[en] This paper analyzes the circulating current which is produced by HT-7U superconducting toroidal power supply-two sets of two-reverse-star converter with an interphase-reactor in parallel running on the basis of the output voltage mathematical equation of three-phase semi-wave converter circuit. A new idea of omitting interphase-reactor between two converters is proposed, and the parameter design of interphase-reactor of HT-7 toroidal power supply is presented. Simulated results demonstrate the validity of this new project

[en] The power supply of EAST contains a reactive compensation system, which consists of the fixed condenser and TCR. In order to prevent negative effects of parallel-resonance on EAST experiment and power net safety, the low-frequency resonance between the reactive compensation system and distributed inductance of the 10 kV grid is analyzed, which shows that the low-frequency resonance point varies from 2.04 to 2.24 with the variance of TCR, and the 2nd harmonic current of EAST power supply will meet up to the national standard after amplified. The simulation on the entire system with MATLAB and PSCAD verifies the results above. (authors)

[en] The author proposes a quench protection project of HT-7U toroidal superconducting tokamak through a forced commutation analysis of DC circuit breaker (DCCB) paralleling fuse. Based on the requirement of quench protection, main parameters are selected. Experimental results demonstrate the validity of this proposed project

[en] This paper analyses the design project of control system and protection system of toroidal field (TF) power supply system of EAST tokamak, and the main parameters of TF power supply system are selected. Through the first experiment of EAST tokamak, the testing curves of control system and protection system demonstrate the validity of this design project. (author)

[en] The ITER test platform contains a reactive power compensation and harmonic suppression system, which consists of the RLC filter branches and thyristor controlled reactor (TCR). When connected to the grid, in order to prevent the negative effects of load rejection on grid, the load rejection overvoltage at 110 kV bus bar by mathematical calculation is analyzed, which shows that there is a high overvoltage on bus bar when the system throws off the load, and its value is not within the allowable range of the national standards and maybe have impact on grid, so we need to take some protective measures. In order to decrease overvoltage, there adds a bypass branch which contains the anti-parallel diode and a resistor to release the main circuit current. The simulation on the whole system with MATLAB verifies the results above. (authors)

[en] This paper analyses the design project of control system and protection system of toroidal field (TF) power supply system of experiment advanced superconducting tokamak (EAST), and the main parameters of TF power supply system are selected. Through the first experiment of EAST tokamak, the testing curves of control system and protection system demonstrate the validity of this design project. (author)

[en] The author introduces a design of high-precision high-voltage fiber-optic analog signal isolation converter based on the technology of Voltage-to-Frequency (V/F) and Frequency-to-Voltage (F/V) conversion. It describes the principle, system configuration and hardware design

[en] A design of the main AC/DC converter system for ITER is described and the configuration of the main AC/DC converters is presented. To reduce the reactive power absorbed from the converter units, the main AC/DC converters are designed to be series-connected and work in a sequential mode. The structure of the regulator of the converter system is described. A simulation model was built up for the PSCAD/EMTDC code, and the design was validated accordingly. Harmonic analysis and reactive power calculation of the converters units are presented. The results reveal the advantage of sequential control in reducing reactive power and harmonics.

[en] Dynamic performance of a reactive power compensation (RPC) system for the international thermonuclear experimental reactor (ITER) power supply is presented. Static var compensators (SVCs) are adopted to mitigate voltage fluctuation and reduce the reactive power down to a level acceptable for the French/European 400 kV grid. A voltage feedback and load power feedforward controller for SVC is proposed, with the feedforward loop intended to guarantee short response time and the feedback loop ensuring good dynamics and steady characteristics of SVC. A mean filter was chosen to measure the control signals to improve the dynamic response. The dynamic performance of the SVC is verified by simulations using PSCAD/EMTDC codes.

[en] The experiment advanced superconducting tokamak (EAST) has a high stored energy superconducting toroidal field (TF) magnet system, so a TF power supply and quench protection are required to provide the power for charge and the reliable means for protection discharge of the TF coil stored energy. This paper describes the design of the TF power supply, current control and coil quench protection