ECE PhD Proposal Review: Ramtin Khalili

PhD Proposal Review: Efficient State and Parameter Estimation in Three-Phase Power Systems

Ramtin Khalili

Location: Microsoft Link

Abstract: As the number of renewable energy sources, bulk energy storage systems, and non-conventional loads increase and connect to the power grid not only at transmission but also sub-transmission and distribution levels, three-phase unsymmetrical network monitoring becomes necessary for reliable operation and control of the overall power grid. The use of modal decomposition of measurement equations has already been shown to simplify the formulation and resulting computational complexity of three-phase state estimation of systems where all the transmission lines are three-phase and fully transposed. When there are untransposed and/or mixed-phase lines, modal decomposition can no longer fully decouple the three-phase measurement equations. This shortcoming is eliminated by a simple yet practical solution based on the commonly used numerical compensation techniques. Thus, it enables the application of the powerful decoupling approach to any type of three-phase networks which may contain untransposed or mixed-phase lines and are fully observable by PMUs. This implicit restriction is then removed by using a transformation that enables the use of SCADA measurements which are more commonly available in power grids. Furthermore, It has been shown that network parameter errors can bias the state estimation solution. Network parameter errors are common due to aging, changes in the ambient temperature, human data entry error, etc. So, an efficient approach is proposed to detect and correct the network parameter errors in three-phase untransposed transmission lines. Preliminary results to illustrate the performance of the proposed methods and associated algorithms will be presented using different test systems.