冲击发电机系统的过电压防护研究

为了设计冲击发电机系统的金属氧化物避雷器MOA保护系统,计算了开断时间极快,产生过电压较断路器操作过电压高的限流熔断器过电压;采用有限元方法分析限流熔断器熔体的熔化、汽化过程,得到熔体的热电耦合模型,该模型可求出熔断器开断过程的电阻-时间特性;在EMTP/ATP中建立熔断器开断试验系统模型,并分析接入不同类型MOA时,发电机端、熔断器端的过电压幅值;建立MOA的有限元模型,研究MOA的热特性和使用寿命。在冲击发电机系统中进行的不同型号限流熔断器开断试验验证了计算结果,该MOA保护方案能有效的保护发电机。

Protection of Overvoltage in Fuse Breaking Test System

To protect the impulse generator,which was the core of high voltage apparatus test system,a metal oxide arrester would be designed. When current-limiting fuses(CLFs) breaking in fuse breaking test system,fuse element melt and gasified,the arc voltage generated by CLFs will transfer arc energy into the inductive elements of the CLFs breaking test system,such as inductor and capacitor.The fuse elements melt so quick that the overvoltage was higher than other switch-operating overvoltage.The melting course of the CLFs was studied,and an electric-thermal model was established with the finite element method to obtain the resistance-time graph for CLFs,and a circuit model of fuse breaking test system was set up.With the calculation results of electric-thermal model,the overvoltage was calculated with EMTP/ATP.For the appointed device to be protected,the design included electric design and thermal design.Electric design could assure the device to run safely without insulation damage and thermal design should maintain the life time of MOA without thermal crash.Considering the electric and thermal demands,the MOA is picked.Guidelines of MOA was developed for selection and application of the non-electric power systems surge arresters.