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A contribution to the online monitoring of partial discharges in high-voltage grid components
(2024)
Increasing utilization of HV power cable lines, and particularly the advent of long HVDC underground links, results in the need to sensitively monitor their condition, such as by tracking the emergence and development of partial discharges. This study demonstrates that existing solutions are poorly suited to the case of HVDC lines, and that a new, more sophisticated monitoring system needs to address a wide array of diverse problems. First of all, the overview of the task and main functional blocks of the monitoring system is given. Following this, selected blocks are subject to detailed examination in subsequent chapters.
The first of these blocks, a high-frequency current transformer (HFCT), is responsible for capturing the signal in the power line and transferring it to the electronics. This component receives in-depth coverage: general design considerations, computation of leakage inductance, operation in presence of a power current, resonant behavior, balanced design. Particular attention is given to the application of Finite Element Analysis (FEA) in relation to the HFCT, however, the demonstrated techniques can also be applied to other magnetic devices. Last section of the chapter presents various stages of development, experimental setups, prototypes, and the final device which has been put into series production.
The next block addresses extraction of signals from noise. A literature analysis is conducted concerning noise suppression in partial discharge recordings, and the application of the signal separation approach based on Linear Predictive Coding is shown.
In the section on localization, examples illustrating problems encountered during the development of a partial discharge localization algorithm are presented.
In the chapter devoted to laboratory tests, various auxiliary experiments conducted during the system's development are compiled, where some of them are: Time Domain Reflectometry (TDR) TDR-based line characterization, estimation of monitoring sensitivity, measurement of the cable attenuation and reflection coefficients of the accessories.
In the final chapter – field tests – the installation of the system on a 110 kV line and the measured transfer function are demonstrated.
In the time of increased awareness about the environment problems by the public opinion and also intensive international efforts to reduce emissions of greenhouse gases, as well increase of the generation of electrical energy to facilitate industrial growth, the conference offers broad contribution towards achieving the goals of diversification and sustainable development.
Focus of the student conference is to promote the discussion of views from scientists and students from Wroclaw University of Technology, Technical University of Ostrava and Brandenburg University of Technology Cottbus-Senftenberg.
The conference is a unique teaching session motivating the students to write science related papers, prepare presentations and discus future developments. It is a formal part of the curriculum offered as an elective module, accompanied by a technical excursion.
With the large-scale expansion of decentralized power generation from renewable energy resources (RES) and reduction of fossil fuel-based power generation, this leads to fundamental structural changes in the power supply system. The transition is characterized by a shift from central to decentral, from directional to bi-directional. As the share of renewable power systems in the electricity grid increases, the inherent uncertainty of renewable energies poses challenges to the grid system’s stability.
To achieve increased efficiency, decarbonisation, decentralization, and digitisation in energy sector, a flexible and resilient energy system is required. Electrical energy data and non-electrical energy data are generated from various sources, including the supervisory control and data acquisition system (SCADA), geographic information system (GIS), and weather information system. Based on these data, different spatial and temporal models of energy systems and their databases are created and connected. This thesis contributes to the analysis of regional power performance. To this end, an efficient simplified grid-oriented network cluster is presented to account for the regional allocation of RES power systems. The model clustering includes the grid topology, temporal and spatial resolution, and the structure of electrical and non-electrical data. This approach contributes to methodological aspects of energy system modelling and analysis.
In addition, based on the proposed cluster model, this thesis presents the physical profile-based and data-driven methods to estimate the regional large-scale photovoltaic (PV) and wind power generations. In order to adapt to the spatial-temporal heterogeneity of the regional renewable power generations and to improve the local power utilization rate, this thesis conducts empirical analyses of the regional energy storage and combined PV and wind power systems using cable pooling with shared grid connection.
In summary, this thesis presents a flexible modelling approach that takes into account the regional allocation of renewable power systems and enables a more accurate estimation of regional power generation. The proposed model and analytical methods can help the efficiency and resiliency of the energy system and support the transition towards renewable energies.
This analysis aims at the investigation of the techno-economic RES potentials and to minimize GHG emissions in the ENTSO-E. The ENTSO-E represents one of the world’s largest economic regions with a GDP of 19,835 billion US dollar (23%) and a primary energy consumption of 29,705 TWh (18%). ENTSO-E is coined with high degrees of fossil energy dependencies (49.9%) from third-party countries and contributes 3,517 Mt CO2eq (9%) to global GHG emissions. The Primary Sources onshore wind, offshore wind, utility-scale PV, and CSP techno-economic potentials are assessed via GIS-based georeferenced spatial analysis. Solar rooftop potentials are calculated based on a per capita approach. The Secondary Sources bioenergy, hydropower, geothermal, and hydrokinetic energy potentials are approximated based on meta-analysis. Primary and Secondary Sources potentials are input into the IES linear optimization model to simulate an energy system with high shares of RES and PTX. It is found that RES-based primary energy production potentials account for 13,492 TWh and energy dependency could be reduced by 6,482 TWh to 20.5%. Compared to the base year 1990, the direct GHG emission reduction amounts to 3,246 Mt CO2eq (70.7%). This reduction does not correspond with the EU reduction target of 80–95%. Hence, RES-based fuel imports, such as synthetic fuels and hydrogen, from third-party countries become necessary, to substitute fossil fuels and reduce domestic emissions. Additional GHG reduction potentials are suspected in the indirect emission sectors agriculture and waste management. In reference to the Sankey methodology, the analysis entails comprehensive energy flow balances for the ENTSO-E 2016 and 2050 energy systems. The ENTSO-E member countries exhibit heterogeneous properties regarding RES potentials, GHG emissions, and energy dependencies, and, hence, must be assessed individually. Integrated energy systems with high shares of RES and PTX represent a promising means to decrease direct energy use and non-energy use emissions as well as energy dependencies significantly.
