In future power systems the resources connected at the distribution level will become increasingl... more In future power systems the resources connected at the distribution level will become increasingly important. A significant share of the additional renewable generation, particularly photovoltaic, is expected to be located at the distribution level. The same can be also expected for electric loads, which will increase due to the spread of electric vehicles and electric heat pumps. To integrate the new resources, the distribution system operators will need to reinforce the network or to adopt advanced control solutions. Both these strategies require important investments, that must be correctly planned. Besides, to determine the best approach from an economic, regulatory and technical point of view, extensive simulations have to be performed on a large number of real distribution networks. However, the network data of real distribution networks are not usually public. In this paper the future evolution of the Italian distribution networks is studied by means of synthetic networks. These networks have characteristics similar to the real distribution networks and are used to outline some preliminary analysis of the impact of new loads and photovoltaic generators.
The local environmental concerns and the decarbonization process favored by European and national... more The local environmental concerns and the decarbonization process favored by European and national policymakers drive the spread of new technologies, such as electric heating/cooling systems, residential photovoltaic generators, and electric mobility. Since these new equipment are mostly connected to the MV and LV levels of the electricity network, their widespread implementation will substantially impact electric distribution systems planning an operation. The analysis of future development scenarios and the impact of new control techniques are, therefore, preparatory for the evolution of the planning and operation of electric networks, specifically the distribution networks. The simulations reported in this paper integrates the network data, including a georeferenced description of the distribution network, with external public databases information. Thanks to the proposed approach, the impact of the new equipment can be studied considering different scenario hypotheses investigating the evolution of the distribution network in detail. In particular, the methodology is applied to the distribution network of Brescia, a city in Northern Italy.
The recent increase of distributed generation in distribution networks has determined the necessi... more The recent increase of distributed generation in distribution networks has determined the necessity of developing new control strategies for the mitigation of power quality issues. One of these functions, considered as one of the most promising solutions for the management of voltage congestions, is represented by the droop control of DG units. The traditional Power Flow formulation often does not allow an easy integration of these functionalities in the simulation environment and alternative techniques are normally used in order to study the effects of local controllers on the network electrical quantities. This paper proposes a simple modification for canonical Power Flow engines that allows the integration of local controllers for distributed generation. The described method guarantees a robust and fast solution of network simulations even for non-linear/piecewise droop control functions.
The increasing share of renewables is creating new challenges for distribution grids and operator... more The increasing share of renewables is creating new challenges for distribution grids and operators have to adopt more and more advanced tools for the evaluation of network investments, especially for scenarios in which distributed generation is expected to drastically grow. In particular, the maximum connectable power (Hosting Capacity) as well as the benefits that Smart Grid technology can bring to the distribution system have to be analyzed in detail and in multiple scenarios. The paper proposes a probabilistic approach for the calculation of the Hosting Capacity based on the random allocation of generation resources, which models the uncertainty related to their position within the network in the next future. Thanks to this approach, control solutions can be exhaustively evaluated and their performance can be compared in several possible scenarios of distributed generation expansion.
Since the last decade, distribution networks are facing a continuously growing penetration of dis... more Since the last decade, distribution networks are facing a continuously growing penetration of distributed generation, mostly thanks to the “clean energy” incentives promoted by national governments. In particular, these initiatives have enhanced the presence of renewable-based generators in electricity grids. Taking advantage of their intermittent nature, the curtailment of a small portion of production does not significantly impacts on the total injected energy but it can provide significant benefits for distribution networks. The paper analyzes some of the most common curtailment strategies applied on different kind of renewable resources, demonstrating their high potential in terms of hosting capacity increase.
Active Distribution Networks (ADNs), which are distribution networks with high presence of Distri... more Active Distribution Networks (ADNs), which are distribution networks with high presence of Distributed Generation (DG) — in particular from Renewable Energy Sources (RESs) — represent a challenge for Distributed System Operators (DSOs). In recent years, the installation of Electrical Storage Systems (ESSs) managed by the DSO is under investigation as a possible option for increasing the flexibility of network operation, enhancing the Power Quality, improving voltage profiles and managing energy losses. The optimization of the connection point in the planning phase (i.e. seasonally, weekly…), obtained through an objective function minimizing network losses under voltage and current constraints, is fundamental for these resources and represents a further option to increase their effectiveness. The paper discusses the definition of a proper metric to rank the different connection points. Besides, it describes a related automatic procedure implemented in an Italian network in order to show the advantage of the methodology.
