تصميم وتنفيذ مرحلة تفاضلية بالاعتماد على المتحكم الدقيق لحماية محولات القدرة

Abstract EN

Differential protection faces many difficulties when used in protection of power transformers, and the most important of these is the magnetizing inrush current, that appears at the transient state for transformer.

Because of the similarity between this current and internal fault current, which occurs in power transformer and leads to false operation for such protection.

The micro controller is used to act as a differential relay, as well as to Discrimination between inrush current and internal fault current, by storing forms of current waves and a differential relay was comparing between them.

In this paper a differential relay was designed and implemented, and programmatically and practically tested.

The results demonstrate the ability designed relay to distinguish between the, inrush currents, internal and external faults.

The results prove less time is required to distinguish between inrush ,internal and fault currents about (20msec.).

The programming and practical results prove also that the differential relay is very fast where the working time does not exceed (500 msec.).