Distribution Network State Estimation And Application

ADO(Advanced Distribution Operation)is one of the main components of smart grid. It requires that the power grid should have flexible and reconfigurable distribution network topology and the ability of monitoring and analysis of the real-time state. Advanced Metering Infrastructure(AMI) is an important foundation for the smart grid. Through the fundamental equipment of AMI, i.e. smart meters, utilities can get power consumers' historical or near real-time various types of measurements. The smart meter interval measurements collected by AMI should be applied to the distribution state estimation resulting in more accurate and comprehensive estimation of distribution network operating state and thus providing more reliable data supports for other high level applications.To begin with, for the asymmetric line and unbalanced load characteristics of the three-phase distribution network, the detailed mathematical models of three-phase components in distribution network is described in this paper. Taking the real and imaginary parts of node voltages as state variables, the Jacobian matrix of node power injection measurements, node voltage amplitude measurements, branch current amplitude measurements and branch power measurements is deduced. Based on OpenDSS, three-phase distribution network state estimation algorithm is established. Also the influence caused by the three-phase load asymmetry on the state estimation accuracy is explored in this paper and the regularized residual bad data identification method is achieved. Through the various measurements collected by smart meters of AMI, in medium-voltage and low-voltage distribution state estimation, methods of processing delayed measurements and energy theft detection are discussed and examples demonstrate the effectiveness.