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Recent content by trbartlett

  1. trbartlett

    CT parameters

    Interesting Ohmly, It is predominantly for monitoring for 'green' compliance which is +-5% but the client wants better acuracy than that. I am interested in your last comment "nor a numericial protection relay". The multilin 745 that is being installed - is this what you refer to as a...
  2. trbartlett

    CT parameters

    Thanks Ohmly, What you speak of is what I am confused about. I am not an old boy at this stuff so have little experiance to draw on. In the beginning I believed that 2.5P was percent error @ F20 fault current 20 x flc and that the 30 was the volts accross the terminals - which is what you...
  3. trbartlett

    CT parameters

    C'mon guys, help me out here. I've checked other ct threads and i know there is a bunch of guys out there that could answer this straight up or at least point me in the right direction.
  4. trbartlett

    CT parameters

    Hello all, I do not have manufacturers (South Wales Electric??)information on diff cts 2.5P30 F20 (600:2.89). I cannot find rated burden (ohms or VA) on nameplate of switchgear - cannot access HV cabinet to check ct's themselves. I want to work out actual ALF - am i completely stuck not having...
  5. trbartlett

    CT - Measurement + post "CT Sizing" 10/02/10 by jwparker

    Me again...with another question. I was thinking about a 400:5 ct's rather than 600:5 for the power monitoring application since i believe the acuracy would be little better however, I was questioned as to whether short time peaks would be captured such as motor starts etc. My immediate thoughts...
  6. trbartlett

    CT - Measurement + post "CT Sizing" 10/02/10 by jwparker

    I have some questions around the same guys... Retrofitting power monitoring to a sub-station which only has protection ct's fitted. It has been decided that 3 measurment ct's will be installed. Substation 66/11kV. Going on tx size, 400Amps seems to be max constant secondary. Protection CT's are...
  7. trbartlett

    CT Sizing

    I have some questions around the same guys... Retrofitting power monitoring to a sub-station which only has protection ct's fitted. It has been decided that 3 measurment ct's will be installed. Substation 66/11kV. Going on tx size, 400Amps seems to be max constant secondary. Protection CT's are...
  8. trbartlett

    HV transformer - neutral earthing resistor

    Many thanks guys for your input. It was very helpful. Cheers.
  9. trbartlett

    HV transformer - neutral earthing resistor

    Thankyou guys. Next time I visit a transformer manufacturer to witness testing I will take the oportunity to have a closer look at the manufacturing process. I am not sure if this is the proper way to keep a thread going and expand a little on my previous question but here goes... The client is...
  10. trbartlett

    HV transformer - neutral earthing resistor

    I have been told and have no reason to disbelieve that transformers above MV (in my country, 33kV)do not normally have NER's. I have been told that it has something to do with insulation and that it would make the manufacture of a high voltage transformer (i.e. 132/66kV 100Mva)cost prohibitive...

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