BOS 563:2013

Description

1.1 This standard specifies requirements for single-phase and three-phase distribution transformers, including installation requirements of the oil-immersed type that
i) are category-sized in accordance with IEC 60076-1 up to and including 3 150 kVA,
j) have rated maximum voltages (Um) that do not exceed 36 kV,
k) have uniformly insulated windings,
l) have a high-voltage and a low-voltage winding or, in the case of an auto-transformer, a series and a common winding and, in each case, if necessary, a stabilizing winding or an auxiliary winding, and
m) are suitable for off-circuit tap changing only. NOTE: Although distribution transformers are generally designed to receive power at a voltage that exceeds 3.3 kV and to deliver power to systems that have a nominal voltage of 230/400 V or 525 V, this standard covers transformers that have any combination of rated primary and secondary voltages. 1.2 This standard is not applicable to transformers that have more than two windings, other than those referred to in 1.1(d).
1.3 This standard applies to distribution transformers that are designed for use, at full continuous rating, under the conditions specified in IEC 60076-1 and also under the following conditions:
n) at an altitude that does not exceed 1 800 m; o) at a system voltage frequency of 50 Hz; and p) under the conditions to which the electrical installations being served could be exposed. Requirements that have to be specified by the NOTE: purchaser and those that have to be agreed upon by the manufacturer and the purchaser are listed in Annex A.