<b>Local voltage controllers (LVCs) are important
components of a modern distribution system for regulating the voltage within
permissible limits. This manuscript presents a sensitivity-based three-phase weather-dependent
power flow algorithm for distribution networks with LVCs. This Part I presents
the theoretical development
of the proposed algorithm, which has four distinct characteristics: a) it
considers the three-phase unbalanced nature of distribution systems, b) the
operating state of LVCs is calculated using sensitivity parameters, which accelerates the
convergence speed of the algorithm, c) it considers the precise switching sequence of LVCs based on
their reaction time delays, and d) the nonlinear influence of weather
variations in the power flow is also taken into consideration. Simulations and
validation results presented in Part II indicate that the proposed approach
outperforms other existing algorithms with respect to the accuracy and speed of
convergence, thus making it a promising power flow tool for accurate distribution
system analysis. </b><div><b><br></b></div>
An Improved Three-Phase AMB Distribution System State Estimator
