ABSTRACT
Power systems contain a variety of components aimed at generating, transmitting and consuming the electrical power in an efficient and reliable manner. In order to properly design, plan and operate a power system, analysis tools are employed. Power flow studies are aimed to compute the steady-state voltage magnitudes, angles and complex powers across the grid elements. Transmission systems are designed and operated to transfer bulk power from the power plants to the end-users via distribution networks in the most efficient, secure and at expected power quality. However, transmission subsystems are facing ever more demanding operating conditions with increased distribution generation penetrations, larger power flows and greater cross-border electricity trading. Power grid components, plying critical roles in transmission include: control centers, transformers, substations, protection, voltage and VAR control. In order to facilitate transmission system operation and management, an extended set of applications and methods are used to monitor, control and optimize generation and transmission systems. For example, FACTS devices can enhance the power flow on existing transmission lines, significantly increasing the power system stability and faster post-fault oscillation damping, one of the blackout causes. Applications and analysis methods include: power or load flow analysis, security monitoring and analysis, preventive and emergency control, fault diagnosis and restorative control. Methods include: network topology analysis, equivalent system modelling, state estimation, on-line and off-line power or load flow studies and contingency analysis. Power flow studies are performed to determine steady state operating condition of a power system, being the most frequently carried out study by power utilities and is required to be performed for power system planning, operation, optimization and control. Power system state estimation plays key role in the energy management systems of providing the best estimates of the electrical variables in the grid that are further used in functions such as contingency analysis, power flow analysis, automatic generation control, dispatch, control, etc. Contingency analysis is a critical function widely used in energy management systems to assess the impact of power system component failures.
