STATION TRANSFORMER
1.0. PURPOSE
The purpose of this calculation is to determine the capacity of Station Transformer for 1 x 660 MW CIREBON Coal Fired Steam Power Plant.
2.0. SUMMARY
2.1 One Station Transformer is provided for the start up of the plant and after that UAT will cater plant load.
2.2 The result of calculation is summarized as follows.
STATION TRANSFORMER
Cooling : ONAN/ONAF
Winding Temp. rise : 60º C
Winding : 3 phase 3 winding
Capacity : 60/30/30 MVA
Note 1 : The above XFMR Capacity is based on the 45ºC Amb. Temp.
3.0. REFERENCE
3.1 Cirebon power plant load data
3.2 IEC 60076-1
3.3 IEC 60076-2
3.4 ANSI C57.91
4.0. DESIGN CRITERIA
4.1 Design ambient temperature is 45º C
4.2 Transformer is three phase three winding having the star-star-star connection, YNyn0yn0, ONAN/ONAF, 150/11.5/11.5 KV.
5.0. ASSUMPTION
5.1 All motor loads having the stand-by operation mode has been excluded in this calculation.
5.2 Transformer data
Description
a. Type : 3 phase, 3 winding, 50Hz
b. Rated : voltage150/11.5/11.5 KV
6.0. CALCULATION
Inputs:
Total Load on one bus of 11kV System in KW = 22158.00 KW
Power factor = 0.85
Total Load on 11kV System in KVA ( L ) = 26068.24 KVA
No Load Voltage (Vn) = 11.5 kV
Full Load rated voltage (Vr) = 11 kV
Full load losses (Wf1) = 294.00 KW at 60 MVA
Actual KVA Load on Transformer (Wa) = 26068.24 KVA
Load Calculation for Power Transfomer:
Considering 10% margin, KVA load = L x 1.1
= 28675.06
So the selected Transformer size = 30000 KVA
7.0. ENCLOSURE
7.1 Load Summary for MV Switchgear
7.2 Load Summary for MCC
