Node Type Distribution and Its Impacts on Performance of Power Grids

The theory of complex networks has been studied extensively since its inception. However,until now, the impact of the node-type distributions is related to network topology and cannot be evaluatedindependently. In this paper, a network structure is modeled via an adjacency matrix (network topology) anda set of node type distribution vectors. Three specific issues that need to be considered for node type distribu-tions in smart grid testing and planning are summarized in this paper. First, a set of metrics are proposed anddefined to evaluate the impact of node-type distributions on network performance independently. Second,another metric named the generation distribution factor is proposed to evaluate the distribution of generationbuses resulting from the specific function and purpose of power grids and by considering the distributionof load buses as given conditions. Third, another metric, i.e., the power supply redundancy metric based onentropy, is proposed to evaluate the inequality of load in power supply. Finally, a discrimination factor isdefined to ensure the overall evaluation and comparison of different networks is made for this inequality.All proposed metrics can be applied to the IEEE-30, IEEE-118, IEEE-300 bus systems, as well as Italianpower grid components. The simulation results indicate that the IEEE-118 system has the best node typedistribution and minimum discrimination; the Italian system has the worst node-type distribution and mostserious discrimination of load power supply.