基于有限元分析法的电抗器匝间短路检测仿真

Simulation of reactor turn to turn short circuit detection based on finite element analysis

干式空心电抗器广泛应用于输电线路中,一般工作于户外,工作环境较为恶劣,由匝间短路故障而引发的火灾众多。因此,采取必要的监测手段,及时发现电抗器异常运行状态并进行维修,是必不可少的。首先分析了干式空心电抗器的结构以及匝间短路电路模型,提出了一种采集电抗器磁场信号的方案,进一步分析了通电线圈的磁感应强度计算原理。在此基础上设计了一种基于有限元分析法的新型电抗器匝间短路检测装置,其中有限元仿真分析是实现该装置的关键步骤。通过建立ANSYS有限元仿真模型,仿真了电抗器正常运行和发生匝间短路时故障层绕组电流与电抗器整体磁场变化。仿真结果表明,当电抗器发生匝间短路时,会在故障层绕组内部形成一个闭合的回路,在瞬间产生较大的感应电流,在电抗器输出端口表现为一个尖峰的突变电流。同时由于故障位置磁场发生畸变,造成空间磁场的分布不均,从而影响到电抗器的稳定运行。将仿真数据作为监测装置的预警值,达到了电抗器匝间短路故障在线监测的要求。

Dry-type air-core reactors are widely used in transmission lines,generally working outdoors,and the working environment is relatively harsh,so there are many fires caused by inter-turn short circuit faults.Therefore,it is necessary to take the necessary monitoring means to detect the abnormal operation of the reactor in time and maintenance it.Firstly,the structure of dry-type air-core reactor and the circuit model of inter-turn short circuit are analyzed,and a scheme for collecting the magnetic field signal of reactor is proposed;then the calculation principle of the magnetic induction intensity of the electrified coil is further analyzed.On this basis,a new type of reactor inter-turn short circuit detection device based on finite element analysis is designed,in which the finite element simulation analysis is the key step to realize the device.Through the establishment of ANSYS finite element simulation model,the changes of winding current of fault layer and overall magnetic field of reactor during normal operation and interturn short circuit of reactor are simulated.The simulation results show that when the inter-turn short circuit occurs in the reactor,a closed loop will be formed in the winding of the fault layer,and a large induction current will be generated in an instant which is shown as a peaked mutation current at the output port of the reactor.At the same time,due to the distortion of the magnetic field at the fault location,the distribution of the spatial magnetic field is uneven,which affects the stable operation of the reactor.Taking the simulation data as the early warning value of the monitoring device,the requirements of on-line monitoring of inter-turn short circuit fault of the reactor are realized.