PLC Based Control of Power Factor Improvement of a Three-Phase Load

Project Title

PLC Based Control of Power Factor Improvement of a Three-Phase Load

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

In industries, three-phase inductive loads such as induction motors are widely used due to their low cost, easy maintenance, reliability and robustness.  Due to inductive loads, power factor is reduced which results in the wastage of power, high billing cost and penalty from electric power supply companies. In order to resolve this issue, a system is needed to be designed which will increase the power factor. In this project, we are designing a system using Programmable Logic Controller (PLC) which will help in improving the power factor of three phase loads using capacitor banks. When the three-phase loads are added in the system, the power factor is reduced, PLC then switches the appropriate capacitor bank into the circuit depending on the load condition to improve the power factor.

Project Objectives

The aim of this project is to

1.  Improve the Power Factor to increase efficiency of the Three Phase system.

2.  Minimize the reactive component to reduce consumer’s electricity bill.

Project Implementation Method

When the start button of any of the three motors is pressed, PLC will read signal as an input from contactor coil of magnetic contactor connected with motor and will send signal as an output to corresponding contactor coil of magnetic contactor to switch the appropriate capacitor bank in order to improve power factor. In case stop button of motor is pressed, PLC will again read signal as an input and will disconnect the capacitor bank. As for safety precautions, MCCB will be used in order to protect the hardware, single pole MCB is used with PLC and for motor’s safety overload relays will be used which will protect motor in case of overload condition.

Benefits of the Project

1.  Many electric utility companies assess a power factor penalty for lower power factor (usually below 0.80 or 0.85). With proposed system, we can eliminate the power factor penalty from the bill by improving power factor.

2.  Improving the power factor will lower the demand charge, helping to reduce the electricity bill.

3.  Increased load carrying capabilities in existing system.

4.  With an improved power factor, the voltage drop in the conductor is reduced.

5.  Cost of the electrical devices and equipment is reduced.

Technical Details of Final Deliverable

Push Button	N/C and N/O
Contactor	2N/O+2N/C
Overload Relays	0.5A – 6.5A
Emergency Stop Push Button	3-Phase
PLC	Mitsubishi
Flexible Cable	2
Flexible Wire	1
Capacitor Bank (for 1 hp motor)	3.2862kVAR (65.41µF)
Capacitor Bank (for 0.5 hp motor)	1.09258kVAR (21.747µF)
Capacitor Bank (for 0.25 hp motor)	0.67557kVAR (13.44µF)
MCCB	30A
4-Core Cable	2.5mm
MCB	2A (Single Pole)
Digital Multifunction Meter	V,I,P,Q,S,Power Factor
Terminal Box	36 x 24
Motor 1	1 HP
Motor 2	0.5 HP
Motor 3	0.25 HP

  Push Button

  Contactor

  Overload Relays

  Emergency Stop Push Button

  PLC

  Flexible Cable

  Flexible Wire

  Capacitor Bank (for 1 hp motor)

  Capacitor Bank (for 0.5 hp motor)

  Capacitor Bank (for 0.25 hp motor)

  MCCB

  4-Core Cable

  MCB

  Digital Multifunction Meter

  Terminal Box

  Motor 1

  Motor 2

  Motor 3

Final Deliverable of the Project Hardware SystemCore Industry Energy Other IndustriesCore Technology Clean TechOther TechnologiesSustainable Development Goals Decent Work and Economic GrowthRequired Resources

Elapsed time in (days or weeks or month or quarter) since start of the project	Milestone	Deliverable
Month 1	Literature Review	Yes
Month 2	Components	Yes
Month 3	Simulation	Yes
Month 4	PLC integration with three phase loads	Yes
Month 5	PLC integration with capacitor banks	Yes
Month 6	Complete Hardware Integration	Yes
Month 7	Results	Yes
Month 8	Results and Report binding	Yes