Heat Rate Optimization

The objective of this module is to present and discuss the factors involved in power plant control, including:

1. Adjustment of active power and reactive power output.
2. Adjustment of the primer mover and auxiliary systems to meet the power output requirement.
3. Types of plant automatic control systems.

On completion of this module, the participant will be able to understand and describe the following concepts, and include them in day-to-day work practices.

• Power system load variations.
• The need for total generating plant output to equal power system load demand plus losses.
• The effect of changes in load demand on system frequency.
• The utilization of speed (frequency) variations to initiate governor response.
• The load dispatcher’s task.
• Adjustment of governor’s set-points to control unit output.
• The effect of system overload and load rejection.
• The demand for reactive power (VARs) by consumers electro-magnetic devices.
• Production of reactive power in the generator (by adjustment of field excitation).
• The effect of increasing excitation current on:

1. Active power output (MW).
2. Reactive power output (MVAR).
3. Terminal voltage.
4. Stator current and consequent stator heating.

• Vector relationship between megawatts and megavars.
• Calculation of megavolt-amperes (MVA).
• Power factor.
• The need for sophisticated control systems to continuously adjust the steam turbine, boiler, and auxiliary equipment to meet the power output requirements of the generator.
• Modes of master control.
• The basic control loop and major components.
• Pneumatic control systems.
• Transmission of sensing signals and control signals.
• Delay due to inertia of the control air system.
• Space limitations on pneumatic control boards.
• Electronic control signals.
• Digital control systems.
• Main CPU installation.
• DCS – Distributed Control Systems.
• Multiple processors.
• The application of PLCs.
• The digital operator interface.
• Advantages of the digital control system.