P12x/EN T/Eb6 - Schneider - error

Application GuideP12x/EN AP/Eb6MiCOM P120/P121/P122/P123 Page 33/7812. COLD LOAD PICK-UP (P122 & P123 ONLY)The Cold Load Pick-up feature allows selected settings of MiCOM P122 and P123 relays tobe changed to react to temporary overload conditions that may occur during cold starts. Thiscondition may happen by switching on large heating loads after a sufficient cooling period, orloads that draw high initial starting currents.When a feeder is energised, the current levels that flow for a period of time followingenergising may differ greatly from the normal load levels. Consequently, overcurrent settingsthat have been applied to give short circuit protection may not be suitable during this period.The Cold Load Pick-up (CLP) logic raises the settings of selected stages for a set duration(tCL). This allows the protection settings to be set closer to the load profile. Cold load pick-upcannot restart until the end of tCL duration. The CLP logic provides stability, withoutcompromising protection performance during starting.The CLP can be started by digital logic Input 52A and/or internal threshold detection by (NotI< & I>) and/or internal threshold detection by (Not I0< & I0>).If the CB positions are not available, to detect the Cold Load Pick-up start, a new internalthreshold is created named autostart.To detect the Cold Load Pick-up, the three phases current should be under 5% of In. Whenthe current grows up to In or more, with a time of less than 200 ms, an internal edgedetection is created.In >IAIBICCLP does not startIn >Time morethan 200msIA IB ICOne phase isupper than 5% ofIn at start.Internel Virtualthreshold 5% InInternel Virtualthreshold 5% InT In, in less than 200msInternel Virtualthreshold 5% InT