In order to meet the pulse power supply needs of HL-3 large-scale tokamak , the domestic first 300 MVA vertical six-phase high-power motor generator (MG) was developed. Because its discharge time is as short as seconds and its power supply parameters are high, in order to ensure the safe operation of the units and tokamak, a rapid demagnetization system had been developed for the MG. The design of the system is based on zinc oxide nonlinear demagnetization resistor, including rotor demagnetization and over-voltage protection devices, DC side peak over-voltage absorbers, non-full-phase and large slip asynchronous operation protectors.The components of the demagnetization device were selected, their parameters were determined, and the dielectric properties and overvoltage protection characteristics of the device were tested. The test results showed that the MG rapid demagnetization system can meet its design requirements.

Motor generator, ZnO resistor, Demagnetization, Overvoltage

为满足中国环流三号(HL-3)大型核聚变装置脉冲供电需求，研制了国内首台 300 MVA 立式六相大功率脉冲发电机。由于其放电时间短至秒级，供电参数高，为了保障机组和聚变装置的安全运行，为脉冲发电机配套研制了一套快速灭磁系统。该系统的设计基于氧化锌非线性灭磁电阻，包含了转子灭磁及过电压保护装置、直流侧尖峰过电压吸收器、非全相及大滑差异步运行保护器。对灭磁装置各元器件进行选型设计和参数确定，并对装置介电性能、过电压保护特性进行了试验，试验结果表明，脉冲发电机快速灭磁系统能满足其设计要求。

脉冲发电机, 氧化锌电阻, 灭磁, 过电压