Siemens SIPROTEC 4, User Manual

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[7sjx_logic_51-phase, 1, en_US]
Figure 2-15 Logic diagram of the voltage-restraint inverse-time overcurrent protection
Dynamic Cold Load Pickup Function
It may be necessary to dynamically increase the pickup thresholds of the overcurrent protection if certain
system components exhibit an increased power consumption when they are switched on after a long period
of zero voltage (e.g. air-conditioning systems, heating installations, motors). Thus, a general increase of
pickup thresholds can be avoided taking into consideration such starting conditions.
This dynamic pickup value changeover fuction is common to all overcurrent elements and is described in
Section
2.4 Dynamic Cold Load Pickup . The alternative pickup values can be set individually for each element
of the time overcurrent protection.
2.2.6
Functions
2.2 Overcurrent Protection 50, 51, 50N, 51N
68 SIPROTEC 4, 7SJ62/64, Manual
C53000-G1140-C207-8, Edition 08.2016