High Voltage Transformer

Discussion in 'The Projects Forum' started by Francois_Swart, Jan 30, 2010.

Thread Status:
Not open for further replies.
  1. Francois_Swart

    Thread Starter Member

    Jun 4, 2009
    14
    0
    Hi everyone.

    I want to design a high voltage transformer. Can anyone be so kind as to supply me with a few equasions and brief explinations of them?

    I wish to make this transformer as efficient and reliable as possible, and at the same time within the minimum space requierments.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
  3. Francois_Swart

    Thread Starter Member

    Jun 4, 2009
    14
    0
    Unfortunately i cannot use a commercially available device. The transformer will have two identical secondary coils of which both are to be rectified to produce negative half cycles at around 2830 Volts each. The outputs will then be used to each charge a high voltage capacitor to around 4000 Volts. As far as current is concerned, the estimated maximum current output from each capacitor wil be around 200 milli-Amps.
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    For what purpose do you need 4000 Volts @ 200 mA?

    Take a note on this:

    Greetings,
    Bertus
     
    Last edited: Jan 31, 2010
  5. Francois_Swart

    Thread Starter Member

    Jun 4, 2009
    14
    0
    I am aware that high voltages are dangerous. The purpose of this device i wish to build is to discharge a 4000-32000 Volt DC surge down a disconected or standby underground cable in order to monitor it for cable theft.
     
  6. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    Are there other things connected to the cable?
    What is the underground cable used for?

    Greetings,
    Bertus
     
  7. eng1ne

    Member

    Dec 4, 2009
    97
    3
    Any transformer manufacturer might be able to design one for your needs.

    Why a 4000 V surge? How is it going to monitor the cable? I guess the cable must be expensive... I also guess it would probably be very long and thus very difficult to steal, otherwise, a CCTV camera would have done the trick.

    At what intervals will the cable be checked?
     
  8. Francois_Swart

    Thread Starter Member

    Jun 4, 2009
    14
    0
    No, the cable is disconnected from anything else. It is used for power distribution between substations and is a standby cable. In the event of a cable fault or theft, it is connected to the switchgear at both substations, while the fault on the main cable is sought and repaired. this makes the standby cable an attractive target for cable thieves, as it cannot be monitored.
     
  9. Francois_Swart

    Thread Starter Member

    Jun 4, 2009
    14
    0
    I used to do cable fault finding, 4000-32000 Volt surges are used to detect the faults in a cable and determine the aproximate distance of the fault.

    As to how it is to monitor the cable, i have two options:

    1. determine the distance where the cable is cut by using the same techniques as for fault finding.

    2. use something similar to the detection circuit on an electric fence.

    The cable costs arond 150 US$ per meter to replace. If you have a cable of say 3000 meters it is very expensive. Cable thieves however steal only between 10 and 30 meters at a time.
     
  10. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    How do you detect the cable?
    Are you following the cable where it goes?

    Can you use a kind of standing wave method using low power RF?

    Greetings,
    Bertus
     
  11. Francois_Swart

    Thread Starter Member

    Jun 4, 2009
    14
    0
    I'm sure it is possible to use a low power pure sine wave signal transmission down the cable with a reciever at the other end that operates a relay which can be connected to a telemetry system.

    However, I also wish to maby use the system to pinpoint the location (within 10 meters) where the break in the cable has occured, in order to catch the thieves red handed.
     
  12. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Cable breaks may be detected with a TDR circuit - http://www.epanorama.net/circuits/tdr.html

    Terminating the cable with a resistor also gives an immediate indication of a break.

    The use of high voltage is not necessary, and may result in a fatality to any unwitting person. That brings one of our rules into play -
     
Loading...
Thread Status:
Not open for further replies.