An Observer based FLL to Estimate the Grid Parameters of Three Phase Systems

Grid synchronization is a crucial task for maintaining correct and stable operation of the power system networks. It needs a less complicated and quick estimating frequency locked loop (FLL) to handle the grid aberrations like nonlinearity, glitches and unbalances. To attain this, a systematic measurement of the key parameters of all the three phases under various disturbances is needed. In this paper, a FLL based on discrete observer is proposed to estimate the magnitude, frequency and phase of a three phase system. This FLL has been tested through simulations for various three phase faults and disturbances. The results show that the proposed technique is appropriate for grid synchronization due to its easy structure, estimation capability in terms of response time and accuracy.