Yuping Teng

Development of the World's First HTS Power Substation

With the increasing depletion of fossil fuels and growing environmental pressure, the mankind has got known the need to vigorously develop the renewable energy and the energy-saving technology. The high Tc superconducting (HTS) power technology will be very helpful to enhance the stability, reliability, and efficiency and transmission capacity of the power grid which would be dominated by the renewable energy. In this paper, we will report the installation and operation of a 10 kV HTS power substation which includes a 75 m/1.5 kA HTS power cable, a 10 kV/1.5 kA HTS fault current limiter, a 1 MJ/0.5 MVA high Tc SMES and a 630 kVA/10 kV/0.4 kV HTS power transformer.

Development of a 10 kA HTS DC Power Cable

The new energy revolution which will be dominated by renewable energy will need to develop a corresponding new power grid. Based on the characteristics of renewable energy resources, and the stability problem of AC network, it was proposed that the DC-based transmission grid should be developed in the future. The high Tc Superconducting (HTS) power cable will be a competitive candidate for large-capacity power transmission of renewable energy. In this paper, the progress of the development of a 360 m/10 kA HTS DC power cable is presented, and the prospects of HTS cable is discussed.

Testing and Demonstration of a 10-kA HTS DC Power Cable

A 10-kA/360-m high-temperature superconducting (HTS) dc power cable has been developed and installed in 2012 in central China. The cable is connecting a rectifier at a substation to a bus bar of an aluminum electrolysis plant. Before operating in the power grid, a series of testing on the performance of the cable was conducted. The testing results show that the performance meets the operational requirements and that the critical current of the cable exceeds 12.5 kA. The 10-kA HTS cable was successfully energized at the Henan Zhongfu Industrial Company Ltd., Gongyi, China, on September 26, 2012. Since then, the cable has been stably and reliably supplying power for the companys aluminum electrolyzing plant.

Testing Results for the Cable Core of a 360 m/10 kA HTS DC Power Cable Used in the Electrolytic Aluminum Industry

IEE has installed a 360-m-long high-temperature superconducting (HTS) dc power cable at the self-supply power plant of Zhongfu Industrial Co., Ltd. in Gongyi, Henan. The cable connects a 19.5 MVA/1.5 kA silicon-controlled rectifier, which connects with a 110 kV/1 kV transformer, to the bus bar of an electrolytic aluminum cell. It is designed to carry 10 kA current and the voltage is 1300 V. The HTS dc power cable core consists of five conductor layers wound with the spliced Bi-2223 wires with the length of 40 km. The cable core has five layers and 23 HTS wires in each layer with the outer diameter of 45 mm. As the items in this project, testing of 4 to 5 m length prototype cables, including a 5 m prototype cable fabricated before the 360 m power cable and a 4 m prototype cable intercepted from the 360 m HTS power cable, is conducted. These prototypes are used to assess the design program, fabrication process, and performance of the 360 m/10 kA HTS power cable including steady state operation at the 10 kA design current and overcurrent fault capability. The critical current of the 5 and 4 m HTS power cable reach 14.3 kA and 13.8 kA at 77 K, 1 μV/cm, respectively. In this paper, the design parameters and fabrication of the 360 m/10 kA HTS dc power cable conducted by IEE are presented. The cable system, installation process and the summary of the results from the testing of 4 and 5 m prototype cables are described. In addition, details of the initial cool-down process and energizing are presented.

Effects of local characteristics on the performance of full length Bi2223 multifilamentary tapes

Abstract The effects of local characteristics on the performance of full length Bi2223 multifilamentary tapes are investigated computationally and experimentally at 77 K and self-field. Generally the current–voltage characteristics of superconductors are described by the standard power law model with parameters such as critical current I c and index n . By measuring the critical current { I c i } and index { n i } values of local tapes, we can get the critical current I c and n value of full length tapes by means of statistical method. The results show that the distribution of local critical currents are non-uniform, and local critical currents have important effect on the performance of the entire tapes. The critical current of the entire tape is different from the mean value of local critical current based on Gaussian statistical distribution along the long tape.

A Real-Time Measuring and Control System for the World's First HTS Power Substation

The worlds first high-temperature superconductor (HTS) power substation (the substation) for the only power distribution grade has been successfully developed in live grid in 2011 in Baiyin, Gansu Province of China. This 10 kV HTS power substation is an integration of 75 m/1.5 kA HTS power cable, 10 kV/1.5 kA HTS fault current limiter, 1 MJ/0.5 MVA high Tc superconducting magnetic energy storage and 630 kVA/10 kV/0.4 kV HTS power transformer. The HTS power substation is operated automatically by a real-time measuring and control system, and it is not necessary to have anyone on duty. Software is developed by using LabView program. The cooling system providing a low-temperature environment for the cryogenic devices is an independent system, and is also the key part to ensure the run of the substation. The real-time measuring and control system for the substation, which comprehensively measures and controls the related signals of the HTS power substation, is introduced, and the controlling system for the cooling system is described in detail in this paper.

