Arcteq AQ F205, Instruction Manual

Page: 290 / 421

Figure. 5.4.5 - 195. Simplified function block diagram of the cold load pick-up function.
Measured input
The function block uses analog current measurement values. A -20 ms averaged value of the selected
magnitude is used for pre-fault data registering.
Table. 5.4.5 - 188. Measurement inputs of the cold load pick-up function.
Signal Description Time base
IL1RMS RMS measurement of phase L1 (A) current 5ms
IL2RMS RMS measurement of phase L2 (B) current 5ms
IL3RMS RMS measurement of phase L3 (C) current 5ms
The pre-fault condition is presented with a 20 ms averaged history value from -20 ms from CLPU
ACT event.
Pick-up
The I
low
, I
high
and I
over
setting parameters control the the pick-up and activation of the cold load pick-
up function. They define the maximum and minimum allowed measured current before action from the
function. The function constantly calculates the ratio between the setting values and the measured
magnitude ( I
m
) for each of the three phases. The reset ratio of 97 % is built into the function and is
always relative to the setting value. The setting value is common for all measured phases. When the I
m
exceeds the setting value (in single, dual or all phases) it triggers the pick-up operation of the function.
Table. 5.4.5 - 189. Pick-up settings.
Name Range Step Default Description
I
low
0.01…40.00×In 0.01×In 0.20×In
The pick-up setting for low current detection. All measured currents must be
below this setting in order for the cold load pick-up signal to be activated.
I
high
0.01…40.00×In 0.01×In 1.20×In
The pick-up setting for high current detection. All measured currents must
exceed this setting in order for the cold load pick-up signal to be activated.
I
over
0.01…40.00×In 0.01×In 2.00×In
The pick-up setting for overcurrent detection. If this setting is exceeded by
any of the measured currents, the cold load pick-up signal is released
immediately.
A AQ Q-F205 -F205
Instruction manual
Version: 2.04
288 © Arcteq Relays Ltd
IM00013