Reliability assessment considering network loss and voltage constraints in composite power systems

The active power correction model based on the DC load flow has been widely used in the reliability assessment of bulk power systems. However, because the network loss is ignored in the DC load flow model, the reliability indices obtained may be over-optimistic, especially when there exists generation deficiency. On the other hand, this model doesn't consider the influence of voltage and reactive power adjustments, consequently the voltage problem of the power system can not be identified with this approach. To deal with this deficiency, the network loss is introduced in the traditional active power adjustment model, which will avoid violation of outputs of the generating units at the slack bus. A comprehensive incremental linear model for the voltage and reactive power adjustment is proposed using PQ decomposition algorithm. The voltage and reactive power adjustment model can be used to analyze the impacts of different voltage adjustment strategies on the system reliability indices. Finally, the IEEE-RTS system is utilized to illustrate the effects of net loss and different voltage adjustment strategies on the system reliability indices.