Formula for calculating current in relay protection section

Isc Function: The short-circuit current is given by Isc = S / (V * PF) Isc_Relay Function: The secondary short-circuit current is given by Isc_Relay = Isc / CT Pickup Function: The relay pickup current is given by Pickup = Relay * VTIsc Function: The short-circuit current is given by Isc = S / (V * PF) Isc_Relay Function: The secondary short-circuit current is given by Isc_Relay = Isc / CT Pickup Function: The relay pickup current is given by Pickup = Relay * VTCoordinating overcurrent relays across multiple protection zones is one of the most consequential tasks in power system design — get it wrong and a single downstream fault trips an entire substation. Use this Protection Relay Setting Calculator to calculate pickup current, time multiplier settings. Pick Up Current Definition: The current level at which the relay begins to operate, overcoming the controlling force. Calculation Example: Protective relaying is a system of devices that detect and respond to abnormal conditions in an electrical power system. The objective is to minimise the impact of electrical faults by ensuring that only the. Information required for relay calculations NERC compliance (PRC- 019,024,025,026,027 overview) Sample application, Global settings Phase Fault Protection 87 – Phase Differential Current 50 – Instantaneous Phase Overcurrent 50DT – Definite Time Overcurrent Ground Fault Protection (High- Impedance. Selective short-circuit protection can be achieved in different ways, such as: Time-graded protection Time- and current-graded protection A straightforward way of obtaining selective protection is to use time grading. The principle is to grade the operating times of the relays in such a way that.