Identify given parameters

Identify the primary parameters required for Plug Setting Multiplier (PSM) calculation: the fault current $I_f = 30A$ and the relay pickup current $I_p = 7.5A$.

$I_f = 30A, I_p = 7.5A$

Apply PSM formula

The Plug Setting Multiplier is defined as the ratio of fault current flowing in the relay coil to the pickup current.

$PSM = \frac{I_f}{I_p}$

Calculate the result

Substitute the given values into the formula: $PSM = 30 / 7.5 = 4$.

$PSM = \frac{30}{7.5} = 4$