MAX197在脉冲鉴幅鉴相式漏电保护器中的应用

Application of MAX197 in Amplitude and Phase Protective Leakage Protector

针对现场使用的零序功率方向漏电保护器[1-3]出现保护死区,提出了解决方案-鉴相的同时加入鉴幅电路,即鉴幅鉴相式保护器。由于在保护死区零序电压与零序电流均很小,采样芯片要求精度高。其中12位的MAX197是性能比较优越的一款,接口简单,转换速度快,操作容易,精度能满足保护器精度要求。在分析MAX197结构、特点和工作原理的基础上,讲述了MAX197在鉴幅鉴相式漏电保护器中的应用,并编写了MAX197与保护器中单片机之间的通信程序,从而解决了零序功率方向保护器保护死区的问题。

The approach of improving the protective dead time problem in field usage of zero-sequence power direction protector is pointed-adding amplitude discrimination circuit to phase- discrimination at the same time, which is also the amplitude and phase protective protector. Because of the smallness of zero sequence voltage and zero sequence current in protection dead time, signal collection chip needs high accuracy. Among them 12 bit MAX197 is one of these that performances are superior, and MAX197 has many advantages, simple interface, fast conversion speed , convenient to operate and its high precision meets requirement of the protector. This paper has related the application of MAX197 in amplitude and phase protective leakage protector based on the analysis of structural features and working principle of MAX197, and has compiled communication program between MAX197 and single chip of the protector, then the dead time problem in zero--sequence power direction protector.