Which of the following reactances is eliminated first in synchronous generator just after the symmetrical fault?
Answer & step-by-step solution
Immediately after a sudden symmetrical fault, damper-winding currents produce the strongest opposing transient flux and therefore the smallest subtransient reactance. The effect associated with the damper winding decays first as those induced currents die out rapidly.
Concept & Reasoning
A synchronous generator fault current passes through subtransient, transient and steady-state stages. Damper circuits dominate the very early subtransient interval; field-winding transients persist longer. As damper current decays, the effective reactance rises from Xd'' to Xd' and finally Xd.
How to Solve It in the Exam
First few cycles → damper winding → subtransient reactance.
Important Exam Point
Link time sequence: damper dies first, field transient next.
Quick Trick
First few cycles → damper winding → subtransient reactance.
Common Mistake
Confusing 'eliminated first' with the physically smallest static leakage reactance.
सममित फॉल्ट के ठीक बाद सिंक्रोनस जनरेटर में निम्नलिखित में से कौन-सा रिएक्टेंस सबसे पहले समाप्त होता है?
उत्तर और चरणबद्ध हल
B — डैम्पर वाइंडिंग रिएक्टेंस। अचानक सममित फॉल्ट के तुरंत बाद डैम्पर-वाइंडिंग धाराएँ सबसे प्रबल विरोधी फ्लक्स बनाती हैं (सबसे छोटा सबट्रांज़िएंट रिएक्टेंस)। ये प्रेरित धाराएँ सबसे जल्दी क्षीण होती हैं, इसलिए डैम्पर प्रभाव पहले समाप्त होता है।
विस्तृत हल (मूल भाषा में)
Concept & Reasoning
A synchronous generator fault current passes through subtransient, transient and steady-state stages. Damper circuits dominate the very early subtransient interval; field-winding transients persist longer. As damper current decays, the effective reactance rises from Xd'' to Xd' and finally Xd.
How to Solve It in the Exam
First few cycles → damper winding → subtransient reactance.
Important Exam Point
Link time sequence: damper dies first, field transient next.
Quick Trick
First few cycles → damper winding → subtransient reactance.
Common Mistake
Confusing 'eliminated first' with the physically smallest static leakage reactance.
સમમિત ફોલ્ટ પછી તરત જ સિંક્રોનસ જનરેટરમાં નીચેનામાંથી કયો રિએક્ટન્સ સૌથી પહેલાં દૂર થાય છે?
જવાબ અને પગલાવાર ઉકેલ
B — ડેમ્પર વાઇન્ડિંગ રિએક્ટન્સ. અચાનક સમમિત ફોલ્ટ પછી તરત ડેમ્પર-વાઇન્ડિંગ પ્રવાહો સૌથી પ્રબળ વિરોધી ફ્લક્સ બનાવે છે (સૌથી નાનો સબટ્રાન્ઝિયન્ટ રિએક્ટન્સ). આ પ્રેરિત પ્રવાહો સૌથી ઝડપથી ક્ષીણ થાય છે, તેથી ડેમ્પર અસર પહેલાં દૂર થાય છે.
વિગતવાર ઉકેલ (મૂળ ભાષામાં)
Concept & Reasoning
A synchronous generator fault current passes through subtransient, transient and steady-state stages. Damper circuits dominate the very early subtransient interval; field-winding transients persist longer. As damper current decays, the effective reactance rises from Xd'' to Xd' and finally Xd.
How to Solve It in the Exam
First few cycles → damper winding → subtransient reactance.
Important Exam Point
Link time sequence: damper dies first, field transient next.
Quick Trick
First few cycles → damper winding → subtransient reactance.
Common Mistake
Confusing 'eliminated first' with the physically smallest static leakage reactance.
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