The essential parameters for relay settings include pickup voltage, dropout voltage, time delay settings, and protection thresholds. Protection relays employ a wide range of configurable parameters to identify defects & trip the breaker in a controlled & selected manner. PSM – Plug Setting Multiplier (Current Setting Multiplier) What is PSM? 2). TSM – Time. The protected zone is the part of the network in which faults cause the protection function to operate. The selection and applications of. This handbook covers the code of practice in protection circuitry including standard lead and device numbers, mode of connections at terminal strips, colour codes in multicore cables, dos and donts in execution. The goal is to strike a balance between.