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  • Users: JAMartinezB
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  1. JAMartinezB

    Harmonics Problem

    Hi, I am having problems with high measurements of THD% current (27%) and voltage (8%). But I'm not sure whether the source of these high THD is my load or the network. I wonder how I could determine when a harmonic problem in the customer side is produced mainly by its loads or by the others...
  2. JAMartinezB

    HARMONICS SOURCE

    Hi, I would like to know how to determine whether a customer is generating harmonics or is receiving them from the net. Something similar like the cause of a voltage drop. If the customer is causing the voltage drop in his inner network, then should be a spike in the current drawn by the...
  3. JAMartinezB

    RESIDENCIAL POWER LIMITER

    Hi, thank you for your answers. Let me explain myself better, where I live the law allows the utilities to charge the demand to the customers if they pass the 10 kW limit. Other away, the customer just pay energy. So, once you sign a contract with the utility and they determine that your...
  4. JAMartinezB

    RESIDENCIAL POWER LIMITER

    Hi, I would like to know if there is a device like a circuit breaker that could be used to limite the power of a household to a selectable value like 10 kW or below and with automatic reset. I have heard about something call MCB (Mini Circuit Breaker), but I'm not sure if these devices have...
  5. JAMartinezB

    OVERVOLTAGE DURING SINGLE LINE FAULT

    Thank you all. Very logical. Regards.
  6. JAMartinezB

    OVERVOLTAGE DURING SINGLE LINE FAULT

    Hi, I would like to know the cause of the overvoltage in non-faulted phases during a single line fault of a three phase system. What interaction in the generator or system impedance causes this? Regards.
  7. JAMartinezB

    kwh-tou-load profiles 3 phase meter

    Thank you all.
  8. JAMartinezB

    kwh-tou-load profiles 3 phase meter

    Hi I´m interested to buy one 3 phase kwh meter with load profile and TOU capabilities for energy audit purpose. It´s has to be indirect metering (with CT), because it´ll reading in the secundary of a 12,500/208 V trafo 300 kVA. Also should be panel o dim mounted. Where could I buy one over...
  9. JAMartinezB

    POWER TRANSFORMER EFFICIENCY

    Thanks again for all your answers. Now I have a best picture of the pf and the efficiency situation. From your answers I could say that 5% of the KVA of a trafo is the not-load kVar is not a good rule of thumb. Regards.
  10. JAMartinezB

    POWER TRANSFORMER EFFICIENCY

    Thank you for your answers. Unfortunately I don´t have the trafo test data. But I have read that the trafos are less efficient if they are loaded less than 80% of the capacity. Also, that the reactive power is around 5% of the kVA. How can I calculate the reactive power consumed and wouldn´t...
  11. JAMartinezB

    POWER TRANSFORMER EFFICIENCY

    Hi Everyone, I have a double ended system with two transformer of 1 MVA 12.5kV/480V Y/Y transformer. Both are energize all the time but only one supply the power to the load. The maximum demand of the system is 350 kW. My concern is about the efficiecy of this system since one trafo is just...

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