Technical requirements and tests included in this standard is the supplement to Chapter 4 of GB 1208-1997. It is applicable to the electric-magnetic current transformers used for electrical protection system, however such kind of protection system places stress upon requiring that the current transformer is the maintenance of a defined performance up to several times the rated current when the current contains an exponentially decaying d.c. component of defined time constant.
2 Normative References
The following normative documents contain provisions which, through reference in this standard, constitute provisions of this standard. At time of publication, the editions indicated were valid. All the standards will be revised, all parties coming to an agreement according to this standard are encouraged to study whether the latest editions of the following standards are applicable.
GB 1984-89 Alternating Current High-voltage Circuit-breakers (eqv IEC 56: 1987)
GB 1208-1997 Current Transformers (eqv IEC 185: 1987)
Foreword II IEC Foreword III IEC Introduction III 1 Scope 2 Normative References 3 Definitions 4 Ratings and Performance Requirements 5 Contents of Specification Appendix A (Normative) Basic Theoretical Equations for Transient Dimensioning Appendix B (Normative) Determination of Core Magnetization Characteristic Appendix C (Normative) Direct Tests Appendix D (Normative) Guide to Performance Criteria for Current Transformer for Protection Relaying Appendix E ( Normative) Determination of Turns Ratio Error
