Variance analysis of robust state estimation in power system using influence function

• Main Authors: Ho, Weng Khuen, Chen, Tengpeng, Ling, Keck Voon, Sun, Lu
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2017
• Subjects: Robust state estimation; M-estimator
• Online Access: https://hdl.handle.net/10356/83621; http://hdl.handle.net/10220/42695
• Institution: Nanyang Technological University

An analytical equation is derived using influence function approximation to calculate the variance of the state estimate for traditional robust state estimators such as the Quadratic-Constant, Quadratic-Linear, Square-Root, Schweppe-Huber Generalized-M and Multiple-Segment estimator. The equation gives insights into the precision of the estimation. Using the equation, the variance of a state estimate can be expressed as a function of measurement noise variances enabling the selection of sensors for a specified estimator precision. It can also be used to search for the optimum estimator parameters to give the minimum sum of variances. The well-known Weighted-Least-Squares variance formula is a special case of the equation and simulations on the IEEE 14-bus system are given to show the usefulness of the equation.