Distribution transformers for Vietnam

Nominal voltage levels in the distribution system

The earlier Circular 39/2015/TT-BCT listed 0.4 kV as the low-voltage level; the current text lists 0.38 kV. Check which figure your utility’s specification uses for the secondary.

Neutral earthing by voltage level

Energy efficiency: labelling and minimum levels

Decision 04/2017/QĐ-TTg lists three-phase distribution transformers among the industrial equipment that must carry an energy label, and it bars the import and production of industrial equipment below the minimum energy performance level (MEPS).

The national standard for that level is TCVN 8525:2015, which gives the minimum efficiency and the method to determine it for three-phase oil-immersed and dry-type distribution transformers up to 4,000 kVA and up to 35 kV, at 50 Hz.

Ask early for test reports to TCVN 8525:2015, since the minimum efficiency applies to imports.

Design standards

Vietnam adopts the IEC 60076 series as TCVN 6306, for example TCVN 6306-1:2015 (IEC 60076-1:2011) and TCVN 6306-11:2009 for dry-type units (IEC 60076-11:2004).

What our published ratings cover

• YBW compact substations: HV 22 kV and 35 kV are both in the published list (10 / 11 / 20 / 22 / 33 / 35 kV; highest voltage Um 24 and 40.5 kV), 50–2500 kVA, LV 380 / 400 / 415 / 433 V.
• Oil-immersed S11 / S13: published HV classes are 10 / 11 kV and 20 kV, with LV 380–433 V on the 10 / 11 kV class and 0.4 kV on the 20 kV class (Dyn11). The 20 kV class is the nearest to 22 kV; 22 kV and 35 kV oil-immersed distribution transformers are quoted on request.
• Power transformers: 35 kV is in the published HV list (33 / 34.5 / 35 / 38.5 kV), 5000–31500 kVA.
• Dry-type units are published for 6–15 kV; 22 kV dry-type is on request.
• Test reports to TCVN 8525:2015 and the rated losses for a 22 kV or 35 kV unit: quoted on request. Loss values on this site are listed per rating for the published classes.

Send with your enquiry

• Electricity company and site (province), and whether the feeder is 22 kV or 35 kV
• Rated power (kVA), HV and LV (0.4 or 0.38 kV), vector group, tapping range
• Oil-immersed, dry-type or compact substation; indoor or outdoor; three-phase or single-phase
• Any utility or project specification, and the efficiency (TCVN 8525) and type-test reports it asks for
• Quantity, delivery port and required date