answersLogoWhite

0

as distance relay is an impedance relay & measures impedance interms of current & voltage.

first zone : 85% of the selected ist portion's impedance interms of resistance & reactance. normally we use 85% to 90% of ist portion to avoid any human & other CT & PT's instruments errors.

secound zone: selected zone ist + 50% of the secound selected portions.

Third ZOne: selected zone ist + zone 2nd + 20% of the thrid selected portions.

Distance relay is CT & PT operated relay & give us exact location of the fault after measuring the level of the fault current & voltage.

User Avatar

Wiki User

13y ago

What else can I help you with?