Examoogle
ExamsTest SeriesCBATRank CheckPrevious Year PapersPassBook StoreMy BooksAI Tutor
🛒0
अA
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
© 2026 Examoogle. India's #1 competitive exam AI tutor.
🔒 SSL Secured📱 UPI Accepted🧾 GST Invoice
Examoogle

Join 60,000+ competitive exam aspirants

or with email
By continuing, you agree to ourTerms of Service&Privacy Policy
Your Cart
Subtotal₹0
Total₹0
Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
Back to Practice Questions
ElectricalPower Generation
PrevNext

The worst blackout in recent history occurred in northern India on two consecutive days in__________

A

30-31 July, 2012

B

25-26 June, 2013

C

20-21 March, 2009

D

None of above

Correct Answer

Concept & PrincipleElectricalPower Generation
Option A

30-31 July, 2012

Quick Summary: The 2012 India blackout was the largest power outage in history, affecting over 620 million people. It occurred in two phases on July 30 and July 31, 2012, due to severe cascading failures in the Northern, Eastern, and North-Eastern regional grids.

💡 Explanation

The 2012 India blackout was the largest power outage in history, affecting over 620 million people. It occurred in two phases on July 30 and July 31, 2012, due to severe cascading failures in the Northern, Eastern, and North-Eastern regional grids.

🔢 Key Formulas

P=V1V2Xsin⁡δP = \frac{V_1 V_2}{X} \sin\deltaP=XV1​V2​​sinδ — Power transfer equation indicating dependence on line reactance and voltage

f=12πLCf = \frac{1}{2\pi\sqrt{LC}}f=2πLC​1​ — Resonant frequency relation governing grid stability harmonics

⚙️ Working Principle

The collapse was caused by a combination of high power demand, low hydro-power generation, and the outage of critical transmission lines (like the 400kV400 kV400kV Bina-Gwalior line). This triggered a cascading effect where overloading led to relay trips, causing the grid frequency to deviate rapidly from the 50Hz50 Hz50Hz nominal value, eventually leading to a total system collapse.

📌 Key Points
  • ▸

    Affected 22 states in Northern, Eastern, and North-Eastern regions.

  • ▸

    The collapse triggered the implementation of the 'Automatic Under-Frequency Load Shedding' (AUFLS) schemes.

  • ▸

    Increased dependence on 'Power System Stabilizers' (PSS) for grid damping.

  • ▸

    Led to the amendment of grid codes to prevent 'N-1' contingency violations.

✅ Advantages
  • ▸

    Enhanced focus on grid security standards.

  • ▸

    Upgradation of SCADA and Wide Area Measurement Systems (WAMS).

❌ Disadvantages / Limitations
  • ▸

    Massive economic disruption and loss in industrial production.

  • ▸

    Risk of damage to sensitive electronic equipment due to voltage surges.

🛠️ Applications / Uses
  • ▸

    Load Dispatch Centers (LDC)

  • ▸

    Transmission Grid Planning

📄 Additional Information
  • ▸

    The blackout highlighted the danger of 'weak links' in an interconnected synchronous grid.

  • ▸

    Option B (2013) and Option C (2009) do not correspond to any grid collapse events of this magnitude.

📊 Diagram / Illustration
Cascading Failure MechanismOverloaded Transmission Line (N-1 Contingency)⇩Relay Trip → Redistribution of LoadSystem Frequency Deviation < 49.5 Hz
✅

A is correct — The 2012 India blackout was caused by cascading transmission failures on 30-31 July 2012.

Core Concepts Used
Click any tag to open in AI Tutor
Cascading Failure N-1 Contingency Grid Frequency Stability
💡 EXAM TIP

In competitive exams, always remember that power system collapse is primarily a result of frequency instability leading to voltage collapse.

Related Questions

ElectricalPower Generation
For rural and remote areas, _________________for generation and distribution is permitted
ElectricalPower Generation
With reference to EC Act-2003,Setting up State Electricity Regulatory Commission (SERC) has been made_________
ElectricalPower Generation
Which of the following generation needs permission from central electricity authority as per Electricity Act-200
ElectricalPower Generation
The captive generation is ________as per Electricity Act-2003
ElectricalPower Generation
As per Electricity Act-2003, The generation of electricity is

Discussion (0)

Loading discussion...
PrevNext