# Homework Help: Tapping in power systems

1. Jul 29, 2015

### ranju

1. The problem statement, all variables and given/known data
What is meant by the term tapping in power system , I studied in my textbook that generally from feeders no tapping is taken to the consumers , therefore current loading of feeder remains the same along its length. I was not getting what is being referred here ..?

2. Relevant equations

3. The attempt at a solution
I am familiar with the tapping we use in case of transformer which is the varying the number of turns , which further changes the voltage ratio.. Is this the same sense tapping in power supply system is being used??

Last edited by a moderator: Aug 4, 2015
2. Jul 29, 2015

### William White

Unless there is a definition I am not aware of, tapping is exactly what you describe.

Primary substation transformers (generally) have on-load tap changers via a diverter and a large number of taps. There are many methods to automatically control the tap when you have two or more transformers in parallel - master/slaves; TAPP ; circulating current etc...

Secondary substation transformers and pole-mounted transformers have off load tap changers and just a few taps (usually about 5) which are set when the transformer is installed. Off load is a bit of a misnmoer, becasue the transformer has not only to be off load but isolated.

3. Jul 30, 2015

### Staff: Mentor

Based on what you provide here, I would conclude that tapping refers to connecting a couple of wires to take power to the premises of each consumer along the route. Where consumers take current from a power line, there will be a drop in remaining current as you progress away from the power station. It's saying that feeders don't have consumers tapping on along the route; feeders carry power between networks, and it is the local network that is responsibe for distributing that power to consumers.

4. Jul 30, 2015

### William White

In 20 years in the power industry (UK) I have never heard that defintion of tapping

what you describe is called a CONNECTION.

5. Jul 31, 2015

### Staff: Mentor

Perhaps ranju could indicate which country his textbook was written for?

6. Jul 31, 2015

### William White

that would be helpful!

You may very well be right, I've just never heard a (consumer) connection called a tap before

7. Jul 31, 2015

### Nidum

One origin of the term tapping in comes from the time when telegraph signals were carried long distance with a single wire and earth return . After making a connection at a remote location operator 'tapped in' a Morse code sequence to tell the master operators that the connection was live . Phrase later came to be used more generally to denote making ad hoc connections to any system .

Same root as phone tapping .

8. Jul 31, 2015

### William White

thats fine

but utility companies don't make ad hoc connections; and tapping has a defined meaning: the operation of a tap changer.

If, in a power systems context, tapping is being used to mean anything other than the operation of a tap changer; then that is very shoddy indeed.

9. Aug 4, 2015

### ranju

Well.. Its written in India..

10. Aug 5, 2015