TN低压配电系统单相接地故障的保护

摘要

Introduce the protection of single-phase to earth fault in TN low voltage distribution system;Deducing the computing formula to maximum length of electric cable with overcurrent protection doubles as earth fault protection.The new formula can be batch computing easily,and the results have more guiding significance to engineering design;Meanwhile some strategies have be presented to respond the unreliable moving of protective devices with overlength cable.%介绍TN系统单相接地短路故障的保护；推导出了采用过流保护兼作接地故障保护时最大电缆允许长度的计算公式；新公式易于用电算工具进行批量计算，且计算结果对工程设计更具指导意义；同时对电缆长度过长导致保护电器不能可靠动作的情况进行了应对策略分析。