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A 600 kJ HTS SMES system has been developed for power system stabilization as a national project in Korea. Successful operating tests of the 600 kJ were recently completed. In this paper, a 2.5 MJ class SMES with HTS magnets of single solenoid, multiple solenoid and modular toroid type were optimized using a recently developed multi-modal optimization technique named multi-grouped particle swarm optimization (MGPSO). The objective of the optimization was to minimize the total length of HTS superconductor wires satisfying some equality and inequality constraints. The stored energy and constraints were calculated using 3-D magnetic field analysis techniques and an automatic tetrahedral mesh generator. Optimized results were verified by 3D finite element method (FEM). [ABSTRACT FROM AUTHOR]

As high temperature superconducting (HTS) power cables have some merits over conventional cables, several demonstration projects on the HTS cable system are presently under way around the world. Korea Electric Power Corporation (KEPCO) also initiated an HTS cable project in 2002 with the Korean government's support. A three phase 100 m HTS cable system with a capacity of 50 MVA has been installed at Gochang test yard, located in Chonnbuk province, Korea. The HTS cable system is composed of a 100 m-long cable, two terminations and a cooling system. The rated current is 1,250 Arms and the rated voltage is 22.9 kV considering compatibility with the conventional power distribution system in Korea. Main purposes of this project are to verify the performance of an HTS cable system and to evaluate the potential of the HTS cable system from the viewpoint of power utilities. The real grid application of the HTS cable system requires the demonstration of system reliability, accumulated operation experiences, and it has to meet the practical needs of the utilities. In such a meaning, this project provides various challenges for KEPCO, and the feedback will be delivered to cable manufacturers. This user initiative test will facilitate the introduction of HTS cable systems into a real grid network. The installation process of the HTS cable system and some results of the preliminary test were presented in this paper. [ABSTRACT FROM AUTHOR]

A 22.9 kV/50 MVA class high-temperature superconducting (HTS) power cable system was developed in Korea. For the optimization of electrical insulation design for HTS cable, it is necessary to investigate the ac and impulse breakdown and partial discharge inception stress of the liquid nitrogen (LN2)/laminated polypropylene paper (LPP) composite insulation system. These results were used to insulation design of the model cable for a 22.9 kV class HTS power cable and the model cable was manufactured. The insulation test of the manufactured model cable was evaluated in various conditions and was satisfied standard technical specification in Korea. Based on these experimental data, the single-phase and three-phase HTS cable of a prototype were manufactured and verified. [ABSTRACT FROM AUTHOR]

During the operation of a HTS power cable in a real grid, large fault current can be introduced to the HTS power cable by several accidents. Large heat is generated until the circuit breaker operates and severe performance degradation or even burn-out can occur within the HTS power cable. Especially, the temperature rise of the HTS power cable should be limited to suppress the bubble generation, which induces partial discharge and it reduces the life time of the HTS power cable. Stabilizer is applied to the cable core to limit the temperature rise when the fault current is introduced. This paper describes the fault current experiment with a sample cable and the results are used to verify the simplified analysis model. Through the analysis results, the amount of the stability is determined for the successful operation of Korean HTS power cable. [ABSTRACT FROM AUTHOR]