TN-S

TN-S: separate protective earth (PE) and neutral (N) conductors from transformer to consuming device, which are not connected together at any point after the building distribution point.

TN-S

TN-S系统完全将地线和零线隔离.

TN-S 的含义

International standard IEC 60364 distinguishes three families of earthing arrangements, using the two-letter codes TN, TT, and IT.

The first letter

The first letter indicates the connection between earth and the power-supply equipment (generator or transformer):
"T" — Direct connection of a point with earth (Latin: terra)
"I" — No point is connected with earth (isolation), except perhaps via a high impedance.

第一个参数指代的是电力系统(生成者)和地之间的连接关系.
"T"表示电力系统直接接地.

The second letter

The second letter indicates the connection between earth and the electrical device being supplied:
"T" — Direct connection of a point with earth
"N" — Direct connection to neutral at the origin of installation, which is connected to the earth

第二个参数指代的是用电设备(消费者)和地之间的连接关系.
"N"表示用电设备直接和零线连接(零线本身已接地).

The third letter

separate protective earth (PE) and neutral (N) conductors

表示完全将地线和零线隔离.

References:
https://en.wikipedia.org/wiki/Earthing_system