Fault Impedance given A-Phase EMF and Sequence Impedances(LGF) Calculator

✖A phase EMF LG is defined as the electromagnetic force of the a-phase in open conductor fault.ⓘ A Phase EMF LG [E_a(lg)]			+10% -10%
✖Positive Sequence Current LG consists of balanced three-phase voltage and current phasors which are exactly at 120 degrees apart rotating counterclockwise in ABC rotation.ⓘ Positive Sequence Current LG [I_1(lg)]			+10% -10%
✖Zero Sequence Impedance LG consists of a balanced three-phase voltage and current, phasors of which all have the same phase angles and rotate counter clockwise together.ⓘ Zero Sequence Impedance LG [Z_0(lg)]			+10% -10%
✖Positive Sequence Impedance LG consists of balanced three-phase voltage and current phasors which are exactly at 120 degrees apart rotating counterclockwise in ABC rotation.ⓘ Positive Sequence Impedance LG [Z_1(lg)]			+10% -10%
✖Negative Sequence Impedance LG consists of balanced three-phase impedance phasors which are exactly at 120 degrees apart rotating counterclockwise in ACB rotation.ⓘ Negative Sequence Impedance LG [Z_2(lg)]			+10% -10%

✖Fault Impedance LG is a measure of the resistance and reactance in an electrical circuit that is used to calculate the fault current that flows through the circuit in the event of a fault.ⓘ Fault Impedance given A-Phase EMF and Sequence Impedances(LGF) [Z_f(lg)]

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Formula

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Fault Impedance given A-Phase EMF and Sequence Impedances(LGF)

Formula

`"Z"_{"f(lg)"} = 1/3*(("E"_{"a(lg)"}/"I"_{"1(lg)"})-("Z"_{"0(lg)"}+"Z"_{"1(lg)"}+"Z"_{"2(lg)"}))`

Example

`"14.44755Ω"=1/3*(("29.38V"/"2.001A")-("8Ω"+"7.94Ω"+"-44.6Ω"))`

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Fault Impedance given A-Phase EMF and Sequence Impedances(LGF) Solution

STEP 0: Pre-Calculation Summary

Formula Used

Fault Impedance LG = 1/3*((A Phase EMF LG/Positive Sequence Current LG)-(Zero Sequence Impedance LG+Positive Sequence Impedance LG+Negative Sequence Impedance LG))
Z_f(lg) = 1/3*((E_a(lg)/I_1(lg))-(Z_0(lg)+Z_1(lg)+Z_2(lg)))
This formula uses 6 Variables

Variables Used

Fault Impedance LG - (Measured in Ohm) - Fault Impedance LG is a measure of the resistance and reactance in an electrical circuit that is used to calculate the fault current that flows through the circuit in the event of a fault.
A Phase EMF LG - (Measured in Volt) - A phase EMF LG is defined as the electromagnetic force of the a-phase in open conductor fault.
Positive Sequence Current LG - (Measured in Ampere) - Positive Sequence Current LG consists of balanced three-phase voltage and current phasors which are exactly at 120 degrees apart rotating counterclockwise in ABC rotation.
Zero Sequence Impedance LG - (Measured in Ohm) - Zero Sequence Impedance LG consists of a balanced three-phase voltage and current, phasors of which all have the same phase angles and rotate counter clockwise together.
Positive Sequence Impedance LG - (Measured in Ohm) - Positive Sequence Impedance LG consists of balanced three-phase voltage and current phasors which are exactly at 120 degrees apart rotating counterclockwise in ABC rotation.
Negative Sequence Impedance LG - (Measured in Ohm) - Negative Sequence Impedance LG consists of balanced three-phase impedance phasors which are exactly at 120 degrees apart rotating counterclockwise in ACB rotation.

STEP 1: Convert Input(s) to Base Unit

A Phase EMF LG: 29.38 Volt --> 29.38 Volt No Conversion Required
Positive Sequence Current LG: 2.001 Ampere --> 2.001 Ampere No Conversion Required
Zero Sequence Impedance LG: 8 Ohm --> 8 Ohm No Conversion Required
Positive Sequence Impedance LG: 7.94 Ohm --> 7.94 Ohm No Conversion Required
Negative Sequence Impedance LG: -44.6 Ohm --> -44.6 Ohm No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

Z_f(lg) = 1/3*((E_a(lg)/I_1(lg))-(Z_0(lg)+Z_1(lg)+Z_2(lg))) --> 1/3*((29.38/2.001)-(8+7.94+(-44.6)))

Evaluating ... ...

