Gao Shuping, Guo Fangbin, Song Guobing, et al. ISLANDING DETECTION METHOD BASED ON CHARACTERISTIC FREQUENCY HARMONIC VOLTAGE[J]. 2025, 46(3): 254-262. DOI: 10.19912/j.0254-0096.tynxb.2023-1931.
ISLANDING DETECTION METHOD BASED ON CHARACTERISTIC FREQUENCY HARMONIC VOLTAGE
When the distributed power supply is disconnected from the main grid
the power supply to the local load should be cut off. In order to quickly and reliably detect this state and ensure the safe and stable operation of the system
this paper focuses on the islanding detection technology for three-phase grid-connected inverters in distributed power systems and proposes a novel passive islanding detection method based on the characteristic frequency harmonic voltages at the distributed generation (DG) side and the power grid side. Firstly
the harmonic responsibility of both sides at the common connection point is divided. According to the result of harmonic responsibility division
the characteristic frequency harmonics that have the greatest influence on the harmonic voltage at the common connection point are selected for islanding detection
and the setting criterion is given. Secondly
the theoretical value of the harmonic voltage ratio at point of common coupling before and after the island is deduced. When the variation of characteristic frequency harmonic voltage parameters on both sides of the islanding exceeds the setting threshold
the islanding is judged to occur. Finally
the proposed method is verified according to IEEE Std.1547.1 islanding detection standard. The simulation results show that this method can detect occurrence of islanding operation quickly
accurately and effectively. This method uses double criteria to reduce the possibility of misjudgment and improve the reliability of islanding detection. Compared with traditional passive islanding detection methods based on harmonic domain
this method can avoid the problems of difficulty in detecting frequency harmonics
difficulty in determining the threshold and being affected by background harmonics.
LIU N, DIDUCH C, CHANG L C, et al.A reference impedance-based passive islanding detection method for inverter-based distributed generation system[J]. IEEE journal of emerging and selected topics in power electronics, 2015, 3(4): 1205-1217.
JANG S I, KIM K H.An islanding detection method for distributed generations using voltage unbalance and total harmonic distortion of current[J]. IEEE transactions on power delivery, 2004, 19(2): 745-752.
XU W, ZHANG G B, LI C, et al.A power line signaling based technique for anti-islanding protection of distributed generators: Part I: scheme and analysis[J]. IEEE transactions on power delivery, 2007, 22(3): 1758-1766.
SEYEDI M, TAHER S A, GANJI B, et al.A hybrid islanding detection method based on the rates of changes in voltage and active power for the multi-inverter systems[J]. IEEE transactions on smart grid, 2021, 12(4): 2800-2811.