×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Cable voltage grade selection

Cable voltage grade selection

Cable voltage grade selection

(OP)
Hi,

I want to select the voltage grade for my 22 kV incoming cable.

I understand for a cable denoted with U0/Un (Um, is

U0 is the rated power frequency voltage between conductor and earth or metallic screen for which the cable is designed.
U is the rated power frequency voltage between conductors for which the cable is designed.
Um is the maximum value of the "highest system voltage'' for which the equipment may be

So based on this i am not able to decide whether i have to go for cable with a voltage grade of 12/20 (24) or 18/24 (36).

as 12/20 (24) can be used for a maximum of 24 kV.

Can anyone provide an explanation to selected which??

RE: Cable voltage grade selection

In IEC 60502-2 CH. 4.1 Rated voltages it is stating :
“The rated voltage of the cable for a given application shall be suitable for the operating conditions in the system in which the cable is used. To facilitate the selection of the cable, systems are divided into three categories: A,B and C.
A if the supply source is disconnected within 1 min maximum.
B if the supply source is disconnected within 60 min maximum.
C-indefinite time.
From Table 1 – Recommended rated voltages U0:
if you intend to use the cable indefinite time in one phase_to_ground fault[ C condition] then for up to 24 kV maximum line_to_line voltage recommended Uo=18 kV -then 18/24 kV].
In A or B condition may be employed 12/20 cable.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources