Table. 5.4.1. - 54. Inverse operating time formulas for nonstandard characteristics.
RI-type
RD-type
Used to get time grading with
mechanical relays
Mostly used in earth-fault protection which grants selective tripping even in non-
directional protection
t = Operating delay (s)
k = Time dial setting
Im = Measured maximum current
Iset = Pick up setting
t = Operating delay (s)
k = Time dial setting
Im = Measured maximum current
Iset = Pick up setting
Table. 5.4.1. - 55. Reset time characteristics setting parameters.
Name
Range
Step
Default Description
Release Time
delay
0.000…
150.000s 0.005s 0.06s
Resetting time. Time allowed in between of pick-ups if the pick-up has not
lead into trip operation. During this time the start signal is held on for the
timers if delayed pick-up release is active.
Delayed Pick-
up release
No
Yes
-
Yes
Resetting characteristics selection either time delayed or instant after pick-up
element is released. If activated the start signal is reset after set release time
delay.
Time calc
reset after
release time
No
Yes
-
Yes
Operating timer resetting characteristics selection. When active the operating
time counter is reset after set release time if pick-up element is not activated
during this time. When disabled the operating time counter is reset directly
after the pick-up element reset.
Continue time
calculation
during release
time
No
Yes
-
No
Time calculation characteristics selection. If activated the operating time
counter is continuing until set release time even the pick-up element is reset.
Behavior of stages with different release time con gurations are presented in the following gures.
AQ-F255
Instruction manual
Version: 2.00
© Arcteq Relays Ltd
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