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Recent content by PAP

  1. PAP

    subsea cable : ground fault problem

    Hi all, Not sure that anybody experienced subsea umbilical cable ground fault problem? It is 1 phase LV cable (service Vmax 600Vac) and monitored with Bender IRDH375 and relay said low insulation value (600kOhm for trip setting). From theory with ungrounded system, it should be able to power up...
  2. PAP

    Allowable starting time for small DC motor

    I've tried to find the safety starting time limit for a small DC motor and got some idea about the motor thermal time constant. Not sure is it appicable during starting period or not as the cooling is normally low. If it is yes, then the final heating = ( I start/I rate)^2 * (1-e^(t start/ time...
  3. PAP

    How to connect ABB relay REM543 for configuration

    I would like to ask the way to connect ABB relay for configuraiton. I've tried with CAP505 and front connection port with optical link (1MK9500001-2) but the software show the problem with communication so I'm not sure the possibility for this problem. details: ABB REM543 CG212AAAA ,sw version...
  4. PAP

    Calculation result from ETAP, LL & LLG fault is higer 3phase fault

    I've run ETAP program for isolated power system. The system consists of 3x6.5MW turbogenerator (10A NGR) supply 6.6kV motors and 2x 6.6/.4kV 3MVA DYN11 transformer (solid earth). The calculation result surprise me and I would ask why this happen? In which case that LL and LLG can go over 3...
  5. PAP

    Gen diff protection: grounding connection on CT secondary

    Hi all, I have a question of installation of CT link to differential protection relay, please see attached file. The problem is secondary CT connection was connect to ground oppose to generator terminal on both side which normal scheme will connect to ground on generator terminal side. (it...
  6. PAP

    Looking for Mitsubishi relay characteristic

    I'm trying to looking for old voltage relay characteristic (curve) :Mitsubishi type CP-D ,CV2 and CV5 . Anyone can help on this. Thank you for your kindness.
  7. PAP

    transformer mothball- keep in place for a few months

    Hello All, I'm trying to find transformer mothball ( keep in place ,not use for a few months) procedure, Could anyone suggest me the standard or procedure about that? My application is distribution transformer 1600kVA- 22kV/400V. Thanks for every suggestion. PAP
  8. PAP

    Partial discharge and Harmonic on dry type transformer

    Hello all, I have a problem of Harmonic in the system but the harmonic monitoring is still in process, however , my concern is the dry type transformer that supply the load have some partial discharge trace. Could anyone may suggest how harmonic can accelerate the partial discharge process in...
  9. PAP

    Temperature rise test for dry type transformer acc. to IEC 60076

    All I have some questions about the temperature rise test for dry type transformer according to IEC 60076. What 're the meanings for this test, Can the test result infer to the operating temperature for transformer? ==================================== The method of standard is test by...
  10. PAP

    the meaning of Operating cycle O-t-CO-t-CO for MV breaker

    Hi all I 'd like to ask the implied meaning of operating cycle "O-t-CO-t-CO" with t range from 0.3s to 3 min , how the difference for varying of the interval time (fast cycle/slow cycle). Thanks all for your help.. PAP
  11. PAP

    Under voltage protection

    Hi all I have a question about the under voltage protection for the main incoming of industrial plant. Its main incoming has only one feeder @ 22kV and connect to step down transformer (to 400V). Some problems were come from under voltage relay and undervoltage release coil in the main circuit...
  12. PAP

    Output voltage of VFD

    Hi Sed2developer As I informed above,I measure the voltage at terminal U2,V2 and W2 .Only (-)230V DC appear between line to ground.From the principle of inverter,if one polarity of DC bus is connected to ground,should the voltage appear when IGBT output were fail or leakage occur? In...
  13. PAP

    Output voltage of VFD

    Hello all Have anyone ever seen the DC output voltage(Line-Ground) of an 3 phase inverter when we supply with 380Vac(L-L),but don't send any starting command and speed reference is still 0 HZ? I 've measure this DC output voltage for all 3 phase,and it show 230Vdc(L-G) and 0 Vdc(L-L) ,but no...
  14. PAP

    Spark problem of DC motor

    Dear all Anyone please help me about the problem of a lot of spraking at commutator - carbon brush of a large DC motor. - Can I use abrasive material to resurface commutator? What material that I can use? - I found some dull surface on commuatator occur consecutively but not all of commutators...
  15. PAP

    Activated carbon plant design

    Anyone please suggest about the technical reference and concept of activated carbon plant design ,both activated by steam and chemical. Thanks PAP
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