消除漏电保护死区的智能保护器设计

为消除漏电死区,减小漏电保护器的拒动作和误动作,介绍了漏电保护的原理,理论论述漏电死区的存在。提出漏电检测的有效方法:以连续的3个周期为处理单元,将对应时刻的漏电流值与前1周期对应时刻的缓变电流值相减,可以在每个周期内确定的时刻采样得到有效的信号值ΔI,然后将连续3个周期相对应时刻的ΔI值分别与突变电流和缓变电流的动作整定值进行比较判断并做出相应的处理。依照提出的检测方法,设计出了漏电保护的硬件电路原理框图和其软件流程图。经测试,该智能保护器可大大提高漏电保护的可靠性和有效性。

Design of intellective leakage protection device to eliminate non-protective area

To eliminate the non-protective area and reduce incorrect operations and failure actions of the leakage protective device,the principle of leakage protection and the theoretical analysis of the existence of non-protective area are introduced.The method to detect leakage effectively is proposed,used three continuous circles as one processing unit,maked a subtract between the leakage current value of the current time and the one of the corresponding time in the previous circle,so the effective signal value ΔI of the every sampling moment in each circle was available,and comparing the continuous and corresponding ΔI to the setted value of the gradually varied current and the mutative current to make the appropriate execution action.According to the protecting method preferred above,the hardware functional block diagram of leakage protection circuit and the software flow chart are given.After tested,the security and reliability of electric leakage protecting are enhanced.