Event block name
Event names
CIN6
Close
CIN6
Bad
CIN7
Intermediate
CIN7
Open
CIN7
Close
CIN7
Bad
CIN8
Intermediate
CIN8
Open
CIN8
Close
CIN8
Bad
CIN9
Intermediate
CIN9
Open
CIN9
Close
CIN9
Bad
CIN10
Intermediate
CIN10
Open
CIN10
Close
CIN10
Bad
5.4.3 Cold load pick-up (CLPU)
The cold load pick-up function is used for detecting so-called cold load situations, where a loss of load
diversity has occured after distribution has been re-energized. The characteristics of cold load
situations vary according to the types of loads individual feeders have. This means that this function
needs to be set specifically according to the load type of the feeder it is monitoring. For example, in
residential areas there are relatively many thermostat-controlled devices (such as heating and cooling
machinery) which normally run in asynchronous cycles. When restoring power after a longer power
outage, these devices demand the full start-up power which can cause the inrush current to be
significantly higher than what the load current was before the outage. This is uncommon in industrial
environments since the restoring of the production process takes several hours, or even days, and the
power level goes back to the level it was before the outage. However, some areas of the industrial
network may find the cold load pick-up function useful.
The operating decisions are based on phase current magnitudes and magnitude changes which the
function constantly measures. The blocking signal and the setting group selection control the operating
characteristics of the function during normal operation, i.e. the user or user-defined logic can change
function parameters while the function is running.
The cold load pick-up function uses a total of eight (8) separate setting groups which can be selected
from one common source.
The operational logic consists of the following:
• input magnitude processing
• threshold comparator
• block signal check
• time delay characteristics
• output processing.
A
AQ
Q-C255
-C255
Instruction manual
Version: 2.06
© Arcteq Relays Ltd
IM00035
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