Functions
2.3 Dynamic Cold Load Pickup
SIPROTEC, 7SJ61, Manual
C53000-G1140-C210-1, Release date 02.2008
80
2.3.2 Setting Notes
General
The dynamic cold load pickup function can only be enabled if address 117 Coldload Pickup was set to
Enabled during configuration of the protective functions. If not required, this function should be set to
Disabled. The function can be turned ON or OFF under address 1701 Coldload Pickup.
Depending on the conditions that should initiate the cold load pickup function address 1702 Start
Condition is set to either No Current, Breaker Contact or to 79 ready. Naturally, the option Breaker
Contact can only be selected if the device receives information regarding the switching state of the circuit
breaker via at least one binary input. The option 79 ready modifies dynamically the pickup thresholds of the
overcurrent protection when the automatic reclosing feature is ready. To initiate the cold load pickup the auto-
matic reclosing function provides the internal signal "„79M Auto Reclosing ready“. It is always active
when auto-reclosure is available, activated, unblocked, and ready for a further cycle (see also Subsection 2.11).
Time Delays
There are no specific procedures on how to set the time delays at addresses 1703 CB Open Time, 1704
Active Time and 1705 Stop Time. These time delays must be based on the specific loading characteristics
of the equipment being protected, and should be set to allow for brief overloads associated with dynamic cold
load conditions.
50/51 Elements (phases)
The dynamic pickup values and tripping times associated with the time overcurrent protection functions are set
at address block 18 for the phase currents:
The dynamic pickup and delay settings for the high-set elements are set at addresses 1801 50c-2 PICKUP
or 1808 50c-3 PICKUP and 1802 50c-2 DELAY or 1809 50c-3 DELAY respectively; the dynamic pickup
and delay settings for the 67N-1 element are set at addresses 1803 50c-1 PICKUP and 1804 50c-1 DELAY
respectively; and the pickup, time multiplier (for IEC curves or user-defined curves), and time dial (for ANSI
curves) settings for the 67N-TOC element are set at addresses 1805
51c PICKUP, 1806 51
c TIME DIAL
and 1807 51c TIME DIAL respectively.
50N/51N Elements (ground)
The dynamic pickup values and time delays associated with non-directional time overcurrent ground protection
are set at address block 19:
The dynamic pickup and delay settings for the high-set elements are set at addresses 1901 50Nc-2 PICKUP
or 1908 50Nc-3 PICKUP and 1902 50Nc-2 DELAY or 1909 50Nc-3 DELAY respectively; the dynamic
pickup and delay settings for the 67N-1 element are set at addresses 1903 50Nc-1 PICKUP and 1904 50Nc-
1 DELAY respectively; and the pickup, time multiplier (for IEC curves or user-defined curves), and time dial (for
ANSI curves) settings for the 67N-TOC element are set at addresses 1905 51Nc PICKUP, 1906 51Nc T-
DIAL and 1907 51Nc T-DIAL respectively.
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