Transmission Congestion Management via Node-Breaker Topology Control

A novel topology control algorithm is proposed here to reduce congestion and overloads, thereby improving security margins in a power network. The proposed heuristic relies on normalized squares of the line currents as a direct indicator of transmission line loading. The sensitivity of this measure with respect to breaker positions forms the basis of the proposed heuristic to select switching actions for a reconfigured network topology that reduces the congestion and overloads while holding generation dispatch essentially fixed. While many prior works have examined this class of problem for line switching actions (i.e., topology changes that insert or remove branches), bus-bar switching actions (topology changes that merge or split nodes/buses) have received less research focus. Here, both line switching and bus-bar switching are implemented using a detailed node-breaker representation of the network. The algorithm adopts a novel form of the AC power flow that allows sparse calculation and reduced computation time. Case studies demonstrate that the proposed approach efficiently reduces congestion and overloads in the base case and in contingency situations.