Gilsoo Jang

This is Part I of a two part paper dealing with control design in power systems using the method of normal forms. In stressed power systems, due to the presence of increased nonlinearity and the existence of nonlinear modal interactions, there exist some limitations to the use of conventional linear control design techniques. The objective of this work is to understand the effect of the nonlinear modal interaction on control performance and to develop a procedure to design controls incorporating

In this study, we mitigated the harmonic voltage in a power system that contained the roughing mill (RM) and finishing mill (FM) motor drives. AC/DC converter type RM drive is a non-linear, large-capacity varying load that adversely affects power quality, e.g., a flicker, voltage distortion, etc. The voltage drop can be compensated within a certain limit by using the proper capacity of a power capacitor bank. In addition, the voltage distortion can be controlled as per the guidelines of IEEE Std

This is part II of a two part paper dealing with control design in power systems using the normal forms technique. The companion paper (part I) describes the general theory and control procedure. Also, the proposed procedure was applied to the Base Case of the 50-generator IEEE Test System. This paper depicts the case studies to show the validation of the proposed method and to observe the effects of controller setting changes. In addition the results dealing with the design of the controller ar

Distribution factors, which are linear approximations of the sensitivities of the system variables for changes in the power injections or any events in the system, play an important role in the security analysis and market applications. Cascading faults, which are triggered by the overloading of lines due to a fault has been the major issue deteriorating the reliability of the power system thereby requiring measures to revert the power flow on overloaded lines. This paper proposes an algorithm,

The variability and uncontrollability of wind power increases the difficulty for a power system operator to implement a wind power system with a high penetration rate. These are more serious factors to consider in small and isolated power systems since the system has small operating reserves and inertia to secure frequency and voltage. Typically, this difficulty can be reduced by interconnection with another robust power system using a controllable transmission system such as a high-voltage dire

The paper presents a new reactive-power-compensation scheme for the Jeju-Haenam HVDC system. Owing to changes in the Jeju AC power-system configuration since the Jeju-Haenam HVDC system was constructed, there is an increasing need to modify the existing reactive-power-compensation scheme. In the paper, a new reactive compensation scheme for the stable operation of the HVDC system has been proposed using integer programming to take into account the reactive power supply from new thermal power pla

Abstract Electric arc furnaces (EAFs) are a main cause of voltage flicker due to the interaction of the high demand currents of the loads with the supply system impedance. In order to adequately understand and analyze the effects on the power system from these loads, obtaining an accurate representation of the characteristics of the loads is crucial. In this paper, a mixed chaotic EAF model to represent the low-frequency and high-frequency variations of the arc current, respectively, and a chain

This study proposes an effective method for voltage quality assessment considering low voltage ride‐through (LVRT) requirement for wind turbines. With increasing wind power generation, there is a strong need for system connection requirements of wind turbines, for stable system operation even under fault conditions. The LVRT requirements specify acceptable voltage magnitude and duration for maintaining the connection to power systems under voltage sags. In general, different grid connection poin

To date, power system analysis has been performed separately for transmission and distribution systems. Due to the small influence of distribution systems on transmission systems, separate analyses have had no accuracy problems in existing power systems. However, as the amount of distributed generation (DG) in distribution systems increases, neighboring distribution systems and even transmission systems can be affected by the distributed generation. Therefore, a power system operator needs a new