| dc.description.abstract | The Generation Master Plan recently (July 2009) developed by Norconsult for the Mozambican Power Sector in Southern Africa highlights a number of candidate projects, most of which will involve building of large Hydro Power Stations around the Zambezi River Basin in the North, and Coal, and Natural gas, based Thermal power plants in Central and Southern Mozambique, respectively. The development of these projects will require substantial grid investments within Mozambique, and across towards South Africa, which is the major economy in the region. Transmission System expansion planning has long term effects on system performance. The effects are irreversible. Based on the Generation Master Plan prepared by Norconsult, issues that need careful consideration include Power Plant Design and Impact on System Dynamics; Optimization of Series and Shunt Compensation; Evaluation of System Harmonic Distortion Levels; and Evaluation of Sub-Synchronous Resonance in case of Thermal Plants feeding Series Compensated Lines. These issues form the basis for continued work.The ability of a power system to maintain Transient Stability when subjected to different contingencies is an important system design criterion. Controllable parameters in a power system include generator terminal voltage, generator input power, and network admittances. These parameters can be controlled to damp mechanical rotor oscillation in generators and thereby improve system Transient Stability. In this Thesis, system design based on Transient Stability performance is carried out for three expansion scenarios. The focus is on Power Plant Design and Transmission Network Configuration. Results show that series reactance of Transmission Systems has a significant impact on Transient Stability. Based on this feature, the most appropriate system configurations (among the alternatives considered) in each Scenario have been established. System requirements based on impact of specified transmission line outages on Transient Stability have also been considered. Transient Stability aspects pertaining to generator excitation system design (including effects of PSS gain and location on damping of rotor oscillations) have also been addressed.The power network is meant to carry active power and if significant reactive power flows are observed on the transmission lines then valuable transmission resource is wasted in carrying reactive power. This entails that along with active power planning, reactive power planning needs careful consideration, i.e. as an integral part of the planning process. Reactive power planning by optimal sizing of VAr sources is presented in this Master Thesis. The focus is on the optimization of series capacitors. The problem is structured as an Optimal Power Flow problem with the objective of Minimizing Active Power Losses while at the same time Minimizing Adjustable Branch Reactance (Series Capacitors). Due to lack of key data, a simplified treatment of this subject is presented, with the objective of illustrating how the concept of optimal power flow can be used to find the optimal size of VAr source at various locations in the system.The simulation tool employed in this work is the Power System Simulator for Engineering (PSS/E). Plotting of graphs is done in MATLAB.Key Words: Power System Expansion Planning; Rotor Angle Stability; Transient Stability; Power System Stabilizer; Series Capacitor; Optimal Power Flow; Transmission System; Exciter | nb_NO |
