This topic contains 10 replies, has 0 voices, and was last updated by  vaithilingam 8 years, 7 months ago.

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  • #10247

    vaithilingam
    Member

    If i have 3 phase input power KW is 35 what will be the load end power distance 35 km whether it will increase or decrease

    #11555

    admin
    Keymaster

    its increase brcause of resistance of wires that is called  VOLTAGE DROP

    #11577

    eageocado
    Member

    considering your answer engr. saad… kindly elaborate further by showing your calculation using the voltage drop formula..

    #11581

    admin
    Keymaster

    considering distance and size of cable,it is likely to decrease.

    #11587

    Calculate your current from

     kW=√3VIcosф

    Work out your impedance Z from point A to B where A is at the sending end and B is 35 m away. Your voltage drop will be approximately I x Z. Your  voltage will drop by this amount.

    #11589

    Sorry, the drop is not I x Z as indicated, but should be 

    I²xZ
    #11578

    Leynin
    Member

    There will naturally be a decrease in the value of voltage at your load terminals due to I²R loss (heat) plus reactive drops if electric motors are connected. Determine the supply current from

     

                         I = 35 X 10³ ⁄ (I x V x cosΦ√3

    and the total impedance of the circuit from the source to the load, ie, the R of a 35m length cable (what is the csa? and is it made of CU?) + the impedance of the connected appliances. There is a standard allowable voltage drop(mV/A/m) for your particular cable, not more than 4% of your supply voltage (IEEE). Check this and use the formula,

     

                         Total voltage drop = (mV/A/m) x I x 35 / 1000

    That will be the value at the load terminals.

    In 2004 in the United States, there were 104 (69 pressurized water reactors and 35 boiling water reactors)
    commercial nuclear generating units licensed to operate, producing a
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    nation’s total electric energy consumption
    #11648

    admin
    Keymaster

    vaithilingam said:

    If i have 3 phase input power KW is 35 what will be the load end power distance 35 km whether it will increase or decrease


    If I get your question right, you are asking for the available power at the end of 35km distance? the “load end power” will depend on the size of your conductor in this 35Km distance and this can be calculated using the voltage drop equation. In addition, the type of load (motors, resistive load, etc) should also be considered.

    #11649

    admin
    Keymaster

    If I get your question right, you are asking for the available power at the end of 35km distance? the “load end power” will depend on the size of your conductor in this 35Km distance and this can be calculated using the voltage drop equation. In addition, the type of load (motors, resistive load, etc) should also be considered.

    Moreover, available power will never increase at the end of the line.

    #11657

    admin
    Keymaster

    Assume

    35m cable length

    10amps / phase

    Cable 10mm² = 0.00343Volts drop per amp per meter from cable manufactures tables) copper

     

    0.00343 x 35m x10 amps = 1.20v drop (at the end of the 35m)

    #11663

    admin
    Keymaster

    The input is 35 KW ,3 phase voltage is specified.We ned to calculate resistance of cable conductor /Km & apply the fourmula of

    Receiving end Power = sending end power   ( 35 KW) – ( power Losses in conductor /cable+ shut capacitence impedence along the O.H.line for 35 Km),Gives you the answer.It will decrese if you use 440 Volts ,if transmit same through 3.3 KV it will increases,as per my little knowledge goes.

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