Partial discharge is the situation in which electricity arcs through an insulating dielectric material when high voltages above the rated voltages for the insulator are applied. Continued partial discharge can cause the insulator to eventually be destroyed and fail, potentially causing catastrophic failure.
Recently a technical academic paper by H Mohamed et al. was released and titled “Partial Discharge Detection Using Low Cost RTL-SDR Model for Wideband Spectrum Sensing”. In the paper they investigate using the RTL-SDR as a low cost means for partial discharge detection in equipment such as power generators, motors, gas insulated switchgear, and power grid equipment for the purpose of improving the future electrical smart grid.
Partial discharge can be detected using a spectrum analyzer to monitor the spectrum for noise signatures associated with a discharge. Using a program written in MATLAB to make the RTL-SDR act as a spectrum analyser they show that the measured spectrum can be used to detect when partial discharge is occurring and that the results are similar to a more expensive spectrum analyzer.