Consider the following statements: HVDC transmission is superior to HVAC transmission due to
1. Lack of reliable DC circuit breakers.
2. Lesser number of conductors for same power carrying capacity.
3. Non-synchronous link between the two different systems simplifying the problem of voltage stability and frequency control.
4. No costly terminal equipment such as converters and inverters are required.
Which of these statements is/are correct?
Answer & step-by-step solution
HVDC converts AC to DC for transmission and back to AC at the receiving end. HVDC can interconnect asynchronous AC systems. Key relation: Typical chain: AC generation → rectifier → DC link → inverter → AC grid/distribution.
Exam focus: HVDC advantage is in the link, not DC generation/distribution in conventional grids. Common trap: Do not claim HVDC eliminates converter terminal equipment.
Statement-wise Verification
- Statement 1 - Incorrect.
Lack of reliable DC circuit breakers.
A limitation is not an advantage of HVDC over HVAC - Statement 2 - Correct.
Lesser number of conductors for same power carrying capacity.
HVDC can interconnect asynchronous AC systems. - Statement 3 - Correct.
Non-synchronous link between the two different systems simplifying the problem of voltage stability and frequency control.
HVDC can interconnect asynchronous AC systems. - Statement 4 - Incorrect.
No costly terminal equipment such as converters and inverters are required.
HVDC requires costly converter stations at terminals
Core Concept
HVDC converts AC to DC for transmission and back to AC at the receiving end. Long lines/cables avoid charging current and skin effect and can have lower losses, but converter stations are costly and LCC schemes consume reactive power. HVDC can interconnect asynchronous AC systems.
Formula / Key Relationship
Typical chain: AC generation → rectifier → DC link → inverter → AC grid/distribution.
Why the Other Options Are Wrong
Option A is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 2, 3. Option C is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 2. Option D is incorrect because it includes incorrect statement(s) 1 and omits correct statement(s) 3.
Exam Shortcut / Approach
HVDC advantage is in the link, not DC generation/distribution in conventional grids.
Common Mistake
Do not claim HVDC eliminates converter terminal equipment.
Quick Revision
Conductor Count and Asynchronous Interconnection is linked with HVDC versus HVAC, HVDC Transmission and Power Systems. HVDC advantage is in the link, not DC generation/distribution in conventional grids.
निम्नलिखित कथनों पर विचार कीजिए: HVDC पारेषण HVAC पारेषण से श्रेष्ठ है क्योंकि
1. विश्वसनीय DC सर्किट ब्रेकरों का अभाव।
2. समान शक्ति वहन क्षमता के लिए कम चालकों की संख्या।
3. दो भिन्न प्रणालियों के बीच असिंक्रोनस लिंक, जो वोल्टेज स्थिरता और आवृत्ति नियंत्रण की समस्या को सरल बनाता है।
4. कन्वर्टर और इन्वर्टर जैसे महँगे टर्मिनल उपकरणों की आवश्यकता नहीं।
इनमें से कौन-सा/से कथन सही है/हैं?
उत्तर और चरणबद्ध हल
B — केवल 2 और 3। HVDC को कम चालक चाहिए और यह असिंक्रोनस AC प्रणालियों को जोड़ सकता है। विश्वसनीय DC ब्रेकरों का अभाव और महँगे कन्वर्टर टर्मिनल HVDC की कमियाँ हैं, लाभ नहीं।
विस्तृत हल (मूल भाषा में)
Statement-wise Verification
- Statement 1 - Incorrect.
Lack of reliable DC circuit breakers.
A limitation is not an advantage of HVDC over HVAC - Statement 2 - Correct.
Lesser number of conductors for same power carrying capacity.
HVDC can interconnect asynchronous AC systems. - Statement 3 - Correct.
Non-synchronous link between the two different systems simplifying the problem of voltage stability and frequency control.
HVDC can interconnect asynchronous AC systems. - Statement 4 - Incorrect.
