Voltage stability analysis using phasor measurement unit

Abstract

This paper provides a brief knowledge of the voltage stability and its measure is used in the state estimation (SE). Changes in voltage value occurs due to the changes in the load. Its evaluation has been done by varying load and for different load cases and varied voltage value is noted. To perform SE, Weighted Least Square (WLS) method is used. Since these method provides the nonlinear estimate, direct measurement of the Phasor Measurement Unit (PMU) is used to form a matrix which can directly estimate the result without going to the whole iterative method. For using the PMU in the system, its optimal placement is carried out using greedy algorithm. Voltage stability has been deduced by the use of the several Voltage Stability Indices and other voltage analysis tools. These indices gives the closeness of the system toward the voltage collapse. Values are found to be between 0 and 1 under the load variation from 70% to 120%. Results are shown for the PMU placed buses. Standard IEEE 14 test bus system has been chosen for analysis part using MATLAB R2015a software.