ABSTRACT
INTRODUCTION Power systems cover a wide range of diverse applications such as rotating electrical machines, renewable energy systems, power electronics, and distribution systems, and they display distinct electrical behaviors. In addition, such systems are usually interrelated and imply highly nonlinear operating characteristics. Although the operators and designers have a good degree of knowledge about the steady-state behavior and the frequency and magnitude of measurable parameters (e.g., voltage, current, speed, torque) of the power systems, various unpredictable signals may also be present specically during initial states of electrical circuits. For example, inrush currents in transformer and starting torque and current characteristics of rotating machines heavily depend on the initial switching instants as well as the load level, which cannot be predicted. Moreover, monitored signals may have unpredictable characteristics specically in power quality measurements in a large power grid, which occur randomly. Furthermore, the frequency bandwidth of measured signals in power systems usually covers a very wide range from direct current (DC) to 10s of kHz. erefore, it can be concluded that the measurement requirements in power systems are unique from the signal characteristic and the analysis viewpoint and require special attention.
