Influence of the weight coefficients of measurements on the consistency of the assessment and calculation results of the power supply system steady-state operation conditions

The aim of this work is to develop an improved procedure for assessing the state of power supply systems based on adjusting the weight coefficients of measurements. To this end, non-linear optimisation methods were used. The control equations and the solution of the simultaneous linear equations were performed using the Crout method. The results of the calculation of the electrical power steady-state mode were considered as a reference. The lower the difference between the evaluation and steady-state calculation results, the higher the accuracy of the overall state assessment procedure. The problem of correcting the weight factors is set and solved as a nonlinear optimisation problem, where the optimisation parameters are taken as the dispersion of the measurements. The objective function was formulated as follows: to minimise the measurement evaluation dispersions that are part of a single control equation by maximising the active power measurements dispersion in the swing bus of the power supply system. In this study, limitations in the form of equation and inequality are monitored. The problem of optimising the dispersions is solved after the first iteration of the state assessment; starting with the second iteration, the state assessment is performed with new measurement weight factors. The calculations were performed on a 6-node test circuit. The control equations are drawn from the current measurements. The measurements data on the selected control equation of the test circuit are used to calculate the target function. The accuracy of the dispersions redistribution and their extreme values are controlled by the limitations. The results showed that, when adjusting the dispersion of measurements, the power assessments at all nodes are closer to the steady-state mode calculation results.

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