Decoupled state and line parameter estimation in three-phase unbalanced distribution system

The line parameters of the distribution feeder play a crucial role in the operation and analysis of the distribution system. In many developing nations, precise knowledge of these parameters are often lacking. This paper proposes a method for accurate estimation of feeder parameter along with the system states using a decoupled state and line parameter estimation technique. This method does not need a phasor measurement unit (PMU) installed at the feeder terminals. The paper also presents a comparison of decoupled method and the augmented vector state and line parameter estimation method. The proposed methodology has been verified through comprehensive case studies conducted on IEEE 123 bus three-phase distribution system. Through detailed simulation studies, it is observed that the proposed methodology is superior to the augmented vector method both in terms of accuracy and computational time.