সিঙ্গেল-ফেজ পাওয়ার বিশ্লেষণ

Understanding Single-Phase AC Power

Single-phase AC power is the standard supply for residential buildings and light commercial facilities. Unlike DC, AC voltage reverses direction periodically (50 or 60 times per second), which enables efficient voltage transformation but introduces the concept of power factor — the relationship between the voltage and current waveforms.

What Causes Low Power Factor?

• Induction Motors: The most common cause. Motors use reactive power to build rotating magnetic fields. Lightly loaded motors have worse PF than fully loaded ones.
• Transformers at Light Load: The magnetizing current drawn by transformer cores is largely reactive.
• Fluorescent Lighting (older ballasts): Magnetic ballasts introduce significant reactive current. Electronic ballasts largely solve this.
• Variable Speed Drives: Can improve motor PF but introduce harmonic distortion which has its own effects on the supply.

Power Factor Correction

Low power factor can be corrected by adding capacitor banks in parallel with inductive loads. Capacitors supply reactive power locally, reducing the reactive current that must flow from the utility. This reduces cable losses, improves voltage regulation, and avoids utility penalties for industrial customers with PF below 0.9.