Browsing by Author "Şekerci Öztura, Hacer"

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Citation - WoS: 1
Citation - Scopus: 1
A day-ahead EMS for transformer aging mitigation in distribution systems via coordinated PV-BESS inverter control under dynamic thermal constraint
(ELSEVIER SCIENCE SA, 2026) Sezai Polat; Emrah Biyik; Hacer Sekerci Oztura; Oztura, Hacer Sekerci; Şekerci Öztura, Hacer; Polat, Sezai; Biyik, Emrah
This paper proposes a novel day-ahead energy management system (EMS) that integrates dynamic thermal rating (DTR) of distribution transformers into the co-optimization of active and reactive power flows from photovoltaic (PV) and battery energy storage systems (BESS). The model comprehensively incorporates inverter and battery degradation costs transformer insulation aging and inverter losses while respecting operational and thermal constraints through both soft and hard constraint formulations. Simulations are performed on a modified IEEE 33-bus distribution system under three operational scenarios. Results demonstrate that aging-related costs can be reduced by up to 78 % through the inclusion of aging cost as a soft constraint and up to 85 % via the enforcement of hard hot-spot temperature (HST) constraints-without the need for transformer or BESS capacity increases. In comparison increasing the BESS capacity from 750 kWh to 1250 kWh yields a 2.4 % decrease in operational cost and 21 % reduction in aging cost. Increasing the transformer capacity from 3000 kVA to 4000 kVA further reduces aging cost by 96 % and operational cost by 5.8 % albeit at significant capital expenditure. The proposed DTR-aware EMS allows for safe transformer operation beyond nominal ratings enabling deferred infrastructure upgrades while maintaining system reliability and economic efficiency.
Citation - WoS: 5
Citation - Scopus: 6
Optimal active and reactive power scheduling for inverter-integrated PV and BESS under inverter current constraints
(ELSEVIER SCIENCE SA, 2025) Sezai Polat; Emrah Biyik; Hacer Sekerci Oztura; Şekerci Öztura, Hacer; Oztura, Hacer Sekerci; Polat, Sezai; Biyik, Emrah
The intermittent nature of renewable energy complicates grid integration requiring an efficient Energy Management System (EMS). This study addresses day-ahead EMS in distribution systems (DS) with a focus on active and reactive power scheduling utilizing the reactive power support of inverters in Photovoltaic (PV) and Battery Energy Storage Systems (BESS). A novel current-based method is proposed accounting for current limits bus voltage inverter lifetime reduction costs and inverter losses modeled as load. This method impacts load flow bus voltage and voltage-dependent loads enabling optimal decisions for compensating inverter losses via the grid BESS or PV. Simulations on the IEEE 33 test system show a 5% reduction in inverter losses with the currentbased method and 6% with the traditional power-based method. Inverter lifetime reduction costs were minimized by 42% and 58% with the current- and power-based methods respectively under summer conditions. In winter reductions reached 49% and 14%. Crucially inverter output depends on bus voltage challenging the assumption of constant rated power. At voltages below 1.00 p.u. inverters underperform achieving only 209 kVA of a 215 kVA rating. These findings emphasize the need for accurate modeling to improve EMS performance and reliability in renewable energy systems.