AbstractsEngineering

Maintaining reliability is a key aspect in power system operations. One process that helps in achieving this goal is automatic generation control (AGC), which is responsible for restoring the system frequency to the nominal value, and the real power interchange between balancing authority (BA) areas to the scheduled values. In this dissertation, we present the limitations of current AGC system implementations, and propose modifications in their design in order to increase their efficiency. The AGC system goal has become more challenging due to the radical transformations occurring in the structure and functionality of power systems. These transformations are enabled by the integration of new technologies, such as advanced communication and power electronics devices, and the deepening penetration of renewable resources. For example, renewable-based generation is highly variable and intermittent, and might undermine the objective of AGC systems. A framework that may be used to quantify the effects of various uncertainty sources, such as load variations, renewable-based generation, and noise in communication channels, on the system characteristics is presented in this dissertation. To this end, we develop a method to analytically propagate the uncertainty from the aforementioned sources to the system frequency and area control error (ACE), and obtain expressions that approximate their probability distribution functions. We make use of the proposed framework and derive probabilistic expressions of the frequency performance criteria, developed by the North American Electric Reliability Corporation (NERC). Such expressions may be used to determine the limiting values of uncertainty that the system may withstand. Our studies show that some advances are necessary in AGC system implementations, due to changes in power systems, such as the deregulation of the power industry and the integration of new technologies. The basic concept of AGC systems that is used by the BA areas has not changed severely over the past years. We aim in proposing AGC system modifications that are realistic and implementable in real large-scale systems. The high complexity of power systems is an obstacle when performing several processes related to reliability. In order to overcome such issues, we propose a systematic reduction of the synchronous generator model with low computational effort. In addition, we use the derived reduced model to describe a BA area dynamic behavior by including only the BA area variables. We use the developed models to design adaptive AGC systems, with self-tuning gain techniques, that decrease the unnecessary regulation and reduce the associated costs, since they take into account the actual system conditions in the determination of the control gains. Furthermore, each BA area implements its own AGC system. However, if all the BA areas were operated as one single BA area, then the regulation amounts as well as the associated costs would be less. Operating separately and locally, individual BA areas are obliged to…