AUTOMATIC POWER FACTOR CORRECTION BY USING ARDUINO UNO (KEY IJP************467)

• Bala Murugan. A

Abstract

Efficient generation of power at present is crucial as wastage of power is a global concern. Power factor measures a systems power efficiency and is an important aspect in improving the quality of supply. In most power systems, a poor power factor resulting from an increasing use of inductive loads is often overlooked. A power factor correction unit would allow the system to restore its power factor close to unity for economical operation. The advantages of correcting power factor include reduced power system losses, increased load carrying capabilities, improved voltages and much more. The aim of this project is to build an Automatic Power Factor Correction (APFC) Unit, which is able to monitor the energy consumption of a system and automatically improve its power factor. An open source energy monitoring library was implemented in the design for accurate power calculation. The APFC device calculates the reactive power consumed by a systems inductive load and compensates the lagging power factor using capacitance from a capacitor bank.Keywords:A.CAlternating current; PFPower Factor; PFC Power Factor Correction; A.P.F.CAutomated Power Factor Correction; EmonlibEnergy Monitoring Library; C.TCurrent Transformer; P.TPotential Transformer.I.INTRODUCTIONPower factor is defined as the ratio between the KW (actual load power) and the KVA (apparent load power) drawn by an electrical load. It is simply a measure of how efficiently the load current is being converted into useful work output 1. The lower the power factor of a system, the less economically it operates. A low power factor can be the result of a significant phase difference between voltage and current at load terminals, a high harmonic content, or even a distorted current waveform. Generally it is the use of inductive loads such as induction motors, power transformers or induction furnaces that causes a current to lag behind voltage. A poor power factor resulting from inductive loads can be improved by power factor correction method, but a poor power factor resulting from distorted current waveform requires a change in equipment design or addition of harmonic filters 3. Since power factor in inductive loads is generally lower, they have to be supplied with reactive power in order to reduce increased power consumption of the machine. All inductive loads require active power (KW) to perform the actual work, and reactive power (KVAR) to maintain the magnetic field. This reactive power is necessary for the equipment to operate, but imposes an undesirable burden on the supply, causing the current to be out of phase with the voltage (current lags the voltage) 5. Low power factor can also result when inactive motors operate at less than full load-such as a surface grinder performing a light cut, a circular saw that is only spinning, an air compressor that is unloaded etc. Losses caused by poor power factor are due to the reactive current flowing in the system and can be eliminated using PFC 3-5. Power factor correction (PFC) is the process of compensating a lagging current by a leading current, through connecting capacitance to the supply. Capacitors contained in most power factor correction system draws current that leads voltage and produces a leading power factor. A sufficient capacitance is connected so that power factor is adjusted as close to unity as possible. Theoretically, capacitors could provide 100% of the needed reactive power, however, practically, correcting power factor much nearer to unity may result in harmonic distortion. If capacitors are connected to a circuit that operates nominally at a lagging power factor, the extent to which the circuit lags will reduce proportionately. Power factor correction is applied to neutralize as much of the magnetizing current as possible and to reduce losses in the distribution system. It offers many benefits to the commercial electrical consumer, including reduced utility bills by eliminating charges on reactive power, reduced losses making extra KVA available from the existing supply. Thus, it improves energy efficiency 6. The rest of the paper is organized as follows: section II discusses the existing methods of PFC and how they work, section III demonstrates our proposed system design, section IV discusses the modules required, section V describes the technical design of the system, section VI shows the system flow chart, section VII shows the results and analysis, finally section VIII draws conclusion of the project.