[论文解读] Implementation of Resistive Type Superconducting Fault Current Limiters in Electrical Grids: Performance Analysis and Measuring of Optimal Locations

Xiuchang Zhang, H. S. Ruiz+2 more|arXiv (Cornell University)|Aug 4, 2015

HVDC Systems and Fault Protection参考文献 38被引用 12

一句话总结

本文提出了一种面向电力系统中阻性超导故障电流限制器（SFCLs）的性能驱动优化框架，采用动态E-J功率定律模型模拟故障条件下超导体的行为。结果表明，建模热力学动态特性和E-J特性可显著提高故障电流抑制预测的准确性，相较于简化的阶跃电阻模型，其预测结果更为可靠；在位置2、3和4处安装三台SFCL可实现最大故障电流降低（395%）并取得最佳性价比。

ABSTRACT

In the past few years there has been a significant rise in the short-circuit current levels in transmission and distribution networks, it due to the increasing demands on power and the addition of sources of distributed generations. It leads to the need of integration of novel protection systems such as the superconducting fault current limiters (SFCLs), ... . SFCL models on the electric distribution networks largely rely on the insertion of a step or exponential resistance that is determined by a predefined quenching time. However, beyond the framework of these models, the study of the performance, reliability, and location strategy for the installation of sole or multiple SFCLs in power grids still lacks of proper development leading to the utter need of comprehensive and systematic studies on this issue. In this paper, we expand the scope of the aforementioned models by considering the actual behaviour of a SFCL in terms of the temperature dynamic power-law dependence between the electrical field and the current density. Our results are compared with step-resistance models for the sake of discussion and clarity of the conclusions. Both SFCL models were integrated into a power system model built based on the UK power standard, and the impact of these protection strategies on the performance of the overall electricity network was studied. As a representative renewable energy source, a 90 MVA wind farm was considered for the simulations. Three fault conditions have been simulated, and the figures for the fault current reduction predicted by both fault current limiting models have been compared in terms of multiple current measuring points and allocation strategies...

研究动机与目标

• 为应对因可再生能源渗透率提高和负荷增长导致现代电网故障电流水平上升的问题。
• 评估传统阶跃电阻SFCL模型的局限性，此类模型会高估实际性能。
• 开发并验证一种更精确的SFCL模型，该模型结合了动态E-J特性与热响应行为。
• 确定SFCL安装的最优数量与位置，以在最小投资下实现最大故障电流降低。
• 为配电网运营商提供SFCL部署策略的可操作指导。

提出的方法

• 基于英国配电网标准构建了详细的电力系统模型用于仿真。
• 实现了两种SFCL模型：一种是简化的阶跃电阻模型，另一种是具有温度依赖电阻的物理精确E-J功率定律模型。
• E-J模型能够捕捉电场（E）与电流密度（J）之间的非线性关系，以及故障事件期间的动态热演变过程。
• 将一个90 MVA的风电场作为典型分布式电源接入系统，以模拟真实的故障场景。
• 在电网关键测量点对多种故障条件进行分析，以评估故障电流降低（FCR）性能。
• 在E-J模型中集成了互补保护方案，以防止SFCL烧毁，并提升故障后的恢复能力。

实验结果

研究问题

• RQ1 与阶跃电阻模型相比，引入E-J功率定律动态特性与热响应行为如何影响SFCL预测的故障电流限制性能？
• RQ2 在多种故障场景和测量点下，SFCL的最优数量与安装位置是什么，以实现最大故障电流降低？
• RQ3 不同的SFCL布置策略如何影响系统可靠性与投资成本效益？
• RQ4 简化的阶跃电阻模型在实际电力系统中在多大程度上高估了SFCL的实际性能？
• RQ5 基于E-J模型的方法能否支持在主动配电网中SFCL部署的可靠、可重复且可扩展的决策制定？

主要发现

• E-J功率定律模型预测的最大故障电流降低（FCR）为395%，显著低于阶跃电阻模型预测的495%，表明阶跃模型最高可能高估性能达20%。
• 最优SFCL安装策略为在位置2、3和4各安装一台SFCL，可实现最高FCR（395%）和最佳成本效益比。
• 安装超过三台SFCL（如四台或五台）带来的额外故障电流降低微乎其微，表明超过三台设备后收益递减。
• E-J模型显示，故障电流降低在所有测量点并非均匀分布——部分位置未见降低，凸显了战略性选址的重要性。
• 结合热力学动态特性和保护方案的E-J模型可实现SFCL在故障后更快恢复，从而提升系统可靠性与运行韧性。
• 本研究证实，准确建模超导体的E-J特性与热行为对于可靠估算SFCL性能及实现最优电网集成至关重要。