Hitendra Patel
SEGE – Air Liquide
Avenue Du Bourget 44
Brussels-1130
Belgium
Monday, 25 January 2015
Dear Sir,
Subject: Power Transformer and Line Loss Calculations at Air Liquide Eggborough Plant
The metered 11kV supply at Air Liquide is connected by a 1.3km cable run to the National Grid 400kV connection via
the Eggborough Power Limited (EPL) Station Transformer 1 (ST1).
Power Transformer Losses:
ST1 Losses - note these calculations were performed on 18/02/1991 and original records reside with EPL.
The following power transformer compensation values are employed by EPL’s COP1 registered ST1 metering.
In = Nominal current.
Vn = Nominal voltage.
All values quoted at Main Transformer nominal tap position.
In (A)
Vn (V)
2,500
11,000
Tap No
No Load (kW at Vn)
Voltage (V)
I squared loss (kW at In)
NOMINAL TAP
40.5
NOMINAL
383.1
(Iron Loss:
0.085%)
(Copper Loss: 0.804%)
Following loss calculated for a decreased prevailing load.
For Prevailing Load:
IPrevailing (A)
Voltage (V)
I squared loss (kW at IPrevailing)
7.5MW @ 11kV
393.6
NOMINAL
9.5
(Copper Loss: 0.127%)
Line Loss:
Cable
Type
XLPE
Length
(m)
410
Cross Sectional Area
(mm2)
630
Resistance per km
(Ω/km)
0.0283
Resistance
(Ω)
0.0116
XLPE
474
800
0.0221
0.0105
XLPE
487
630
0.0283
0.0138
TOTAL (per phase)
0.0359
Prevailing Load:
7.5MW @ 11kV
IPrevailing (A)
Total Resistance (Ω)
I squared loss (kW at IPrevailing)
393.6
0.1
16.7
Yours Sincerely,
John Strachan (Managing Director)
(Line Loss:
0.222%)