Simple certificate for power distribution network security assessment

Abstract

The integration of volatile renewable energy sources, non-traditional load managements, and unforeseen natural disasters introduce uncertainties that could easily jeopardize the security of power systems. Meanwhile, constructing the real solvable boundary-crucial for contingency analysis, security assessment, and planning network processes-in multidimensional parameter space is burdensome and time consuming; hence there is an urgent need for a tool to identify the security region, or the set of viable injections. This thesis presents fast and reliable inner approximation techniques for solvable boundaries of power distribution systems based on Banach fixed point theorem and Kantorovich theorem. The novel method is in a simple "certificate" form-a single lined inequality condition that involves the system variables and parameters. Our certificate is noniterative, therefore computationally efficient, and the simulation results confirm that the presented approach constructs regions that are sufficiently large for most security-constrained functions. The construction for our "certificates" begins with re-formulating power-flow equations into appropriate forms such that they are applicable to the aforementioned two major theorems. Practical applications of the proposed technique include fast screening tool for feasible injection change, certified solvability margins, and new computationally robust continuation power flow algorithms.