To Study the impact of hydro-thermal scheduling on power system dynamic performance though relevant analysis.

Experiment No. : -02

Name of the Experiment: –

To Study the impact of hydro-thermal scheduling on power system dynamic performance though relevant analysis.

Abstract: –

Apparatus Required:-

Simulation Model: –

Figure 1 Block diagram of Hydro-thermal power plant with frequency bias.
Figure 2 Block Diagram of Subsystem “Control Area 1”
Figure 3: Block diagram of subsystem “Thermal power plant”
Figure 4: Block diagram of subsystem “Hydroelectric power plant”

Theory: –

Result: –

Figure 5: “Frequency response of Hydro-thermal scheduling on power system”

Conclusion: –

To be written by student.

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For your reference:

Figure 1 Block diagram of Hydro-thermal power plant with frequency bias.

This model represents the top-level supervisory loop of Control Area 1 in a Load Frequency Control (LFC) simulation.

It wraps the physical generation subsystems (the thermal and hydro models from previous steps) inside a closed-loop controller using a frequency bias parameter.

Components and Mathematical Models

  • Frequency Bias Factor (Frequency_Bias1)
    • Gain Value: 0.43
    • Formula: B1 = 0.43 pu MW/Hz
    • Details: This represents the Area Frequency Bias factor B1. It dictates how much the control area changes its generation in response to a frequency deviation. It is typically calculated as:

Where D1 is system damping and R1 is governor droop.

  • Main Plant Dynamics (Control Area1)
    • Input Port: Controlled_Response (receives the biased error signal).
    • Output Port: Del_F1 (△ f1).
    • Details: It groups the governor, steam turbine, penstock, hydro turbine, and generator/load blocks together.
  • Monitoring & Output Blocks
    • DelF1 Tag: Sends the frequency deviation signal (△ f1) to other interconnected control areas.
    • Omega1 Block: Converts the frequency deviation (△ f1) into angular velocity deviation △ ω1 for rotor stability analysis.
    • Time Scope: Tracks frequency settling time against real-time simulation seconds.

Figure 2 Block Diagram of Subsystem “Control Area 1”

This model represents the internal contents of the Control Area 1 subsystem seen in your previous step. It implements the secondary control loop using an Integral Controller to coordinate and distribute control actions between the Thermal Plant and the Hydro Plant.

  1. Integral Controller (Gain1 + Integrator1)
    • Transfer Function:
  • Details: This block acts on the Controlled _ Response (which represents the Area Control Error, or ACE).
  • The Negative Sign (-0.45): Represents negative feedback. If system frequency rises above normal, the controller reduces the generation command to bring the frequency back down.

2. Thermal Plant Subsystem (Thermal_Plant)

  • Input: Receives the integrated control command signal at its Controller_response port.
  • Internal Dynamics: Contains the Governor, Steam Turbine, and Generator-Load blocks.
  • Output: Del_F1 (△ f1), which is the final system frequency deviation.

3. Hydro Plant Subsystem (Hydro_Plant)

  • Input Tag H (Controller_Response): This signal tag routes the master controller response over to the hydro generation unit.
  • Internal Dynamics: Contains the hydro governor, transient droop compensator, and penstock non-minimum phase turbine dynamics.
  • Output Tag J (Del_Pghy1): Sends the change in hydro mechanical power generation back up into the thermal plant’s internal summing junction (DelPghy block in the first image) to support the grid load.

Figure 3: Block diagram of subsystem “Thermal power plant”

This model represents a Load Frequency Control (LFC) (or Automatic Generation Control) block diagram of a single-area power system.

It is used to maintain a stable system frequency (e.g., 50 Hz or 60 Hz) by balancing mechanical power generation with electrical load demand when sudden disturbances occur.

Figure 4: Block diagram of subsystem “Hydroelectric power plant”