Theses and dissertations (Engineering and Built Environment)
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Item Power loss minimization and voltage profile improvement in transmission networks using a network modification algorithm(2023-05) Ntombela, Mlungisi; Musasa, Kabeya; Leoaneka, Moketjema ClarenceA number of algorithms that aim to reduce power system losses and improve voltage profiles by optimizing distributed generator (DG) location and size have already been proposed, but they are still subject to several limitations. Hence, new algorithms can be developed or existing ones can be improved so that this important issue can be addressed much more appropriately and effectively. In their formulations, the majority of algorithms focused only on real power loss minimization. Power systems operate with reactive power controller installed at various locations, which are essential to their operation. Therefore, the effect of reactive power control must be taken into consideration when optimizing DG allocation for voltage profile improvement. State-of-the-art optimization algorithms can be used to improve the effectiveness of the existing one in taking into account the effect of reactive power control. This study proposed a modification methodology based on a hybrid optimization algorithm, consisting of a combination of the genetic algorithm (GA) and the improved particle swam optimization (IPSO) algorithm m for minimizing active power loss and maintaining the voltage magnitude at about 1 p.u. The buses at which DGs should be injected were identified based on optimal real power loss and reactive power limit. When applying the proposed optimization algorithm for DGs allocation in power systems, the search space or number of iterations was reduced, increasing its convergence rate. The proposed modification methodology was tested in an IEEE-30 bus electrical network system with DGs allocations and the simulations were conducted using MATLAB software. The hybrid GA and IPSO (HGAIPSO) method has less iterations and is more effective at solving optimization issues than other optimization algorithms like GA, PSO, and IPSO. An IEEE-30 bus network system with DGs allocations was used to evaluate the effectiveness of the proposed HGAIPSO, and the test results were compared to those from alternative techniques (i.e. GA, PSO and IPSO). The outcomes of the simulation demonstrate that the suggested HGAIPSO can be an effective and promising optimization technique for issues with transmission network modification. IEEE-30 bus test system with DGs included at various locations, Type 1, Type 2, and Type 3 DGs allocation, respectively, showed decreases in overall real power loss of 40.7040%, 36.2403%, and 42.9406%. For the IEEE-30 bus, the highest bus voltage profiles are up to 1.01pu.Item Voltage stability in distribution network(2020-09) Masikana Sboniso Brutus; Sharma, Gulshan; Akindeji, Timothy KayodeVoltage stability studies and to maintain the flat voltage profile is quite important in order to maintain the healthy operation of electric power network as well as to provide the quality and cheap electric energy to the modern power users. Further with the advancement of power electronics technologies and its application to design flexible alternating current transmission devices (FACTS) have made it easier to alleviate the voltage stability problem in a quicker and cheaper way in the modern DNs. Therefore, this research work shows an attempt to investigate and solve the problem of voltage instability in the distribution network (DN) with the help of FACTS. All buses and lines are calculated in terms of voltage stability index (VSI) and to identify the optimal location of FACTS. The bus or line with minimum voltage profile in terms of VSI are more sensitive to the voltage collapse and it may further lead to blackouts. Hence, the FACTS are permanently installed at the weakest point to enhance voltage profile and improve the voltage stability in the DN. The present study is tested on standard IEEE-15 bus DN and application results are shown to verify the feasibility of the present studies for DN. The beauty and future promise of UPFC in power quality improvement was authenticated on the IEEE-15 bus DN carried out using MATLAB software tool, five different scenarios were considered by increasing the load up to 40% at an interval of 10% from its nominal operating load. With the aim of determining the impact of UPFC on bus voltage and system losses, the load flow analysis was contributed on each scenario with and without UPFC placement in the DN. After UPFC placement there was a significant enhancement of voltages of all busses as well as weakest bus voltage jump from 0.5750 to 0.9750 p.u. and shifting that bus as well as system from voltage instability to stable zone. The active and reactive power loses were decrease by 9.83% and 27.27% that fulfil the beauty of the UPFC installation in the DNs as well as it promise to mitigate the voltage instability problem of the modern DNsItem Investigating the application of Static Synchronous Compensator (STATCOM) for mitigating power transmission line losses(2017) Adebiyi, Abayomi Aduragba,; Akindeji, Timothy Kayode; Naidoo, Timothy KayodeVoltage instability and increased power loss on transmission lines are major challenges in power transmission due to ever increasing load growth. This work investigates the effect of Static Synchronous Compensator (STATCOM) to mitigate power losses and enhance the voltage stability of a transmission system. STATCOM, a shunt-connected power electronic device, operate as a Voltage Source Converter (VSC) to improve power transfer capacity of transmission lines by injecting a set of three-phase balanced sinusoidal current with controllable magnitude and phase angle into the transmission lines to regulate the line voltage and compensate for reactive power at the Point of Common Coupling (PCC). To validate the capacity of STATCOM in this light, a modified model of IEEE 14 bus test system was simulated using DIgSILENT PowerFactory v15. Four different load profiles were included by increasing the base load in a step of 10%. In each case, power flow was run with and without STATCOM incorporated in the network with a view to determine the impact of STATCOM on bus voltage and transmission line losses. The simulation results are obtained were recorded and analyzed. It is noted that there was sufficient improvement in the new voltage profile obtained for the weak buses of the system, the active and reactive power losses were mitigated by 17.73% and 24.80% respectively when STATCOM was incorporated at normal load. The results showed that STATCOM could give quick voltage support to reduce the likelihood of voltage collapse and mitigate power losses along the transmission lines. Reduction of reactive power losses along the lines is higher than the active power losses resulting in the improvement of the voltage profile as the device is connected to the system.