Surge Impedance Loading (SIL) is the power level at which a transmission line is terminated with a load equal to its surge impedance. At this specific loading point, the reactive power generated by the line's capacitance is perfectly balanced by the reactive power consumed by its inductance. This balance results in a flat, stable voltage profile along the entire length of the line, and the line operates with maximum efficiency and minimal losses.

SIL is a benchmark used by engineers to evaluate the performance of a transmission line. For long transmission lines, operating significantly above SIL can cause a voltage drop, while operating below SIL can lead to overvoltage. Our company's tools and equipment are designed to help our customers build and maintain power systems that can be operated close to their surge impedance loading for optimal performance.