Using digital protection relay in electrical network of rock coal mining industry involves blocking short-circuit triggering before switching on next motor if protection function detects machine-dependent current limit being exceeded

摘要

The relay has additional functions as well as its short-circuit triggering protection function that can be active at the same time and can be blocked relative to each other. It involves successively switching on the motors associated with the machine during start-up and increasing the current amplitude in steps and blocking the short-circuit triggering before switching on the next motor if one of the protection functions detects a machine-dependent current limit being exceeded.