Fast and Stable Detection Scheme of Point of Common Coupling Voltage for Renewable Energy Systems Tied to Distortion Grids

Due to the rapid development of renewable energy technology, renewable energy systems with power electronic equipment have gradually become the main components of the power system. However, the traditional detection methods do not always satisfy the need for accurate and high-speed sequence component acquisition of the power grid at point of common coupling (PCC) under distortion grids, which leads to the decline of the reliability of renewable energy system. To this end, a detection scheme based on the cascaded enhanced delayed signal cancellation (CEDSC), triangular orthogonal signal construction (TOSC) and adaptive stabilization algorithms is derived mathematically. The CEDSC can effectively suppress multiple harmonics and noise. Afterwards, the sequence components can be calculated by the TOSC and proposed mathematical calculation algorithms. The adaptive stabilization algorithm of the proposed scheme can avoid calculation errors and thus improves the robustness. The results show that in distorted grids, the dynamic response time of this scheme to detect positive and negative sequence components is about 8 ms. Compared with the traditional methods, this scheme has obvious comprehensive advantages in the detection accuracy and response time. Moreover, the proposed scheme has the characteristics of strong robustness, which improves the grid-connected stability of renewable energy systems.