The paper describes the development of a permanent light marking system for high-voltage overhead power lines based on the domestic element base. We calculated and chose a power source for gas-filled lamps using the energy of the electrostatic field of high-voltage cables. The paper presents laboratory studies of the volt-ampere characteristic of a gas-filled light source and the possibility of direct use of the electrostatic field of a three-phase high-voltage power line for the lamp power supply. We performed high-voltage pulse tests of the device with the pulse parameters typical for lightning discharges and experimentally proved the stability of the developed system to overvoltage on overhead lines. Peter the Great St. Petersburg Polytechnic University provided a model of an overhead transmission line in the laboratory of high-voltage equipment for assembly and bench high-voltage tests of the device. We studied the spectral characteristics of the lamps and put the device into trial operation.