Power flow in networks modeled at substation level in two stages

The importance of power flow in networks modeled at the bus section level for generalized state estimation and real-time operation has been highlighted in the literature. However, the impacts on increasing the size of the problem and hence on the computational effort required by such approach may jeopardize its application. This work proposes a new methodology, capable of significantly reducing the computational cost involved in the extended power flow. This is achieved by applying a two-stage strategy. In the first stage a conventional power flow at the bus-branch level is triggered and its results properly exploited to the next stage. The paper describes in detail the strategies and linear relationships involved in the second stage, which provides complex voltages as well as the power flow distribution inside the substations, as in the extended power flow available in literature. Results obtained with the IEEE 14-bus test system illustrate the applicability and highlight the relevance of the new approach.