基于幅值差动原理的低压配电网剩余电流保护方法

Residual Current Protection Method of Low Voltage Distribution Network Based on Amplitude Differential Principle

随着低压配电网规模的不断扩大,漏电故障及其保护问题日益突出。传统漏电保护方法需要多级配合,且灵敏度低、易误动,在分析低压配电线路单相漏电故障特征的基础上,提出一种基于幅值差动原理的低压配电网剩余电流保护方法,给出了该方法的实现流程并分析了其适应性。该方法适用于TT系统和TN-S系统,依托配电物联网平台实现,可以排除下游线路对地不平衡电容电流在正常运行时对剩余电流的影响,保护灵敏度高;不需要多级保护配合,动作速度快、可靠性高;不需要精确对时,实施方便。利用仿真验证了该方法的有效性。

With the continuous expansion of the scale of low-voltage distribution networks,leakage faults and their protection problems have become increasingly prominent.Traditional leakage protection methods need multi-level coordination,have low sensitivity and are easy to act wrongly.Based on the analysis of the characteristics of single-phase leakage faults in low-voltage distribution lines,this paper proposes a residual current protection method of low voltage distribution network based on amplitude differential principle,presents the implementation process of the method and analyzes its adaptability.This method is suitable for TT system and TN-S system,can be realized by relying on the power distribution internet of things platform,can eliminate the influence of the residual current caused by unbalanced capacitance current of downstream line to the ground in normal operation,and has high protection sensitivity;it does not need multi-level protection coordination,and has fast operation speed and high reliability;This method is no need for accurate timing and easy to implement.The effectiveness of the method is verified by simulation.