Linear dependence between nodal powers in probabilistic a.c. load flow

The paper describes how positive and negative dependence between the nodal powers of a power system can be formulated and included in the probabilistic a.c. load-flow problem. A typical system is analysed using nodal powers that are assumed, first, to be totally independent, and, secondly, to exhibit dependence. This analysis indicates clearly that it is not possible to predetermine the effect of dependence and illustrates how the standard deviations and the shape of the probability-density curves of the calculated parameters change when dependence between the input nodal powers is assumed.