剩余电流动作保护器是用来对漏电和触电进行保护的电器产品，对防止人身触电伤亡和漏电火灾等具有重要作用。目前的剩余电流动作保护器存在以下不足： 当人触电后，在剩余电流动作保护器完成切断电源之前，人一直处在危险触电电压和电流之下；有些剩余电流动作保护器由于机械机构故障、触点熔死等原因，经常出现拒动作或延时动作，这样触电者所受电击的危害程度会更严重，很容易造成伤亡；同时，对于重要用户来讲，在没有备用电源的情况下，由于单相故障跳闸导致的损失将十分严重。本课题研究的目的是针对上述不足，提出一种新型低压三相剩余电流保护原理并对该三相剩余电流动作保护器进行较深入的研究。 本文根据三相剩余电流的特点，提出三相剩余电流保护原理电路模型和数学分析关系，从理论上对各种情况电路的运行进行了分析。在理论分析的基础上，运用ORCAD/PSPICE仿真软件对其理论分析进行验证和寻找合理的参数。最后，设计相应的硬件完成试验验证。 理论分析及仿真表明：这种新型低压三相剩余电流动作保护器，在没有发生触电时电路不工作；当发生单相人身触电时，电路提供的高阻抗，使人身触电电流降了98%，有效地实现了故障点的隔离。测试试验表明，三相剩余电流动作保护器使人身触电电流降了55%，这在一度程度上减轻了故障电流对人体的伤害。在发生单相故障过程中三相负载的线电压平衡，负载正常运行；同时亦可控制相应的执行机构动作，切断电源。

The Residual Current Protection Device, which is used for protecting human and equipment in time of creepage , plays the very important role in avoid of the creepage fire and casualty of getting an electric shock. Yet there are some disadvantages existing in the actual Residual Current Protection Devices—when somebody gets an electric shock, before the Residual Current Protection Device shut off the electric source, the person is in danger of high-voltage which far from the human safety voltage. Moreover, some Residual Current Protection Devices often trip out and delay because of the rusting, node melt, and so on. Thus the harm of getting an electronic shock gets heavier and the human is prone to death. Without another replaced electric source, for the important user, shutting off the electric source suddenly, their loss will be great. This research’s aim is tend to put forward a new type of low—voltage three—phase Residual Current Protection Device to overcome the former’s disadvantages. According to the facts of the three—phase Residual Current Protection Device’s operation, a reasonable model of physical and mathematical about the Residual Current Protection Device is established. This paper analyzed the working theory of resonance circuit in diversified condition. the theory analysis is validated and the reasonable parameters are found through the ORCAD/PSpice simulation software, then the corresponding hardware is designed and many experimentations are achieved. The theory analysis, simulation research show: The new types of low—voltage three—phase Residual Current Protection Device don’t trip switch when the circuit works naturally. However, when somebody gets an electric shock, the resonance circuit is sprung. Therefore large impedance comes into being and limits the touching-voltage and greatly reduces the current through human’s body. After somebody gets an electric shock and before the Residual Current Protection Device will shut off the power source, the current through human’s body reduced 98%. And experimentation result show: the current through human’s body reduced 55%. In this process, the three—phase load’s loop voltage unaltered, which keeps the three—phase load operating normally. In the same time, the detected tache detects the useful signal and implement to switch trip.