Electronics Hub - Minimizing Penalty in Industrial Power Consumption by Engaging APFC Unit

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  • Electronics Hub - Minimizing Penalty in Industrial Power Consumption by Engaging APFC Unit

Electronics Hub - Minimizing Penalty in Industrial Power Consumption by Engaging APFC Unit

Product Description

The project is designed to minimize penalty for industrial units by using automatic power factor correction unit. Power factor is defined as the ratio of real power to apparent power. This definition is often mathematically represented as KW/KVA, where the numerator is the active (real) power and the denominator is the (active + reactive) or apparent power.

Reactive power is the non working power generated by the magnetic and inductive loads, to generate magnetic flux. The increase in reactive power increases the apparent power, so the power factor also decreases. Having low power factor, the industry needs more energy to meet its demand, so the efficiency decreases.

In this proposed system the time lag between the zero voltage pulse and zero current pulse duly generated by suitable operational amplifier circuits in comparator mode are fed to two interrupt pins of the microcontroller. It displays the time lag between the current and voltage on an LCD.

The program takes over to actuate appropriate number of relays from its output to bring shunt capacitors into the load circuit to get the power factor till it reaches near unity. The microcontroller used in the project belongs to 8051 family.

Further the project can be enhanced by using thyristor control switches instead of relay control to avoid contact pitting often encountered by switching of capacitors due to high in rush current.

Project Highlights

  • Easy to use, Self-explanatory kit.
  • All-inclusive solution kit.
  • Extensive audio-visuals available.
  • Branding-free material.
  • Pre-programmed Microcontroller.
  • Automatic Power Factor Correction.
  • Call/mail for Tech Support from 10 am - 7 pm.
  • Can be Customized for Arduino, Raspberry Pi, PIC

Block Diagram

Hardware Requirements

  • 8051 series Microcontroller
  • Op-amps
  • LCD
  • Shunt Capacitors
  • Relays
  • Relay driver IC
  • Choke
  • Crystal
  • Switches
  • Slide Switch
  • Resistors
  • Capacitors
  • Diodes
  • Transformer
  • Voltage Regulator
  • Lamp

Software Requirements

  • Keil compiler
  • Languages: Embedded C or Assembly

User Reviews

electronicshub

"I live in Hyderabad, a place that is known for engineering colleges. Went with frnd and bought a set from Ameerpet(tht hs rdymade stuff like this) and it failed just b4 viva. Thats when we got this thx to a senior who is sorta like a geek.. and let me tell u.. Its one reason why me and my frnds got thru the final sem. Works great and is useful too later.. "

Ravi Teja
Order No: HYF1290
electronicshub

"A must-buy. It helped me practice in real time and learn how to make a project by looking at an actual workable unit. (fyi - you get a fully built unit and another full set of components to build another by yourself) so it was great value for us. We shared the costs by 3 (our team for the project) but i got to keep my unit as the other two kept the original. Showed it for my on-campus and got thru too becuase it not just looked neat and profesionally bt worked great later. (still have it in my room, now working with GE in Bangalore) "

Anusha
Order No: BLR2933
electronicshub

"We have used it for our institution - it is available in lab and has been good for explaining various models in live during class. Strongly suggest every college dept to have it for labs as it is working well - even with regular use at lab for more than 1 year. Note:We got the unit complementarity before launch in 2014 and have later purchased few batches. The team behind it is professional and know what electronics students need and i am writing this review on their request on 13/05/2016"

Mr. Ramesh Kumar Jha
Order No: BQF3698

Q&A

Q:  Which microcontroller is used in this project?
A:  A 40 pin microcontroller from 8051 family is used in this project.

Q:  Which inductive load is used in this project?
A:  A 40 W tube choke is used in this project.

Q:  Can I replace choke by induction motor?
A:  Yes, it is possible to replace the choke by induction motor.

Q:  Why 100W bulb is used?
A:  A 100 W bulb is used to demonstrate as Linear or resistive load

Q:  Can a bulb of lower watt be used?
A:  Yes, a lower wattage bulb can be used.

