Showing posts from January, 2015

High Voltage test for Power Cable

High Voltage Test Guide for Power Cables

A complete high voltage test guide for power cable is essential for both of cable users and contractors to get clear idea about cable pre-commissioning and commissioning. Underground power cables should be tested before on-site commissioning or re-commissioning is known as SAT or Site-Acceptance-Test. Although cables are tested by the manufacturer in their factory is known as FAT or Factory-Acceptance-Test before delivery. FAT ensured the quality and specifications of the cables that followed as per international standard (like IEC, IEEE, BS) and customer’s requirements; on the other hand SAT is limited in that it gives no information about the quality of the circuit. The summary of this test results is simple just PASS or FAIL information; but this test gives the user a very degree of confidence that when they switch on to energize the line will operate satisfactorily.
Cable testing at site gives the satisfaction that during laying and carrying…

Recycling of Underground Power Transmission Line

What happened to Underground Power Cable Line after finished Lifetime: What will be happen to underground power transmission line atend of service life, the cable can be recovered for recycling or left inplace forever.
In conventional overhead power transmission line, every part of material including conductor is easy to recollect and recycling.
Direct buried cable is not so easy to recollect from 1.5 meter deep earth, but lots of oil-filled cable which already buried and we can’t just left in place after end of their service life, they are containing some hazardous materials, leaking oil to vicinity for long time!
Good news is that, modern special graded XLPE cables replacing older oil-filled cable technology, polyethylene which has cross-linked molecules to allow extremely high temperature without melting.
Typically each circuit line has 3 conductors and the amount of copper up to 25 tons per kilometer for a larger size core. This hues amount of copper can recycle into same graded cop…

Underground Power Cable Bonding Methods

How Bond Your Cable?Widely used bonding system for High Voltage or Extra High Voltagepower cables are as follows:
Both End Bonding Systems
Single Point Bonding System
Cross Bonding System
Both End Bonding systems The simplest arrangement to eliminate sheath induced voltage is Both End Bonding system. It is very easy and simple to ground both end of cable sheath. Minimum materials are required which lead to economical. But circulating current flows through cable sheath and heat produces which increase loss and reduce cable life. Circulating current is proportional to the length of the cable and the magnitude of the load current. This system normally applies to short cable section of tens of meters long.
Single point bonded system
A simple system is single point bonding which arrangement does not allow any path to flow circulating currents or external fault currents. In this system the sheaths of cables are grounded at one end and other end are open or connected with SVL and grounded through …