Reactive Power Loop Flows in Transmission Grids

As conventional power plants are decommissioned, an efficient dispatch of reactive power compensators is required to maintain transmission grid voltages within their limits. To evaluate the efficiency, a detailed analysis of reactive power flows among compensators, branches and loads is required. Reactive power loop flows (RPLFs) between two compensators are often unnecessary and hence their detection and minimization increases the efficiency of the reactive power dispatch. This paper presents a new method to detect and reduce RPLFs. First, reactive flows are evaluated and classified into different categories using power flow decomposition (PFD). On the basis of detected RPLFs, sensitivities are used to determine new control settings for different compensation technologies. A significant share of RPLFs is detected and reduced for an exemplary application on a synthetic transmission grid model. Despite numerous corrective control adjustments, voltage profile and grid losses change only slightly, thus showing the effectiveness of the presented method.