A Digital Signal Processing Method for Power-Frequency Current and Voltage Signals Using Stochastic Dithering and Low-Bit Quantization

The trend toward the decarbonization of the energy sector is changing the structure of generating capacity through the widespread introduction of renewable energy sources. Modern wind and solar power plants are integrated into electric power systems via inverters. In recent years, electrical devices based on fully controlled transistors have become widely used to control electric power system modes, including FACTS devices, as well as to manage technological processes in industrial power supply systems. The resulting short- and long-term deviations in power quality indicators (PQIs) from standard values lead to significant errors in digital signal processing (DSP) within intelligent electronic devices (IEDs). This is due to the use of generally accepted assumptions in DSP. IEDs perform protection, automation, and control functions, and their malfunction can contribute to the initiation and escalation of accidents. In electric power systems, deviations in current and voltage signals from nominal values are also possible due to electromechanical and electromagnetic transients. This article presents a developed method for DSP of industrial-frequency currents and voltages. This method differs from existing approaches by using stochastic dithering and low-bit quantization. To illustrate the advantages of the developed method, simulations were performed, and the results thereof are presented in the article. Using this method improves the accuracy of DSP by compensating for deviations in PQI in industrial-frequency currents and voltages. The stability of the response parameters of protection, automation and control devices in various circuit and operating modes will contribute to the reliable operation of electric power systems at this stage of their development. The developed method can be implemented in intelligent electronic devices from various manufacturers without requiring hardware modifications, affecting only the DSP algorithms in the measuring elements.