LOW VOLTAGE DISTRIBUTION NETWORK STATE ESTIMATION BASED ON SMART METER READINGS

PURPOSE. The use of renewable generation sources causes bidirectional power flows and overvoltages in low voltage distribution networks. The information on the current values of all mode variables, which is necessary for the efficient monitoring and control of the distribution network can be obtained through the processing of measurements from the smart meters. The paper proposes a new approach to the solution of the state estimation problem of a three phase distribution network based on the measurements of voltage modules and nodal powers or currents. METHODS. It is proposed to solve the nonlinear state estimation problem on the basis of nodal power and voltage measurements instead of Newton’s method traditionally used for this purpose. The quadratic function of residuals at each simple iteration and at linear state estimation based on the measurements of nodal currents and voltages is minimized by the weighted least squares method with or without constraints on zero currents at the transit nodes or by the Hachtel matrix method. RESULTS AND THEIR DISCUSSION. The effectiveness of the proposed methods is illustrated using linear and nonlinear state estimation for each hour of the daily curve of nodal power variations for the three phase 32 node low voltage test network. CONCLUSIONS. Application of the simple iteration method for nonlinear state estimation makes this procedure as trivial as the procedure of linear state estimation. The Hachtel matrix method allows to obtain the minimum value of the objective function compared to the value of the objective function for the weighted least squares method with and without constraints.

distribution network, renewable generation, observability, state estimation, smart meters, simple iteration method

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