BS EN 60146-1-3:1993

Cooperating organizations
National foreword
Foreword
1 Scope
2 Normative references
3 Rated values for convertor transformers
3.1 Rated current values
3.2 Temperature limits of cooling media
4 Losses and voltage drops in transformers and
     reactors
4.1 Losses in the transformer windings
4.2 Losses in interphase transformers, current
     balancing reactors, series-smoothing reactors,
     transductors and other current regulating
     accessories
4.3 Voltage drops in transformers and reactors
5 Tests for convertor transformers
5.1 Measurement of commutating reactance and
     determination of inductive voltage drop (type test)
5.2 Short-circuit test (type test and routine test)
5.3 Temperature rise test (type test)
Annex
A (normative) Corrections to be applied when cooling
      medium temperature is higher than standard
ZA (normative) Other international publications
     quoted in this standard with the references of the
     relevant European publications
Tables
1 Temperature rise limits
2 Connections and calculation factors
National annex NA (informative) Committees responsible
National annex NB (informative) Cross-references

Relates to the characteristics wherein convertor transformers differ from ordinary power transformers. Includes the following sections: rated values for convertor transformers; losses and voltage drops in transformers and reactors; tests for convertor transformers.

This Part 1-3 of the International Standard relates, in general, to those characteristics wherein convertor transformers differ from ordinary power transformers. In all other respects, the rules specified in IEC 76 shall apply to convertor transformers also, as far as they are not in contradiction with this standard.

It should be borne in mind that a rectifier transformer operates with non-sinusoidal current waveshape. In single-way connection, the current in each cell winding contains a d.c. component which calls for special attention in design and testing. In some cases, a special design is necessary when external short-circuits and cell failures would cause abnormal stress.

For certain types of transformers, the waveshape of the normal operating voltage is non-sinusoidal. The core loss of such equipment is to be determined by applying a sinusoidal voltage having the same half-cycle arithmetic mean value and the same fundamental frequency as the voltage applied in service.