| Abstract | Conventionally, the optimal operation of the electrical system have been based on the economic criterion. Economic dispatch is widely being used by most of the power utilities as part of their Energy Management System. However, recent concern of the utilities about power quality, especially in terms of improve voltage profile, requires to consider additional objective in the Optimal Power Flow formulation. Optimal Reactive Dispatch (ORPD) is the sub problem of OPF, which have two objectives of improving the system voltage profile and minimizing the system transmission loss. This is achieved through redistribution of reactive power in the network by optimal setting the generator terminal voltage or reactive power outputs, transformer tap settings and output of the other compensating devices such as shunt capacitor, reactors, synchronous condensers, etc. The fast progress in the field of power electronics, microprocessors, microelectronic and communication technology has resulted into introduction of new devices for more flexible operation of the power systems known as Flexible AC Transmission System (FACTS) devices. These devices include Static Var Compensators (SVC), Thyristor Controlled Series Compensators (TCSC), Thyristor Controlled Phase Shifting (TCPS), Static Condensers (STACON), Unified Power Flow Controllers (UPFC), etc. These devices have been mainly studied and applied for improving the dynamic behavior of the power system, avoiding loop flow and sub synchronous resonance problems. Only little study has been done to explore the capability of these devices as the candidate control in the optimal power flow and specially the loss minimization. Therefore, the objective of the thesis is find the placement of some of FACTS devices for improving the system voltage profile and minimizing the electrical transmission system losses. Three FACTS devices SVC, TCSC and TCPS have been considered in the thesis. Static models of these devices have been utilized along with their operating limits. The thesis has considered problem: Optimal reactive power dispatch with FACTS devices is used to determine optimal setting parameters. The placement of FACTS devices is dete1mined by a sensitive based method and L indices. Sensitivity of total real power transmission loss at a peak-load of system with respect to the parameter of SVC, TCSC, and TCPS and L indices of SVC for steady state voltage voltage stability have been used for sitting of these devices. With the given placement of FACTS devices, ORPD have been used to dete1mine their optimal setting of FACTS parameter tested. The limits of FACTS devices were dete1mined through peak load and off-peak load of power system. The studies proposed ORPD have been tested on the IEEE 30 bus test system and a Southern Vietnam Electrical Transmission System of Electricity of Viet Nam. A comparison of the voltage profile and transmission losses have been made from ORPD without FACTS devices and ORPD with FACTS devices. |