MINIMUM ENERGY PERFORMANCE (MEPS) ACCORDING TO TCVN 8525: 2015
TCVN 8525: 2015 compiled by the National Technical Standards Committee, proposed by The Directorate for Standards, Metrology, and Quality, announced by the Ministry of Science and Technology to replace TCVN 8525: 2010.
1. Scope of application
This standard specifies levels and methods for determining minimum energy efficiency levels applicable to oil-immersed and dry-type three-phase distribution transformers, rated up to 4,000kVA, with rated voltage up to 35kV, working in the power grid with a rated frequency of 50Hz.
For the scope of this standard, a distribution transformer is a transformer having: Rated input voltage less than or equal to 35kV; rated output voltage is less than or equal to 0.4kV, working in a power grid with a rated frequency of 50Hz.
2. Minimum Energy Efficiency (MEPS)
Ratio, expressed as a percentage, between the energy output and energy input of a distribution transformer, at a load factor of 50% and a power factor of 1.
Table of minimum energy efficiency (MEPS) values for oil-immersed three-phase distribution transformers:
|
kVA |
MEPS (%) |
|
≤ 25 |
98,40 |
|
31,5/32 |
98,50 |
|
50 |
98,66 |
|
75 |
98,77 |
|
100 |
98,87 |
|
125 |
98,92 |
|
160 |
98,97 |
|
180 |
99,01 |
|
200 |
99,06 |
|
250 |
99,10 |
|
315/320 |
99,16 |
|
400 |
99,19 |
|
500 |
99,21 |
|
560 |
99,22 |
|
630 |
99,26 |
|
750 |
99,28 |
|
800 |
99,30 |
|
1 000 |
99,32 |
|
1 250 |
99,35 |
|
1 500 |
99,37 |
|
1 600 |
99,39 |
|
2 000 |
99,41 |
|
2 500 |
99,42 |
|
3 000 |
99,44 |
|
3 200 |
99,46 |
|
3 500 |
99,48 |
|
4 000 |
99,50 |
3. Method for determining energy efficiency
The energy efficiency formula is determined as follows:
Explain:
E50%: The transformer's percent efficiency at 50% load factor and 1 power factor;
S: Rated power of the distribution transformer in kVA;
Pk: Load loss of distribution transformer, in kW;
P0: No-load loss of the distribution transformer, in kW.
The result of the E50% calculation shall be corrected to a standard temperature of 75°C according to IEC 60076-1 for oil-immersed transformers and a standard temperature according to the general provisions for the test. of IEC 60076-11 for dry-type transformers.
