Which type of panel are using for improving power factor in industry for load?

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Examoogle · Accepted Answer

APFC

Explanation: APFC stands for Automatic Power Factor Controller, which is an intelligent panel designed to automatically switch capacitor banks in and out of the circuit to maintain a target power factor. It is the industry standard for optimizing energy efficiency and avoiding penalties from utility companies due to inductive lagging loads.

Working Principle: The APFC panel uses a power factor controller (a microcontroller-based relay) that monitors the voltage and current waveforms of the load. When the actual power factor falls below a set threshold, the controller calculates the amount of reactive power (kVAR) needed and switches on the appropriate capacitor steps through contactors or thyristors to compensate for the reactive power demand of the inductive load.

Key Formulas: $Q_{req} = P(	an\phi_1 - 	an\phi_2)$ — where $Q_{req}$ is required reactive power compensation, $P$ is active power, and $\phi$ is the phase angle.; $	ext{PF} = \cos\phi = \frac{P}{S}$ — definition of power factor as the ratio of real power ($P$) to apparent power ($S$).

Key Points: Reduces the line current drawn from the supply for the same load, decreasing $I^2R$ losses.; Eliminates heavy penalties charged by utility providers for low power factor operation.; Extends the life of electrical equipment by reducing thermal stress due to lower current.; Enables higher utilization of transformer and cable capacity.

Advantages: Prevents manual intervention through automation; Improves system voltage stability; Reduces electricity bills; Minimizes harmonic distortion

Disadvantages: High initial investment cost; Requires regular maintenance of capacitors and switching devices; Sensitive to harmonic interference

Applications: Large manufacturing industrial plants; Commercial building complexes; Large induction motor installations; Distribution substations

Additional Info: Target power factor is usually maintained between 0.95 and 0.99.. Option B (Star-Delta) is a motor starting method, not a power factor control method.. Option C (Soft Panel) typically refers to a Soft Starter for motors to reduce inrush current, not for power factor correction.

Answer: A is correct — APFC (Automatic Power Factor Controller) is the dedicated system used to dynamically compensate reactive power and maintain optimal power factor in industrial loads.

Exam Tip: Always remember that Star-Delta starters are for starting induction motors, whereas APFC panels are for system-level load compensation.

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