Voltage Feedforward Positive Feedback Based Active Islanding Detection Method

The Voltage Feedforward Positive Feedback based islanding detection method is an improved active islanding detection technique primarily used in distributed generation systems. By incorporating voltage feedforward and positive feedback mechanisms, this method significantly enhances detection reliability and speed while eliminating blind spots common in traditional approaches.

The core methodology involves injecting specific disturbance signals into the power grid and rapidly capturing grid-side voltage variations through the voltage feedforward module. The positive feedback mechanism amplifies disturbance effects, enabling quick identification and protection triggering during islanding conditions. The feedforward component significantly improves detection speed, while the positive feedback structure maintains high detection sensitivity even under light load conditions, achieving blind spot-free detection. In implementation, the algorithm typically monitors voltage phase shifts or magnitude variations, with feedforward gains calibrated to grid impedance characteristics.

Compared to conventional passive detection methods, this technique minimizes power quality impact while avoiding false trips caused by inappropriate frequency or voltage threshold settings. It demonstrates excellent application prospects in microgrid and photovoltaic generation systems. The control logic can be implemented using dq-frame transformation for voltage tracking, with positive feedback gains programmed to scale proportionally with detected deviations.

The method's key advantages manifest in three aspects: 1) High detection speed, completing islanding identification within grid standard specified timeframes through optimized signal processing algorithms; 2) Blind spot-free operation, effective across various load conditions via adaptive threshold adjustments; 3) Minimal grid power quality impact, compliant with grid-connected equipment standards through precisely controlled disturbance injection parameters.