Current Transformer Selection Using Matlab Model

Abstract

The requirements for the correct functioning of power system protection equipment is the optimum selection of current transformers (CTs). The main purpose of a current transformer is to translate the primary current in a high voltage power system to single level that can be handled by delicate electromechanical or electronic device. For a power system engineer to accurately and successfully specify the different current transformers required for the protection of substation power transformers, the protection engineer has to pay attention to steady state performance as well as transient performance of current transformers. This paper presents a study on current transformer selection in a 132/33kV transmission substation using MATLAB model. This paper shows how the current transformer ratio, knee points voltage, thermal current, dynamic current and burden on the various cores can be selected together simultaneously to provide a low-cost, high-performance system. This work is expected to be a good reference source for the new generation utility protection engineers in selecting the CTs in power system installation.

Keywords: Current Transformer, Knee Points Voltage, Thermal Current, Dynamic Current, CT- Burden, MATLAB

DOI: 10.7176/ISDE/10-7-03

Publication date: August 31^st 2019