System Impedance Ratio (SIR)

What is the need to understand SIR for a protection Engineer? What is the impact of SIR on Relays ?? How SIR is calculated ????

[@pratibhaprajapati7984]

Great SIR

[@sanjeevrana8317]

Excellent 👌👍

[@mohdazhar1063]

Very informative, very well way of making someone understand.👏👏

[@ganpathji]

Clear cut explanation. Thank you

[@prasannas3260]

Awesome explanation and eager to waiting for your next video sir

[@srikanth63061095]

Clearly explained

[@sunilsaini7969]

SIR WAITING MORE INFORMATIVE VIDEOS

[@sanjeevrana8317]

Club with Short circuit ratio

[@Sureshkumar-pq6tw]

Dear sir, The line impedance doesn't change with respect to fault current.Then how you took 50%?

[@KNDBEpicLearn]

Absolutely correct. The Distance relay works on the comparison of the Set impedance with the measured impedance. The set impedance is based on Z=R+jX which will not vary as you have mentioned. The measured impedance is Z=V/I which is based on the fault current path. The fault current chooses the least resistance path (fault path) which is mid way of the transmission line in this example and hence the Measured impedance would be lesser than the set impedance which results in the operation of the relay