IDMT Relay
IDMT Relay
(OP)
Is there an electronic replacement/alternative for the IDMT relay? It has been quite some time since I worked in the industry but I was told that the good-old IDMT has been virtually shelved on new or refurbed protection schemes.
Regards,
Lyledunn






RE: IDMT Relay
Regards,
Lyledunn
RE: IDMT Relay
This new relays can do much more than the old elctromechanical relays - You can choose different curves, do metering, see fault data, have much lower burdens, do self testing, etc, etc. Some manufacturers are ABB, Reyrolle, SEL, Siemens, Strike, GE, just to name a few.
Some of the disadvantages of the modern relays are:
Can't see the disc turning
Must have some kind of power supply
Can't do series tripping (where you use the CTs to supply the tripcoil during a trip)
But, the advantages of the new relays are much more than the few disadvantages.
RE: IDMT Relay
The lateastrelayshave all these three modes inbuilt in one relay cabinet itself.
RE: IDMT Relay
RE: IDMT Relay
Please start a new thread when you are asking questions not relevant to the original question.
The CDG34 has an extremely inverse curve.
http
An approximate equation (IEC extremely inverse curve)
t = 80 x k / [((I-fault/I-set)^2)-1]
where:
t = time in seconds
k = time multiplier
I-fault = Fault current
I-set = Current setting
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