小接地电流系统单相接地微机保护中的两种选线方法

本文介绍某大型化肥厂６ｋＶ中性，是不接地供电网络单相接地微机保护中应用的基波零序电流方向、异相电流增量差值等两种选线方法的基本原理，选线判据，程序框图设计，应用特点，具有一定的实用价值与普遍意义。

Two Methods of Line Selection for the Microcomputer Protection of Grounded Fault of Single Phase in Small Grounded Current Systems

This paper introduces the fundamental principle,the criterion the programming flowchart and the application characteristic for two methods of line selection,which are the fundamental harmonic zero-phase-sequence current direction method and the out of phase current incremental difference method.Both of them are used in the microcomputer protection of grounded fault of Single phase within the 6 kV supply network with unearthed neutrals of a large fertilizer manufacturer.they are also two practical methods and have general meaning;