DIN EN 50629:2016-03

This European Standard has been prepared on behalf of the European Commission under mandate EC 24/2011 within the framework of Directive 2009/125/EC of the European Parliament and of the Council of 21 October 2009, which establishes basic conditions for the specification of ecodesign requirements relating to products for the energy sector. The power transformers with a maximum voltage for equipment Um > 36 kV considered in this standard have a rated power in the range between 4 MVA and 1 000 MVA. It is considered that the approach of the energetic characteristic described in this standard is also applicable to transformers that do not belong to the scope of this standard. For large power transformers, defining efficiency based on transmitted and consumed active power alone is not suitable for evaluating the energetic characteristic, since losses are either constant (no-load losses) or depend on the current (load losses) and would therefore result in zero if only reactive power is transmitted. (The transmission of reactive power is very important for the operation of power grids). Therefore, conventional efficiency calculations are not useful for comparing transformer designs that can be used within a range of operating conditions. In general, for large power transformers, it is not possible to specify optimum values for load and no-load losses at a given power level because a variety of different applications affect the energetic characteristic. To establish an index for a specific transformer, but one that is applicable within a wide range and does not vary from one second to the next depending on system conditions, the energetic characteristic of power transformers has to be characterized. For this purpose, a parameter - Peak Efficiency Index (PEI) has been established. It is based on the losses caused by the active power and the total transmitted power, and is independent of the phase angle of the load, the load factor and the rated power. This European Standard provides a standard procedure for evaluating the energetic characteristic of power transformers using the Peak Efficiency Index, includes comparative values for the PEI, and explains why certain transformers have efficiencies that are higher or lower than the comparative values. Establishing an appropriate value for the minimum Peak Efficiency Index will affect the efficiency of the total installed transformers by eliminating those units with low efficiency, except for some transformers that are subject to special restrictions. Using a minimum value for the Peak Efficiency Index establishes a lower limit for the efficiency of a transformer, but the application of appropriate loss capitalization when purchasing transformers is a prerequisite to selecting the transformer with the best efficiency in economical terms. Users who do not use loss capitalization are strongly encouraged to consider the benefits of doing so. For large units above 100 MVA, the economically achievable efficiency of a transformer may be limited by electrical characteristics of the system (for example, impedance) and specific conditions for transport and installation. Since the units in question are normally purchased by operators of large power transmission systems who typically use high loss capitalization values, these units of over 100 MVA are usually already state of the art in terms of efficiency. For transformers of uncommon design or with significant size or weight limitations, it may be unreasonable to meet the minimum efficiency requirement for technical or economic reasons. In these cases, it is permissible to demonstrate that the highest reasonable efficiency has been achieved. This European Standard applies to new three-phase and single-phase power transformers with a highest voltage for equipment exceeding 36 kV and a rated power equal or higher than 5 kVA, or a rated power equal to or higher than 40 MVA regardless of the highest voltage for equipment. The scope of this European Standard is the following:- Defining the appropriate energy efficiency criteria;- Setting of benchmark minimum efficiency levels for new transformers based on an assessment of the energy efficiency of the European transformer population installed in the last 10 years;- Proposing higher minimum efficiency levels for improving the energy efficiency of new transformers;- Providing guidance for consideration of Total Cost of Ownership (TCO: total life cycle cost). This European Standard provides also a form for efficiency data collection to inform future efficiency benchmark levels. The following transformers are not within the scope of this standard: - instrument transformers; - grounding transformers; - traction transformers mounted on vehicles; - starting transformers, - test transformers; - arc welding transformers - explosion-proof and mining transformers; - transformers for deep water applications. The responsible committee is Subcommittee DKE/UK 321.2 "Transformatoren, Leistungen und Abmessungen" ("Transformers, performances and dimensions") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.