Examoogle
ExamsTest SeriesRank CheckPrevious Year PapersPassBook StoreMy BooksAI Tutor
ЁЯЫТ0
рдЕA
Examoogle

India's most trusted platform for competitive exam PDF books. Expert-authored, watermark-protected, instant access.

Exams & Practice
All Exams & SyllabusMock Test SeriesPrevious Year PapersPractice Questions (MCQs)Recruitment Notifications
Quick Links
Examoogle AI TutorExam NewsBook StoreMy BooksLogin / Sign Up
Support
About UsRefund PolicyPrivacy PolicyTerms of UseContact Us
┬й 2026 Examoogle. India's #1 competitive exam AI tutor.
ЁЯФТ SSL SecuredЁЯУ▒ UPI AcceptedЁЯз╛ GST Invoice
Examoogle

Join 60,000+ competitive exam aspirants

or with email
By continuing, you agree to ourTerms of Service&Privacy Policy
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Back to Practice Questions
ElectricalPower System
PrevNext

For a fixed receiving end and sending end voltages in a transmission system, what is the locus of the constant power

A

A straight line

B

An ellipse

C

A parabola

D

A circle

Correct Answer

Concept & PrincipleElectricalPower System
Option A

A straight line

Quick Summary: In a transmission system represented by the general ABCD network constant equation, the locus of constant power at the receiving end is a circle in the complex power plane ($P + jQ$). However, for a fixed sending end voltage ($V_s$) and receiving end voltage ($V_r$), the power circle diagram relates active and reactive power, resulting in a circle.

ЁЯТб Explanation

In a transmission system represented by the general ABCD network constant equation, the locus of constant power at the receiving end is a circle in the complex power plane (P+jQP + jQP+jQ). However, for a fixed sending end voltage (VsV_sVsтАЛ) and receiving end voltage (VrV_rVrтАЛ), the power circle diagram relates active and reactive power, resulting in a circle.

ЁЯФв Key Formulas

Pr+jQr=ABVr2тИа(╬▓тИТ╬▒)тИТVsVrBтИа(╬▓+╬┤)P_r + jQ_r = \frac{A}{B}V_r^2\angle(\beta - \alpha) - \frac{V_s V_r}{B}\angle(\beta + \delta)PrтАЛ+jQrтАЛ=BAтАЛVr2тАЛтИа(╬▓тИТ╬▒)тИТBVsтАЛVrтАЛтАЛтИа(╬▓+╬┤) тАФ Receiving end power equation

R=VsVrBR = \frac{V_s V_r}{B}R=BVsтАЛVrтАЛтАЛ тАФ Radius of the receiving end power circle

тЪЩя╕П Working Principle

The receiving end power Pr+jQrP_r + jQ_rPrтАЛ+jQrтАЛ is determined by the equation Sr=VrIrтИЧS_r = V_r I_r^*SrтАЛ=VrтАЛIrтИЧтАЛ. Substituting the transmission line equation Ir=ABVrтИТ1BVsI_r = \frac{A}{B}V_r - \frac{1}{B}V_sIrтАЛ=BAтАЛVrтАЛтИТB1тАЛVsтАЛ, the locus equation takes the form (PrтИТP0)2+(QrтИТQ0)2=R2(P_r - P_0)^2 + (Q_r - Q_0)^2 = R^2(PrтАЛтИТP0тАЛ)2+(QrтАЛтИТQ0тАЛ)2=R2, which defines a circle in the PтИТQP-QPтИТQ plane.

ЁЯУМ Key Points
  • тЦ╕

    The power circle diagram is a graphical representation of the power flow in a transmission line.

  • тЦ╕

    For a fixed VsV_sVsтАЛ and VrV_rVrтАЛ, the receiving end power locus is a circle.

  • тЦ╕

    The radius is proportional to the product of VsV_sVsтАЛ and VrV_rVrтАЛ and inversely proportional to the magnitude of the BBB parameter.

тЬЕ Advantages
  • тЦ╕

    Allows visual determination of power limits.

  • тЦ╕

    Easily identifies stability margins under variable load conditions.

тЭМ Disadvantages / Limitations
  • тЦ╕

    Assumes constant voltage magnitudes which may not hold under severe faults.

  • тЦ╕

    Requires complex mapping for non-linear loads.

ЁЯЫая╕П Applications / Uses
  • тЦ╕

    Power system stability analysis.

  • тЦ╕

    Transmission line capacity planning.

ЁЯУД Additional Information
  • тЦ╕

    The question text provided suggests a 'straight line' which is technically incorrect for power circles; it is a circle. The correct locus is a circle.

  • тЦ╕

    The AAA and BBB constants represent the generalized circuit constants of the transmission line.

ЁЯУК Diagram / Illustration
Power Circle LocusPQLocus
тЬЕ

A is technically incorrect as the locus of constant receiving end power for fixed VsV_sVsтАЛ and VrV_rVrтАЛ is a circle, not a straight line.

Core Concepts Used
Click any tag to open in AI Tutor
ABCD Parameters Power Circle Diagram Transmission Line Stability
ЁЯТб EXAM TIP

Always remember that in power flow analysis, power-voltage relations typically yield circular loci due to the squared terms in the voltage and current relationships.

Related Questions

ElectricalPower System
The specified quantities of Generation bus is
ElectricalPower System
When an alternator connected to the bus-bar is shut down the bus-bar voltage will
ElectricalPower System
The current drawn by the line due to corona losses is _______
ElectricalPower System
The specified quantities of load bus are
ElectricalPower System
The advantages of high transmission voltage are ______

Discussion (0)

Loading discussion...
PrevNext