M. Tech. Electrical Engineering. / The main focus of this dissertation is to present the modelling and simulation of the Centurion suburb of the Tshwane Municipality electric power system using MATLAB/SIMULINK package. The basic system is tested under large and small disturbances to study the dynamic behaviour of the system and the stability margins associated with the different configurations of the system.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains vi, 87 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 68-71).

Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains x, 129 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 122-129).

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains viii, 78 p. : ill. Includes abstract. Includes bibliographical references (p. 61-63).

This thesis describes the implementation of the Flexible AC Transmission Systems (FACTS) devices to develop a market-based approach to the problem of transmission congestion management in a Balancing Market. The causes, remedies and pricing methods of transmission congestion are briefly reviewed. Balancing Market exists in markets in which most of the trading is done via decentralized bilateral contracts. In these markets only final adjustments necessary to ensure secure system operation is carried out at a centralized Balancing Market. Each market player can participate in the Balancing Market by submitting offers and bids to increase and decrease its initially submitted active generation output. In this research a method is proposed to reduce costs associated with congestion re-dispatch in a Balancing Market by optimal placement of FACTS devices, and in particular Thyristor Controlled Phase Shifter Transformers (TCPST). The proposed technique is applicable to both Mixed Integer Linear Programming (MILP) and Mixed Integer Non-Linear Programming (MINLP). In the MILP a power system network is represented by a simplified DC power flow under a MILP structure and the Market participants' offers and bids are also represented by linear models. Results show that applications of FACTS devices can significantly reduce costs of congestion re-dispatch. The application of the method based on the MINLP creates a nonlinear and non-convex AC OPF problem that might be trapped in local sub-optima solutions. The reliability of the solution that determines the optimal placement of FACTS devices is an important issue and is carried out by investigation of alternative solvers. The behavior of the MINLP solvers is presented and finally the best solvers for this particular optimization problem are introduced. The application of DC OPF is very common in industry. The accuracy of the DC OPF results is investigated and a comparison between the DC and AC OPF is presented.

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

Thesis (M.S.)--California Polytechnic State University, 2009. / Title from PDF title page; viewed on August 10, 2009. Major professor: Taufik, Ph.D. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Electrical Engineering." "May 2009." Includes bibliographical references (p. 97-100). Will also be available on microfiche.

Thesis (Ph. D.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 29, 2007) Includes bibliographical references.

<p>The growing energy demand has caused the interconnected power systems to operate close to their stability limit. As a consequence, poorly damped low-frequency oscillations are becoming a common phenomenon. Such oscillations weaken the system security and if not effectively damped can lead to widespread blackouts. A contemporary solution is the addition of Power System Stabilizers (PSSs) to generators. A relatively recent solution based on the advancements in high-power semiconductors is the Flexible AC Transmission System (FACTS) technology meant for transmission locations. FACTS technology comprises of a multitude of FACTS devices among which the <i>Unified Power Flow Controller (UPFC)</i> possesses a unique capability of providing both power flow and voltage control. Particularly, with a suitable transient control system the UPFC can satisfactorily mitigate power system oscillations.</p> <p>This thesis proposes an adaptive control scheme that supplements an existing Proportional-Integral (PI) UPFC control system in damping power system oscillations. PI control is a well-established theory and a commonly used industrial controller. However, its application in a power system that experiences continuously changing system conditions demands its frequent re-tuning. On the other hand, the proposed scheme is a Self Tuning (ST) controller that automatically adapts to the system changes and thereby provides an optimal control for a wide range of operating scenarios. The proposition of assisting the primary PI control action is unique in its approach since it retains the functionality of the existing PI controllers and also enhances the overall damping performance through an add-on ST control loop.</p> <p>The proposed novel ST scheme consists of a Constrained Recursive Least Squares (CRLS) identifier that tracks system parameters recursively and a self-tuning Pole Shift (PS) controller that works on the identified system model to generate a robust control output. Also, to effectively smoothen out the rapid variations of identified system parameters and consequent ringing of control output during large disturbances, the thesis specifies the replacement of the standard-RLS identifier with a "constrained" RLS (CRLS) identifier. The damping enhancement achieved by the proposed controller has been verified through time-domain simulations. The test results clearly depict that the proposed add-on scheme not only enhances the overall damping but is also robust with respect to power flow level, fault type and location. Its inherent flexibility and the positive test results suggest that with little modification, it can be easily applied to other FACTS devices currently incorporated in transmission networks.</p>

While two objectives of deregulation are to reduce service interruptions and achieve lower energy costs, deregulation has actually introduced new problems in both areas. Since the transmission network was built in the last century, mainly for the regulated power systems, with mostly local power transfers, the increased long distance power transfer introduced by free energy trading has made congestion happen more frequently. When congestion happens, service interruptions occur and higher energy costs arise. We approach the issue from the viewpoints of both planning and online operations. Accordingly, we develop a reactive online remedying method that uses Flexible AC Transmission (FACTS) devices to eliminate congestion with minimum transaction curtailment to maintain market force. We also develop a proactive preventive method for offline planning, such as in the day-ahead market, which uses FACTS devices to maximize the Total Transfer Capability so that more transactions can be scheduled without causing congestion in the system. Optimal Power Flow is used for both methods with FACTS devices treated as control variables so that they can be adjusted to the best FACTS parameters to minimize the transaction curtailment or maximize the Total Transfer Capability. We demonstrate that FACTS devices are very effective for both situations. Since the installation of FACTS devices involves heavy infrastructure investment, an effective pricing method needs to be in place to encourage this investment by guaranteeing sufficient return. This research uses a novel pricing scheme to charge for both utilizing the FACTS devices and having the FACTS devices operating at their limits. The owners of the FACTS devices will then be able to recover their investment. With the above control method and the pricing method, we can make better use of the existing transmission network and relieve congestion. However, deregulation may also degrade system reliability since the generation companies are not obligated to sell into the market and market participation is driven by market forces instead. We use the market share based short-term adequacy analysis method to address generation resource adequacy issues. The market share based method uses the market share time series for the generation companies to reflect their market behavior in the new environment. Multiple regression modeling, a tool of time series analysis, is used to model involved factors. We demonstrate how the market share based short-term adequacy analysis method can capture the adequacy problems that the traditional method cannot. In addition, it can also help to remedy the adequacy problems, which can in turn reduce service interruption and thus the energy price.