Z_f(lg) = 14.4475528902216

STEP 3: Convert Result to Output's Unit

14.4475528902216 Ohm --> No Conversion Required

FINAL ANSWER

14.4475528902216 ≈ 14.44755 Ohm <-- Fault Impedance LG

(Calculation completed in 00.004 seconds)

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Home » Engineering » Electrical » Power System » Fault » Shunt Faults » Unsymmetrical Faults » L-G Fault » Impedance » Fault Impedance given A-Phase EMF and Sequence Impedances(LGF)

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Created by Nisarg

Indian Institute of Technology,Roorlee (IITR), Roorkee

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Chandigarh University (CU), Punjab

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< 10+ Impedance Calculators

Positive Sequence Impedance using A-Phase EMF (LGF)

Go Positive Sequence Impedance LG = (EMF Induced in Primary Winding LG/Positive Sequence Current LG)-(3*Fault Impedance LG)-Zero Sequence Impedance LG-Negative Sequence Impedance LG

Negative Sequence Impedance using A-Phase EMF (LGF)

Go Negative Sequence Impedance LG = (EMF Induced in Primary Winding LG/Negative Sequence Current LG)-(3*Fault Impedance LG)-Positive Sequence Impedance LG-Zero Sequence Impedance LG

Zero Sequence Impedance using A-Phase EMF (LGF)

Go Zero Sequence Impedance LG = (EMF Induced in Primary Winding LG/Zero Sequence Current LG)-(3*Fault Impedance LG)-Positive Sequence Impedance LG-Negative Sequence Impedance LG

Fault Impedance given A-Phase EMF and Sequence Impedances(LGF)

Go Fault Impedance LG = 1/3*((A Phase EMF LG/Positive Sequence Current LG)-(Zero Sequence Impedance LG+Positive Sequence Impedance LG+Negative Sequence Impedance LG))

Fault Impedance using Fault Voltage and A-Phase Current(LGF)

Go Fault Impedance LG = Fault Voltage LG/A-Phase Current LG-(1/3*(Zero Sequence Impedance LG+Positive Sequence Impedance LG+Negative Sequence Impedance LG))

Fault Impedance given Sequence Voltages(LGF)

Go Fault Impedance LG = (Zero Sequence Voltage LG+Positive Sequence Voltage LG+Negative Sequence Voltage LG)/(3*Positive Sequence Current LG)

Positive Sequence Impedance for L-G-F

Go Positive Sequence Impedance LG = (EMF Induced in Primary Winding LG-Positive Sequence Voltage LG)/Positive Sequence Current LG

Negative Sequence Impedance for L-G-F

Go Negative Sequence Impedance LG = (-1)*Negative Sequence Voltage LG/Negative Sequence Current LG

Zero Sequence Impedance for L-G-F

Go Zero Sequence Impedance LG = (-1)*Zero Sequence Voltage LG/Zero Sequence Current LG

Fault Impedance using A-Phase Voltage(LGF)

Go Fault Impedance LG = A Phase Voltage LG/A-Phase Current LG

Fault Impedance given A-Phase EMF and Sequence Impedances(LGF) Formula

What are the Sequence Components?

The positive sequence consists of balanced three-phase voltage and current phasors which are exactly at 120 degrees apart rotating counterclockwise in ABC rotation. The negative sequence consists of balanced three-phase voltage and current phasors which are exactly at 120 degrees apart rotating counterclockwise in ACB rotation. Zero sequence consists of a balanced three-phase voltage and current, phasors of which all have the same phase angles and rotate counterclockwise together.

How to Calculate Fault Impedance given A-Phase EMF and Sequence Impedances(LGF)?

