The article presents a digital processing algorithm for monitoring short-circuit currents in the power supply network. It is proposed to carry out control by calculating the rate of change of current. An algorithm based on a digital differentiating filter with suppression of high-frequency components has been developed. Based on the Fourier series, a non-recursive filter is formed, the characteristics of which are improved using the Lanczos smoothing method. It is proposed to use a recursive filter transformed from a non-recursive one using the B.L. Ho algorithm to save processing. The algorithm is easily implemented as programs for microprocessor systems. A filter based on an analog prototype is presented. A simulation of the short circuit process has been carried out.

Keywords: power supply, short-circuit current, data processing algorithm, power supply system monitoring, digital differentiating filter