DIN EN 61378-1:2012-05

This standard deals with the specification, design and testing of power transformers and reactors which are intended for integration within semiconductor converter plants. It is not applicable to transformers designed for industrial or public distribution of a.c. power. The standard is limited to application of power converters of any power rating. Typical applications are: thyristor rectifiers and diode rectifiers for electrolysis, thyristor rectifiers for large drives, thyristor rectifiers for scrap melting furnaces and diode rectifiers feeding inverters for variable speed drives. The standard also covers the regulating unit utilized in such application as step down regulating transformers or autotransformers. The valve winding highest voltage for equipment is limited to 36 kV. This standard is not applicable to transformers for HVDC power transmission. These are highvoltage transformers, and they are subjected to d.c. voltage tests. The standards for the complete converter plant (such as the IEC 60146 series, or other publications dedicated to particular fields of application) may contain requirements of guarantees and tests (such as insulation and power loss) for the whole plant, including the converter transformer and possibly auxiliary transformers and reactor equipment. This does not relieve the application of the requirements of this standard concerning the guarantees and tests applicable to the converter transformer itself as a separate component before being assembled with the remainder of the converter plant. The guarantees, service and type tests defined in this standard apply equally to transformers supplied as part of an overall converter package, or to those transformers ordered separately but for use with converter equipment. Any supplementary guarantee or special verification has to be specifically agreed in the transformer contract. The converter transformers covered by this standard may be of the oil-immersed or dry-type design. Unless specific exceptions are stated in this standard, the transformers comply with IEC 60076 series for oil-immersed transformers, and with IEC 60076-11 for dry-type transformers. For some converter applications, it is possible to use common distribution transformers of standard design. The use of such standard transformers in the special converter applications may require a certain derating. This matter is not specifically covered in this standard, which deals with the requirements to be placed on specially designed units. It is possible, however, to estimate this derating from the formulae given in 5.1, and also from clause 9 of IEC 60076-8:1997. The standard deals with transformers with one or more active parts installed in the same tank like regulating (auto)transformer and one or two rectifier transformers. It also covers transformers with transductors and/or one or more interphase transformers. For any combination not listed above an agreement between the purchaser and manufacturer is necessary regarding the determination and the measurement of the total losses. This standard deals with transformers star Y and delta D and any other phase shifting connections (like zig-zag, extended delta, polygon, etcetera). Phase shifting windings can be placed on either the regulating or rectifier transformer. The following modifications have been made with respect to DIN EN 61378-1 (VDE 0532-41):1999-09: a) the standard has been completely editorially revised; b) the most important connections of the converter applications are explained; c) new example calculations for various applications are supplemented; d) new paragraphs have been incorporated on the topics zig-zag connection, phase displacement, transductors, current sharing, losses and hot spots in high current windings, leakage fields; e) seven informative annexes have been supplemented on the topics current sharing measurement, duty cycles, design review, determination of loss due to magnetic field, short-circuit measurements, phase displacement; f) an informative Annex on the correlation between IEC 61378-1 and IEC 60146-1-1 ratings has been supplemented; g) numerous figures have been supplemented to clarify technical relationships. The responsible committee is K 321 "Transformatoren" ("Transformers") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.