Modelagem de transformadores reguladores de tensão com estimação de taps no estimador de estado baseado na matriz de admitância nodal

Abstract

This work presents the modeling of voltage regulator to enable the insertion of the tap positions as state variables in the Admittance Matrix based State Estimation method. The representation of the voltage regulators improves the network model and the quality of the state estimation. The Admittance Matrix based state estimation uses rectangular current equations on the formulation and rectangular voltage as state variables. This method can deal with radial and meshed grids and uses the classical nodal analysis for the solution process. The taps are implemented as continuous state variables increasing the state vector and the Jacobian matrix of the system. The adopted algorithm present three steps: initialization of the variables; state estimation and discretization of the taps. IEEE 34 and 123 node test feeders were used to analyze the performance of the method with the implementation of the voltage regulators. Analyzes were performed with the regulator tap positions as parameter and as state variables. It was verified that the error decreases significantly with the taps as state variables when is compared with the taps as parameters. It was also verified that the initial state of the taps, the different kinds of measurements and the redundancy adopted affect the number of iterations that the process needs to achieve the convergence, in addition to the quality of the estimation. It was noted that the method has advantages when dealing with absolute voltage measurements when compared to rectangular current measurements, which correspond to the main equations of the method. Therefore, this is a method with large application capacity in real distribution systems, as most of the available measurements are absolute voltage measurements.