Modeling and simulation of custom power devices
In the recent years, the utilities are becoming increasingly concerned over the issues of power quality and power flow control. At the same time, there has been a tremendous interest in the application of power electronic converters to solve problems such as those of power quality and power flow control. Due to the complexity of the system with embedded power controllers, computer aided simulations will play a crucial role in the evolution of this technology.The goal of this dissertation is to develop simulation models for three power electronic converters: (i) a 12-pulse Static Compensator (STATCOM), (ii) a Pulse Width Modulated (PWM) STATCOM, and (iii) a PWM Dynamic Voltage Restorer (DVR). These converters are also referred to as Custom Power Devices (CPD's). Their primary function is to improve the power quality of a distribution system. The models developed in this dissertation are important for utility engineers to explore possible solutions from both design, planning and operation point of view. The challenge involved in the development of the models is two fold.Firstly, the voltage and current waveforms of power converters are discontinuous. The discontinuous waveforms, coupled with the large size of a typical power system, pose a challenge to develop computationally efficient simulation models. In this dissertation, a new modeling technique is developed. The resulting power converter model, called the Transient Behavioral Model (TBM), will effectively replace the extensively used Ideal Switch Model (ISM) for the simulation of many power converters in power systems. The TBM is almost as accurate as the ISM and, at the same time, its continuous nature makes it computationally more efficient than the discontinuous ISM.Secondly, the design of these devices has to be system specific. Presently, these devices exist only in their prototype forms. In this dissertation, due to the lack of available information to develop the models, simulation studies are performed on a realistic distribution system in order to determine the various design parameters for the models. The TBM is shown to be extremely effective for these simulation studies.
- Electrical engineering