基于电流采样值的相敏过电流保护

针对中低压电网中过流保护存在灵敏度低的缺点,提出了一种新型微机式过电流保护即基于电流采样值的相敏过电流保护,并分析了它的基本原理、具体的实现方法及可靠性问题。这种相敏过电流保护既利用了故障时电流大小的变化,也利用了电流相位的变化,有较高的灵敏度。由于它能够根据故障电流的相位进行相位整定,对故障电流反应敏感而对非故障电流反应不敏感,能适应不同的相位变化情况因此具有很大的灵活性和适用性。此外,它还具有结构简单、实现容易、成本较低等优点。

New Type of Phase-Sensitive Overcurrent Protection Based on Sampled Value of Current

A new type of overcurrent protection,phase-sensitive overcurrent protection based on sampled value of current,is suggested in this paper.And its basic principle,hardware structure,method of realization and reliability are analyzed.Furthermore,the phase-sensitive overcurrent protection distinguishes short-circuit faults by means of changes of both magnitude and phase angle of current.So it can operate correctly with high sensitivity.And because it can be set as the phase angle of fault current,it always responds to fault current sensitively rather than any other no-fault current.As a result,it has great flexibility and adaptability.Besides,it also has many other advantages such as simpler hardware structure,lower cost,easier realization,etc.