Chizuru Suzawa

Electric properties of a 66 kV 3-core superconducting power cable system

A 100 m-long, 66 kV, 3-core high temperature superconducting power cable system prototype has been developed and installed in order to verify its properties and performance for practical use. The cable is a cold dielectric type with three cable-cores placed in co-axial stainless corrugated pipes. After cooling the cable to LN/sub 2/ temperature, long duration tests, such as that for nominal current-voltage loading and that for load fluctuation, were performed for a one-year period. The cable was warmed to room temperature after each test to investigate the influence of the heat cycle. Critical current was more than 2.7 kA at 77.3 K, and AC loss was 0.7 W/m/phase at 1 kArms. The magnitude of shielding current was almost equal to the transport current. Capacitance, dielectric losses and other electric properties were also measured. All values showed no change during the tests, and were in good agreement with calculated expectations.

Design and experimental results for Albany HTS cable

The Albany Project plans to install a 350 m High Temperature Superconducting (HTS) cable in the power grid of the Niagara Mohawk Power Company to carry 800 Arms at 34.5 kV. The type of the cable has 3 HTS cores in one cryostat with Bi-2223 used for HTS conductor and shield layers. The three cores are housed within double SUS corrugated pipes which provides thermal insulation. The tapes are manufactured with a new innovative sintering method with controlled over pressure (CT-OP) technology. Polypropylene laminated paper (PPLP) is used as electrical insulation. The cable will be installed in long underground conduit. A cable joint will be made in an underground vault to connect a 30 m length of the cable with the remaining 320 m. The original Bi-2223 30 m cable will be replaced with a 30 m YBCO cable after long-term operation. The terminations at both ends of the cable will have three bushings in a cryogenic vessel. Typical performance evaluation experiments, such as cable bending tests, voltage tests, and fault current tests, have been conducted with sample cables to check the design. Voltage tests for 69 kV AC and 200 kV impulse were successfully applied to a 5 m cable in accordance with the Association of Edison Illuminating Companies (AEIC) code of 35 kV class cable. The cable will be manufactured and installed in 2004 and 2005, then, long-term operation will be started.

Fabrication and Installation Results for Albany HTS Cable

The Albany project has installed a high temperature superconducting (HTS) cable with a 350 m length in 34.5 kV and 800 Arms in the real power grid of the National Grid Power Company. The type of the cable is a 3 cores in a cryostat. Bi-2223 wires manufactured with SEI new sintering method, CT-OP, is used as both superconducting conductor and shield. The Cable was manufactured and shipped to the Albany test site after passing various tests such as Ic measurement, voltage tests, pressurized tests, and so on. Cable installations into a 320 m long conduits and a 30 m long conduit under ground was completed successfully. The cable was pulled with 2.5 ton tension, which is within its allowable limit. A joint between the 320 m cable and the 30 m cable was assembled in an underground vault. Cable terminations were also assembled at both ends of the cable. After all of the installation, the initial cooling was conducted successfully and then in-grid operation was started on July 20th in 2006 after confirmation of cable performance.

Verification tests of a 66 kv HTSC cable system for practical use (first cooling tests)

Abstract Tokyo Electric Power Company and Sumitomo Electric Industries, Ltd. have been jointly developing elementary technologies for an high temperature superconducting (HTSC) cable system, such as conductor wound with HTSC wires, thermal insulation pipes, terminations and so on. Verification tests of a 100 m HTSC cable system integrating these elementary technologies have been conducted in collaboration with Central Research Institute of Electric Power Industry (CRIEPI) to verify its long term electric and cryogenic properties. The cable conductor is composed of four layers of Bi-2223 wires wound spirally around a former. Polypropylene laminated paper impregnated with liquid nitrogen is adopted as cable insulation for its properties of high insulation strength and low dielectric loss. HTSC wires are also wound around the electrical insulation to form an electrical and magnetic shield. To reduce heat invasion from ambient temperature part, multi-layer insulation is wound between the co-axial stainless corrugated pipes where high vacuum is maintained. The cable was partially installed into a ∅ 150 mm duct and formed in a U-shape. Each end has a splitter box and three terminations. The cable and the terminations are cooled using two separate sets of a pressurized and sub-cooled liquid nitrogen cooling system. The cable has been developed and laid at CRIEPIs test site and long-term tests have been under way since June, 2001. This paper presents the design of the cable and some results of the first cooling tests.

