STATE-SPACE FORMULATION FOR THE NODAL LOAD OBSERVER FOR SMART ELECTRICAL GRIDS WITH IMPERFECT MEASUREMENT INFRASTRUCTURE

W. Heins, G. Gewiss, C. Bohn, H.-P. Beck

Abstract

This paper presents a discrete-time state-space formulation of the nodal load observer for middle-voltage distribution grids, developed at Clausthal University of Technology. The nodal load observer is a procedure for the on-line reconstruction of unknown load and generation in a middle-voltage distribution grid based on measurements of complex nodal voltage or line current. Conceptually it is inspired by the idea of applying the state observer concept, as known from control system theory for general dynamic systems, to a set of algebraic equations. A first draft of the method was developed. In the present paper, an alternative formulation is presented, which leads to a discrete-time version of the method and reveals that in fact the nodal load observer can be interpreted as a disturbance observer structure and is closely related to dynamic state estimation, which allows for system-theorybased general analysis and extensions.

Keywords

distribution grid, dynamic state estimation, state observation, nodal load estimation, nodal load observer, disturbance observer, Kalman filter

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IMEKO-WC-2012-TC20-P4.pdf

DOI

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IMEKO TC

TC20 - Measurements of Energy and Related Quantities

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