一是要注意互感器铭牌额定电压，应与被测线路的电压相对应。 One is to note that the nominal voltage of the current transformer plate should correspond to the voltage of the measured line. 二是对准确度的选择，电能计量用的电流互感器一般应为0.2级，不符合0.2级者一般不采用，特殊用户其准确度相应高一级。 Second, choice of accuracy, power metering current transformer with generally should be 0.2, does not conform to the 0.2 level are generally not used, special user corresponding high level of accuracy. 三是额定负载容量的选择，电流互感器的额定二次电流，应根据二次回路中所带负载电流的大小来选择。既使额定负荷阻抗应与互感器等级相对应，额定负荷阻抗小则电压互感器精度高。由于电流互感器的铭牌二次电流已标准化，其实际输出容量主要由二次电流回路阻抗来决定。 Three is the choice of the rated load capacity, the rated secondary current of the current transformer, should be selected according to the size of the load current in the secondary circuit. The rated load impedance should correspond to the level of the transformer, and the rated load impedance is high in accuracy. Due to the standardization of the secondary current of the current transformer, the actual output capacity is determined by the impedance of the secondary current circuit. 四是额定电流的确定。电路中的一次运行负荷电流，应保证在正常运行中的实际负荷电流，达到额定值的60%左右，至少应不少于30%。同时应在电流互感器二次电流10%—120%范围内。电流过小则电流互感器精度降低，电流过大不但电流互感器精度降低，而且还能使电流互感器烧毁，这点在计量配置中尤为重要。 Four is the determination of the rated current. A running load current in the circuit should ensure that the actual load current in normal operation is about 60% of the rating, at least not less than 30%. At the same time, the current transformer should be 10% to 120% current. Too little electricity is reduced accuracy of current transformer, current not only accuracy of current transformer is reduced, but also can make the current transformer is burned, it is particularly important in the configuration of measurement.