Reverse Power Protection of Alternator and General Protection

Project Title

Reverse Power Protection of Alternator and General Protection

Project Area of Specialization Wearables and ImplantableProject Summary

The system is designed in such a way that it will release the breaker and prevent motoring of alternator if a reversal of power occurs. This protection device is also used to prevent damage to the prime mover, which might be stopped due to some fault.

According to the construction of synchronous machine it can be operated as a generator as well as a motor, the only difference is the direction of power flow. In case of alternator, there are some faults occur which change the direction of power flow and make the alternator become motor due to the failure of turbine, synchronization, governor valve etc . All these faults occur naturally in generating-station which damages the generator and turbine. For the protection of generator from reverse power flow, the directional power relay is used in between the generator and the bus-bar which senses the direction of power flow in line . The arrangement of the directional power relay is dependent on the type of prime mover.

In this project two motors are used which will act like a prime mover to the generator units. For simplicity we only use two units to perform the protection from reverse power. Across the bus-bar we are using load, Ammeter, Voltmeter and wattmeter to observe the effect of failure of one unit. The circuit breaker and the directional relay are connected in between the bus-bar and generator. To check the model performance turn off the one motor to

circuit breaker and the directional relay. Which will disconnect the faulty generator from the bus-

assume that there is some fault in prime mover and we will check the performance of the

bar and hence the generator and prime mover can be protected which is the goal of this project model.

Project Objectives

• To protect the alternator from reverse power flow.
• To analyze faults like overloading, motoring action during synchronization and short circuiting.  
• To investigate the under voltage, over voltage, reverse power and short circuit fault in the circuit

Project Implementation Method

The working of this model is simple, as stated earlier that the construction of synchronous motor and generator is same. The only difference is the direction of power. During faulty condition when the alternator has stopped working and become a motor, the directional power relay sense the direction of power flowing and the circuit breaker trip off  . The directional power relay is allows the power flow from generator to bus bar but not in reverse direction from bus bar to generator . In this project the two motors act as a turbine or prime mover for the generator bank. Note that for simplicity of the project we will be using two units as shown in block diagram. The combine power of these unit add at the bus bar and then applied to the load, where voltmeter, ammeter and wattmeter are used to check the model performance during fault condition on load. The main components of this model are below:

• Motors
• Alternators
• Circuit breakers
•  Power relay
• Bus bar
• Load
• Power supply for motors
• microcontroller
•  
• To check the performance of this model, turn off the supply of one motor which will consider as the failure in prime mover, this time the alternator will take supply from a common bus bar and will act as a motor which can burn the winding and can damage the prime mover. The presence of directional power relay and circuit breaker on each unit will protect the system from this situation  which is the main objective of this project model

Benefits of the Project

This model will protect the alternator from many faults like reverse power protection, overload situation, motoring action during failure of synchronization etc . And will also protect the prime mover from mechanical damage. This protection is economical than all other type of protection, as well as this is the simple model with easy working principle. The use of this model in practical power station will provide critical protection with low cost and have many advantages in power station.

Technical Details of Final Deliverable Fault Analaysis:

when fault occure such like Over voltage,Under voltage and Reverse power then microcontrollar gets samples from voltage divider and convert it into digital samples so then compare the value with pre define limit in microcontollar(MCU) if the current value exceed the limit then MCU gives signal to the relay and relay trip the system  or unit from Bus baar.

When short circuit fault occure then current sensor(AC-742) sense the current and continuesly gives report to the mini MCU. During short circuit fault mini MCU take action and give signal to the relay to trip down.

System Protection:

After fault occured our system will be clearly protected from more damaging and isolate the faulty unit from bus baar to safe more working units from over loading and damaging.

Smart System:

This project protect and isolate the system units within micro seconds while previous system was take time when giving result but the results may some time failed of previous system 

it can also save the time,economey and give very sharp response when taking action.

Final Deliverable of the Project HW/SW integrated systemType of Industry Energy Technologies OthersSustainable Development Goals Industry, Innovation and Infrastructure, Responsible Consumption and ProductionRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	51245
motors	Equipment	4	3000	12000
generators	Equipment	4	3500	14000
ardinuo	Equipment	4	1000	4000
relay	Equipment	4	500	2000
belt	Equipment	2	300	600
resistors	Equipment	40	10	400
capicitors	Equipment	20	30	600
current sensor	Equipment	4	500	2000
LCD	Equipment	6	800	4800
wires	Equipment	20	20	400
diodes	Equipment	15	15	225
crystal oscillator	Equipment	4	50	200
foundation board	Equipment	1	2000	2000
solder	Equipment	1	700	700
DMM	Equipment	1	2500	2500
bus baar	Equipment	1	500	500
buttons	Equipment	4	50	200
socket	Equipment	4	50	200
dimers	Equipment	4	200	800
button board	Equipment	4	50	200
transistors	Equipment	4	50	200
voltage regulators	Equipment	4	80	320
voltage divider	Equipment	4	100	400
load circuit	Equipment	1	1000	1000
foundation setter	Equipment	1	1000	1000