No costly terminal equipment such as converters and inverters are required.
HVDC requires costly converter stations at terminals
Core Concept
HVDC converts AC to DC for transmission and back to AC at the receiving end. Long lines/cables avoid charging current and skin effect and can have lower losses, but converter stations are costly and LCC schemes consume reactive power. HVDC can interconnect asynchronous AC systems.
Formula / Key Relationship
Typical chain: AC generation → rectifier → DC link → inverter → AC grid/distribution.
Why the Other Options Are Wrong
Option A is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 2, 3. Option C is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 2. Option D is incorrect because it includes incorrect statement(s) 1 and omits correct statement(s) 3.
Exam Shortcut / Approach
HVDC advantage is in the link, not DC generation/distribution in conventional grids.
Common Mistake
Do not claim HVDC eliminates converter terminal equipment.
Quick Revision
Conductor Count and Asynchronous Interconnection is linked with HVDC versus HVAC, HVDC Transmission and Power Systems. HVDC advantage is in the link, not DC generation/distribution in conventional grids.
નીચેનાં વિધાનો ધ્યાનમાં લો: HVDC પારેષણ HVAC પારેષણ કરતાં શ્રેષ્ઠ છે કારણ કે
1. વિશ્વસનીય DC સર્કિટ બ્રેકરનો અભાવ.
2. સમાન પાવર વહન ક્ષમતા માટે ઓછા વાહકો.
3. બે અલગ પ્રણાલીઓ વચ્ચે અસિંક્રોનસ લિંક, જે વોલ્ટેજ સ્થિરતા અને આવૃત્તિ નિયંત્રણની સમસ્યા સરળ બનાવે છે.
4. કન્વર્ટર અને ઇન્વર્ટર જેવાં મોંઘાં ટર્મિનલ ઉપકરણોની જરૂર નથી.
આમાંથી કયું/કયાં વિધાન સાચું/સાચાં છે?
જવાબ અને પગલાવાર ઉકેલ
B — ફક્ત 2 અને 3. HVDCને ઓછા વાહકો જોઈએ અને તે અસિંક્રોનસ AC પ્રણાલીઓને જોડી શકે છે. વિશ્વસનીય DC બ્રેકરનો અભાવ અને મોંઘાં કન્વર્ટર ટર્મિનલ HVDCની ખામીઓ છે, લાભ નહીં.
વિગતવાર ઉકેલ (મૂળ ભાષામાં)
Statement-wise Verification
- Statement 1 - Incorrect.
Lack of reliable DC circuit breakers.
A limitation is not an advantage of HVDC over HVAC - Statement 2 - Correct.
Lesser number of conductors for same power carrying capacity.
HVDC can interconnect asynchronous AC systems. - Statement 3 - Correct.
Non-synchronous link between the two different systems simplifying the problem of voltage stability and frequency control.
HVDC can interconnect asynchronous AC systems. - Statement 4 - Incorrect.
No costly terminal equipment such as converters and inverters are required.
HVDC requires costly converter stations at terminals
Core Concept
HVDC converts AC to DC for transmission and back to AC at the receiving end. Long lines/cables avoid charging current and skin effect and can have lower losses, but converter stations are costly and LCC schemes consume reactive power. HVDC can interconnect asynchronous AC systems.
Formula / Key Relationship
Typical chain: AC generation → rectifier → DC link → inverter → AC grid/distribution.
Why the Other Options Are Wrong
Option A is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 2, 3. Option C is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 2. Option D is incorrect because it includes incorrect statement(s) 1 and omits correct statement(s) 3.
Exam Shortcut / Approach
HVDC advantage is in the link, not DC generation/distribution in conventional grids.
Common Mistake
Do not claim HVDC eliminates converter terminal equipment.
Quick Revision
Conductor Count and Asynchronous Interconnection is linked with HVDC versus HVAC, HVDC Transmission and Power Systems. HVDC advantage is in the link, not DC generation/distribution in conventional grids.
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