Avoiding Complete Divergence of State Estimators in Large Power Grids
This talk describes implementation of a multi-area state estimation approach where a converged solution can be obtained for a large part of the network even if the conventional state estimator does not converge. This is accomplished by locating and isolating the area which contains the gross error that is responsible for divergence. The talk will present results related to area partitioning, network observability and the developed multi-area state estimation algorithm as well as a software package and associated graphical user interface (GUI) developed for a large utility for this purpose.
Detecting and Correcting Parameter Errors in Power Grids
This talk presents a method to detect permanent errors in utility data bases related to branch parameters. The method will be described first for systems explicitly containing fully transposed lines and symmetric branch models. It will then be extended to three-phase non-symmetrical mixed-phase power networks. The main advantages of the method are that it does not require modification of existing state estimators, it is a stand-alone application which can be executed on or offline, does not require any user intervention or a priori selection of a suspect parameter set, and can identify all existing erroneous parameters in a large-scale power system data base while differentiating them from any existing measurement errors. The talk will provide results obtained by applying the developed techniques to synthetic as well as actual power systems.
Tracking Faults and Network Model Changes Using Phasor Measurements
In this tutorial, we will discuss potential network applications which can benefit from availability of synchronized phasor measurements. We will first describe a fault location procedure which relies on voltage measurements provided by a limited number of PMUs to detect and locate faults on any of the transmission lines in a large power grid. The same approach will then be used to solve the problem of detecting unreported topology changes in external networks. This problem is particularly important for real-time contingency analysis of interconnected power grids when ICCP links fail and real time data are temporarily or permanently not available from neighboring systems. Finally, we will present a tracking estimator for non-transposed three phase transmission line model parameters based on PMU measurements which will enhance the performance of control and protection functions relying on accurate line models.
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