Question

What is the environmental concern for SF6 used in GIS? How is the environmental concern being addressed?

Short answer

TheSF6 causes the greenhouse effect and it is reduced by not using it pure and mixing it with the other gases.

Step-by-step solution

Define the gas insulated substation.

The GIS is defined as gas insulated substation is the substation that operates at high voltage such that all the major components of the substation are placed in a sealed environment. The sealed components are subjected to the SF6 gas that works as the insulation

Determine explanation for the answer.

The SF6 gas causes the greenhouse effect. The greenhouse effect causes the global warming that is 25000 times larger of what that is occurred in 25 years.

Consider the effect of SF6 effect on the environment is reduced by mixing the SF6 with the nitrogen. The other forms include ultra-diluted SF6/N2 such that SF6 content is $\le 1\%$.

Consider the gas pressure range in the GIS equipment is as follows:

Table 1

Gas mixture nitrogen	Gas mixture SF6	Pressure in MPa
95	5	1.3
90	10	0.94
80	20	0.71
100	0	0.4

Therefore, the SF6 causes the greenhouse effect and it is reduced by not using it pure and mixing it with the other gases.