低压漏电保护器现场校验仪的设计与实现-电子与通信工程专业论文.docxVIP

I I 摘 要 摘 要 低压断路器和低压漏电保护器是低压配电网中使用最多的电气设备，其可靠性和稳 定性的高低直接影响着整个配电系统的正常运行。低压断路器具有过载、短路以及欠电 压条件下的保护功能，低压漏电保护器不仅具备上述功能，还具备漏电保护功能。为叙 述方便，将二者统称为低压保护器。低压保护器通过厂家的型式试验后出厂使用，使用 过程中由于老化或者接线端子接触不良等因素会造成保护器的使用寿命降低。 低压保护器的脱扣特性和灵敏度是其最为重要的特性，二者直接说明了低压保护器 的机械性能和电气性能，配电系统中若发生漏电、过载或短路现象，低压保护器脱扣特 性异常不仅会给保护器所接设备带来安全隐患，同时也可能会造成电气火灾或引发触电 事故。 本文设计了用于保护器脱扣特性现场测试的模拟负载，该负载基于 IGBT 斩波电路。 与传统模拟负载相比，其特点是电流大，功率高。设计了漏电流模拟负载，该负载基于 数字电位器，特点是数字可调。采用 Silicon Labs 公司生产的 C8051F020 作为微控制器， Cirrus Logic 公司生产的 CS5460A 作为电计量芯片。在此基础上，设计了测量电压、电 流、有功功率、动作时间、波形显示等算法并编写了相应 C 语言程序。讨论了设计过程 中遇到的一些问题，给出了相应的解决方法。 关键词 低压保护器 脱扣特性 灵敏度 现场测试 模拟负载 斩波 II II Abstract Abstract Low voltage circuit breaker and low voltage leakage protector is the most used electrical equipment in low voltage distribution network, its reliability and stability directly affect the normal operation of the whole distribution system. Low voltage circuit breaker has protection function with the condition--overload, short circuit, and under voltage. Low voltage leakage protector not only has that function, but also has the electric leakage protection function. For convenience, both will be collectively referred to as low voltage protector. Low voltage protector will be used after the manufacturers’ test. In using process the protector’s life will be reduced due to the factors such as aging or poor contact terminals. Tripping characteristics and sensitivity is the most important feature of low voltage protector, they show the mechanical properties and electrical properties of low voltage protector. In case of leakage, overload or short circuit phenomenon in power distribution system, abnormal tripping characteristics not only can bring hidden danger to the equipment, also may cause electrical fire or electric shock accident. The simulated load for tripping characteristics of protector is designed, which based on IGBT chopper circuit. Compared with the traditional simulated load, it is characterized by large current, high power. I designed the leakage cu