基于反时限特性的控制与保护开关电器的设计

根据国标GB14048.9要求,控制与保护开关电器应具备过载延时反时限动作特性、电源故障指示、短路保护、漏电保护、缺相保护、漏电保护等功能。为替代传统的热磁脱扣电器,提出了一种基于单片机反时限算法的控制与保护开关电器,该系统由DC-DC模块、模拟采样电路、运算放大电路和脱扣电路构成,采用硬件校准方式进行电流校准,并实现了三相电流检测和漏电检测;提出了继电器脱扣和分励脱扣两种方式;同时开展了反时限算法的分析,建立了过载反时限算法与控制与保护开关电器的关系,提出了一种离散化的过载反时限特性算法,最后,进行了过载反时限特性试验,就不同电气环境下的反时限特性做了详细的测量与论证。研究结果表明,该研究为进一步进行控制与保护开关电器的优化工作奠定了基础。

Design of control and protective switching devices based on inverse time characteristic

According to the GB14048.9,control and protective switching devices（CPS） must have the functions of inverse time characteristics,power failure indication,short protection,electric leakage protection and phase short protection.In order to replace the traditional thermal magnetic release device,a method for a type of control and protective switching devices based on inverse time algorithm with microcontroller was presented.The system was consisted with DC-DC circuit,analog sampling circuit,operational amplifier circuit and tripping circuit.The hardware mode was used to calibrate current,and the detection of three-phase current and leakage current was realized.The two release action modes were proposed,including relay-trip and shunt-trip.After the analysis of inverse time algorithm,the relationship between inverse time over-current algorithm and control and protective switching devices was established.A method was presented to discrete the inverse time over-current algorithm.The inverse time over-current characteristic was tested,and the detail measurement and demonstration of inverse time characteristics in different electrical environment were done.The experimental results show that the analysis lays the foundation for the futher more optimization of control and protective switching devices.