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HV & LV Metering Issue

Hi All,

We have site which has been running for 6 months now. It's industrial process served via a 2MVA transformer fed from HV RMU at 11,000V. The transformer is cast resin with less than 1% loss. Our works were installing the transformer and LV panel with a significant post contract fitout by the developer including process supplies. It’s metered at HV but the site is reporting discrepancies between the HV and the LV meter on the incomer. The HV meter is indicating up to 50% more usage than the LV meter. Given that the 2 should generally even out, taking into account transformer and other losses I can only assume they have a significant harmonic issue caused by the process load which is greatly reducing the losses at the transformer. This was my initial thought when I saw the figures. Thoughts from the community?


Thanks in advance.
Parents
  • It has to be some metering cock-up like that - you my lose perhaps 5% to the angels and so much hot air and warm steel, but to lose 50% something would have to be on fire at that power level- you have not said that it is, so it has to be instrumentation. (harmonci curents are not lost, they end up as heat in the star delta trasformation) Check your meters first, and then get the DNO in (cheaper that way round, just in case it is not the HV side at fault.)
Reply
  • It has to be some metering cock-up like that - you my lose perhaps 5% to the angels and so much hot air and warm steel, but to lose 50% something would have to be on fire at that power level- you have not said that it is, so it has to be instrumentation. (harmonci curents are not lost, they end up as heat in the star delta trasformation) Check your meters first, and then get the DNO in (cheaper that way round, just in case it is not the HV side at fault.)
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