Point Estimate Schemes for Probabilistic Three-Phase Load flow

This paper applies the point estimate method to account for the uncertainties that affect the evaluation of the steady state operating condition of an unbalanced three-phase power system.Moreover, since the point estimate method requires that the input random variables are uncorrelated. a suitable adjustment to take into account the correlation is applied. Different point estimate schemes (2m, 2m + 1 and 4m + 1 schemes) are presented and tested. The accuracy of the proposed techniques is tested on a three-phase unbalanced IEEE 34-bus test system; the results obtained applying the Monte Carlo simulation are assumed as reference. Both correlated and uncorrelated input random variables are considered, and multimodal probability density functions are tested. The conclusion is that the 2m + 1 scheme gives the best solution in terms of accuracy and computational efforts; in the case of correlated input random variables, an adequate procedure to take into account the correlation must be applied