Development and design of a power supply system for intelligent monitoring equipment in smart grids

In recent years, a variety of distributed intelligent monitoring equipment has been installed in smart grids, and this equipment often requires low-power DC supply. This paper examines a power supply system which is used by distributed intelligent monitoring equipment in smart grids. The power supply system taps-off low-power from the transmission line or bus bar through the Faraday electromagnetic induction principle. First, the induction coil through which the transmission line or bus bar pass obtains low AC power, then AC voltage is rectified and filtered to a DC voltage which is converted into 5V by a DC/DC converter. A lithium battery (LB) was used as a standby power module to solve the dead zone of the induction coil. Finally, a power management module based on the STC15F2K60S single chip was able to switch between the energy of the induction coil and standby module by monitoring battery voltage and output voltage, so that output voltage and current can supply the intelligent monitoring equipment. Experiments indicated that this power supply system could stably supply 5W power in 5V when the current of the transmission line or the bus bar is in the range of 0 similar to 1000A.