On the use of colours for presenting power system connectivity information

A coloring concept is presented which shows the voltage level and the status of the power system element and allows the identification of the existing connectivity units. Connectivity units may be nodes, network groups (network islands), network districts (sets of interconnected nodes on the same level), and power source groups (elements fed by a common source point). The task of connectivity unit coloring is converted to the task of coloring a graph. This enables graph theory to be applied. An update algorithm is provided to update graph colors after vertex-edge changes caused by switch indication changes. Issues in implementing such a power system coloring function within a full graphic based energy management system are discussed. A typical example is the trade-off between software effort, computational complexity (performance), and the number of colors required