Integrating AGC to Generation Scheduling for Real-Time Operational Optimization

  • Ali T. Al-AwamiEmail author
Research Article - Electrical Engineering


This work proposes a new real-time operational framework for electric grids. This framework is based on converting generation scheduling optimization, which is conventionally triggered only in discrete instants of time, into a closed-loop control-based problem that automatically adjusts the generator power outputs constantly as system conditions change. However, maintaining frequency deviations within acceptable levels solely by the control-based generation scheduler is not sufficient. Therefore, to ensure adequately fast action, automatic generation control (AGC) is still needed. This work aims to provide a novel integrative approach that combines AGC and control-based generation scheduling into one framework. Simulation results show the efficacy of the proposed integrative framework in achieving effective frequency regulation while operating the system optimally in real time.


Automatic generation control Frequency regulation Generation scheduling Renewable energy 

List of Symbols


Unit index

\(\Delta \omega \)

Frequency deviation from the nominal value

\(\Delta P_\mathrm{m} \)

Mechanical power deviation

\(\Delta P_\mathrm{e} \)

Electrical power deviation

\(\Delta P_\mathrm{L} \)

Frequency-insensitive component of the load

\(\Delta P_\mathrm{v} \)

Governor valve position deviation

\(\Delta P_\mathrm{g} \)

Governor actuating signal

\(\Delta P_\mathrm{ref} \)

Load reference set point

\(\Delta P \)

Required generation adjustment

\(P_\mathrm{base} \)

Generation base points obtained by ED


Angular momentum of the generator shaft


Load-to-frequency sensitivity in kW/Hz

\(\tau _\mathrm{t} \)

Turbine time constant

\(\tau _\mathrm{g} \)

Governor valve time constant


Regulation (or droop) characteristic of the machine


Supplementary control gain


Participating factor

\(k_\mathrm{p}, \, k_\mathrm{i} \)

Proportional and integral control gains


Operating cost function


Parameters for the operating cost function


Minimum power output of a generating unit

\(P^\mathrm{max} \)

Maximum power output of a generating unit

\(P_\mathrm{load} \)

System load


Lagrangian function

\(\lambda \), \(\beta \)

Lagrange multipliers


Optimal power output of a generating unit


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The author would like to acknowledge the support of the Deanship of Research at King Fahd University of Petroleum & Minerals (Project No. RG171003) and the support provided by the King Abdullah City for Atomic and Renewable Energy (K.A.CARE).


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Copyright information

© King Fahd University of Petroleum & Minerals 2019

Authors and Affiliations

  1. 1.King Fahd University of Petroleum and MineralsDhahranSaudi Arabia
  2. 2.K.A.CARE Energy Research & Innovation CenterDhahranSaudi Arabia

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