What is difference between earth leakage relay and
restricted earth fault relay ?
Answer Posted / prasun bhaumik
REF sense the residual or differential current in between
two sets of CTs installed at two sides of protected unit
i.e Tr or Gen. It is a high imedance differential
protection it will only operate when
1) There is a earth fault inside the object which will
produce sufficient differential current.
2) In case fault occures out side the zone any of the CT
may satuarate then it will mal operate.
But earth leakage relay is conncetd with a CT which is
commonly ring type and surronded the earthing path of the
instrument or cable with armour it operates on Over current
principle not differential principle so there is no
requirement of stabilizing resistance as in the case of REF
| Is This Answer Correct ? | 12 Yes | 4 No |
Post New Answer View All Answers
For a 6.6kV Motor it is recommended to do megger test with 500 V d.c and not more than 5kV d.c but the Hi voltage withstand test should be performed by 12kV AC. Why the dc voltage test should be limited but AC voltage withstand test could be with such a high voltage?
how to determine Sq.mm size of finolex power cables.
In three pin plug 6 amp. 220V ac rating. Why earth pin diameter is higher than other two pin? What its purpose ?
How to do bus bar short circuit calculation for 230KV/11kv, 60 MVA Substation?
prove that power consumed in 3 phase delta system is 3 times as compared to 3 phase star system
how we arrange the hv side with delta connection in case 33/11kv of transformer.
How to calculate mf when meter equipment and meter are connected
in what type of applications v can use q meter?
State and define norton’s theorem?
why the neutral line is not giving shock to us if we touch it ?
How to select the earthing transformer,for DELTA TO DELTA TRANSFORMER OR ALTERNATOR SIDE.Pls post your answers and calculation.
A 100W electric lamp is supplied from a 115V, 60HZ source. The peak instantaneous power dissipated in the lamp filament is
What is the meaning of dedicated earthing?
any idea abt REVERSE METERING concept.........?