Which type of energy meter is provided for load demand more than 150 HP?

Question

Examoogle · Accepted Answer

HT

Explanation: For industrial loads exceeding 150 HP (approximately 112 kW), the electricity distribution companies mandate the use of High Tension (HT) metering. This ensures accurate measurement at the supply voltage level, reducing the complexity and errors associated with large current-carrying low-voltage conductors.

Working Principle: In HT metering, Potential Transformers (PTs) and Current Transformers (CTs) are used to step down the high voltage and heavy current to manageable values for the energy meter. This allows the use of standard measuring instruments while effectively handling the high power demand of the consumer, ensuring safety and precision in billing.

Key Formulas: $P = \sqrt{3} V_L I_L \cos \phi$ — Total real power measurement; $CT \ Ratio = \frac{I_{primary}}{I_{secondary}}$ — Current transformer transformation ratio

Key Points: HT supply is typically provided at 11 kV or 33 kV for large industrial consumers.; 150 HP is approximately equivalent to 112 kW of power demand.; HT metering eliminates the need for very heavy cross-section cables required at low voltage levels for high current capacity.

Advantages: Lower line losses due to transmission at higher voltage; Higher measurement accuracy for heavy industrial loads; Reduced conductor material requirement

Disadvantages: Requires high-voltage insulation; Installation cost is significantly higher than LT setups; Requires specialized safety maintenance

Applications: Large industrial factories; Large commercial complexes; Bulk supply consumers

Additional Info: Most state electricity boards specify HT metering for loads exceeding 75 kW or 100 HP.. Option B (LT MD) refers to Low Tension Maximum Demand meters, which are generally used for smaller commercial or light industrial consumers.

Answer: C is correct — Loads exceeding 150 HP require HT metering to ensure accurate energy measurement at the high-voltage distribution level.

Exam Tip: Always remember that electricity distribution classification in India is primarily based on connected load or maximum demand; industrial loads above 100-150 HP almost universally fall under HT tariff categories.

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