Islanding Detection Scheme based on DFT of dV/dQ Parameter and Power System Load Switching

This paper presents a new active islanding detection method based on power system loads switching (PSLS) and monitor the discrete Fourier transform of rate of change of voltage over reactive power (DFT(dV/dQ)). In the power systems, the voltage and reactive power are simultaneously changed very faster than other parameters, because there is no related inertia to change them. Moreover, the frequency analysis of rate of change of voltage over reactive power is very sensitive and has a high reliable performance to islanding detection than other passive parameters. In large power mismatches, islanding immediately are detected with DFT(dV/dQ), however, for small power mismatches, it has a nondetection zone (NDZ). Therefore, to covering the NDZ of the DFT(dV/dQ), the PSLS active method is initiated. For PSLS implementation, some of the power systems loads are candidate and one of them is used at need time. Therefore, by measuring the changes in DFT(dV/dQ), conditions are precisely detected. This proposed method can uses in the presence of any type of DG. The proposed method has been assessed on a typical network in presence of synchronousandinverter-based DGs in MATLAB/Simulink software. The simulation results confirm the high efficiency and speed in detection of the proposed method.

کلیدواژه ها:

islanding detection ، power system ، power system load switching ، discrete Fourier transform ، rate of change of voltage over reactive power.