Fault Impedance given A-Phase EMF and Sequence Impedances(LGF) calculator uses Fault Impedance LG = 1/3*((A Phase EMF LG/Positive Sequence Current LG)-(Zero Sequence Impedance LG+Positive Sequence Impedance LG+Negative Sequence Impedance LG)) to calculate the Fault Impedance LG, The Fault Impedance given a-Phase EMF and Sequence Impedances(LGF) formula is defined as the impedance which is connected to the earth. Fault Impedance LG is denoted by Z_f(lg) symbol.

How to calculate Fault Impedance given A-Phase EMF and Sequence Impedances(LGF) using this online calculator? To use this online calculator for Fault Impedance given A-Phase EMF and Sequence Impedances(LGF), enter A Phase EMF LG (E_a(lg)), Positive Sequence Current LG (I_1(lg)), Zero Sequence Impedance LG (Z_0(lg)), Positive Sequence Impedance LG (Z_1(lg)) & Negative Sequence Impedance LG (Z_2(lg)) and hit the calculate button. Here is how the Fault Impedance given A-Phase EMF and Sequence Impedances(LGF) calculation can be explained with given input values -> 14.44755 = 1/3*((29.38/2.001)-(8+7.94+(-44.6))).

FAQ

What is Fault Impedance given A-Phase EMF and Sequence Impedances(LGF)?

The Fault Impedance given a-Phase EMF and Sequence Impedances(LGF) formula is defined as the impedance which is connected to the earth and is represented as Z_f(lg) = 1/3*((E_a(lg)/I_1(lg))-(Z_0(lg)+Z_1(lg)+Z_2(lg))) or Fault Impedance LG = 1/3*((A Phase EMF LG/Positive Sequence Current LG)-(Zero Sequence Impedance LG+Positive Sequence Impedance LG+Negative Sequence Impedance LG)). A phase EMF LG is defined as the electromagnetic force of the a-phase in open conductor fault, Positive Sequence Current LG consists of balanced three-phase voltage and current phasors which are exactly at 120 degrees apart rotating counterclockwise in ABC rotation, Zero Sequence Impedance LG consists of a balanced three-phase voltage and current, phasors of which all have the same phase angles and rotate counter clockwise together, Positive Sequence Impedance LG consists of balanced three-phase voltage and current phasors which are exactly at 120 degrees apart rotating counterclockwise in ABC rotation & Negative Sequence Impedance LG consists of balanced three-phase impedance phasors which are exactly at 120 degrees apart rotating counterclockwise in ACB rotation.

How to calculate Fault Impedance given A-Phase EMF and Sequence Impedances(LGF)?

The Fault Impedance given a-Phase EMF and Sequence Impedances(LGF) formula is defined as the impedance which is connected to the earth is calculated using Fault Impedance LG = 1/3*((A Phase EMF LG/Positive Sequence Current LG)-(Zero Sequence Impedance LG+Positive Sequence Impedance LG+Negative Sequence Impedance LG)). To calculate Fault Impedance given A-Phase EMF and Sequence Impedances(LGF), you need A Phase EMF LG (E_a(lg)), Positive Sequence Current LG (I_1(lg)), Zero Sequence Impedance LG (Z_0(lg)), Positive Sequence Impedance LG (Z_1(lg)) & Negative Sequence Impedance LG (Z_2(lg)). With our tool, you need to enter the respective value for A Phase EMF LG, Positive Sequence Current LG, Zero Sequence Impedance LG, Positive Sequence Impedance LG & Negative Sequence Impedance LG and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

How many ways are there to calculate Fault Impedance LG?

In this formula, Fault Impedance LG uses A Phase EMF LG, Positive Sequence Current LG, Zero Sequence Impedance LG, Positive Sequence Impedance LG & Negative Sequence Impedance LG. We can use 3 other way(s) to calculate the same, which is/are as follows -

Fault Impedance LG = A Phase Voltage LG/A-Phase Current LG
Fault Impedance LG = (Zero Sequence Voltage LG+Positive Sequence Voltage LG+Negative Sequence Voltage LG)/(3*Positive Sequence Current LG)
Fault Impedance LG = Fault Voltage LG/A-Phase Current LG-(1/3*(Zero Sequence Impedance LG+Positive Sequence Impedance LG+Negative Sequence Impedance LG))

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