In the time of increased awareness about the environment problems by the public opinion and also intensive international efforts to reduce emissions of greenhouse gases, as well increase of the generation of electrical energy to facilitate industrial growth, the conference offers broad contribution towards achieving the goals of diversification and sustainable development.
Focus of the student conference is to promote the discussion of views from scientists and students from Wroclaw University of Technology, Technical University of Ostrava and Brandenburg University of Technology Cottbus-Senftenberg.
The conference is a unique teaching session motivating the students to write science related papers, prepare presentations and discus future developments. It is a formal part of the curriculum offered as an elective module, accompanied by a technical excursion.
A cellular approach to optimize the integration of renewable generation into distribution networks
(2022)
The steady growth of the renewable-based technologies in the last twenty years has changed the character of the power systems significantly. Until today, there are more than 112 GW installed photovoltaic and wind parks in Germany and around 90% of the installed renewable generators are integrated into distribution networks. As a result, distribution networks are often facing congestion problems and more investments are needed for the required network development plans.
The political decisions in Germany for increasing the share of renewables in electricity consumption up to 65% until 2030 and the nuclear phase out until 2022 and further shutdowns of the coal power plants raised serious concerns about the reliability of power supply and feasibility of the transition plan.
The present dissertation has a look over the recent developments and offers a methodology for reduction of the resulted costs from further integration of renewable generators into the distribution networks. The suggested methodology is based on a cellular approach and helps also to postpone the unnecessary costly network expansions. Furthermore, it helps to integrate the renewable generators in an optimized way which has an added value to move towards the defined sustainability goals.
The proposed methodology has two steps. The first step is made up of the cellular approach and grey wolf optimization in MATLAB environment. In this step, the optimal combination of technologies for fulfillment of the defined goals are found out. The second step consists of the quasi dynamic simulations in PowerFactory environment. In this step, the suggested results from MATLAB optimization are investigated in semi-real situations. With the quasidynamic simulations, it is checked whether the results are tolerable from the point of view of network operation and whether it is possible to facilitate the network operation with certain strategies.
In the time of increased awareness about the environment problems by the public opinion and also intensive international efforts to reduce emissions of greenhouse gases, as well increase of the generation of electrical energy to facilitate industrial growth, the conference offers broad contribution towards achieving the goals of diversification and sustainable development.
Focus of the student conference is to promote the discussion of views from scientists and students from Wroclaw University of Technology, Technical University of Ostrava and Brandenburg University of Technology Cottbus-Senftenberg.
The conference offers prominent academics and industrial practitioners from all over the world the forum for discussion about the future of electrical energy and environmental issues and presents a base for identifying directions for continuation of research.
In the time of increased awareness about the environment problems by the public opinion and also intensive international efforts to reduce emissions of greenhouse gases, as well increase of the generation of electrical energy to facilitate industrial growth, the conference offers broad contribution towards achieving the goals of diversification and sustainable development.
Focus of the student conference is to promote the discussion of views from scientists and students from Wroclaw University of Technology, Technical University of Ostrava and Brandenburg University of Technology Cottbus-Senftenberg.
The conference offers prominent academics and industrial practitioners from all over the world the forum for discussion about the future of electrical energy and environmental issues and presents a base for identifying directions for continuation of research.
In the time of increased awareness about the environment problems by the public opinion and also intensive international efforts to reduce emissions of greenhouse gases, as well increase of the generation of electrical energy to facilitate industrial growth, the conference offers broad contribution towards achieving the goals of diversification and sustainable development.
Focus of the student conference is to promote the discussion of views from scientists and students from Wroclaw University of Technology, Technical University of Ostrava and Brandenburg University of Technology Cottbus-Senftenberg.
The conference offers prominent academics and industrial practitioners from all over the world the forum for discussion about the future of electrical energy and environmental issues and presents a base for identifying directions for continuation of research.
In the time of increased awareness about the environment problems by the public opinion and also intensive international efforts to reduce emissions of greenhouse gases, as well increase of the generation of electrical energy to facilitate industrial growth, the conference offers broad contribution towards achieving the goals of diversification and sustainable development.
Focus of the student conference is to promote the discussion of views from scientists and students from Wroclaw University of Technology, Technical University of Ostrava and Brandenburg University of Technology Cottbus-Senftenberg.
The conference offers prominent academics and industrial practitioners from all over the world the forum for discussion about the future of electrical energy and environmental issues and presents a base for identifying directions for continuation of research.