A hybrid active islanding detection technique for single-phase inverter-based distributed generation system

Abstract

Islanding detection is mandatory for grid connected inverter-based distributed generation systems. At present, there are passive, active, hybrid and communication based islanding detection techniques. The effectiveness of these methods depends on the Non-Detection Zone (NDZ), cost, complexity and degradation in inverter output power quality. This paper analyses various possibilities of active/reactive power mismatch during grid disconnection and its impact on voltage amplitude and frequency at the Point of Common Coupling (PCC). An inverterbased Distributed Generation (DG) system operating in constant power mode, interconnected with local RLC load and the grid is considered for analysis. An active islanding detection technique based on the combination of Reactive Power Variation (RPV) and Positive Feedback Frequency Shift (PFFS) is proposed in this paper. This technique eliminates NDZ and accelerates the speed of islanding detection without degrading the inverter power quality. A detailed simulation study of the proposed islanding detection technique with several case studies of active/reactive power mismatch is carried out using MATLAB/Simulink. The proposed islanding detection technique is verified on Hardware in Loop (HIL) system implemented using Real Time Windows Target (RTWT) of MATLAB/Simulink, NI PCIe-6251 Data Acquisition Card (DAC) and TMS320F28335 controller.

Power Equations for Non-Detection Zone of Islanding Detection in Renewable-Energy-based Microgrids with Multiple Connection Points to Micro-Grids

“…On the other hand, active methods depend on the grid's reaction to a minor injected disturbance to detect the islanding condition. The hybrid strategy is a fusion of the active and passive techniques used to overcome NDZ [7][8][9][10][11][12][13][14][15][16][17][18][19]. Islanding in a power network can only occur when there is an equilibrium between the active and reactive powers.…”

Islanding detection of distributed generation systems using hybrid technique for multi-machine system

“…Thus, it reduces the instances of applying a perturbation. The hybrid islanding detection techniques [12][13][14][15][16] are employed to overcome the short comings of both active and passive techniques, to detect the islanding of a distribution system with renewable energy sources. The application of this technique has been done on a system with two DGs.…”