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  • what is the implecation when a main distrubution panel reads negative KVAR

    JCgal

    Member

    Updated: Oct 27, 2024
    Views: 1.1K
    hi all CEans,

    is someone can explain why negative KVAR occur in a Main distribution line where all of its load in an inductive (Aircon, Chillers, Water pump and UPS with static switch).

    thanks,
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Replies

  • freak16

    Member • Jan 15, 2011

    Can you elaborate your question please?
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  • Arp

    Member • Jan 15, 2011

    i dont know inside details of that but from my basic knowledge what i suppose polarities with which it is connected to mains is not correct
    suppose with same voltage polarity if i reverse the polarity of current coil(anything measuring current) or vice versa then there may be a chance of getting -ve kvar.
    so i advice u to flip your current measuring device terminals once and plz let me know whether the problem resolve or not.
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  • JCgal

    Member • Jan 16, 2011

    To elaborate, before we conduct the annual preventive maintenance of electrical system the reading is positive but now it is negative. i am wondering how this happened the load are all RL. The problem here is this MDP support all the critical equipment when this happened million of dollars will be lost in an instance.

    thanks for the reply.
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  • JCgal

    Member • Jan 16, 2011

    Arp
    i dont know inside details of that but from my basic knowledge what i suppose polarities with which it is connected to mains is not correct
    suppose with same voltage polarity if i reverse the polarity of current coil(anything measuring current) or vice versa then there may be a chance of getting -ve kvar.
    so i advice u to flip your current measuring device terminals once and plz let me know whether the problem resolve or not.
    Hi arp, thank you for your info. actually we have the same idea but i was hesitating because no one was altering the connection even before we conducted the PM of electrical system. Also i was suspecting that the UPS (2 unit of 80KVA) was affecting this measurement because the UPS room humidity wasn't stable (45%-55% normal but now it was 60% - 65%). The aircon that we using in both UPS and DAta center room was Precise Aircon unit meaning this unit will automatically adjust the temp and humid in normal level.
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  • ankurjariwala

    Member • Jan 27, 2011

    ARP is right.....kindly reverse the polarity of the main CT (by shorting the CT shorting links to ground).....
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