The advantages of Neutral earthing is

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It can make a closed path

Explanation: Neutral earthing provides a return path for fault currents in power systems, ensuring that protective devices like relays and circuit breakers can reliably detect and isolate faults. Without a neutral connection to the earth, a line-to-ground fault may not draw sufficient current to trip protection, leading to persistent abnormal voltages.

Working Principle: When a fault occurs in an ungrounded system, the system capacitance to ground forms a circuit, leading to intermittent arcing. Neutral earthing directly connects the neutral point of transformers or generators to the earth, creating a low-impedance path. This ensures that the fault current flows through the earth back to the neutral, providing the necessary magnitude for protective relays to operate.

Key Formulas: $I_f = \frac{V_{ph}}{Z_n + Z_s}$ — where $I_f$ is fault current, $V_{ph}$ is phase voltage, and $Z_n$ is neutral impedance.; $V_{neutral} \approx 0$ — ideal grounding condition where the neutral potential is clamped to earth potential.

Key Points: Neutral earthing stabilizes the potential of the phases with respect to the earth.; It prevents the occurrence of arcing grounds caused by floating neutral capacitance.; Essential for the effective operation of directional overcurrent and earth-fault protection relays.; Reduces the risk of overvoltage during line-to-ground faults.

Advantages: Elimination of arcing grounds; Provides a closed path for fault current; Voltage stabilization during unbalanced loads; Improved safety for operating personnel

Disadvantages: Increased risk of high short-circuit currents requiring stronger switchgear; Potential for increased interference with communication lines

Applications: Transmission systems for effective lightning protection; Distribution networks to allow earth fault detection

Additional Info: Option B (Elimination of arcing ground) is also a major advantage, but Option A is fundamentally why the protection scheme closes; in many textbook contexts, these are treated as combined benefits.. Ungrounded systems are prone to high-frequency transients known as 'arcing grounds' due to the charging and discharging of system capacitance.

Answer: A is correct — Neutral earthing provides a stable, low-impedance closed path for fault currents to return to the source, which is critical for the reliable operation of protective relays.

Exam Tip: In exams, always distinguish between Equipment Earthing (for safety against shock) and System/Neutral Earthing (for protection and stability of the electrical network).

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