Danilo Obradovic

Danilo Obradovic
KTH Royal Institute of Technology | KTH · Department of Electric Power Systems (EPS)

MSc and Licentiate in Electrical Engineering

About

12
Publications
1,778
Reads
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29
Citations
Citations since 2017
12 Research Items
29 Citations
201720182019202020212022202302468101214
201720182019202020212022202302468101214
201720182019202020212022202302468101214
201720182019202020212022202302468101214
Additional affiliations
September 2022 - present
Hitachi Energy
Position
  • HVDC System Design and Simulation Engineer

Publications

Publications (12)
Article
Full-text available
In many power systems, the increased penetration of inverter-based renewable generation will cause a decrease in kinetic energy storage, leading to higher frequency excursions after a power disturbance. This is the case of the future Nordic Power System (NPS). The look-ahead study reported in this paper shows that the chosen units participating in...
Preprint
Full-text available
Frequency Containment Reserves might be insufficient to provide an appropriate response in the presence of large disturbances and low inertia scenarios. As a solution, this work assesses the supplementary droop frequency-based Emergency Power Control (EPC) from HVDC interconnections, applied in the detailed Nordic Power System model. EPC distributi...
Article
Full-text available
Fundamental sensor feedback limitations for improving rotor angle stability using local frequency or phase angle measurement are derived. Using a two-machine power system model, it is shown that improved damping of inter-area oscillations must come at the cost of reduced transient stability margins, regardless of the control design method. The cont...
Preprint
Full-text available
A large share of renewable energy sources integrated into the national grids and an increased interconnection capacity with asynchronous networks, are the main contributors in reducing the kinetic energy storage in the Nordic Power System. Challenges arise to operate system after a loss of generation and to minimize the offshore systems interaction...
Article
Full-text available
This paper presents a comprehensive analysis of the impact that supplementary power control of an HVDC link has on the electromechanical dynamics of power systems. The presented work addresses an interesting phenomenon that may occur when an HVDC power controller is installed to support frequency stability. In specific cases, a high gain HVDC frequ...
Thesis
Full-text available
With ambitions of reducing the environmental pollution, power systems integrate larger shares of Renewable Energy Sources (RES) to phase out conventional thermal and nuclear generators. Since RES (such as wind and solar power) are connected to the grid through power electronics devices, they do not inherently contribute to system inertia. With decr...
Conference Paper
In this paper, strategies for a holistic integration of multiple HVDC links into existing power systems are presented. High Voltage Direct Current (HVDC) links can support the operation of AC grids on different timescales. Contrary to AC transmission lines, the power flow on HVDC links can be freely controlled. Due to their ability of rapidly contr...
Conference Paper
The Frequency Containment Reserve (FCR) one of the balancing actions to keep the frequency within acceptable limits. The objective of the FCR (also known as primary control) is to stabilize the system frequency within a short time interval after a disturbance. Related to that, maximum steady-state frequency deviation and maximum Instantaneous Frequ...
Preprint
Full-text available
In the Nordic region, many interconnectors are formed by HVDC links, as Scandinavia, Continental Europe and the Baltic region are non-synchronous AC systems. This paper presents two cost benefit analyses on the utilization of HVDC interconnectors in the Nordic countries: in the first we investigate the utilization of HVDC interconnectors for reserv...
Preprint
Full-text available
In this work, fundamental sensor feedback limitations, using a linear controller with local frequency measurement, are considered. It is shown that improved damping of inter-area oscillations must come at the cost of reduced transient stability margins, regardless of control design. The results are verified in the Kundur four-machine two-area test...

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Projects

Project (1)
Project
It is believed that HVDC connections will play a key role in an efficient and secure operation of the future system, mainly due to their capability to bulk power transmission over long distances and to provide fast and flexible control. However, today the operation of multi HVDC connections is not coordinated to the extent where safe system operation is ensured. This project's primary goal is to develop control strategies to support and improve AC system frequency stability. Moreover, these control actions should be carefully coordinated to avoid negative interaction with other stability types and operation factors in all interconnected systems. The aim is to use the current power system infrastructure, without implying large additional investment costs.