阻能力,对分布电容和噪声干扰导致的计算误差也具有良好的应对能力。Flexible DC distribution network is an important development direction of the future distribution network because it has good renewable accommodation capability. The control response speed of power electronic devices is fast, which leads to the fast switching of each stage after the fault and different fault characteristics, and brings the challenges to the rapidity and adaptability of the protection methods. On the basis of analyzing the fault characteristics of each stage after the fault of flexible DC distribution lines, this paper proposes a pilot comparison protection method for flexible DC distribution networks, which is applicable to the whole fault process. In this method, the quadratic integration value of the voltage at the corresponding reference point is calculated by the electrical quantities at the measuring point. According to the positive and negative polarity of the quadratic integration value,it is judged whether the fault point is between the measuring point and the reference point, which is used as the fault judgment result of the protection unit. The pilot protection can judge the internal and external faults of the protected line by comparing the fault judgment results of the protection units on both ends. The fault simulation model of the flexible DC distribution network is built using PSCAD/EMTDC, and the correctness of the proposed method is verified by setting different fault locations. The simulation results show that the proposed method can accurately judge the internal and external faults in the whole fault process,and has high reliability, good applicability and strong resistance to transition resistance. It also has a good ability to deal with the calculation errors caused by distributed capacitance and noise interference.

关 键 词：柔性直流电网 配电网 纵联保护 参考点电压 电压二次积分 

分 类 号：TM721.1[电气工程—电力系统及自动化] TM773