Q:  Why 2.5 µF fan capacitors are used?
A:  2.5µF fan capacitors are used to compensate lagging power factor

Q:  Can inductance be increased?
A:  Yes,inductance can be increased by increasing the wattage of bulb from 100W to 200W

Q:  Why is penalty imposed on industries?
A:  Abrupt increase in reactive power leads to damage in supply system, for not maintaining the reactive power electricity board will impose penalty on industry

Q:  How is APFC done?
A:  APFC (Automatic Power Factor Compensation) is done by microcontroller by sensing the Lagging current

Q:  What is the relation between reactive power and power factor?
A:  When there is increase in reactive power, power factor decreases

Q:  What is the formula for calculating smoothing capacitor value?
A:  There is some approximated formula .Peak to peak ripple voltage = Load current in amps / (2*line frequency in hertz *capacitance in farads). But as rule of thumb for 1 A current 1000uF is best. Thus it is load dependent.

Q:  Why are two transformers being used?
A:  One transformer is used as PT while the other is as CT. Hence 2 numbers are must. This is an academic project which is designed to understand the technology used and not designed for real time use. The load capacity is about 200 watts.

Q:  Can we watch the waveforms of current lagging behind the voltage?
A:  For watching 2 channels on CRO/DSO one needs common ground point. The common ground point is available for ZVS and ZCS pulses as they are at the DC side ,thus they can be seen. But for ac waveform watching if we take the CT output ac to one channel we cannot connect the PT (12 volt from the transformer) to the other channel as there would be no common ground reference possible. The only way is to use 2 more step -down transformers and connect one as PT (230 volt to 12 volt)by connecting the same to 230 volt side to mains and the secondary of the same transformer ,one point can go to the common point of the CRO/DSO while the other can be used for the 1st channel. The 2nd transformer is used as a CT and the low voltage side is connected across the 2nd 10-Ohm/10 watt resistor. The 230 volt side is connected to a 4.7 k resistor. Then one point goes to common point of DSO/CRO and the other to the 2nd channel of the DSO/CRO. All these are to be carried out at your place.

Q:  How value of capacitor is decided?
A:  The value of capacitor coming into the circuit is decided by the program. We had taken some arbitrary value of 2.2uF (C) by trial, apparently adequate enough to compensate the PF developed by the simple inductor used. The total capacitance value goes on increasing by C or C+C or C+C+C or C+C+C+C as the inductive current goes on increasing. One can increase the inductive current by changing the wattage of the lamp which is used in series with the inductor. For example a 15 watt lamp will produce too little a lagging current while a 100 watt can result in much higher inductive current.

Q:  How does the project calculate the number of inductors to be used?
A:  The project takes into consideration the time difference between voltage and current in a capacitive circuit. A controller adds capacitors in a sequence to bring inductors onto the circuit till near unity PF is achieved. Kit is supplied with 4 capacitors and 1 inductor though there is provision for using 2. The controller adds capacitors in a sequence for getting increasing capacitive current in order to bring appropriate inductors onto the circuit till near unity PF is achieved. The number of inductors to come to the circuit is decided by the program till it finds the current in line with the voltage.

Q:  How do you calculate the output of the ZCD? The difference in time. Do you subtract waveform from PT with waveform from CT or you divide PT/CT?
A:  The start of the ZV pulse and the start of the ZC pulse in time scale is taken into consideration. It is neither subtraction nor division.

Q:  Why is the lamp used in series with the inductor?
A:  A lamp is used in series, because a standard 40 watt tube light choke cannot be directly connected to mains.

Q:  How do you calculate the output of the ZCD? Is it by time difference? Do you subtract waveform from PT with waveform from CT or divide PT/CT?
A:  The start of the ZV pulse and the start of the ZC pulse in time scale is taken into consideration. It is neither subtraction nor division.

Q:  Is the capacitor special for power factor correction or can I use any capacitor with the same rating?
A:  Please note this is a project for understanding the technology and is not meant for commercial use. So we have used easily available capacitors in the market. They are fan capacitors. However one can use any type for the project as long as the capacitance and voltage rating are met. But the real PF correction capacitors are different.

Q:  How did you calculate the value of capacitor connected parallel with the load?
A:  The value of capacitor coming into the circuit is decided by the program. We had taken some arbitrary value of 2.2uF (C) by trial, apparently adequate enough to compensate the PF developed by the simple inductor used. The total capacitance value goes on increasing by C or C+C or C+C+C or C+C+C+C as the inductive current goes on increasing. One can increase the inductive current by changing the wattage of the lamp which is used in series with the inductor. For example a 15 watt lamp will produce too little a lagging current while a 100 watt can result in much higher inductive current.

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