Use this Protection Relay Setting Calculator to calculate pickup current, time multiplier settings (TMS), operating time, coordination time interval (CTI), and plug setting multiplier (PSM) using fault current, CT ratio, and IEC 60255 curve parameters. Relay coordination is the process of selecting settings that will assure that the relays will operate in a reliable and selective way. Plug Setting Multiplier (PSM):. This technical report refers to the electrical protections of all 132kV switchgear. All calculations are based on the available documentation/ information.