An Index for Determination and Manipulation of Steady State Voltage Stability of Transmission and Distribution Infrastructures

This paper introduces the concept of static stability limit breakdown margin for circuit elements and demonstrates that it is linked with steady state voltage stability of unbalanced, multiphase T&D systems. It is shown that the proposed index can be effectively utilized to recognize and reinforce the system elements that limit the voltage stability. The reinforcement may come in the form of adding a new line, impedance modification or reactive compensation. Thus by changing stability margin, the voltage stability limits of system buses can be manipulated to increase the net load capability of the buses in events of system contingencies and/or load/generation fluctuations. The proposed concepts are implemented using Graph Trace Analysis (GTA), and demonstrated using standard IEEE Transmission, Distribution, and Integrated Transmission and Distribution models built from standard IEEE models.