DS3800HRIA
在没有接地故障的情况下，电流的矢量和I∆ 等于零；
如果发生接地故障∆ 值超过额定剩余工作电流
我
∆N
，位于圆环体二次侧的电路向
导致断路器跳闸的专用分闸线圈。
可根据故障类型对RCD进行一次分类
它们可以检测到的电流：
-交流型：确保剩余正弦交流电跳闸，
是否突然施加或缓慢上升；
-A型：确保剩余正弦交流电跳闸，以及
剩余脉动直流电，无论是突然施加还是缓慢上升；
-B型：确保剩余直流电流跳闸，剩余正弦电流跳闸
交流电和剩余脉动直流电，无论是否突然
应用或缓慢上升。
操作延时的另一种分类是：
-未播放类型；
-延时S型。
图1：剩余电流装置的工作原理
4.7剩余电流装置（RCD）
ABB |电气设备457
4保护人类
我∆ 我∆
我∆ 0.3安
t 0.5秒
我∆ 0.3安
t 0.5秒
RCD可以与其他设备耦合，也可以不耦合；可以区分
其中：
-纯剩余电流断路器（RCCB）：它们只有
电流释放，只能防止接地故障。它们必须耦合
带热磁断路器或保险丝，用于防止
热应力和动应力；
-带过流保护的剩余电流断路器（RCBO）：它们
是热磁断路器和RCD的组合；为了这个
原因是，它们提供过电流和接地保护
故障电流；
-外环形剩余电流断路器：用于工业
具有高电流的植物。它们由连接到
带绕组的外圆环，用于检测剩余电流；万一
接地故障时，信号指令断路器的断开机构
或线路接触器。
给定I∆N
运行剩余电流是剩余电流的一个重要参数
电流器件是剩余的非工作电流，代表
不引起断路器的剩余电流的大值
旅行等于0.5 I∆N
因此，可以得出以下结论：
-对于I∆ < 0.5⋅我
∆N
RCD不得运行；
-对于0.5⋅我
∆N
<我∆ < 我∆N
RCD可以运行；
-对于I∆ > 我∆N
RCD应运行。
对于额定工作剩余电流的选择，有必要考虑：，
除了与接地系统协调外，还包括
电厂泄漏电流；每个相位上的矢量和不得为
大于0.5⋅我
∆N
以避免意外跳闸。

In absence of an earth fault, the vectorial sum of the currents I∆ is equal to zero; in case of an earth fault if the I∆ value exceeds the rated residual operating current I ∆n , the circuit at the secondary side of the toroid sends a command signal to a dedicated opening coil causing the tripping of the circuit-breaker. A first classification of RCDs can be made according to the type of the fault current they can detect: - AC type: the tripping is ensured for residual sinusoidal alternating currents, whether suddenly applied or slowly rising; - A type: tripping is ensured for residual sinusoidal alternating currents and residual pulsating direct currents, whether suddenly applied or slowly rising; - B type: tripping is ensured for residual direct currents, for residual sinusoidal alternating currents and residual pulsating direct currents, whether suddenly applied or slowly rising. Another classification referred to the operating time delay is: - undelayed type; - time delayed S-type. Figure 1: Operating principle of the residual current device 4.7 Residual current devices (RCDs) ABB | Electrical devices 457 4 Protection of human beings I∆ I∆ I∆ 0.3 A t 0.5 s I∆ 0.3 A t 0.5 s RCDs can be coupled, or not, with other devices; it is possible to distinguish among: - pure residual current circuit-breakers (RCCBs): they have only the residual current release and can protect only against earth fault. They must be coupled with thermomagnetic circuit-breakers or fuses, for the protection against thermal and dynamical stresses; - residual current circuit-breakers with overcurrent protection (RCBOs): they are the combination of a thermomagnetic circuit-breaker and a RCD; for this reason, they provide the protection against both overcurrents as well as earth fault current; - residual current circuit-breakers with external toroid: they are used in industrial plants with high currents. They are composed by a release connected to an external toroid with a winding for the detection of the residual current; in case of earth fault, a signal commands the opening mechanism of a circuit-breaker or a line contactor. Given I∆n the operating residual current, a very important parameter for residual current devices is the residual non-operating current, which represents the maximum value of the residual current which does not cause the circuit-breaker trip; it is equal to 0.5 I∆n . Therefore, it is possible to conclude that: - for I∆ < 0.5⋅I ∆n the RCD shall not operate; - for 0.5⋅I ∆n < I∆ < I∆n the RCD could operate; - for I∆ > I∆n the RCD shall operate. For the choice of the rated operating residual current, it is necessary to consider, in addition to the coordination with the earthing system, also the whole of the leakage currents in the plant; their vectorial sums on each phase shall not be greater than 0.5⋅I ∆n in order to avoid unwanted tripping.