Superimposed quantities, also known as delta quantities, are the transient signatures of fault currents and voltages that can be utilized by protective relays to achieve fast fault detection for electric power grid applications. With the installation of superconducting fault current limiters (SFCLs) on power transmission lines, the profiles of superimposed quantities in power system faults are affected due to the altered impedance properties at transmission line terminals, which may further affect protective relay performance. In this article, we investigate the impact of a resistive SFCL on superimposed quantity profiles. The equivalent circuit of a resistive SFCL connected to an electric power transmission system is first illustrated based on which the simulation model is established in an electromagnetic transients program. Various types of power transmission line faults are simulated. The superimposed current and voltage quantities at transmission line terminals are obtained. The simulation results demonstrate that the acquired superimposed quantities are significantly affected by the SFCL. Possible consequences to protection functions are discussed.

中文翻译：

---

电阻性SFCLs对电力系统故障中叠加量的影响

叠加量，也称为增量量，是故障电流和电压的瞬态特征，保护继电器可利用这些特征实现电网应用的快速故障检测。随着在输电线路上安装超导故障限流器 (SFCL)，输电线路终端阻抗特性的改变会影响电力系统故障中叠加量的分布，这可能进一步影响保护继电器的性能。在本文中，我们研究了电阻性 SFCL 对叠加数量分布的影响。首先说明了连接到电力传输系统的电阻SFCL的等效电路，在此基础上建立了电磁瞬态程序中的仿真模型。模拟各种类型的输电线路故障。获得在输电线路终端的叠加电流和电压量。仿真结果表明，SFCL 对获取的叠加量有显着影响。讨论了保护功能的可能后果。