Toward Distributed Contingency Screening Using Line Flow Calculators and Dynamic Line Rating Units (DLRs)

In this paper, we propose a qualitatively new approach for calculating power flows accurately in a distributed way, by which transmission lines are equipped with smart distributed line flow calculators. A mathematical formulation underlying this distributed power flow calculator is described. These line flow calculators use minimal information about their own characteristics, and communicate with the nodes to which they are directly connected and with the neighboring transmission lines only. Based on this information exchange they compute in a distributed way their own line flows very accurately. This is done without having to exchange any information with the system operator. When combined with the dynamic line rating units (DLRs) placed at the same lines which accurately estimate thermal line flow limits, these smart line calculators autonomously detect the proximity to the thermal limits and could signal to the system operator their status. This is a qualitatively different approach capable of monitoring transmission line congestion status. The method is equally effective for both normal and contingency conditions. Information about topology must only be exchanged between line calculators and neighboring components. As such, this method could become very powerful for implementing Wide Area Situational Awareness (WASA) in a distributed way. Preliminary simulations demonstrate the feasibility of this algorithm for an arbitrary sized system, without loss of generality, the IEEE 14 bus system is used to show how the algorithm would work for any large scale system.