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  1. HVmariner

    MV Switchgear IEC 62271-200, Internal Arc Test. Mandatory?

    Hi JuanGomez, Sorry for this late answer. In fact, stating in a general way that equipment should comply with IEC is not enough. My understanding is as follows: - Basically, any equipment should comply with the local (country) codes. - In addition, according to your contract with your customer...
  2. HVmariner

    MV Switchgear IEC 62271-200, Internal Arc Test. Mandatory?

    Hi JuanGomez, Indeed IEC 62271-200 is not clear on where IAC applies or not. Based on my past experience in using these switchboards onbaord vessels, the answer is easy: even if IEC is not clear, the Internal Arc Withstand is required by some classification societies. Now, based on my new...
  3. HVmariner

    Is limiters

    Davva, I've just find more information on Schneider solution (see doc. attached): It really looks like the ABB Is-limiter system. Regarding installation of the ABB Is limiter, we had investigated different solutions: - a completed seperate cubicle as you discribe, - just purchasing the...
  4. HVmariner

    Is limiters

    Hi Davva! I've studied this when working for a company concurrent to ABB in the electrical propulsion business. I've been informed last year by Schneider Electric (Grenoble-France) of developments being made to propose the same type of device as the ABB Is-limiter. If you need, I could find...
  5. HVmariner

    GSU Ground Fault CT Size

    Measuring the voltage across the impedance will tell you there is a ground but not where, whereas measuring the current on feeders will make it possible to say on which feeder the ground fault is located.
  6. HVmariner

    Short Circuit Contributors

    Hi nightfox1925, As a supplier of complete installations comprising converters and harmonic filters, I've been working on Isc calculation on marine HV networks. My conclusions are : 1. For converters: Only converters with thyristor bridges on network side (ie static frequency converters) can...
  7. HVmariner

    GSU Ground Fault CT Size

    Hi Slavag! If ground fault is limited to say 5A, why use a core CT with primary current so high (75-100A)?
  8. HVmariner

    Short-circuit calculation with IEC363

    In fact it is not clearly explained. To understand this, it is necessary to read very carefully what is written in chapter 8.5 page 71 (especially the last paragraph): "If the effects of the primary circuit components cannot be neglected, then the impedance due to the transformer must be...
  9. HVmariner

    Switched capacitors at generating plant

    Just a little suggestion: If you know in which configuration of the network (ie which loads are connected) you really need to have the capacitors connected, why not proceed like this: - keep the generators excitation as it is (for them to control the bus voltage). - add some sequential devices...
  10. HVmariner

    short-circuit calcultation following IEEE

    Thanks for your help jghrist. After further researches, I found that this standard is not yet published, and no date is currently known... Regards,
  11. HVmariner

    short-circuit calcultation following IEEE

    Hi everybody! Currently trying to estimate the contribution to a short-circuit of synchro-converters and harmonic filters in a 6.6kV network, I've seen on the IEEE website that an article P551 as been issued in May2000, containing "Recommended Practice for Calculting AC SC Currents in...
  12. HVmariner

    Short-circuit calculation with IEC363

    Hi all! I am currently trying to calculate following IEC363 standard the short-circuit current on the secondary side of a distribution transfomer supplied by 3 6.6kV generators of different powers. Would any-one know if it possible to avoid using the "equivalent generator" method...
  13. HVmariner

    Short-circuit contribution of synchro-converters and HF

    Hi! I am currently trying to calculate short-circuit currents for a 6.6kV marine network (so following IEC363 standard). I've got two main issues: 1/ What is the contribution of synchro-converters to the short-circuit? It seems that the contribution changes, depending on the operating mode...

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