Electrical Distance Approach for Searching Vulnerable Branches During Contingencies

The large-scale power system outage is one of the most catastrophic disasters in modern society that results in enormous damage of billions per year for U.S. economy. So, system operators are required to maintain plans for any unforeseen event that forces power system to operate without reliability. Contingency analysis is one of the well-known methods to paint the future scenarios in the power system. However, large numbers of possible ${N-k}$ combinations make its assessment computationally prohibitive. This paper proposes a new method to search most vulnerable transmission lines efficiently based on electrical distance. Specifically, a new electrical network is first built based on the impedance matrix (by inverting admittance matrix). Then, we will prune this impedance matrix based on the number of connections in topology network. Next, the common connections in two different structures (i.e., electrical network and topology network) will be observed for contingency experiments. Our results verify that violations of transmission lines limit due to contingencies are mostly associated with those common branches. In addition, voltage profiles are studied to validate that the vulnerable transmission lines found above are critical in power system stability.