An algorithm for compensating secondary currents of current transformers

Author

Kang, Y.C. ; Park, J.K. ; Kang, S.H. ; Johns, A.T. ; Aggarwal, R.K.

Author_Institution

Dept. of Electr. Eng., Seoul Nat. Univ., South Korea

Volume

12

Issue

1

fYear

1997

fDate

1/1/1997 12:00:00 AM

Firstpage

116

Lastpage

124

Abstract

Current transformer (CT) saturation may cause power system relays to malfunction. The conventional method used to deal with the problem is overdimensioning of the transformer core so that CTs can carry up to 20 times the rated current without exceeding 10% ratio correction. However, this not only reduces the sensitivity of power system relays, but also increases the CT core size. This paper presents a technique of estimating the secondary current corresponding to the CT ratio under CT saturation. The proposed algorithm can improve the sensitivity of relays to low level internal faults, minimize the instability of relays for external faults, and might ultimately assist in reducing the dimension of the required CT core cross-section

Keywords

compensation; current transformers; fault currents; power system protection; power system relaying; power transformers; relay protection; transformer cores; current transformer saturation; low-level internal faults; power system relay sensitivity; secondary current compensation algorithm; transformer core overdimensioning; Circuit faults; Current transformers; Fault currents; Magnetic cores; Magnetic flux; Power system protection; Power system relaying; Protective relaying; Relays; Student members;

fLanguage

English

Journal_Title

Power Delivery, IEEE Transactions on

Publisher

ieee

ISSN

0885-8977

Type

jour

DOI

10.1109/61.568231

Filename

568231