Browsing by Author "Pisica, Ioana"
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Conference Object Citation Count: 1Analysis of Local and Centralized Control of PV Inverters for Voltage Support in Distribution Feeders(IEEE, 2021) Ceylan, Oğuzhan; Paudyal, Sumit; Pisica, IoanaHigher photovoltaic penetration on distribution system brings operational challenges including overvoltage issues. With smart inverters, efficient voltage control can be achieved through adjusting active/reactive powers of inverters. However, reactive power may not be as effective as active power in regulating voltage due to high R/X ratio of distribution networks. Thus, active power curtailment (APC) techniques in coordination with reactive power control are required in distribution networks. In this study, we aim to evaluate the performances of a sensitivity based method and an optimal power flow (OPF) based centralized method of reactive power control (in coordination with APC) from inverters in managing voltage profile on distribution networks. We performed simulations on a 730-node MV/LV system upto 100% PV penetration. Based on the case studies using different penetration levels of PVs, we observed that: a) sensitivity based method is not always able to solve overvoltage issues and energy curtailments are high, and b) OPF-based method can ensure that voltage remains within the operational bound with significantly less energy curtailment.Conference Object Citation Count: 0Multi-Agent model of electricity networks - a perspective on distribution network charges(Institute of Electrical and Electronics Engineers Inc., 2019) Ceylan, Oğuzhan; Ceylan, OğuzhanIn the UK, DNOs are regulated by Ofgem to use two common distribution use of system charging methodologies: Common Distribution Charging Methodology and Extra-High Voltage Distribution Charging Methodology. To account for the changing landscape of the energy sector, Ofgem has recently published a consultation paper on changes to DUoS charging structure. This paper looks into the implications of distribution network charging in consumer-level adoption of low carbon technologies and vice-versa, using an agent-based model approach.Article Citation Count: 0Multi-Criteria Decision Making in Optimal Operation Problem of Unbalanced Distribution Networks Integrated With Photovoltaic Units(Ieee-inst Electrical Electronics Engineers inc, 2024) Ebadi, Ramin; Ceylan, Oğuzhan; Aboshady, F. M.; Ceylan, Oguzhan; Pisica, Ioana; Ozdemir, AydoganThe use of renewable energy sources is increasing day by day due to their economic and environmental benefits. However, improper penetration of renewable energy into power grids can lead to problems such as over-voltages and higher active power losses. Therefore, the voltage regulation problem in distribution networks is critical due to the increasing integration of renewable energy sources. On the other hand, an increase in renewable energy penetration leads to lower operational costs due to decreased energy purchases from the overhead grid. Therefore, it can be challenging for distribution system operators (DSOs) to decide the trade-off between more Photovoltaic (PV) integration for cost minimization or less penetration to minimize voltage deviation from a rated value. In this study, we formulated this trade-off as a novel multi-objective optimization framework, aiming to minimize operating costs and voltage deviations from a rated value in an unbalanced distribution grid. The proposed formulation is applied to the modified IEEE 34-bus unbalanced distribution network, where the epsilon-constraint method is utilized for solving the resulting multi-objective optimization problem along with the Exterior Penalty Functions (EPF) method. The simulation results show that the proposed approach provides the DSO with a better view of decision-making in the optimal operation of the distribution networks.Conference Object Citation Count: 0Semi-Centralized Control of Distributed Generation in Smart Grids(IEEE, 2018) Ceylan, Oğuzhan; Pisica, Ioana; Paudyal, SumitThis paper proposes a semi-centralized intelligent control approach for voltage regulation in distribution grids based on sensitivity calculations. The model checks the voltage magnitudes of each end of each lateral in the system one by one then if any of these violates the allowed voltage magnitudes each node in a single lateral sends its reactive power capability and sensitivity information to the sensor located at the beginning node of that lateral. This information is sorted at the sensor and required voltage is computed and assigned to the bids one by one. This paper tests this approach on a modified 33 Node Distribution Test system with several renewable energy sources: photovoltaics (PVs) and wind turbines (WTs) and presents the numerical results based on a 15 minute resolution load data PV outputs and WT outputs.Conference Object Citation Count: 0Voltage Control of Unbalanced Distribution Systems with Penetration of Renewable Sources: A Gradient-Based Optimization Approach(IEEE, 2022) Ceylan, Oğuzhan; Senyuz, Hande; Aboshady, Fathy; Ceylan, Oguzhan; Pisica, Ioana; Ozdemir, AydoganThe penetration of distributed energy resources (DERs), including renewable energy sources (RES), into electric power systems has led to several challenges for the system operators. Despite various economic and environmental benefits offered by RES, the issue of voltage rise due to active power injection from RES is still an open problem. On the other hand, voltage decrease due to high load in distribution systems is another challenge faced by operators. In this study, we investigated the problem of over-voltage and under-voltage in the operation of unbalanced 3-phase distribution systems with penetration of RES. Moreover, We utilize derivative-based Exterior Penalty Function (EPF) optimization to solve the voltage deviation problem. The results of the tests conducted on a modified IEEE 13 Bus Test System have confirmed that the use of the tap changer voltage regulators and reactive power from PVs connected close to inverters can effectively contribute to the voltage control problem.