Examoogle • User • info@examoogle.com • EE-2024-8821

Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked

ElectricalPower System

The zero sequence current of a generator for line to ground fault is j2.4 pu. Then the current through the neutral during the fault is

$j2.4\text{ pu}$

$j0.8\text{ pu}$

$j7.2\text{ pu}$

$j0.24\text{ pu}$

Correct Answer

⚙️ TE • Technical Direct FormulaElectricalPower System

Option C

$j7.2\text{ pu}$

Quick Summary:

Given: Zero sequence current of the generator $I_{0}$ = j2.4 pu

📐MAMath SolutionDirect Formula

📋 Given

Zero sequence current of the generator $I_{0}$ = j2.4 pu

🔢 Formula Used

In=3×I0I_n = 3 \times I_0In​=3×I0​

🔢 Step-by-Step Solution

Identify the relationship

In a three-phase system, the current flowing through the neutral ( $I_n$ ) during an unsymmetrical fault is the sum of the sequence currents of the three phases.

In=Ia+Ib+IcI_n = I_a + I_b + I_cIn​=Ia​+Ib​+Ic​

Apply Sequence Component theory

The zero sequence current is defined as $I_0 = \frac{1}{3}(I_a + I_b + I_c)$ . Therefore, the total neutral current is equal to three times the zero sequence current.

In=3×I0I_n = 3 \times I_0In​=3×I0​

Calculate the result

Given the zero sequence current $I_0 = j2.4\text{ pu}$ , substitute this value into the formula to find the neutral current.

In=3×(j2.4)=j7.2 puI_n = 3 \times (j2.4) = j7.2\text{ pu}In​=3×(j2.4)=j7.2 pu

✅

C is correct because the neutral current is defined as three times the zero sequence current, resulting in $j7.2\text{ pu}$ .

Core Concepts Used

Click any tag to open in AI Tutor

Symmetrical Components Zero Sequence Current Neutral Current Unsymmetrical Fault Analysis

💡 EXAM TIP

This concept is vital for designing grounding schemes; note that the neutral current is zero in balanced systems but becomes significant during single-line-to-ground faults.

Discussion (0)

Loading discussion...

Prev Next

Correct Answer

Related Questions

Discussion (0)