SUBMITTED BY:-Ahmed Soliman Alian Mohamed

Amit Kumar Md. Sahzad Ansari

Taquee Equbal Bachelor of Engineering

DEPARTMENT OF ELECTRICAL AND ELCETRONICS ENGINEERING

Guided by : Mr. S. MATHAN KUMAR

Protection of an induction motor (IM) against possible problems, such as overvoltage, over current, overload, over temperature, and under voltage, occurring in the course of its operation is very important, because it is used intensively in industry as an actuator. IMs can be protected using some components, such as timers, contactors, voltage, and current relays. This method is known as the classical method that is very basic and involves mechanical dynamic parts. Computer and programmable integrated circuit (PIC) based protection methods have eliminated most of the mechanical components.

However, the computer-based protection method requires an analog-to-digital conversion (ADC) card, and the PIC-based protection method does not visualize the electrical parameters measured.

In this proposed method for IMs, a new protection method based on a programmable logic controller (PLC) has been introduced. In this method, all contactors, timers and the conversion card are eliminated. Moreover, the voltages, the current, the speed, and the temperature values of the motor, and the problems occurred in the system, are monitored and warning messages are shown on the computer screen. This PLC-based protection method costs less, provides higher accuracy as well as safe and visual environment compared with the classical, and the PIC-based protection systems.

Classical monitoring techniques for three-phase IMs are generally provided by some combination of mechanical and electrical monitoring equipment. Mechanical forms of motor sensing are also limited in ability to detect electrical faults, such as stator insulation failures. In addition, the mechanicalparts of the equipment can cause problems in the course of operation and can reduce the life and efficiency of a system. In computer based protection system, measurements of the voltages, currents, temperatures, and speed were achieved and transferred to the computer for final protection decision. Although all the variables of the motor were

considered, usage of an analog-to-digital conversion (ADC) card increases the cost and the size of the system.

A programmable integrated circuit (PIC) based protection system, the solutions of various faults of the phase currents, the phase voltages, the speed, and the winding temperatures of an IM occurring in operation have been achieved with the help of the microcontroller, but these electrical parameters have not been displayed on a screen.

This method explains a PLC-based protection and monitoring method for a three-phase induction motor. The new solutions for various faults of the phase currents, the phase voltages, the speed, and the winding temperatures of an IM occurring in operation have been achieved with the help of a PLC. If only a PLC is used as a protection relay for a system, it costs more. But the use of a PLC can be the right choice if it is considered in an automation system in order not to use extra microprocessor such as a PIC.

3.1. CURRENT TRANSFORMER: A current transformer (CT) is used for measurement of electric currents. Current transformers, together with potential transformers (PT), are known as instrument transformers. When current in a circuit is too high to directly apply to measuring instruments, a current transformer produces a reduced current accurately proportional to the current in the circuit, which can be conveniently connected to measuring and recording instruments. A current transformer also isolates the measuring instruments from what may be very high voltage in the monitored circuit. Current transformers are commonly used in metering and protective relays in the electrical power industry.

3.2. VOLTAGE TRANSFORMER: A voltage transformer (VT) is used for measurement of voltage. Voltage transformers, together with current transformers (CT), are known as instrument transformers. When voltage in a circuit is too high to directly apply to measuring instruments, a voltage transformer produces a reduced voltage accurately proportional to the voltage in the circuit, which can be conveniently connected to measuring and recording instruments. A voltage transformer also isolates the measuring instruments from what may be very high voltage in the monitored circuit. Voltage transformers are commonly used in metering and protective relays in the electrical power industry.

3.3. PLC:A programmable logic controller (PLC) or programmable controller is a digital computers used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or lighting fixtures. PLCs are used in many industries and machines. Unlike general-purpose computers, the PLC is designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control machine operation are typically stored in battery-backed or non-volatile memory. A PLC is an example of a real time system since output results must be produced in response to input conditions within a bounded time, otherwise unintended operation will result.

3.4. INDUCTION MOTOR:An induction motor (or asynchronous motor or squirrel-cage motor) is a type of alternating current motor where power is supplied to the rotor by means of electromagnetic induction. An induction motor is sometimes called a rotating transformer because the stator (stationary part) is essentially the primary side of the transformer and the rotor (rotating part) is the secondary side. It is of two types, squirrel-cage and slip ring induction motor.

3.5. ENCODER:It is used to encode the signal received from the induction motor into a suitable form before sending it to the PLC.

3.6. TRUE RMS TO DC CONVERSION CARD:It is used to convert the RMS signal received from CT and PT into DC signal before sending the signal to the PLC as it can accept only DC signal.

3.7. SENSOR:It is used to sense the various signals such as temperature signal, rotor speed signal etc. from the induction motor and then send it to the PLC.

4. ADVANTAGES OF PROPOSED METHOD:• Low power consumption• Maximum efficiency• Less cost• Easy implementation• Reduces the man power• Provides higher accuracy• Provides safe and visual environment• Faster operation• More reliable

5. PROPOSED APPLICATIONS:

•In various industries such as power plants, steel plants etc.•In laboratories

6. LITERATURE REVIEW:This proposed project has been taken from the “IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 23, NO. 3, SEPTEMBER 2008” which is the paper of Mr. Ramazan Bayindir, Member, IEEE, Mr. Ibrahim Sefa, Member, IEEE, Mr. ˙Ilhami Colak, Member, IEEE, and Mr. Askin Bektas who all are from Gazi university, Turkey. For doing this project, I would like to thank the authors of this paper, the Principal, the Dean (Electrical Sciences), my Project Guide, my Project coordinator, my Department Faculties and my Friends who helped in collecting the related materials and carrying out this project. I have also used internet and my college library for collecting related materials.

7. REFRENCES:•Mr. Ramazan Bayindir, Member, IEEE, Mr. Ibrahim Sefa, Member, IEEE, Mr. ˙Ilhami Colak, Member, IEEE, and Mr. Askin Bektas, Gazi University, Turkey “IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 23, NO. 3, SEPTEMBER 2008”.•U.A. Bakshi and M.V. Bakshi. “Electrical Machines II”.•Wikipedia•Science alert (www.scialert.net)