11 kV Cable

I have a circuit in which the the transformer is of rating

 - 11kV / 415V, 50Hz, 1600kVA, Dyn11, 5% impedance connected to a 12kV, 50Hz ,630A indoor VCB with a 3cx70mm² 11kV cable.

The short circuit breaking current (AC RMS) rating of VCB is 31.5kA for 3 second.What should be the short current rating and time duration  of the 11kV cable ?


asked 12/23/2013
ram3166
ram31

1 Answer

http://www.engineering.schneider-electric.se/Attachments/ed/guide/06_determining_conductor_cross_sectional_areas.pdf

 

This link will be helpful for you. Page 544 is the right one for your question and equation is from IEC standard. Now, your question is a little bit unclear because time duration and current withstand capacity of cable are in direct proportion so usually u have to first take in consideration time for withstanding and than u will get current value and vise versa. Just read the document and if u have any question, don't hesitate to ask.

answered 12/23/2013 Mirko Lezajic 8
Mirko Lezajic

Your Answer

In order to provide an answer to this question, you must Login

I am flagging this question because...




10 inform moderator flags remaining

I am deleting this question because...




I am flagging this answer because...




10 inform moderator flags remaining

Flagging a Post

You have already flagged this post. Clicking "Remove Flag" below will remove your flag, thus reducing the count by one as well.

I am deleting this answer because...





Dielectric loss in cables

Dielectrics (insulating materials for example) when subjected to a varying electric field, will have some energy loss.   The varying electric field causes...

Tip – Latitude and Longitude on Large Scale Plans

If you are working on a large plan, get the real coordinates [latitude, longitude] for two or more points and add them to the drawing. That way you can...

Understanding Motor Duty Rating

One of the comments on my Motor Starting Series was asking for something on duty cycles. Here it is. As a purchaser of a motor, you have responsibility...

Introduction to Lighting

When looking at the design of a lighting scheme it is useful to have an understanding on the nature of light itself and some of the basic theory associated...

Surface Treatment – Ladders, Trays and Baskets

Steel ladders, trays and baskets form the backbone of cable containment systems. Often these items need some form of surface treatment to prevent corrosion...

Medium Voltage Switchgear Room Design Guide

Many medium voltage (MV) indoor switchgear rooms  exist worldwide. The complexity of these rooms varies considerably depending on location, function and...

How to measure power supply quality

If your are ever called out to troubleshoot something on your electrical system, one of the first things consider is the supply voltage. You want to ensure...

Lightning Risk Assessment (IEC 62305)

IEC 62305 'Protection against lightning' requires a risk assessment be carried out to determine the characteristics of any lightning protection system...

Maxwell's Equations - Introduction

Maxwell's Equations are a set of fundamental relationships, which govern how electric and magnetic fields interact. The equations explain how these fields...

Material Properties

Everything physical in electrical engineering from insulations to conductors revolves around materials. Here we are listing common materials along with...

Our website uses cookies so that we can provide a better experience.
To learn more about what cookies are and how to manage them visit AboutCookies.org