DESIGN AND IMPLEMENTATION OF AN IOT-ENABLED AUTOMATIC POWER FACTOR CORRECTION SYSTEM USING ESP8266
Low power factor in inductive electrical loads increases line current, reactive-power demand, voltage drop, and system losses. This paper presents a low-cost Automatic Power Factor Correction (APFC) prototype built around an ESP8266 controller, an ACS712 current sensor, relay-switched capacitor stages, a 16 x 2 LCD, and the Blynk IoT platform. The prototype supports local and remote visualization of current, estimated power factor, capacitor status, load status, and automatic/manual operating modes. In the supplied firmware, power factor is estimated from known load states and programmed correction increments rather than being directly calculated from simultaneous voltage-current phase measurement. The control algorithm applies current thresholds, a three-reading stability condition, and a five-second inter-stage delay to reduce relay chatter and capacitor inrush effects. For the transformer-only load model, the programmed power factor increases from 0.62 without compensation to 0.73 with the first capacitor stage and to 0.96 with both stages. The original interface records show representative low-power-factor and corrected states of 0.62 and 0.96, respectively. The work demonstrates the feasibility of an IoT-assisted APFC teaching prototype while also identifying the need for calibrated voltage sensing, zero-crossing/phase-angle measurement, and controlled meter-based experiments before industrial deployment.