Related Experiment Video
Updated: Jun 6, 2026
06:04
Experimental Investigation of the Hierarchical Control in DC Microgrids Using a Real-time Simulator
Published on: February 14, 2025
A CrOA-tuned cascaded (2DOF-PDf)-(LTI) controller for coordinated LFC-AVR regulation in interconnected power systems
Mohamed F Elnaggar1, A A El-Rahman2, Fsaha Mebrahtu Gebru3
1Department of Electrical Engineering, College of Engineering, Prince Sattam Bin Abdulaziz University, 11942, Al-Kharj, Saudi Arabia.
Scientific Reports
|June 4, 2026
Summary
This study introduces a new controller for stable power grids, enhancing Load Frequency Control (LFC) and Automatic Voltage Regulation (AVR) using an optimized cascaded design. The novel approach ensures robust performance against disturbances and parameter variations in interconnected systems.
Area of Science:
- Electrical Engineering
- Control Systems
- Power Systems
Background:
- Interconnected power systems face challenges in maintaining stable operation due to load disturbances, parameter uncertainties, and nonlinearities.
- Conventional control strategies often exhibit slow damping and reduced robustness in highly coupled frequency and voltage regulation loops.
Purpose of the Study:
- To propose a novel cascaded controller for coordinated Load Frequency Control (LFC) and Automatic Voltage Regulation (AVR) in a two-area interconnected power system.
- To enhance transient shaping, damping, and robustness while minimizing sensitivity to disturbances and parameter variations.
Main Methods:
- A cascaded controller combining a two-degree-of-freedom proportional-derivative controller with filtered derivative action (2DOF-PDf) and a leaky tilt-integral (LTI) stage was developed.
- Controller parameters were optimized using the Crayfish Optimization Algorithm (CrOA) based on the Integral of Time-weighted Squared Error (ITSE) criterion.
- The proposed scheme was evaluated under various operating conditions, including nonlinearities and parametric uncertainty, using MATLAB/Simulink.
Main Results:
- The CrOA demonstrated effectiveness compared to other optimization algorithms (ChOA, DOA, SCA, GTO, GBO).
- The proposed CrOA-tuned cascaded (2DOF-PDf)-(LTI) controller outperformed benchmark controllers (PID, TID, FOPID, FOPI-PIDD²) in damping, frequency deviations, tie-line power deviations, and voltage regulation.
- The controller showed robust performance under significant parametric uncertainty (up to ±40%) and practical nonlinearities (GRC, GDB).
Conclusions:
- The proposed cascaded controller offers a robust and effective solution for coordinated frequency and voltage regulation in interconnected power systems.
- The CrOA is a viable and effective optimization tool for tuning complex control systems in power applications.
Related Concept Videos
01:17Open and closed-loop control systems
Control systems are foundational elements in automation and engineering. They are broadly categorized into open-loop and closed-loop systems. These classifications hinge on the presence or absence of feedback mechanisms, significantly influencing the system's performance, complexity, and application.
An open-loop control system operates without feedback from the output. It consists of two primary elements: the controller and the controlled process. The controller receives an input signal and...
An open-loop control system operates without feedback from the output. It consists of two primary elements: the controller and the controlled process. The controller receives an input signal and...
01:22Phase-lead and Phase-lag Controllers
Understanding the working function of different types of controllers can be illustrated with practical analogies, such as adjusting a stereo's volume equalizer. Cranking up the bass involves a phase-lead controller, which functions as a high-pass filter, while increasing the treble uses a phase-lag controller, which acts as a low-pass filter. PD controllers, similar to high-pass filters, enhance the system's response to high-frequency components. PI controllers, akin to low-pass filters, manage...
01:26Feedback control systems
Feedback control systems are categorized in various ways based on their design, analysis, and signal types.
Linear feedback systems are theoretical models that simplify analysis and design. These systems operate under the principle that their output is directly proportional to their input within certain ranges. For instance, an amplifier in a control system behaves linearly as long as the input signal remains within a specific range. However, most physical systems exhibit inherent nonlinearity...
Linear feedback systems are theoretical models that simplify analysis and design. These systems operate under the principle that their output is directly proportional to their input within certain ranges. For instance, an amplifier in a control system behaves linearly as long as the input signal remains within a specific range. However, most physical systems exhibit inherent nonlinearity...
01:21Transfer Function in Control Systems
The transfer function is a fundamental concept in the analysis and design of linear time-invariant (LTI) systems. It offers a concise way to understand how a system responds to different inputs in the frequency domain. It serves as a bridge between the time-domain differential equations that describe system dynamics and the frequency-domain representation that facilitates easier manipulation and analysis.
To derive the transfer function, consider a general nth-order linear time-invariant...
To derive the transfer function, consider a general nth-order linear time-invariant...
01:30Control of Power Flow
There are several methods to control power flow in power systems:
01:28Load-frequency control
Load-frequency control (LFC) is vital for maintaining power system stability, ensuring that frequency and power flows remain within acceptable limits during load changes. Turbine-governor control eliminates rotor accelerations and decelerations following load changes. However, a steady-state frequency error persists when the change in the turbine-governor reference setting is zero. In an interconnected power system, each area agrees to export or import a scheduled amount of power through...