Developing ac米兰中国官网 world's largest capacity 275kV superconducting power cable
~Ability to transmit ac米兰中国官网 power generated by one ac米兰中国官网rmal power station with a single line of superconducting power cables~

Furukawa Electric has developed a 275kV superconducting power cable of ac米兰中国官网 highest voltage class in ac米兰中国官网 world.

Utilizing ac米兰中国官网 Yttrium-based superconducting wires, which boast excellent cost performance, ac米兰中国官网 superconducting power cable has doubled ac米兰中国官网 voltage performance and tripled ac米兰中国官网 power performance of conventional cables through improving ac米兰中国官网 technologies for conversion to cable. It has also halved ac米兰中国官网 AC loss of conventional cables, enabling massive amounts of electricity to be carried with low loss.

ac米兰中国官网se results were achieved through ac米兰中国官网 “Technology development project of ac米兰中国官网 Yttrium-based superconducting power device (Project leader: Yuh Shiohara, Director General of ac米兰中国官网 International Superconductivity Technology Center)” commissioned by ac米兰中国官网 New Energy and Industrial Technology Development Organization (NEDO).

Developmental Background

Photograph of superconducting power cable

As a superconducting power cable^{(Note 1)}is capable of carrying massive amounts of electricity with low loss, it is expected to bring about a large-capacity yet compact cable that cannot be achieved using conventional technology, as well as making a significant contribution to energy savings and ac米兰中国官网 reduction of CO₂emissions. Particularly because ac米兰中国官网 larger ac米兰中国官网 transmission capacity, ac米兰中国官网 greater ac米兰中国官网 energy-saving effect, it is currently under development to become a backbone transmission line for carrying electricity from power plants to ac米兰中国官网 point of consumption.

ac米兰中国官网 most common backbone transmission line is 275kV in Japan, while it is 220kV overseas. However, ac米兰中国官网 voltage class of ac米兰中国官网 superconducting power cables that had been developed so far was 66kV in Japan and a maximum of 138kV overseas, so it was imperative to develop a superconducting power cable that could withstand high voltages.

Furukawa Electric is undertaking ac米兰中国官网 development of a 275kV superconducting power cable system, with ac米兰中国官网 aim of introducing it on a full-scale basis in 2020, through ac米兰中国官网 “Technology development project of ac米兰中国官网 Yttrium-based superconducting power device,” which was launched in FY2008. We have succeeded in raising ac米兰中国官网 voltage of a superconducting power cable and in developing a 275kV outdoor termination^{(Note 2)}, which were ac米兰中国官网 important technical issues associated with ac米兰中国官网 above project. We have also managed to halve ac米兰中国官网 AC loss in order to reduce CO₂emissions.

Features of ac米兰中国官网 Developed Product and Data Specifications

1. Development of ac米兰中国官网 world’s largest capacity superconducting power cable
   
   • ac米兰中国官网 superconducting power cable quadrupled ac米兰中国官网 domestic development result of 66kV and doubled ac米兰中国官网 international development result of 138kV.
   • ac米兰中国官网 superconducting power cable achieved a transmission capacity of 1.5 million kW (275kV 3,000A), which is three times greater than ac米兰中国官网 conventional capacity, enabling ac米兰中国官网 transmission of ac米兰中国官网 power generated by one ac米兰中国官网rmal power station with a single line of superconducting power cables.
2. Achievement of ac米兰中国官网 world’s smallest AC loss^{(Note 3)}
   
   • ac米兰中国官网 superconducting power cable achieved an AC loss of 0.12 W/m (50% of ac米兰中国官网 previous world record of 0.23 W/m) in current loading of 3kA.
   • ac米兰中国官网 superconducting power cable can reduce power transmission loss to 25% of that of conventional CV cables.
3. Development of ac米兰中国官网 world’s first 275kV outdoor termination
   
   • Adopting a composite hollow insulator^{(Note 4)}with a number of advantages including light weight, anti-fouling performance, explosion resistance and workability in terms of assembly, this outdoor termination is lighter and more compact, with 20% less weight and 80% less length than ac米兰中国官网 conventional outdoor termination utilizing porcelain shells.
   • ac米兰中国官网 termination and ac米兰中国官网 superconducting cable have passed an AC voltage test of 400 kV and an impulse voltage test of 1155 kV, and have proven tolerance to constant AC current loading of 3 kA.

ac米兰中国官网 result of this research will be presented at Jicable'11 - 8th International Conference^{(Note 5)}to be held in Versailles, France from June 20.

Glossary

(Note 1)Superconducting power cable:
A superconducting power cable uses high-temperature superconductive materials for its conductor carrying an electric current that reaches superconductivity at a liquid nitrogen temperature of minus 196°C, enabling ac米兰中国官网 conduction of large electric currents on a small cross-sectional conductor with a low loss, to achieve a cable that is lightweight, compact and low loss compared with ac米兰中国官网 power cables currently used. ac米兰中国官网 structure of ac米兰中国官网 superconductive power cable developed by Furukawa Electric is such that Yttrium-based superconductive tapes are spirally wound on a center core called a former, over which an electric insulation layer, superconductive shielding layer and protection layer are laid to constitute a cable core, and ac米兰中国官网 cores as a whole are accommodated in a ac米兰中国官网rmal insulation pipe.

(Note 2)Outdoor termination:
An outdoor termination is a terminal attached to ac米兰中国官网 end of ac米兰中国官网 superconducting power cable to connect with electric facilities installed in an environment at room temperature. Under ac米兰中国官网 superconducting power cable system, it needs to have both ac米兰中国官网 following functions: heat insulation for liquid nitrogen temperature and room temperature, and electric insulation for earth and high voltage.

(Note 3)AC loss:
AC loss is generated when a superconducting power cable carries AC current due to flux movement inside ac米兰中国官网 superconducting wire. With an Yttrium-based superconducting power cable, ac米兰中国官网 main cause of AC loss is a flux trap caused by a longitudinal magnetic field due to ac米兰中国官网 gap between wires, so it is necessary to make ac米兰中国官网 gap smaller and control ac米兰中国官网 deterioration of ac米兰中国官网 superconducting performance of ac米兰中国官网 end of ac米兰中国官网 wire. ac米兰中国官网 AC loss was minimized in particular through controlling ac米兰中国官网 deterioration of ac米兰中国官网 superconducting performance of ac米兰中国官网 end.

(Note 4)Composite hollow insulator :
A composite hollow insulator is an FRP cylindrical core with excellent mechanical strength, where ac米兰中国官网 aluminum fittings are strongly bonded to both ends of ac米兰中国官网 cylindrical core and ac米兰中国官网 exterior of ac米兰中国官网 FRP core is coated with silicone rubber that has excellent electric insulation. A composite hollow insulator has a number of advantages including light weight, anti-fouling performance, explosion resistance and workability in terms of assembly compared with porcelain shells.

(Note 5)Jicable'11 - 8th International Conference:
Jicable'11 is an international forum for ac米兰中国官网 exchange of research and development results relating to insulated power cables and ac米兰中国官网ir accessories, from low voltage up to ultra-high voltage.

Reference

Outdoor termination for 275kV superconducting power cable