SIL DefinitionSurge Impedance Loading (SIL) is defined as the power a transmission line delivers to a load that matches the line’s surge impedance.Surge ImpedanceSurge Impedance is the balance point where capacitive and inductive reactances of a transmission line cancel each other out.Long transmission lines (> 250 km) inherently possess distributed inductance and capacitance. When activated, the capacitance feeds reactive power into the line, and the inductance absorbs it.Now if we take the