Etap Knowledge Base: Transformer Losses

ETAP Knowledge Base

Transformer Losses Description: Calculation of Transformer Losses in Load Flow studies Category:

Load Flow

Type:

Calculation

Keywords:

Power Losses Power Losses on 2W transformer Transformer data (Rating): kV := 13.8

Percent Impedance at 100 MVA Base (Values taken from the LF Branch Connection report)

MVA := 100

R% := 0.2

2

Z :=

kV

X% := 10.0

MVA

Z = 1.904

in ohms where Z = R + jX

Z% := 10.0

Transformer impedance in ohms R := Z⋅ X := Z⋅

R% 100 X% 100

−3

R = 3.809 × 10 X = 0.19

Case 1:

Case 2:

I1 := 419.8

I2 := 630.7

Losses due to transformer resistance

Losses due to transformer resistance

P1 := R ⋅ I1

2

P3φ := P1⋅ 3

P1 = 671.233

P2 := R ⋅ I2 3

P3φ = 2.014 × 10

in kW

Losses due to transformer reactance Q1 := X⋅ I1

2

Q3φ := Q1⋅ 3

4

Q1 = 3.356 × 10

2

P3φ := P2⋅ 3

5

in kvars

3

P3φ = 4.545 × 10

in kW

Losses due to transformer reactance Q2 := X⋅ I2

Q3φ = 1.007 × 10

3

P2 = 1.515 × 10

2

Q3φ := Q2⋅ 3

4

Q2 = 7.575 × 10

5

Q3φ = 2.273 × 10

in kvars

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