GE GL317D Instruction Manual page 36

Gas pressure and density
Introduction
Constant
temperature
Constant density
Conclusion
07- 2016
Description and operation
SF gas monitoring
6
The electrical characteristics of switchgear depend on the density of SF
i.e. the mass of gas pumped into a compartment of a given volume.
At constant temperature, an increase of gas density results in a higher gas
pressure against the walls of compartment.
At constant density, with an fixed compartment volume, the pressure
changes in the same way as the temperature. Since the gas density
remains invariable owing to the fact that no modification occurs in the
quantity of gas or the volume of the relevant compartment, the electrical
characteristics of the switchgear will remain unchanged.
Since it is difficult to measure the gas density directly, it is essential to
know accurately its absolute pressure and temperature.
GE Information
gas
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