DESIGN OF AUTOMATIC CONTROLLER OF HUNTING OF A GENERATOR AT SOMANGA GAS PLANT

 

INTRODUCTION

 In synchronous generator, difference of the stator frequency and rotor frequency is slip. Slip is the output of generator, when the generator is under loaded or overloaded suddenly, the frequency fluctuation try to overcome the changes. If this fluctuation continues rising and falling the slip i.e. output of the generator is disturbed, consequence generator will not able to take the load and produce noises. This phenomenon of generator fail to load and produces noises due to frequency oscillation on its equilibrium position caused by many reasons such as sudden overload or under load or fault in the system is called hunting

 

The steady state or stable operation of a generator the load torque is equal as well as opposite to the electromagnetic torque. The rotor of the generator runs at synchronous speed in the steady condition, maintain a constant value of the torque angle. The equilibrium get disturbed if sudden change occurs in the load torque. Thus, a resulting torque takes place which changes the speed of the generator.

The speed of the generator slows down temporarily, and the torque angle is sufficiently increased. This is done to restore the torque equilibrium and synchronous speed when there is a sudden increase of the load torque

If the value of angle is increased, the electromagnetic torque is also increased. As the result, the generator is accelerated. As the rotor reaches the synchronous speed, the torque angle is larger than the required value. Here the rotor speed continues to increase beyond the synchronous speed.

As the rotor accelerates above synchronous speed, the torque angle decreases. The point where the generator torque becomes equal to the load torque, the equilibrium is not restored because now the rotor speed is greater than the synchronous speed. Therefore, the rotor continues to swing backwards and as a result, the torque angle goes on decreasing.

 

PROBLEM STATEMENT

 

Power stability has been a problem at SOMANGA GAS PLANT located at Kilwa district, Lindi region due to outage of generator caused by hunting phenomenon.

 

Somanga gas plant consist of two generators operating parallel i.e same frequency and same voltage under normal operation. Under hunting situation of one generator causes the frequency of it to loss synchronism operation (parallel operation) gradually and the load share remain depend to the remain generator which acts as master generator. If this persist for a long time the outage of hunting machine acts as slave generator will occur and the remain generator will be overloaded by the system load and also may trip

 

In view of that project intend to design a circuit for which will control hunting of generator to retain it to equilibrium before outage and also to ensure load balance and to protect system from overload

 

OBJECTIVES OF THE PROJECT

MAIN OBJECTIVE.

To design automatic circuit for control load share and frequency of hunting generator in order to ensure stability and continue availability power supply.

Ø    SPECIFIC OBJECTIVES.

•        To establish design specification.

•        To design sensing unit.

•        To design the for partial load shedding.

•        To design switching circuit.

•        To interface all peripherals with control unit.

•        To design power supply unit to power all the peripherals.

 

SIGNIFICANCES OF THE PROJECT

•        To minimize power outage or power fluctuation due to delay switching by operator.

•        To increase power stability and availability.

•        To increase income by minimize power outage.

•        To reduce mechanical stress of machines due to frequent outage and overload.

BLOCK DIAGRAM OF EXISTING SYSTEM

      BLOCK DIAGRAM OF PROPOSED SYSTEM

  PROPOSED CIRCUIT FOR NORMAL OPERATION OF THE SYSTEM