What is a typical physical indicator of partial discharge in electrical systems?

The presence of audible buzzing is a typical physical indicator of partial discharge in electrical systems. Partial discharge occurs in high voltage equipment due to the insulation breakdown or defects, and it can create a phenomenon where electrical discharges occur intermittently, often resulting in noise. This buzzing sound is usually associated with the high-frequency oscillations that occur during these discharges, which can be more pronounced in poorly insulated or damaged equipment.

In contrast, the other indicators like visible flames, high heat, and flickering lights are generally not directly associated with partial discharge. While high heat may occur as a result of continuous electrical arcing, it is not a specific indicator of partial discharge. Visible flames would indicate a more severe fault or arcing situation rather than partial discharge. Flickering lights usually signal issues with power quality, such as voltage fluctuations or load changes, rather than being a direct result of partial discharges in the insulation system. Thus, the auditory signal of buzzing is a more characteristic and identifiable sign of this phenomenon in electrical systems.