The principal informations obtained from load flow studies in a power system are
1. magnitude and phase angle of the voltage at each bus.
2. reactive and real power flows in each of the lines.
3. total power loss in the network.
4. transient stability limit of the system.
Select the correct answer using the codes given below
Answer & step-by-step solution
Load-flow studies determine the steady operating state of a power network: bus voltage magnitudes/angles, line real and reactive power flows and system losses. The bus-admittance matrix is sparse. Key relation: Bus variables: P,Q,|V|,δ; each bus specifies two and solves two.
Exam focus: PQ, PV and slack buses differ by which two variables are specified. Common trap: Transient stability is not a direct output of ordinary load flow.
Statement-wise Verification
- Statement 1 - Correct.
magnitude and phase angle of the voltage at each bus.
Load-flow studies determine the steady operating state of a power network: bus voltage magnitudes/angles, line real and reactive power flows and system losses. - Statement 2 - Correct.
reactive and real power flows in each of the lines.
Load-flow studies determine the steady operating state of a power network: bus voltage magnitudes/angles, line real and reactive power flows and system losses. - Statement 3 - Correct.
total power loss in the network.
The bus-admittance matrix is sparse. - Statement 4 - Incorrect.
transient stability limit of the system.
The correct principle is: The bus-admittance matrix is sparse.
Core Concept
Load-flow studies determine the steady operating state of a power network: bus voltage magnitudes/angles, line real and reactive power flows and system losses. The bus-admittance matrix is sparse. One bus is designated slack to absorb the power mismatch; Newton-Raphson is generally preferred for large systems because of its convergence characteristics.
Formula / Key Relationship
Bus variables: P,Q,|V|,δ; each bus specifies two and solves two.
Why the Other Options Are Wrong
Option A is incorrect because it omits correct statement(s) 3. Option B is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 1, 2. Option D is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 1, 3.
Exam Shortcut / Approach
PQ, PV and slack buses differ by which two variables are specified.
Common Mistake
Transient stability is not a direct output of ordinary load flow.
Quick Revision
Bus Voltages Line Flows and Losses is linked with Load Flow Outputs, Load Flow and Power Systems. PQ, PV and slack buses differ by which two variables are specified.
पावर सिस्टम में लोड फ्लो अध्ययन से प्राप्त मुख्य जानकारियाँ हैं
1. प्रत्येक बस पर वोल्टेज का परिमाण और कला-कोण।
2. प्रत्येक लाइन में प्रतिक्रियाशील और वास्तविक शक्ति प्रवाह।
3. नेटवर्क में कुल शक्ति हानि।
4. प्रणाली की क्षणिक स्थिरता सीमा।
नीचे दिए गए कूटों का उपयोग करके सही उत्तर चुनिए
उत्तर और चरणबद्ध हल
C — 1, 2 और 3। लोड फ्लो स्थिर संचालन अवस्था देता है: बस वोल्टेज परिमाण/कोण, लाइन P और Q प्रवाह तथा कुल हानि। क्षणिक स्थिरता सीमा अलग स्थिरता अध्ययन से मिलती है, साधारण लोड फ्लो से नहीं।
विस्तृत हल (मूल भाषा में)
Statement-wise Verification
- Statement 1 - Correct.
magnitude and phase angle of the voltage at each bus.
Load-flow studies determine the steady operating state of a power network: bus voltage magnitudes/angles, line real and reactive power flows and system losses. - Statement 2 - Correct.
reactive and real power flows in each of the lines.
Load-flow studies determine the steady operating state of a power network: bus voltage magnitudes/angles, line real and reactive power flows and system losses. - Statement 3 - Correct.
total power loss in the network.
The bus-admittance matrix is sparse. - Statement 4 - Incorrect.
transient stability limit of the system.
The correct principle is: The bus-admittance matrix is sparse.
Core Concept
Load-flow studies determine the steady operating state of a power network: bus voltage magnitudes/angles, line real and reactive power flows and system losses. The bus-admittance matrix is sparse. One bus is designated slack to absorb the power mismatch; Newton-Raphson is generally preferred for large systems because of its convergence characteristics.
Formula / Key Relationship
Bus variables: P,Q,|V|,δ; each bus specifies two and solves two.
Why the Other Options Are Wrong
Option A is incorrect because it omits correct statement(s) 3. Option B is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 1, 2. Option D is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 1, 3.
Exam Shortcut / Approach
PQ, PV and slack buses differ by which two variables are specified.
Common Mistake
Transient stability is not a direct output of ordinary load flow.
Quick Revision
Bus Voltages Line Flows and Losses is linked with Load Flow Outputs, Load Flow and Power Systems. PQ, PV and slack buses differ by which two variables are specified.
પાવર સિસ્ટમમાં લોડ ફ્લો અભ્યાસથી મળતી મુખ્ય માહિતી છે
1. દરેક બસ પર વોલ્ટેજનું માન અને કળા-કોણ.
2. દરેક લાઇનમાં પ્રતિક્રિયાશીલ અને વાસ્તવિક પાવર પ્રવાહ.
3. નેટવર્કમાં કુલ પાવર લોસ.
4. પ્રણાલીની ક્ષણિક સ્થિરતા મર્યાદા.
નીચે આપેલા સંકેતોનો ઉપયોગ કરી સાચો જવાબ પસંદ કરો
જવાબ અને પગલાવાર ઉકેલ
C — 1, 2 અને 3. લોડ ફ્લો સ્થિર સંચાલન અવસ્થા આપે છે: બસ વોલ્ટેજ માન/કોણ, લાઇન P અને Q પ્રવાહ તથા કુલ લોસ. ક્ષણિક સ્થિરતા મર્યાદા અલગ સ્થિરતા અભ્યાસથી મળે છે, સામાન્ય લોડ ફ્લોથી નહીં.
વિગતવાર ઉકેલ (મૂળ ભાષામાં)
Statement-wise Verification
- Statement 1 - Correct.
magnitude and phase angle of the voltage at each bus.
Load-flow studies determine the steady operating state of a power network: bus voltage magnitudes/angles, line real and reactive power flows and system losses. - Statement 2 - Correct.
reactive and real power flows in each of the lines.
Load-flow studies determine the steady operating state of a power network: bus voltage magnitudes/angles, line real and reactive power flows and system losses. - Statement 3 - Correct.
total power loss in the network.
The bus-admittance matrix is sparse. - Statement 4 - Incorrect.
transient stability limit of the system.
The correct principle is: The bus-admittance matrix is sparse.
Core Concept
Load-flow studies determine the steady operating state of a power network: bus voltage magnitudes/angles, line real and reactive power flows and system losses. The bus-admittance matrix is sparse. One bus is designated slack to absorb the power mismatch; Newton-Raphson is generally preferred for large systems because of its convergence characteristics.
Formula / Key Relationship
Bus variables: P,Q,|V|,δ; each bus specifies two and solves two.
Why the Other Options Are Wrong
Option A is incorrect because it omits correct statement(s) 3. Option B is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 1, 2. Option D is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 1, 3.
Exam Shortcut / Approach
PQ, PV and slack buses differ by which two variables are specified.
Common Mistake
Transient stability is not a direct output of ordinary load flow.
Quick Revision
Bus Voltages Line Flows and Losses is linked with Load Flow Outputs, Load Flow and Power Systems. PQ, PV and slack buses differ by which two variables are specified.
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