WAZIPOINT Engineering Science & Technology: Why Earthing Switch or Disconnector is Used in Transmission Line?

Thursday, January 3, 2019

Why Earthing Switch or Disconnector is Used in Transmission Line?

Why Earthing Switch or Disconnector is Used in Transmission Line?

How Earthing or Disconnector Switch Play Rule to Personnel Safety Even in a Isolated Disconnected Line? 

The function of earth or disconnector switch is to discharge the capacitive voltage that stored in generator side or long transmission line conductors in the isolated system just after opening the CB (Circuit Breaker) and Isolator.

So, we understand that the main purpose of earth switch is to ground the isolated bus/conductor. Generally earth switch is mechanically interlinked with isolator. Means when isolator opens the circuit then earth-switch closes & vice-vars.

When earth switch is connected to the isolated but charged system it discharges the stored energy to earth, so that maintenance work can be carried out either in line on generator side.

So earth switch provides extra safety to the working personnel during transmission line maintenance.
You may interrelated to read:

In my practical experiences I found three cases regarding the necessity of earthing in dead line too.

When the line crews working a dead line where parallel another line is alive. The line crews experienced the voltage exist and they felt some electrical shook.

When we construct parallel two circuits high voltage transmission line and energized a single circuit first. We found that other circuit also experiencing around 1kV in control panel metering system. This happened due to induced voltage.

When we construct a long overhead transmission and it was causing electric shook before touching with any energized line. Finally we discovered the voltage developed in it due to conductor capacitive behavior.

When Earthing Switch or Disconnector Should be Operated?

Operating the earth switch in an energized line may causes sever accident. The condition of earth switch operation is as below;

  1. Earth switches should be operated only when the isolators are in open;
  2. All earth switches can be operated manually. Semaphore indicator can be seen for position feedback (on/off) in switch yard control panel.

Latest Earth Switch or Dis-connector

What we discussed is for maintenance purpose earth switch mainly, but in latest GIS (Gas Insulated Switch) system switch-gear used automatic high speed earth switch. In this system when any fault occurred the faulty part automatically isolated and earthed by high speed auto earth switch and protect the equipment immediately.


  1. Thank you for some other excellent article. The place else may anyone get that kind of info in such an ideal manner of
    writing? I've a presentation subsequent week, and I am on the look for such information.

  2. Amazing! Its genuinely remarkable post, I have got much clear
    idea about from this post.

  3. Very rapidly this web page will be famous amid all blogging and site-building visitors,
    due to it's good articles or reviews

  4. Hi my friend! I want to say that this article is awesome, nice
    written and include approximately all vital infos.
    I would like to see more posts like this.

  5. Good way of explaining, aand fаԛstidious piece of writing too obtain information on the topic of my presentation focᥙs, whiсh i am ցoing to present in university.

  6. I want to to thank you for this fantastic read!! I certainly enjoyed every
    little bit of it. I have you book-marked to check
    out new things you Ahaa, its nice dialogue regarding this paragraph at this place at this
    weblog, I have read all that, so now me also commenting at
    this place. I am sure this piece of writing has touched all the internet viewers, its really really nice paragraph on building up new web site.


  7. Some truly rattling work on behalf of the owner
    of this web site, utterly outstanding subject material.

  8. A lot of thanks for your whole hard work on this site.
    Kate takes pleasure in carrying out internet research
    and it's really easy to see why. A lot of people know
    all of the powerful means you provide informative secrets via the web site and as well welcome contribution from the others
    on that theme while our own simple princess is always starting
    to learn a lot. Take pleasure in the remaining portion of the new year.

    You're performing a really great job.[X-N-E-W-L-I-N-S-P-I-N-X]I am really impressed
    with your writing abilities as smartly as
    with the layout for your weblog. Is that this a paid topic or did you modify it yourself?

    Anyway stay up the excellent quality writing, it's rare to look a nice weblog
    like this one these days.

  9. Hello my loved one! I want to say that this article is awesome, great written and include approximately all important infos.
    I'd like to look extra posts like this.

  10. Pretty nice post. I just stumbled upon your weblog and wanted to say
    that I have truly enjoyed browsing your blog posts. After all
    I will be subscribing to your rss feed and I
    hope you write again very soon!

  11. This is really interesting, You're a very skilled blogger.

    I've joined your rss feed and look forward to seeking more
    of your excellent post. Also, I have shared your
    site in my social networks!


Thank you very much to visit and valuable comments on this blog post. Keep in touch for next and new article. Share your friends and well-wisher, share your idea to worldwide.

You may like the following pages