Wavelet transform for voltage dips detection in a microgrid with distributed generation

The paper examines application of wavelet transform for voltage dips detection in microgrids with distributed generation. IEEE13 test grid with added 1.6 MW distribution generators is used for evaluation. Distribution generators are two 0.8 MW doubly-fed induction generators. Matlab/Simulink environment is used for modelling and evaluation of proposed algorithm for voltage dips detection. Six types of fault are examined and conclusions are derived. As a further confirmation of the obtained results, authors utilized the existing laboratory setup at the Faculty of Technical Sciences, in order to get as realistic as possible voltage dips signals from the grid, recorded over distribution transformer (small scale distribution transformer). Voltage dips are produced with grid emulator. These signals are then used for emulation, and analyzed with different wavelet methods. In paper is shown that wavelet is not appropriate solution as part of control of distribution generator grid-tie inverter in order to fast detect voltage dips, if the measurement is performed in place of inverter. None of the wavelets when using highest frequency band can't detect voltage dips fast and accurate at this spot in the grid. Solution to this problem can be to use signals that are measured at the connection point of the generators to the grid.