电压跌落的配电线路全线速切治理方案

为了提高配电网暂态电压质量的整体水平,将三段式电流保护的动作特性引入到CBEMA敏感特性曲线,首次提出了基于电流保护的电压跌落治理性能评估模型,分析了目前配电线路三段式电流保护的电压跌落治理能力和影响其性能的主要因素。理论分析和算例结果表明,改善电流保护的电压跌落治理性能只能从增大无时限电流速断保护的范围入手。文章还提出了单端失选择性全线速切保护的改进方案。经济性分析和算例结果表明,该方案在不增加成本的前提下大大提高了配电系统的暂态电压质量。

A Scheme of the Fast Tripping Current Protection for Distribution Lines Based on the Voltage Sag Mitigation

Leading the protection operation characteristic of three-step current protection into CBEMA sensitivity characteristic curve, the evaluation model of voltage sag mitigation performance is proposed for the first time, the voltage sag mitigation ablility of existing three-step current protections and the main factors influencing their mitigation performance are analyzed. Analysis results of theory and calculation examples show that to improve the voltage sag mitigation performance the only approach is the extension of instantaneous relay protection zone. On this basis, an improved fast tripping without selectivity protection scheme is proposed. Results from economic analysis and case simulations show that using this approach the transient voltage quality level in distribution system can be evidently improved without cost increase.