电流互感器二次侧与测量仪表的电流线圈串联形成闭合回路，由于阻抗很小，所以二次接近短路状态，电压很低，但如果二次开路的话，电流互感器其实就相当于一个升变压器，它二次开路的话，二次没有了电流，失去了电流的平衡作用，铁芯磁通剧增，导致二次电压大大升高，可升至数百伏甚至数千伏，既容易造成对人的电击，又可能击穿二次线路和电气元件的绝缘，是十分危险的情况。
The secondary side of the current transformer is connected in series with the current coil of the measuring instrument to form a closed loop. Because of the small impedance, the secondary circuit is close to the short-circuit state and the voltage is very low. But if the secondary circuit is opened, the zhushifen.07858.netjubingxi.07858.netguolvqiy.89ix.com jiezhifab.89ix.comyouxiangy.89ix.comshiyanc.89ix.comcurrent transformer is actually equivalent to a lifting transformer. If it is opened twice, the secondary circuit has no current and loses the balance of current. The flux of the iron core increases sharply, which leads to the secondary circuit. Voltage rises to hundreds of volts or even thousands of volts. It is not only easy to cause shock to people, but also possible to break down the insulation of secondary lines and electrical components, which is a very dangerous situation.
另外，铁芯磁通大大加剧，铁芯会发热，可能烧毁互感器，而且，由于互感器二次电流为零，电流表和功率表指示为零，电流继电器也不能正常运作，失去了对一次电路的监视和保护作用。
In addition, the core flux is greatly increased, the core will be heated, and the transformer may be burned. Moreover, because the secondary current of the transformer is zero, the ammeter and power meter indicate zero, the current relay can not operate normally, and it loses the function of monitoring and protecting the primary circuit.