Graduation Year

2022

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Engineering

Major Professor

Zhixin Miao, Ph.D.

Committee Member

Lingling Fan, Ph.D.

Committee Member

Yicheng Tu, Ph.D.

Committee Member

Kaiqi Xiong, Ph.D.

Committee Member

Chung Seop Jeong, Ph.D.

Keywords

Cyber attack, Dynamic modeling, SCADA system, Stability control, Voltage source converter

Abstract

With more and more renewable energy generation integrated into the utility grid, the modern power system circumstance and its operating characteristics have changed significantly. Since most renewable energy resources are inverter-based resources (IBR), the prominent characteristics of the power electronics and the cyber distribution in the renewable energy generation system make the power grid stability more diverse and complex.

This dissertation addresses the power system resilience problems from two points of view. The first one is from the inverter level, which deals with the problems of short circuit ratio (SCR) drop. With low SCR, the IBR system operation point may be changed and face a high risk of low-frequency oscillation. This research has analyzed the IBR system from the control system perspective. Two components are discussed in detail: robust cascade control and stability enhancement module. Analysis carried out by simulation and hardware experiments. After modification of the conventional control scheme, these techniques show capabilities of handling IBR stability performances in weak grids.

The second problem addressed is the high level of renewable energy generation. On the one hand, the cyber security and system stability of the smart grid are getting more and more attention in the industrial area. On the other hand, the phasor measurement unit (PMU) is widely used to measure and estimate the magnitude and phase angle of an electrical phasor in the power grid. Cyber attacks on PMU sensors and communications of supervisory control and data acquisition (SCADA) systems could paralyze the power system. This dissertation first introduces a PMU-based real-time hardware implementation. Then, cascading faults and several cyber attack methods are tested on this testbed. For the cyber attack, two protection methods are presented based on data analysis and system topology.

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