| Power reactor is an important reactive power compensation device, which has been widely uesed in the high-voltage or the ultra high-voltage power system. In order to stabilize the voltage of power system, controll the reactive power, and improve the stabilty of power system, the capacity of a controllable reactor is controlled in real time according to the operation states of power system. Owing to the defects of non-ignorable harmonic disturbance, unstable reactance and higher loss, the application scope of some controllable reactors is limited with the development of power system. The use of superconducting materials in the controllable winding can improve the effciency of the controllable reactor by significantly decreasing the loss of winding and enlarging the capacity of equipment, thanks to the near zero resistance and the high current carrying density offered by superconductivity (compared with copper wire, the current carrying density of superconductivity tape is more than one hundred times).The background and the development status of high temperature superconductivity-controllable reactor (HTS-CR) is introduced in this paper. The basic theories of electromagneitc design and cryogenic design of the HTS-CR winding are also fully introduced. The key technologies needed to be solved in the design of the superconcuting winding and the electromagnetic performance of the HTS-CR are well studied. Based on the test of a 380 V HTS-CR prototype and the design of HTS winding of a 35 kV/3.5 MVar single-phase HTS-CR, both the experimental verifications and the design practices of the above-mentioned key technologies are accomplished, respectively. The highlights of this paper mainly reflect in the following aspects:1) In response to the perfermance requirment of controllable reactor from the power system and the power inducstry, a novel HTS-CR is developed. Based on the experiment of a 380 V HTS prototype, the HTS-CR is verified has a performance of stable reactance, low harmonic, and small loss of controllable winding.2) In response to both the multi-coil electromagnetic coupling and the alternating current (AC) flowing of the HTS-CR, the field circuit coupling FEM is proppsed to complete the design of HTS winding, which is proved by test. The accuracy of the criterion 1?V/cm, which is used in the critical current measuring of HTS winding with "four probe method", is researched by calculation and test. In contrast, the whole domain critical current calculation method, which can reflect the partial critical current value of HTS winding morer accurately is proposed.3) In response to the magnet circulating current problems of large capacity HTS-CR with many parallel-connected HTS tapes and the large AC loss of HTS winding, the new method to decrease the circulating current of superconducting winding and the new method to reduce the AC loss of HTS winding are proposed. Both the two methods are used in the electromagnetic design of 35 kV/3.5 MVar single-phase HTS-CR.4) In response to the overlarge thermal load of HTS-CR magnet, especially the AC loss of partical magnet is huge, based on the cryogenic design of 35 kV/3.5 MVar single-phase HTS-CR, a new cryogenic cooling scheme, which achieves the optimal design of both the crogynic cooling pipes and the flow rate of liquid nitrogen around the HTS double pancakes with large AC loss, is proposed. |
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