中文摘要：

有功功率差动保护在消除线路分布电容影响、应对高阻故障等方面独具优势,但近处金属性故障时的性能缺陷限制了其实际应用。为解决此问题,文中依据叠加原理,提出了虚拟有功功率的概念,并对内、外部故障时线路两端虚拟有功功率的特征进行了分析。以此为基础,提出了分相虚拟有功功率差动保护动作判据,并对其动作特性进行了定性分析。借助PSCAD搭建500kV输电线路模型,全面仿真和评估了不同故障位置、故障类型、过渡电阻、无功元件调整、非同步数据等多种因素对保护方案的影响。理论分析及仿真结果表明,该保护方案可准确辨别故障区间且近处金属性故障无死区,耐过渡电阻能力较强,数据交换量少,同步要求低,无需电容补偿措施。

英文摘要：

The active power differential protection has unique advantages in dealing with distributed capacitance and high resistance faults.However,the defect of close metallic faults with small resistance limits its practical application.In order to overcome this shortcoming,a concept of virtual active power emanating from referring to the superposition principle is proposed,and the different characteristics for virtual active power under the internal fault and the external fault conditions are analyzed.On this basis,a split-phase action criterion for virtual active power differential protection is proposed and its operation characteristics are analyzed qualitatively.By using the model of 500 kV transmission lines on PSCAD,a number of simulations have been conducted for different fault locations,fault types,transition resistances,reactive elements operations and asynchronous data to evaluate the influences on the protection scheme performance comprehensively.Theoretical analysis and simulation results show that the proposed protection scheme is able to correctly identify the fault sections without dead zone for close metallic faults but a great capability against fault resistance,less data exchanges,a low requirement for synchronization and no need of capacitance compensation.