隔离变压器在电源系统防雷中的应用

分析了危害弱电设备的主要电涌类型及特点，探讨了在实际防雷工程中低压配电系统中常用的氧化锌（ZnO）电涌保护器（SPD）存在启动电压偏高,对耐过电压能力较低的电气电子设备存在对电涌防护不到位的问题；将隔离变压器作为防电涌器件引入到弱电设备防雷工程中,利用初级绕组与次级绕组之间只有电磁耦合,无直接电气通道的特性隔离共模过电压；利用铁芯的磁饱和、磁滞现象抑制和削减雷击感应过电压的差模分量。将隔离变压器用于氧化锌电涌保护器之后作为精保护单元,弥补氧化锌电涌保护器的缺点,使弱电设备得到可靠保护,经实际运用验证了它的防雷效果。

Application of Isolation Transformer in Lightning Protection of Power System

An analysis is made of the types of electric surges that invade weak current equipment, and the problem that the threshold voltage and residual voltage of Zn0 surge protection devices, which are commonly used in lightning protection engineering, tend to be high and cannot protect weak current equipment well. It is proposed that the common mode and differential mode components of the lightning induced over voltage should be treated separately while protecting. Isolating transformers are introduced as anti surge devices into the lightning protection engineering of weak current equipment, considering the characteristic that there is only electromagnetic coupling and no direct electrical channel between primary winding and secondary winding to isolate the common mode voltage. The magnetic saturation and magnetic creeping phenomena of iron cores are used to restrain and reduce the differential mode components of the lightning induced over voltage. Using the isolating transformer as essential protection unit in the Zn0 surge protection device to cover the disadvantage of Zn0 surge protection device, the weak current equipment can be protected. The effect of lightning protection is proved through practical application.