This Standard applies to newly manufactured current transformers for use with electrical measuring instruments and electrical protective devices at frequencies from 15 Hz to 100 Hz.
Although the requirements relate basically to transformers with separate windings, they are also applicable, where appropriate, to autotransformers.
Chapter 13 covers the requirements and tests, in addition to those in Chapter 4 to Chapter 11, that are necessary for current transformers for use with electrical measuring instruments.
Chapter 14 covers the requirements and tests, in addition to those in Chapter 4 to Chapter 11, that are necessary for current transformers for use with electrical protective relays, and in particular for forms of protection in which the prime requirement is the maintenance of accuracy up to several times the rated current.
For certain protective systems, where the current transformer characteristics are dependant on the overall design of the protective equipment (for example high-speed balanced systems and earth-fault protection in resonant earthed networks), additional requirements are given in Chapter 15 for class PR transformers and in Chapter 16 for class PX transformers.
Chapter 15 covers the requirements and tests in addition to those in Chapter 4 to Chapter 11 that are necessary for current transformers for use with electrical protective relays, and in particular for forms of protection in which the prime requirement is the absence of remanent flux.
Chapter 16 covers the requirements and tests in addition to those in Chapter 4 to Chapter 11 that are necessary for current transformers for use with electrical protective relays, and in particular for forms of protection for which knowledge of the transformer’s secondary excitation characteristic, secondary winding resistance, secondary burden resistance and turns ratio is sufficient to assess its performance in relation to the protective relay system with which it is to be used.
Current transformers intended for both measurement and protection shall comply with all the clauses of this standard.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB 156-2003 Standard Voltages (IEC 60038:1983 + A1:1994 + A2:1997, IEC standard voltages, MOD)
GB 311.1-1997 Insulation Co-ordination for High Voltage Transmission and Distribution Equipment (neq IEC 60071-1:1993)
GB/T 2900.15-1997 Electrotechnical Terminology — Transformer, Instrument Transformer, Voltage Regulator and Reactor (neq IEC 60050(421):1990, IEC 60050(321):1986)
GB/T 3954-2001 Aluminium Rod for Electrical Purpose
GB/T 4796 Classification of Environmental Parameters and Their Severities of Electric and Electronic Products (GB/T 4796-2001, idt IEC 60721-1:1990)
GB 5585.1-1985 Copper or Aluminium and its Alloy Bus Bars for Electrical Purposes — Part 1: General (neq IEC 60028:1925)
GB/T 7252-2001 Guide to the Analysis and the Diagnosis of Gases Dissolved in Transformer Oil (neq IEC 60599:1999)
GB/T 7354-2003 Partial Discharge Measurements (IEC 60270:2000, Partial discharge measurements, IDT)
GB/T 7595-2000 Quality Criteria of Transformer Oils in Service
GB/T 11021-1989 Thermal Evaluation and Classification of Electrical Insulation (eqv IEC 60085:1984)
GB/T 11604 Test Methods for Measuring Radio Interference from High Voltage Equipment (GB/T 11604-1989, eqv CISPR 18-1:1982, CISPR 18-2:1986)
GB/T 13384-1992 General Specification for Packagings of Mechanical and Electrical Products
GB 16847-1997 Requirements for Protective Current Transformers for Transient Performance (idt IEC 60044-6:1992)
GB/T 16927.1-1997 High Voltage Test Techniques — Part 1: General Test Requirements (eqv IEC 60060-1:1989)
GB/T 17623-1998 Determination of Componental Contents of Gases Dissolved in Insulating Oil by Gas Chromatography Method (neq IEC 60567:1992)
JB/T 5356 Test Guide for Current Transformers Test (JB/T 5356-2002)
JB/T 5895-1991 Guide for the Selection of Insulators in Respect of Polluted Conditions (neq IEC 60815:1986)