Development of a 100 m, 3-core 114 MVA HTSC cable system

Abstract We have started a project to develop a 100 m 3-core 66 kV/1 kA/114 MVA high temperature superconducting (HTSC) cable system to certify the manufacturing capability and the practicability of an HTSC cable system for use as actual power system equipment. The cable is designed based on the results of a 30 m, 3-core test cable. The cable is composed of a conductor and a shield wound with Ag–Mn sheathed Bi-2223 tapes, electrical insulation with polypropylene laminated paper impregnated with liquid nitrogen and thermal insulation with co-axial corrugated pipes. The three cores are housed in this thermally insulated pipe. The cable has been developed and laid at CRIEPIs test site and long-term tests have been under way since June.

Development of a High Tc Superconducting Cable

A High Temperature Superconducting (HTSC) cable is expected to transport large electric power with a compact size because of its high critical current density. A 30m 66kV-lkA HTSC power cable system has been developed. The critical currents measured at 67K~80K are 1800A~800A. At the loading test, the 40kV-500A was successfully applied with a constant tan δ and capacitance. During the test, the temperature and pressure of circulating liquid nitrogen were controlled to 72K and 20kPa, respectively. Heat leak through the thermally insulated pipe was estimated as 1.5W/m, which is good performance for a long HTSC cable.

NIJI-III Compact Superconducting Electron Storage Ring

The NIJI-III is a compact superconducting electron storage ring for industrial applications. Features of the ring include four strongly curved large-bore superconducting bending magnets utilizing quadrupole coils with a circular cross section surrounded by an air core and a cold bore. The circumference of the ring is 15.54 m with a critical wavelength of 13 A. Development of the NIJI-III is near completion. This report examines the design and performance of the NIJI-III.

Development of HTS Cable System for ALBANY Project

High temperature superconducting (HTS) cable is anticipated to transmit a large amount of electricity with a compact size and can reduce the transmission loss and greenhouse gas emission. The Albany project is being undertaken to verify the practicability of a long HTS cable in the real grid by performing a long-term operation test. The cable is 350-meter long and carries 800 A at 34.5 kV between two electric power substations (Menands and Riverside) in Albany, N.Y. [1]. The project is scheduled to run from 2002 to 2007 and is proceeding as planned. The HTS cable and its apparatus were manufactured in Japan, and the cable was shipped to the USA in the middle of August. After it arrives at the site, the cable installation and the apparatus assembly will be carried out sequentially. This system is expected to begin operating early next year after initial cooling. This paper gives an overview and the current status of the development of the HTS cable system.

Fabrication of High-Tc Superconducting Test coil for SMES

To investigate the possibility of the application of high-Tc superconducting wire to SMES (Superconducting Magnetic Energy Storage) for power system, a high-Tc test coil was manufactured and the characteristics of the coil operating at liquid nitrogen temperature were investigated. The energy to be stored was determined to be l00J and,in order to design the coil, basic characteristics, such as mechanical properties and critical current density of the high-Tc wire and cooling characteristics were measured. After these fundamental investigations, a high-Tc SMES test coil was designed and fabricated. The coil has 10 double pancake coils, the inner diameter is 80mm, the outer diameter is 200mm, the height is 93mm and the total weight is about 20kg. The coil operated with DC of 34.2A and l00J was stored at 77K stably. Moreover, it successfully operated with 2Hz, triangular current of 34.2A-peak,simulating SMES operation,without a quench phenomenon.

Initial Loading Test of 30m Long High Tc Superconducting Power Cable Prototype

A 30m long 66kV-lkA high-Tc superconducting prototype cable system was developed. This system consists of a single phase cable (made with cable manufacturing machines with some additional improvement), terminations, a 66kV XLPE cable for current loop, and a closed cycle liquid nitrogen cooling system. After cooled down, loading tests was performed. The Ic of this cable is 1600A(over the peak value of AClkA). AC40kV-lkA was successfully applied in sub-cooled liquid nitrogen (72K,1.2kg/cm2 bs) regardless of mechanical history, such as handling in the factory, transportation, laying, and the axial force due to contraction during cool down.