Ridmt: Reset Inverse Definite Minimum Time Characteristics - DEMA CPM 310 G User Manual

RIDMT: Reset Inverse Definite Minimum Time
Characteristic
RIDMT curves are used to obtain the inverse D.M.T. resetting characteristics for IEEE/ANSI and
custom curves that are needed to provide selectivity schemes when electromechanical relays are
protecting a primary line in series with the one CPM 310 G protects. The RIDMT parameters differ
Table of CPM 310 G Protection and Reset Curves Parameters
with the tripping curve, the on page 22
shows these parameters. The sample image below shows the CO2 short time inverse trip
characteristic and it RIDMT curve. The formula below is to calculate the reset delay for CO2 RIDMT
curve. □
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Sample RIDMT Curve: CO2 RIDMT Reset Curve
For other RIDMT curves, see the table at p.22
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