1 Protection and control devices Fault types and currents Overload Operating conditions in an electrically undamaged circuit which cause an over-current. Short-circuit The accidental or intentional connection, by a relatively low resistance or impedance, of two or more points in a circuit which are normally at different voltages. Residual current (I∆) It is the vectorial sum of the currents flowing in the main circuit of the circuitbreaker. Rated performances Voltages and frequencies Rated operational voltage (Ue ) A rated operational voltage of an equipment is a value of voltage which, combined with a rated operational current, determines the application of the equipment and to which the relevant tests and the utilization categories are referred to. Rated insulation voltage (Ui ) The rated insulation voltage of an equipment is the value of voltage to which dielectric tests voltage and creepage distances are referred. In no case the maximum value of the rated operational voltage shall exceed that of the rated insulation voltage. Rated impulse withstand voltage (Uimp ) The peak value of an impulse voltage of prescribed form and polarity which the equipment is capable of withstanding without failure under specified conditions of test and to which the values of the clearances are referred. Rated frequency The supply frequency for which an equipment is designed and to which the other characteristic values correspond. Currents Rated uninterrupted current (In ) The rated uninterrupted current for a circuit-breaker is a value of current, that the circuit-breaker can carry during uninterrupted service. Rated residual operating current (I∆n ) It is the r.m.s. value of a sinusoidal residual operating current assigned to the CBR by the manufacturer, at which the CBR shall operate under specified conditions.

1.保护和控制装置
故障类型和电流
超载
电气未损坏电路中的工作条件会导致
过流。
短路
由相对较低的电阻或电阻引起的意外或有意连接
阻抗，指电路中通常处于不同位置的两个或多个点的阻抗
电压。
剩余电流（I∆)
它是流经断路器主电路的电流矢量和。
额定性能
电压和频率
额定工作电压（Ue）
设备的额定工作电压是一个电压值，它与额定工作电流相结合，决定了设备的应用
以及相关测试和使用类别。
额定绝缘电压（Ui）
设备的额定绝缘电压是指设备所承受的电压值
介电测试参考电压和爬电距离。在任何情况下
额定工作电压的大值应超过额定工作电压的大值
绝缘电压。
额定冲击耐受电压（Uimp）
规定形式和极性的脉冲电压的峰值
设备能够在规定的条件下耐受而不发生故障
以及参考间隙值的试验。
额定频率
设备设计的供电频率，以及
其他特征值对应。
洋流
额定不间断电流（In）
断路器的额定不间断电流是一个电流值
断路器可在不间断运行期间进行操作。
额定剩余工作电流（I∆n）
它是分配给控制器的正弦剩余工作电流的r.m.s.值
CBR由制造商提供，CBR应在规定条件下运行
条件