饱和铁芯型高温超导故障限流器的仿真分析与计算.docVIP

饱和铁芯型高温超导故障限流器的 仿真分析与计算 硕士学位论文 饱和铁芯型高温超导故障限流器的仿真分析与计算 Simulation and Analysis for Saturated Core High Temperature Superconducting Fault Current Limiter 论文题目：饱和铁芯型高温超导故障限流器的仿真分析与计算 摘 要 随着电力系统容量的不断增加，电网短路电流水平也随之增大，可能超过断路器的额定开断容量，使得开关不能正常动作。传统的限制短路电流的方法是加装限流电抗器，其缺点是在系统正常运行时有一定的电压降和能耗。若用超导故障限流器(SFCL)取而代之，当系统正常运行时，限流器处于超导态，损耗小，对电力系统运行几乎无影响；一旦电网发生故障，SFCL瞬时产生高阻抗，从而有效地限制故障电流。本文主要分析研究了三相饱和铁芯型超导限流器的运行特性以及结构对其的影响因素，探索高效仿真计算方法。 首先分析了饱和铁芯型超导故障限流器的工作原理及其特点，并在磁化曲线分段线性化的基础上，进行电磁理论分析；分析铁芯磁场分布与铁芯气隙之间的关系，铁芯交流柱要达到一定的磁感应强度，在有气隙时比无气隙时需要更大的直流励磁；当直流励磁足够大时，能够抵消气隙的影响，使铁芯进入同等程度的饱和深度；直流励磁一定时，截面比λ越大，有气隙时和无气隙时铁芯交流柱磁场越接近，即截面比λ越大气隙的影响越小。为限流器的设计提供分析方法和理论依据。 其次基于能量摄动法计算饱和铁芯型SFCL非线性电感，结合电路方程组对三相饱和铁芯型SFCL的瞬态特性进行仿真；并将380V三相饱和铁芯型SFCL样机的仿真结果与试验数据进行对比分析，结果基本相符；并用该方法对35kVSFCL样机的瞬态仿真计算，所计算的参数达到设计要求。 最后对三相饱和铁芯型SFCL的绕组电动力、稳态压降和铁芯夹件涡流损耗进行计算。结果表明，35kV三相饱和铁芯型SFCL的设计参数，在抗短路电动力及稳态压降方面已达到设计要求；380V样机稳态压降的计算结果与实验数据吻合；涡流损耗主要集中在与交流线圈端部接近的地方，并且在限流状态时夹件涡流损耗迅速增大，此时局部发热问题也更加严重，因此，在不影响夹件机械强度的条件下，合理地在涡流相对集中的地方开槽或开孔可以减小涡流损耗。  ABSTRACT As electric power systems grow and become more interconnected, the fault currents levels have risen to exceed the available circuit breaker interruption ratings. Traditionally, to alleviate the cost of replacements of switchgears and buses, large resistors or series reactors have been used to limit the short circuit currents, so that the underrated switchgears can be operated safely. Unfortunately, resistors or reactors can cause power losses and voltage drop under normal operating conditions, thus weakening the system, Due to its low-loss nature in superconducting condition during non-fault operating, Superconducting fault current limiter(SFCL) offers a good solution to current limiting. In the event of a fault, SFCL inserts impedance into the circuit and limits the fault currents to safe level. First, the operating principle and the characteristics of the saturated core SFCL are analyzed. The relations between the static operation points and air space in the core are have been achived. The