Development of a Combined YBCO/Bi2223 Coils for a Model Fault Current Limiter

Recently, the high-temperature superconducting (HTS) devices and superconducting technologies have become widespread in the field of electric power. The 2G wires are expected to be used in future power applications because it has high properties in high temperature and high magnetic fields. One of the most promising applications for HTS coils in electrical engineering is for high-temperature superconducting fault current limiter. In this paper, the design, fabrication, and experiment of the combined YBCO/Bi2223 coils were described. Nine coils wound with 122 m YBCO tapes and three coils wound with 376 m Bi2223/Ag tapes, were assembled into the combined coils. The YBCO coils were in a noninductance configuration and the Bi2223/Ag coils were in a solenoid configuration. For getting higher resistances and rapid response to the fault current, the structure of the combined coils, the heat stability, and the insulation of the YBCO coils were the main targets in the development of the YBCO coils.

Development of a 1250-kVA Superconducting Transformer and Its Demonstration at the Superconducting Substation

A three-phase 1250-kVA/10.5-kV/0.4-kV hightemperature superconducting (HTS) transformer has been designed and fabricated. The windings of the HTS transformer are wound by copper-alloy-reinforced multifilamentary Bi2223/Ag tapes, and the structures of the primary and secondary windings are solenoid and double pancake, respectively. The three-phase three-limb core is made of domain-refined high-induction-type grain-oriented silicon sheet steel, and the cryostat is made of glass-fiber-reinforced plastics. According to the tests, the no-load loss is 2319.2 W at an exciting current of 0.254% of the rated level, the short-circuit impedance of the transformer is 5.6% of the rated value, and the average load loss is 249.6 W. In addition, the leakage current between the primary and secondary windings is about 12.6 mA under the condition of 35 kV/1 min/50 Hz, and the negative full-wave lighting impulse test with a peak voltage of 75 kV/1.0 μs/50 μs from the primary winding is carried out without breakdown. The experimental results show that the developed HTS transformer meets the requirements of the Chinese standards, and the demonstration of the HTS transformer at the superconducting power substation since September 9, 2014 has been reliable, showing its potential for long-term operation in the grid.

Development of Online Monitoring and Controlling System for the 630 kVA Three-Phase High Temperature Superconducting Transformer

The 630 kVA three-phase high temperature superconducting (HTS) transformer is one of the key parts of the superconducting power substation, which has been successfully developed and put into operation in live grid for the first time around the world in 2011. The real-time monitoring system ensures the safe operation of HTS transformer and superconducting power substation. The system measures those signals pertaining to the operation of HTS transformer, such as voltage, current, liquid level, and an automatic supply of liquid nitrogen is achieved. This paper introduces the structure and testing features of 630kVA/10.5kV HTS transformer, and illustrates the influences on the testing procedures, as well as solutions, while the system runs in adverse magnetic environment. The project covers schematic design, structure design, function implementation and system integration. The data collected for liquid nitrogen loss is also analyzed and discussed. The successful development of 630kVA three-phase HTS real-time monitoring system is a foundation for the normal operation of superconducting power substation. Consequently, the experiences gained from this project will certainly benefit the development of high-capacity and high voltage superconducting transformer in the future.

Stability Analysis of the Cable Core of a 10 kA HTS DC Power Cable Used in the Electrolytic Aluminum Industry

High temperature superconducting (HTS) dc power cable shows a wide application prospect in the field of power transmission for its nearly lossless and rather high capacity. IEE has installed a 360-meter long high temperature superconducting (HTS) dc power cable at the self-supply power plant of Zhongfu Industrial Company Ltd. in Gongyi, Henan and the system has operated for two years. The cable connects a 19.5 MVA/1.5 kA silicon-controlled rectifier, which connects with a 110 kV/1 kV transformer, to the bus bar of an electrolytic aluminum cell. It is designed to carry 10-kA current and the voltage is 1300 V. The HTS dc power cable core consists of five conductor layers wound with the spliced Bi-2223 wires with the length of 40 km. The cable core has five layers and 23 HTS wires in each layer with the outer diameter of 45 mm. The HTS dc power cable is fabricated with the spliced superconducting wires which will have effect on the overall superconductivity. Also, since dc output of the rectifier contains a proportion of the ac harmonic ripple, the large dc and small ac will generate the loss in the cable core. In the operation of the 10 kA HTS dc power cable, anode effect will occur in electrolytic aluminum tank, which will lead to a large fault current in the cable and even lead to the power off protection. In this paper, stability of the spliced Bi-2223 wire, stability of the cable core under the cold shrinkage force, loss under the large dc and small ac ripple are analyzed by the theoretical and experimental methods. The test results of ac ripple loss, anode effect, and stable operation are also presented.