Small-signal stability, transient stability and voltage regulation enhancement of power systems with distributed renewable energy resources.

摘要

The environmental and economic impact of fossil fuel generating plants has resulted in the need to find more efficient and clean sources of electricity power generation. As an alternative, promising power generation options such as renewable energy sources, especially wind energy, are receiving increased interest.;This dissertation addresses some important problems in power system operations (stability and power quality) when renewable energy resources (generation and storage) are integrated into the conventional power system. In particular, the use of energy storage (STATCOM/Battery) to enhance the small-signal stability, transient stability, and voltage regulation of an electrical power system with renewable power generation is investigated as follows. • A linearized model of the nonlinear power system in the region of a steady-state operating point is used in conjunction with an LMI-based control design method, including D -stability, to achieve small-signal angle and frequency stability, voltage regulation, when the system is perturbed by changes in mechanical power inputs to the synchronous generators in the system. • A nonlinear model of the power systems with energy storage is used with an Interconnection and Damping Assignment-Passivity-Based Control design (IDA-PBC) framework to achieve transient power angle stability along with frequency and voltage regulation after the occurrence of a large disturbance (a symmetrical three-phase short circuit transmission line fault). • Using the combination of the IDA-PBC control law and a reduced-order nonlinear observer, voltage regulation and system stability enhancement are simultaneously accomplished following both temporary and permanent faults.;To illustrate the effectiveness of the STATCOM/Battery to enhance small-signal and transient stability, the LMI-based controller design with D -stability and IDA-PBC controller design are validated using the following simulation studies: (1) a single machine infinite bus (SMIB) (2) a two-machine (synchronous generator and doubly-fed induction generator) connected to an infinite bus. For the small-signal case, simulation results show that the proposed controller can simultaneously achieve frequency and voltage regulation along with improved transient performance. For the large-signal case, the results show that the proposed controller provides improved critical clearing times (CCTs) and an enlarged domain of attraction (DOA) along with improved frequency and voltage regulation.