Differential protection of transformers traditionally uses second and/or fifth harmonics to block its operation during inrush conditions. The second and/or fifth harmonics produced during fault condition, when a protection system is required to operate, have in some cases blocked or delayed operation of transformer differential protection. The problem is to distinguish fault and inrush situations and allow the protection system to operate when there is fault, and to block it during inrush conditions. In order to achieve this, we propose to measure the rate of change of the third harmonic as an additional indicator of the fault condition. If the rate of change of the third harmonic exceeds some predefined threshold and the second and/or fifth harmonic are detected, the protection system will be allowed to operate, and otherwise it is blocked.

Item Type:	Refereed Conference Paper
Keywords:	current transformer saturation, harmonic restraint/blocking, inrush, symmetrical components
Research Division:	Engineering
Research Group:	Electrical engineering
Research Field:	Electrical energy generation (incl. renewables, excl. photovoltaics)
Objective Division:	Energy
Objective Group:	Renewable energy
Objective Field:	Biofuel energy
UTAS Author:	Negnevitsky, M (Professor Michael Negnevitsky)
ID Code:	83291
Year Published:	2012
Deposited By:	Centre for Renewable Power Energy Systems
Deposited On:	2013-03-07
Last Modified:	2017-10-03
Downloads:	24 View Download Statistics