| Author: | Hu, Yong |
| Title: | Development of a novel model-independent monitoring and analyzing system to tackle various oscillations in high power electronic converter-penetrated power systems |
| Advisors: | Bu, Siqi (EE) |
| Degree: | Ph.D. |
| Year: | 2023 |
| Subject: | Oscillations Electric power system stability Electric power systems -- Control Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Electrical Engineering |
| Pages: | xv, 139 pages : color illustrations |
| Language: | English |
| Abstract: | The investigation of various oscillations is crucial for the stable operation of high power electronic converter (PEC)-penetrated power systems. In order to tackle the various oscillations, a precise system modeling would be important. The commonly-used modeling-based methods include the damping torque analysis (DTA) and modal analysis (MA). However, the large quantities of system components make the system modeling nearly an impossible task. To date, the energy flow analysis (EFA) has been applied in the stability analysis of power grids, which is based on the measurement technology. Nevertheless, the existing research of EFA is still insufficient. Specifically, the relationship between EFA and the modeling-based methods (i.e., DTA and MA) is not essentially revealed. Moreover, EFA is mainly used for monitoring and analyzing the oscillations of synchronous generator-dominated power grids, but has not been extended and generalized to that of PEC-penetrated power systems. In this thesis, firstly, the connection between DTA and EFA are systematically examined and revealed for the better understanding of the oscillatory damping mechanism of the electromechanical oscillation. Specifically, the concepts of the aggregated damping torque coefficient and frequency-decomposed energy attenuation coefficient are proposed and derived. On this basis, the frequency spectrum analysis of the energy attenuation coefficient is employed to rigorously prove that the results of DTA and EFA are essentially equivalent, which is valid for arbitrary models of synchronous generators in multi-machine power systems. Secondly, a novel EFA is proposed based on the signal reconstruction and decomposition to quantitatively investigate the electromechanical oscillations in multi-machine power systems. Specifically, the time-domain implementation (TDI) and frequency-domain implementation (FDI) of the proposed EFA are designed. On this basis, the consistency between the proposed EFA and MA is strictly proved, which is applicable for arbitrary models of synchronous generators in the multi-machine environment. Also, the application procedure of the proposed EFA in monitoring and analyzing the electromechanical oscillations is given. Thirdly, as a major part of the full converter-based wind generation (FCWG), the potential dynamics of the permanent magnet synchronous generator (PMSG) can be utilized to improve the oscillatory stability of the PEC-penetrated power grid with the introduction of the auxiliary resonance controller (ARC) to the machine-side control of FCWG. However, the machine-side oscillations (MSOs) of FCWG would also be complicated. Thus, the proposed EFA is extended to the machine side of FCWG for numerically investigating multiple types of MSOs of FCWG. Finally, a generalized oscillation loop is structured based on the second-order differential operations of a studied control loop of PEC. On this basis, a generalized EFA is proposed for monitoring and analyzing of the various oscillations of PEC-penetrated power grids. Taking the control loops of the grid-side converter (GSC) of FCWG as an example, the application of the generalized oscillation loop and generalized EFA is further discussed considering the potential modal resonance between GSC oscillations (GSOs) and external grid oscillations (EGOs) to consolidate the oscillatory stability of the PEC-penetrated power system. |
| Rights: | All rights reserved |
| Access: | open access |
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