What is IDMT? What is the principle

Answer Posted / ashish

its a type of overcurrent - earth fault relay --
IDMT -- inverse definite min. time , having diff types--
normal inverse / long inverse / short inverse type

the relay are of 3 types
1) electro mechanical (whose opeartion way is described by
others)
2) static and latest are 3) numericals --no moving part.

the simple way to explain its principle is that
THE RELAY OPERATIONAL TIME IS INVERSELY PROPORTIONAL TO
THE FAULT CURRENT. IN NORMAL INV IDMT FOR A 2.0 TIMES
CURRENT WITH TMS (TIME MULTIPLIER SETTING) of 1.0 THE RELAY
OPERATInG TIME IS 10 SEC,.. WHEREAS FOR THIS SAME SETTINGS
IF CURRENT IS DOUBLED THE TIME REQUIRED IS ALMOST 5 SEC..

but after 20 amp(in 1 A relay) the time reqd is same.

Is This Answer Correct ?    29 Yes 6 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What is inrush current?

635


what is reactive power?, why its measured in VA ? is it transient behavior of system?

1789


lamination figures

1407


Show the schematic arrangement of diesel power station layout and give its principle of operation.

2533


What are the essential characteristics of signal flow graphs?

663






why Lightening Arrester Probe sharp at Top of telecom tower.

1092


the typical output of a solar cell is........

1836


What is an iron loss or core loss pi?

623


List out the different frequency domain specifications?

751


WHAT IS THE MEANING OF BALANCED / UNBALANCED IN STABILIZER TYPES.

1967


How to calculate the efficiency of Turbo Generator(Alternator) in general....?

2244


Dear sir, How to calculate 3.5 core pvc aluminium armoured cable meter wise carrying amps rating.Please give the solution with a good example.

1303


List out the the types of Mounting Light fixture?

1199


Define what is power quality meter ?

659


How can you calculate the size of the down conductor cable for the lightning protection system. Is 70mm2 cable can replace 95mm 2 bare copper cable when the copper tape size is 25Wx3 thk mm.

4949