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    EEE267 Transformer Tests Math Problems PDF

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    maakbd
    This document provides the solution to a math problem regarding transformer tests. Open and short circuit tests were performed on a 75 kVA, 4600-230V transformer. The test data is used to calculate the equivalent circuit parameters referred to the high side. The parameters calculated are: resistance R = 40.6 Ω, reactance X = 7.164 Ω. Additionally, the per-unit values of the parameters are calculated using the base impedance of 282.1333 Ω.

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    Attribution Non-Commercial (BY-NC)
    Download as PDF, TXT or read online from Scribd

    EEE267 Transformer Tests Math Problems PDF

    Uploaded by

    maakbd
    267 views3 pages
    This document provides the solution to a math problem regarding transformer tests. Open and short circuit tests were performed on a 75 kVA, 4600-230V transformer. The test data is used to calculate the equivalent circuit parameters referred to the high side. The parameters calculated are: resistance R = 40.6 Ω, reactance X = 7.164 Ω. Additionally, the per-unit values of the parameters are calculated using the base impedance of 282.1333 Ω.

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    EEE267_Transformer_tests_math_problems.pdf

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    EEE267_Transformer_tests_math_problems.pdf

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    This document provides the solution to a math problem regarding transformer tests. Open and short circuit tests were performed on a 75 kVA, 4600-230V transformer. The test data is used to calculate the equivalent circuit parameters referred to the high side. The parameters calculated are: resistance R = 40.6 Ω, reactance X = 7.164 Ω. Additionally, the per-unit values of the parameters are calculated using the base impedance of 282.1333 Ω.

    Copyright:

    Attribution Non-Commercial (BY-NC)
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    267 views3 pages

    EEE267 Transformer Tests Math Problems PDF

    Uploaded by

    maakbd
    This document provides the solution to a math problem regarding transformer tests. Open and short circuit tests were performed on a 75 kVA, 4600-230V transformer. The test data is used to calculate the equivalent circuit parameters referred to the high side. The parameters calculated are: resistance R = 40.6 Ω, reactance X = 7.164 Ω. Additionally, the per-unit values of the parameters are calculated using the base impedance of 282.1333 Ω.

    Copyright:

    Attribution Non-Commercial (BY-NC)
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 3

    EEE 267: Electrical and Electronic Technology

    Mohammad Asif Zaman


    Lecturer,
    Department of Electrical and Electronic Engineering,
    Bangladesh University of Engineering and Technology, Dhaka 1000.


    Math problems regarding transformer tests. (12
    th
    April, 2011)


    Problem 1: Data obtained from short-circuit and open-circuit tests of a 75 kVA, 4600 230V, 60Hz
    transformer are:

    Open-Circuit Test (Low-side data) Short-Circuit Test (High-side data)
    V
    OC
    =230 V V
    SC
    =160.8 V
    I
    OC
    =13.04 A I
    SC
    =16.3 A
    P
    OC
    =521 W P
    SC
    =1200 W

    Determine the equivalent circuit parameters referred to the high side. Also find the circuit parameters
    in terms of per-unit value.

    Solution:

    Circuit parameter calculation:

    From the open circuit data:

    OC OC fe
    P V I =
    or,
    521
    2.265
    230
    OC
    fe
    OC
    P
    I A
    V
    = = =

    As the open circuit test is done on the low-side, the circuit parameters calculated from the open-circuit
    data will be referred to the low-side.

    Now,
    ,
    230
    101.5
    2.265
    OC
    fe LS
    fe
    V
    R
    I
    = = = O

    Also,
    2 2
    OC fe M
    I I I = +

    or,
    2 2 2 2
    (13.04) (2.265) 12.842
    M OC fe
    I I I A = = =

    So,
    ,
    230
    17.91
    12.842
    OC
    M LS
    M
    V
    X
    I
    = = = O


    As the circuit parameters referred to the high-side is required, the low-side circuit parameters must be
    converted. To do this, the turns ratio of the transformer must be calculated.

    The turns ratio can be calculated from the transformer rating.

    4600
    20
    230
    a = =
    Now,

    2 2
    , ,
    2 2
    , ,
    (20) 101.5 40600 40.6
    (20) 17.91 7164 7.164
    fe HS fe LS
    M HS M LS
    R a R k
    X a X k
    = = = O = O
    = = = O = O



    From the short circuit data:

    ,
    SC
    SC
    eq HS
    V
    I
    Z
    =

    or,
    ,
    160.8
    9.865
    16.3
    SC
    eq HS
    SC
    V
    Z
    I
    = = = O

    As the short circuit test is done on the high-side, the circuit parameters calculated from the short-circuit
    data will be referred to the high-side.


    Now,
    2
    , SC SC eq HS
    P I R =

    or,
    , 2 2
    1200
    4.517
    (16.3)
    SC
    eq HS
    SC
    P
    R
    I
    = = = O

    And,
    2 2
    , , , eq HS eq HS eq HS
    Z R X = +

    or,
    2 2 2 2
    , , ,
    (9.865) (4.517) 8.77
    eq HS eq HS eq HS
    X Z R = = = O


    So, the circuit parameters referred to the high side are:

    ,
    ,
    ,
    ,
    40.6
    7.164
    .
    4.517
    8.77
    fe HS
    M HS
    eq HS
    eq HS
    R k
    X k
    Ans
    R
    X
    = O

    = O

    `
    = O

    = O
    )


    [Note: Students should draw the approximate equivalent circuit diagram referred to the high side and put the circuit
    parameter values in the circuit diagram.]

    Per-unit value calculation:

    The base impedance referred to the high side is:

    2
    2
    , , , ,
    , 3
    , , ,
    (4600)
    282.1333
    75 10
    base HS base HS base HS base HS
    base HS
    base HS base HS base HS base
    V V V V
    Z
    I I V S

    = = = = = O



    So, the circuit parameters in per-unit values are:

    ,
    ,
    ,
    ,
    ,
    ,
    ,
    ,
    ,
    ,
    ,
    ,
    40600
    143.9 . .
    282.1333
    7164
    25.392 . .
    282.1333
    .
    4.517
    0.016 . .
    282.1333
    8.77
    0.0311 . .
    282.1333
    fe HS
    fe PU
    base HS
    M HS
    M PU
    base HS
    eq HS
    eq PU
    base HS
    eq HS
    eq PU
    base HS
    R
    R p u
    Z
    X
    X p u
    Z
    Ans
    R
    R p u
    Z
    X
    X p u
    Z

    = = =

    = = =

    = = =

    = = =

    )

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