Correct option is B
In relay protection systems, current grading involves selecting relays with different current settings for different sections of a power system.
The main advantage of this method is to overcome the long time delays that occur in graded time-lag systems.
In graded time-lag systems, the relay settings are adjusted to ensure that only the relays closest to the fault act quickly, but this can sometimes cause delays.
Current grading helps by ensuring that the fault is detected and cleared more efficiently, avoiding delays in the tripping process.
