Elimination of leverage points via matrix stretching in PMU measured systems

Abstract

The state estimator is a critical analytical tool in a power system. Accurate and efficient knowledge of the states, bus voltage phasors, of a system provides access to other analytical tools to ensure security and reliability such as load forecasting, economic dispatch, and frequency control. Given accessible and accurate measurement data, state estimators produce excellent results. However in the presence of bad data and challenging network topologies, the resulting estimates are biased and inaccurate. Least Absolute Value (LAV) estimation is considered in this thesis with systems measured by Phasor Measurement Units (PMUs). LAV estimators have the desirable property of robustness in the presence of bad data. However leverage points in the system can cause bias in the LAV estimate. In this thesis a method of eliminating leverage measurements in PMUs is presented using matrix stretching. A 14-bus system is first considered to introduce the method. Then matrix stretching is tested on a 118 bus system to show the effectiveness on large systems. The matrix stretching is successfully shown to eliminate leverage points in both systems--Author's abstract