Fault Identification of 3-Phase Slip Ring Induction Motor

Fault Identification Of 3-Phase Slip Ring Induction Motor

By,Manivannan.V

Mohammed Aasique Iqbal.SRamanathan.P

Suresh Kumar.K.B

GUIDE NAME : Mrs. M.Ummu Salma / AP

Objective

• A computer based protection system has been introduced to monitor the various faults of the Induction Motors and it is achieved with the help of the microcontroller.

• We find the suitable technique for the identification of possible faults occurring in the thermal power station I-expansion Neyveli.

Existing System• The existing technology to detect and protect the

induction motor fault using programmable logic controllers. This system has several drawbacks which can affect the performance of the system.

• Some applications that perform a single function, is not efficient in the use of PLC.

• Cost of the PLC is very high as compare to the microcontroller.

• Cost of the PLC directly proportional to contact in PLC.

• It does not having ADC so we have make separate system to convert analog to digital. So the system may complex.

Proposed system

• In our project fault detection and protection of induction motor, we are implementing the microcontroller ATMEGA16 in terms of PLC.

• And we are using the software proteus 7 profession to simulate the entire system. Proteus 7 profession software in more reliable and managing system in not tedious process as compare to other process.

Microcontroller over PLC• Microcontroller ATMEGA16 has 8-ADC system

available in it.• As compare to PLC the cost is much reduced.• The advantages of microcontroller are that all

MCUs have on-chip resources to achieve a higher level of integration and reliability at a lower cost.

• An on-chip resource is a block of circuitry built into the MCU which performs some useful function under control of the MCU.

In our project we are simulating four major types of faults detection and protection of induction motor.•Single phase to ground fault(L-G)•short circuit with in the single phase.•Phase to phase faults (L-L).•Open circuited phases.

Block diagram

POWER SUPPLY•The power supply which runs the motor here for induction motor the nature of the power supply is 415volts, 50hz ,3-phase Alternating Current supply.CURRENT TRANSFORMER•Current transformers are used in electric metering for large load situations to reduce the current level presented to the metering circuit in order to make it more manageable and safe..

POTENTIAL TRANSFORMER•Potential transformer is used to operate as voltmeters.The primary winding of the transformer is connected across the line carrying the voltage to be measured and the voltage circuit is connected across the secondary winding.SIGNAL CONDITIONING UNIT•The signal conditioning system has two modules such as rectifier with filter and voltage regulator.

RECTIFIER UNIT•The rectifier which is designed to convert the 5v AC to 5v DC here the full wave bridge rectifier uncontrolled rectifier are used so that the AC voltage which is converted to pulsating DC voltage and to avoid the unwanted signal present in pulsating DC we have to provide the filters so that in our circuit parallel connected capacitor act as a filter which allow only the DC .

VOLTAGE REGULATOR•In over signal conditioning system after the conversion of AC to DC, then it should not excised the rated value because in damage the microcontroller so, the zener diode which act as a voltage regulator. In Zener diode the reverse voltage is constant so that the zener diode is connected to limit the value.

MICRO CONTROLLER•The ATmega16 microcontroller used in this lab is a 40-pin wide DIP (Dual In Line) package chip. This chip was selected because it is robust, and the DIP package interfaces with prototyping supplies like solder less bread boards and solder-type perf-boards.•Surface mount devices are more useful for circuit boards built for mass production. The pin out details tells us where power and ground should be connected, which pins tie to which functional hardware, etc.

RELAY•A simple electromagnetic relay consists of a coil of wire surrounding a soft iron core, an iron yoke which provides a low reluctance path for magnetic flux, a movable iron armature, and one or more sets of contacts.• When an electric current is passed through the coil it generates a magnetic field that attracts the armature, and the consequent movement of the movable contact(s) either makes or breaks (depending upon construction) a connection with a fixed contact.

ATMEGA 16• A microcontroller often serves as the “brain” of a

system. Like a mini, self-contained computer, it can be programmed to interact with both the hardware of the system and the user.

• The ATmega16 microcontroller used in this lab is a 40-pin wide DIP (Dual In Line) package chip. This chip was selected because it is robust, and the DIP package interfaces with prototyping supplies like solderless bread boards and solder-type perf-boards.

Pin-out Diagram

HARDWARE IMPLEMENTATION

• The 3 phase supply is given to the equivalent circuit of the slip ring induction motor which is formed using chokes.

• The supply is given to the rotor resistance starter.

• The starter energises the 3phases.

• The starter energizes the motor and thus the motor is started.

• Potential transformer is connected across each phase and the voltage is monitored.

• The equivalent voltage of the fault occurred is provided to micro-controller chip.

• If any abnormality is found, then the micro controller acts and trips the motor and displays the fault.

• Current transformer is connected along each phase and the current is monitored.

• The current cannot be directly fed to the micro-controller and hence an equivalent voltage is provided using a current to voltage converter.

• If any abnormality is found, the micro-controller acts and trips the motor and displays the fault.

• Micro controller AT MEGA16 is programmed for each faults, so that the fault is displayed and motor is tripped using relay as soon as the fault occurs.

• The types of faults are also displayed in the output LCD screen

Simulation• In our project we are simulating four major

types of faults detection and protection of induction motor they are:

• Single phase to ground fault(L-G) • Short circuit with in the single phase.• Phase to phase faults (L-L).• open circuited phases.

System

Normal condition

Line Current Phase Voltage

Fault Condition(for e.g.. L-G fault)

Line curremt

Conclusion

• The low cost, reliable - compact size and easy installation of this system provide reliable, economical motor protection not normally found in existing switch gear or motor control.

• This system is flexible in the range settings, so it can be applied to different motor in every situation, quickly changed if the need arises.

• In this microcontroller controlled system we implemented, however, the elimination of the motor from the system can be realized in the expected value very sensibly.

• More flexible and reliable operation of the system is provided by applying a specific amount of delay for opening the circuit according to the failure of the motor.