The direction of the development of large-scale electric power networks has very much coincided with the history of increasing voltage values ever since the advent of Joule heat loss. However, a high-temperature superconducting (HTS) technology has changed the direction of that history. Furthermore, the HTS technology will rapidly accelerate the speed of such change due to its extremely high current density with no Joule heat loss. For these reasons, many different types of HTS electric power transmission applications have been being discussed, and selected items have been developed. Within a few decades, the technology of HTS ac and dc power transmission applications had already been developed and close to the required level for industrialization. Moreover, some of these applications have been installed, energized, and are operating within real power networks. In this paper, we report on the current status and progress in HTS applications of ac and dc power transmission. In particular, this paper focuses on the application field of superconducting cable among various HTS power applications. In South Korea, the Korea Electric Power Corporation, Naju, aims to introduce more new technologies in order to develop the Korean power network, and it believes that an HTS is a key factor in the development of the next generation of power grid, which will be discussed in detail in this paper.

This paper discusses the design and electromagnetic analysis of an induction-type coilgun system with a pulse power module. The voltage, current, force, velocity, acceleration, and efficiency of the coilgun system were analyzed using the finite-element method (FEM). A simplified FEM model was developed for ensuring both accuracy and rapid calculation times. Based on the results of the electromagnetic analysis, the geometry of the coilgun system was defined with the Taguchi method. The coil-type armature was applied for increasing the mutual inductance and projectile force. The electromagnetic analysis results were also compared with the analytical analysis results. The designed coilgun system was found to exhibit high energy efficiency and safety of the system. The design specifications and analysis results concerning the coilgun can, hence, be effectively utilized to develop a large-scale multistage induction-type coilgun system.

This paper presents some discussions and findings related to the development of the capacitor bank-based pulsed power supply module (PPSM) for an electromagnetic induction coilgun (EIC). Three PPSMs were designed for a three-stage EIC to launch a 21.68-kg projectile at a minimum velocity of 20 m/s. The energy of the PPSM in the first, second, and third stages was 200, 100, and 100 kJ, respectively. Two light-triggered thyristors (LTT) were used as the main switches of the module. The synchronous behaviors of the series LTT, dump circuit, laser diode driver circuit, and protection scheme are analyzed and discussed. The PPSM was built and tested as an EIC system. The simulation results of the PPSM were in agreement with the experimental results. The peak current was about 42 kA at a maximum voltage of 10 kV as in the simulation. The maximum current in the 4-kV launch experiment was 16.47 kA. The velocity of the projectile was more than 25 m/s, which is consistent with the design goal.

This paper presents a new capacitor bank topology for a pulsed power system to improve the efficiency of multistage synchronous induction coilgun. In the proposed method, a switch, such a gate turn-off thyristor, is inserted in parallel to a crowbar diode and load to generate an attractive force between the next stator and the armature. A mathematical model was developed, and finite-element method simulations were conducted to verify the proposed topology. The results show that the proposed method improves the energy efficiency and launch velocity. The improvement in energy efficiency is confirmed from the simulation results of a three-stage synchronous induction coilgun.

A wind farm is a collection of a few tens or a few hundreds of wind turbine generator installed in close vicinity. There is a need for further research to examine the performance of wind farm and wake models in difficult environments. This paper deals with the modelling of the wake effect in wind farms using real time digital simulator. There are many different models to analyse the wake effect. Jensen model is one of the widely used wake models at the moment. The model is simpler and requires a short time for calculations. Power loss of the modelled wind farm with the wake effect is analysed under the effects of wind direction and the wind speed time delay. The modelling of a wind farm for wake effect simulation is described and some exemplary simulations are also performed to show the influence of wake effect.

Electromagnetic induction coilgun systems have been receiving great attention, recently, due to the advantage of noncontact between the stator and armature coils. Several studies present the simulation and analysis of the coilgun system by using the finite-element method. However, there are still deficiencies in current modeling studies of the coilgun system. This paper presents a design of a multistage pulsed power induction coilgun system using the Taguchi method to maximize its efficiency and reduce the time and cost of the design process. A coilgun system is analyzed and designed using a state-space equation system. The Taguchi method is applied in order to evaluate and determine the geometric variables, the layer, turn layer numbers for both the stator and armature coils, and the trigger positions of each stage. Then, a 2-D finite-element model of the coilgun system using the MagNet program was developed to compare the design and analysis results. The energy efficiency of the three-stage coilgun system is 31.3%, and this is expected to increase with the increase in the number of stages.