Abstract:
Khartoum north power station is a thermal power station that has three phases.
Each phase consists of two units with their components, namely, a boiler with
auxiliaries, a turbine with auxiliaries, and a generator with auxiliaries. The
cooling tower is one of turbine auxiliaries. It is a heat rejection device used to
transfer process waste heat to the atmosphere. Make-up water for the cooling
tower`s reservoir must be supplied under level control. In case of a
malfunction of the ball float system the supplied water to condenser will not
be regular which may cause a vacuum problem resulting in load instability or
even causes the unit to trip. In this research, the ball float system was
suggested to be replaced by a level sensor which provides a level signal to a
PLC. The PLC controls the motor that operate the supply valve of the cooling
tower via the PID control module of the PLC. The optimum control
parameters of the PID control module were obtained by trial and error runs of
the Simulink module of the MatLab package. The suggested control system
was simulated and was found to perform nicely.
