Thesis Defense – Hasan Yılmaz (MSEE)

Hasan Yılmaz – M.Sc. in Electrical and Electronics Engineering

Asst. Prof. Göktürk Poyrazoğlu – Advisor

Date: 29.12.2025

Time: 13:00

Location: AB1 245

“Reactive Power Market Design for PV-Rich Distribution Networks”

Asst. Prof. Göktürk Poyrazoğlu, Özyeğin University

Prof. Dr. Bora Alboyacı, Kocaeli University

Asst. Prof. Yunus Yalman, Ankara Yıldırım Beyazıt University

Abstract:

The increasing integration of distributed photovoltaic (PV) generation sources into medium-voltage distribution networks offers significant opportunities for sustainable energy systems while introducing new technical and economic challenges. As PV generation meets local consumption, the active power drawn from the transmission network decreases, whereas reactive power demand persists; this situation increases the Q/P ratio at the High-Voltage/Medium-Voltage (HV/MV) connection point and imposes financial penalties on Distribution System Operators (DSO). Modern PV inverters can function as flexible reactive power sources owing to their dynamic P–Q capability curves. This thesis proposes a local market model for procuring reactive power as an ancillary service from PV inverters at the distribution level. The proposed model is structured in which the DSO serves as both the system operator and the market operator. The market-clearing problem is formulated as an optimal power flow problem with a 24-hour time horizon and hourly settlement periods. The model’s original contributions include a sustainability threshold, a ±10% tolerance-band mechanism, and an Expected Payment Function comprising components for capacity, utilization, and opportunity cost. This conceptual framework reduces the penalty risk for DSOs, creates a new revenue stream for PV owners, and establishes the theoretical foundation for market-based reactive power management in networks with high PV penetration.

Bio:

Hasan Yılmaz graduated from Sakarya University, Faculty of Engineering, Department of Electrical and Electronics Engineering in 2007. He is currently pursuing his M.Sc. studies in Electrical and Electronics Engineering at Özyeğin University. With approximately 15 years of industry experience, he is responsible for grid investments and R&D activities at AKSA Electricity Distribution companies. His research focuses on smart grids, distributed energy resources, and reactive power management. He has published a study titled "Reactive Power Market Design for Unutilized Resources to Address Net Metering Penalties in Türkiye."