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SarkariResultOutAdditional Assistant Engineer (Electrical) · 2026

Previous Year Question

What is the primary function of a protective relay in an electrical system?
  1. To control the speed of motors
  2. To detect faults and initiate the tripping of circuit breakers
  3. To maintain the power factor
  4. To regulate voltage

Correct answer: B

Explanation

A protective relay continuously evaluates electrical quantities to recognize abnormal or fault conditions. When its operating criterion is met, it sends a trip command to the appropriate circuit breaker to isolate the faulty section.

Step-by-step solution

Fault Detection and Tripping explanatory diagram

Correct Answer

B — To detect faults and initiate the tripping of circuit breakers

Explanation

A protective relay continuously evaluates electrical quantities to recognize abnormal or fault conditions. When its operating criterion is met, it sends a trip command to the appropriate circuit breaker to isolate the faulty section.

Key Concept

Fault Detection and Tripping

Exam Point

Relay detects/decides; circuit breaker interrupts.

Exam tip

Relay detects/decides; circuit breaker interrupts.

Quick method

Relay detects/decides; circuit breaker interrupts.