Consider following statements: Assertion: When a line-to-line (L-L) fault takes place at the terminals of an open-circuited generator, the phase voltages are sometimes indeterminate though line voltages are always determinable. Reason: During L-L fault, a zero-sequence voltage is always indeterminate. Of these statements:
Answer & step-by-step solution
For an L-L fault there is no zero-sequence current, so the zero-sequence network is not fixed by current flow. At open-circuited generator terminals this can leave the common zero-sequence voltage reference indeterminate even though line-to-line voltages remain uniquely determined. Hence both assertion and reason are true and the reason explains the assertion: option A.
Concept and Reasoning
For an L-L fault there is no zero-sequence current, so the zero-sequence network is not fixed by current flow. At open-circuited generator terminals this can leave the common zero-sequence voltage reference indeterminate even though line-to-line voltages remain uniquely determined. Hence both assertion and reason are true and the reason explains the assertion: option A.
Calculation / Key Relation
L-L fault: I0=0
line voltages are independent of common zero-sequence voltage shift
Exam Takeaway
A common phase-voltage shift cancels in line-to-line voltages.
Common Mistake
Do not infer that indeterminate phase reference makes line voltage indeterminate.
Quick Trick
A common phase-voltage shift cancels in line-to-line voltages.
निम्नलिखित कथनों पर विचार कीजिए:
अभिकथन (A): जब किसी ओपन-सर्किट जनरेटर के टर्मिनलों पर लाइन-टू-लाइन (L-L) फॉल्ट होता है, तो फेज़ वोल्टेज कभी-कभी अनिर्धार्य होते हैं, यद्यपि लाइन वोल्टेज हमेशा निर्धार्य होते हैं।
कारण (R): L-L फॉल्ट के दौरान शून्य-अनुक्रम वोल्टेज हमेशा अनिर्धार्य होता है।
इन कथनों में से:
उत्तर और चरणबद्ध हल
A — दोनों सत्य और R सही व्याख्या। L-L फॉल्ट में शून्य-अनुक्रम धारा नहीं होती, इसलिए शून्य-अनुक्रम नेटवर्क धारा से निर्धारित नहीं होता। ओपन-सर्किट जनरेटर पर यह सामान्य शून्य-अनुक्रम वोल्टेज संदर्भ को अनिर्धार्य छोड़ देता है, जबकि लाइन-टू-लाइन वोल्टेज निश्चित रहते हैं।
विस्तृत हल (मूल भाषा में)
Concept and Reasoning
For an L-L fault there is no zero-sequence current, so the zero-sequence network is not fixed by current flow. At open-circuited generator terminals this can leave the common zero-sequence voltage reference indeterminate even though line-to-line voltages remain uniquely determined. Hence both assertion and reason are true and the reason explains the assertion: option A.
Calculation / Key Relation
L-L fault: I0=0
line voltages are independent of common zero-sequence voltage shift
Exam Takeaway
A common phase-voltage shift cancels in line-to-line voltages.
Common Mistake
Do not infer that indeterminate phase reference makes line voltage indeterminate.
Quick Trick
A common phase-voltage shift cancels in line-to-line voltages.
નીચેનાં વિધાનો ધ્યાનમાં લો:
કથન (A): જ્યારે ઓપન-સર્કિટ જનરેટરના ટર્મિનલ પર લાઇન-ટુ-લાઇન (L-L) ફોલ્ટ થાય છે, ત્યારે ફેઝ વોલ્ટેજ ક્યારેક અનિર્ધારિત હોય છે, જોકે લાઇન વોલ્ટેજ હંમેશા નક્કી કરી શકાય છે.
કારણ (R): L-L ફોલ્ટ દરમિયાન શૂન્ય-ક્રમ વોલ્ટેજ હંમેશા અનિર્ધારિત હોય છે.
આ વિધાનોમાંથી:
જવાબ અને પગલાવાર ઉકેલ
A — બંને સાચાં અને R સાચી સમજૂતી. L-L ફોલ્ટમાં શૂન્ય-ક્રમ પ્રવાહ હોતો નથી, તેથી શૂન્ય-ક્રમ નેટવર્ક પ્રવાહથી નક્કી થતું નથી. ઓપન-સર્કિટ જનરેટર પર આ સામાન્ય શૂન્ય-ક્રમ વોલ્ટેજ સંદર્ભને અનિર્ધારિત છોડે છે, જ્યારે લાઇન-ટુ-લાઇન વોલ્ટેજ નિશ્ચિત રહે છે.
વિગતવાર ઉકેલ (મૂળ ભાષામાં)
Concept and Reasoning
For an L-L fault there is no zero-sequence current, so the zero-sequence network is not fixed by current flow. At open-circuited generator terminals this can leave the common zero-sequence voltage reference indeterminate even though line-to-line voltages remain uniquely determined. Hence both assertion and reason are true and the reason explains the assertion: option A.
Calculation / Key Relation
L-L fault: I0=0
line voltages are independent of common zero-sequence voltage shift
Exam Takeaway
A common phase-voltage shift cancels in line-to-line voltages.
Common Mistake
Do not infer that indeterminate phase reference makes line voltage indeterminate.
Quick Trick
A common phase-voltage shift cancels in line-to-line voltages.
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