A Simple Approach to Zero Crossing Detection of Voltage and its Application in Distributed Power Supply

Turning on and off the relays at or near the zero-crossing point of the supply voltage is essential for their reliable and safe operation, as well as for minimizing disturbances in current and voltage waveforms. This paper presents two innovative software approaches for detecting zero crossings in distributed power supply systems, which are crucial for enhancing voltage regulation and minimizing disturbances in voltage and current waveforms. By enabling precise relay operations at zero crossing points, these methods not only improve system stability but also protect relays from potential malfunctions. The versatility of these approaches is highlighted by their compatibility with a universal voltage range of 85–265 V and frequencies of 50 Hz or 60 Hz, requiring minimal hardware for implementation. Additionally, the methods facilitate frequency measurement, which allows for the assessment of other critical parameters such as voltage, current, power, power factor, and energy consumption. The paper also introduces a frequency measurement technique capable of detecting islanding in grid-connected systems, further enhancing the reliability of power supply systems. Validation of these methods using the PSIM® simulator demonstrates their effectiveness and ease of implementation, as they can be executed through straightforward coding. One of the approaches also takes into account the aging process of the components.