Optimal Controller and Filter Realisations using Finite-precision, Floating- point Arithmetic.

The problem of reducing the fragility of digital controllers and filters implemented using finite-precision, floating-point arithmetic is considered. Floating-point arithmetic parameter uncertainty is multiplicative, unlike parameter uncertainty resulting from fixed-point arithmetic. Based on first- order eigenvalue sensitivity analysis, an upper bound on the eigenvalue perturbations is derived. Consequently, open-loop and closed-loop eigenvalue sensitivity measures are proposed. These measures are dependent upon the filter/ controller realization. Problems of obtaining the optimal realization with respect to both the open-loop and the closed-loop eigenvalue sensitivity measures are posed. The problem for the open-loop case is completely solved. Solutions for the closed-loop case are obtained using non-linear programming. The problems are illustrated with a numerical example

Location of low-frequency oscillation sources using improved D-S evidence theory

This paper presents a method for localizing oscillation sources based on data fusion Dempster–Shafer (D-S) evidence theory. This study is based on data of each bus from the system collected by phasor measurement units (PMUs). Then the D-S evidence theory algorithm is employed to establish the mass function and the trust degree of each bus. Three traditional methods are used to locate the oscillation source and to provide the calculation results for structuring the mass function of the algorithm. Finally, the decision of oscillation sources localization is made according to synthesis decision value. The higher the synthesis decision value, the higher the possibility is of an oscillation source. The WECC179 bus power system is applied for verification, and the D-S evidence theory method is compared with the above traditional three methods. It is proved that the algorithm can significantly improve the accuracy of locating sources of negatively damped oscillations and forced power oscillations, effectively reduce misjudgment. Meanwhile, this algorithm is also effective for the positioning complex dual oscillation sources.</p

Coordinated Risk Mitigation Strategy for Integrated Energy Systems under Cyber-Attacks

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