Improvement of the Sensitivity of Differential Protection of Power Transformers

Electrical and Data Processing Facilities and Systems = Электротехнические и информационные комплексы и системы 2014
Jevgeņijs Kozadajevs, Aleksandrs Dolgicers

This paper presents the development of micro-processor based device for improving the sensitivity of differential protection of power transformers. Power transformers failure may lead to high scale system’s operations disruption and heavy economic losses, that’s why the lever of requirements for power transformer protections is so high. Differential protection is usually used as a main protection against internal faults such as inter-windings faults, inter-coil faults or coil-core faults. For safe protection against incomplete winding faults protection device must be capable to detect differential current from such a low value as 0.01% from nominal. However, transformer for relay protections needs are produced with error classes 5P and 10P meaning error rate 5 and 10 % correspondently. The idea for a new device is to use information obtained from measurement current transformers. The micro-processor based device may “teach” itself by forming some error correction table in it’s memory on the basis of core outputs compare during normal operation. In case of fault device may operate with much higher sensitivity thus sensing fault on it’s early stage.

Atslēgas vārdi
Differential protection of power transformers, current transformer, sensitivity of relay protection, internal faults.

Kozadajevs, J., Dolgicers, A. Improvement of the Sensitivity of Differential Protection of Power Transformers. Electrical and Data Processing Facilities and Systems = Электротехнические и информационные комплексы и системы, 2014, Vol. 10, No. 2, 5.-13.lpp. ISSN 1999-5458.

Publikācijas valoda
English (en)