Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Electrical and Computer Engineering

Committee Chair

Reza Adhami

Committee Member

Nagendra Singh

Committee Member

Yuri B. Shtessel

Committee Member

Dashen Shen

Committee Member

S. S. Ravindran


Electric power systems--Control., Electric power system stability., Electric power distribution.


The objective of this dissertation is to develop algorithms for the protection and control of the power smart grids. Incorporating the alternative energy resources into the power grid bring signicant challenge associated with protection, control, and security of the smart grids. In smart grids, it is dicult to measure the main variables such as impedance, fault distance and machine angle from nonlinear relationship between measured power and the estimation of the voltages and currents phasors. This is mainly due to the fact that the real-time parameter estimations are usually obtained from the linearized model. Therefore, there exist large estimation errors in these variables with the presence of the disturbance. One of the smart sensor devices which is used to deliver accurate wide area measurement is the synchronized phasor measurement unit (PMU). PMU measures the instantaneous voltage and cur- rent phasors by using global positioning system (GPS) providing phasors precisely. This device was rst introduced by Phadke and his research group in 1980. The PMU was rst was supported by the US government for wide area measurement of parameters in the Western North America Power System. This dissertation aims to resolve the phasor estimation issues and improving the accuracy of PMU measure- ments. New algorithms for improving the phasor estimation accuracy under power system transients are proposed after carefully studied by comparing to the existing methods. These algorithms improve the PMU performance based applications. The eect of electromagnetic transients can be eliminated using the proposed phasor esti- mation method. A new approach for phasor estimation under saturation conditions in real-time is proposed as well. The proposed algorithm for saturation detection can be used to indicate the phasor quality so that the power system applications are able to be aware of whether the phasors they use are valid. Test results indicate unique characteristics for each phasor unit and good dynamic behavior consistency among most of the tested PMUs. The effect of CT saturation on PMU output is eliminated using the even and odd components.

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