Using Digital Relays for Improved Power Transformer Differential Protection

Abstract

Power transformers form a vital component of the electrical power system; hence the protection of this equipment is a matter of priority towards ensuring a stable power supply. The unplanned outages of a power transformer could cost utility millions of dollars. It is therefore of great importance to minimize the frequency and duration of unwanted outages due to power transformer faults. This work focuses on improved methods of power transformer differential protection using weighted least square scheme. This scheme ensures security for external faults, inrush currents, over excitation conditions and provides dependability for internal faults.