Design and Key Technology Research of Distribution Network Residual Voltage Detection Module Based on Domestic Components

Aiming at the problems existing in traditional residual voltage detection in voltage-time type feeder automation systems, such as response lag, power failure detection blind spots, and reliance on imported core chips, this paper proposes a design scheme of a low-power residual voltage detection module based on a domestic M0 chip. A hybrid power supply architecture composed of a lithium-thionyl chloride battery and a supercapacitor is adopted, combined with a transformer isolation acquisition and an optocoupler isolation wake-up circuit, realizing long-term power supply and microsecond-level response under power failure conditions. In addition, this paper constructs a multi-criterion residual voltage judgment algorithm that integrates the decay time constant and a triple-window verification mechanism. Experimental verification shows that the module can reliably identify residual voltage pulses of not less than 50% U_n within 60 ms, meeting the standardization requirements of the State Grid. It can effectively reduce the number of fault reclosing operations, provide key technical support for distribution network feeder automation, and has important engineering value for promoting the localization and intelligent upgrading of distribution network equipment.