接地保护与接零保护安全性比较

Comparison to the Safety Performances of Connecting Zero Protection and Connecting Earth Protection

我国现存标准或规范仍在推荐使用接零保护(TN系统),这是一种人为增大故障电流、以过流保护装置(过流保护断路器或熔断器)对漏电进行防护的方法。在漏电保护器RCD广泛应用的今天,完成漏电防护的首要装置是RCD,而不再是过流保护装置。通过基于RCD的漏电防护水平评价和对本质安全性的综合比较,得出的结论是接地保护(TT系统)比接零保护(TN系统)更安全。

Existing standards or codes have still reecommended to use connecting zero protection （TN system） in China which is a method to protect current leakage by over- current protective devices （over - current breaker or fuse）, through increasing fault current deliberately. With the residual current protective device （RCD） being used widely now, the basic device used to perform the current leakage protection is RCD, rather than over - current protective devices. Thigh evaluation of current - leakage protection based on RCD and synthetio comparison to their instinct safety performances, this paper gets the conclusion that the connecting earth protection（TT system） is safer than the connecting zero protection （TN system）.