A Holistic Assessment Method of Power System Imbalances in the Presence of Variable Energy Resources

  • Aramazd Muzhikyan

Student thesis: Master's Thesis


One of the main roles of power system operator is maintaining the balance between power generation and consumption. In traditional power systems, mainly consisting of conventional (thermal) generation units, the balance is maintained effectively by day-ahead scheduling and real-time control of necessary resources (generation, reserves and regulation). The scheduled amount of reserves and regulation is assessed partially following NERC requirements and partially from experience (specific to each power system). However, penetration of variable energy resources (wind, solar, etc.) into power system changes the established standards and requirements. Variable energy resources (VER) introduce a new level of variability and uncertainty, which makes balancing of the system a challenging task. The assumptions made for traditional power system are not true, making existing methods of resource assessment and scheduling not effective. In this work power system imbalance mitigation is modeled as a consecutive implementation of regulation, real-time markets and operator manual actions. This integrated representation allows better understanding of relations between power system operations different time scales. This work establishes relations between scheduled resource adequacy and VER variability, forecasting uncertainty and timescales of power system operations. The results show, that reserve and regulation requirements depend on different characteristics of VER (day-ahead and real-time forecast, variability) and the properties of the power system (available ramping capabilities). The validity of established relations is demonstrated by simulations results.
Date of Award2013
Original languageAmerican English
SupervisorAmro M. Farid (Supervisor)


  • Smart Power Grids; Energy Storage; Variable Energy Resources
  • Power System.

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