Alstom GL314 - Page 82

Installation
Calculation of th e SF
6
gas f illing pressure
for using the p ressure gauge (tool)
L31--901EN/02
2/6
08--2000
E ALSTOM
Examp le of the filling pressure calculatio n
Example
Determination of the circuit--breaker’s filling pressure with SF
6 gas.
Parameters Values
p
re
SF
6
gas rated filling effective
pressure for the insulation
0.65 MPa (94.3 psi)
Ambient temperature 5°C
Local atmospheric pressure 93.2 kPa
SF
6
gas filling
The table below gives the calculation steps of the pure SF
6
filling pressure :
Step Action Result
1 In the chart (page 5) “Values of the
SF
6
gas effective pressures in ac-
cordance with the temperature”,
read the p
re
valueonthet°C=5
row.
0.603 MPa
2 Calculate the difference of the at-
mospheric pressure :
0.1013 -- 0.0932
0.0081 MPa
3 Calculate the rated effective pres-
sure p
re
:
0.603 + 0.0081
0.6111 MPa
4 Filling is carried out to the calcu-
lated pressure, plus 0,01 MPa,
that is to say : 0.6111 + 0.01
Pure SF
6
gas filling pressure
0.621 1 MPa