The fast growth of distributed generation (DG), in particular from non-programmable renewable res... more The fast growth of distributed generation (DG), in particular from non-programmable renewable resources, poses many challenges on the management of MV networks. Storage systems, operated by the Distributor System Operator (DSO) or by third parties, may mitigate both the local and global effects of the DG. A major challenge is the identification of the optimal position and power exchange according to the desired objective. This paper introduces an innovative approach for the identification of the optimal position and the optimal exchange power profile for storage systems. The proposed approach, oriented to the minimization of the energy losses, has been based on simple analytical expressions, which gives a fast and immediate perception of the efficiency problem and a detailed physical explanation of the differences between the selected positions. This method could be extended from the storage system to all the local resources.
In order to perform significant cost/benefit and scalability/replicability analyses, it is necess... more In order to perform significant cost/benefit and scalability/replicability analyses, it is necessary to process a large set of distribution networks. However, the small number of networks available in literature is one of the main limitations on studying the impact of advanced control systems and their industrialization potential. To overcome this problem a methodology to generate artificial and realistic networks is presented. The methodology is based on a preliminary study carried out on real networks models. Starting from them the main topology, electrical and energetic information are identified and processed by means of an automatic procedure aimed at creating new networks with the desired characteristics.
The local environmental concerns and the need to replace fossil fuels with renewable sources to d... more The local environmental concerns and the need to replace fossil fuels with renewable sources to decrease carbon dioxide emissions, are driving the spread of new technologies, such as electric heating/cooling systems, residential photovoltaic generators, and electric mobility. These new equipment will be mostly connected to the electricity distribution networks, managed by distribution system operators. The definition of realistic future scenarios, in terms of network topology and user characteristics, is essential to determine the impact of these resources. This paper shows a methodology for integrating the network data with external public databases information to forecast the future impact of electromobility. In particular, the electromobility scenario is defined by exploiting public information regarding the position of public parking areas and the Origin-Destination (O-D) matrixes. This information, together with a georeferenced description of the distribution network, can be used to determine the impact on the network of electric vehicles recharge. The methodology is applied to the distribution network of Brescia, a city in Northern Italy.
The reduction of greenhouse emissions will require that renewable energy sources represent a sign... more The reduction of greenhouse emissions will require that renewable energy sources represent a significant portion of the generation energy mix. An important contribution is expected by resources installed at the distribution network level, such as photovoltaic generators. The distribution networks will then play a key role for the decarbonisation of the power system and they will require both conventional reinforcements and innovative control solutions. These issues are not new, since in the past years some countries already faced the problem of combining network refurbishment and advanced control strategies to install a significant share of distributed generation. The objective of this paper consists of showing how historical data can be used to estimate the future evolution of the power system. The analysis is focused on the Italian electricity distribution system, where the distributed generation already represents a large percentage of the energy mix.
The centralized control is one of the methods proposed, also by the Italian Regulatory Authority ... more The centralized control is one of the methods proposed, also by the Italian Regulatory Authority (consultation 255/15), to integrate more renewable energy sources in the electrical networks. Due to the limited number of available measurements in the distribution system, one of the key problems for a centralized control scheme is the correct estimation of the network state. In general, the placement of the measurement devices on the network is performed in order to obtain an averagely accurate state estimation. However, the paper demonstrates how centralized controllers efficacy highly depends on the accurate monitoring of few strategic areas of the network while the impact of the global uncertainty of the state estimation in other grid nodes is marginal.
In future power systems the resources connected at the distribution level will become increasingl... more In future power systems the resources connected at the distribution level will become increasingly important. A significant share of the additional renewable generation, particularly photovoltaic, is expected to be located at the distribution level. The same can be also expected for electric loads, which will increase due to the spread of electric vehicles and electric heat pumps. To integrate the new resources, the distribution system operators will need to reinforce the network or to adopt advanced control solutions. Both these strategies require important investments, that must be correctly planned. Besides, to determine the best approach from an economic, regulatory and technical point of view, extensive simulations have to be performed on a large number of real distribution networks. However, the network data of real distribution networks are not usually public. In this paper the future evolution of the Italian distribution networks is studied by means of synthetic networks. These networks have characteristics similar to the real distribution networks and are used to outline some preliminary analysis of the impact of new loads and photovoltaic generators.
The local environmental concerns and the decarbonization process favored by European and national... more The local environmental concerns and the decarbonization process favored by European and national policymakers drive the spread of new technologies, such as electric heating/cooling systems, residential photovoltaic generators, and electric mobility. Since these new equipment are mostly connected to the MV and LV levels of the electricity network, their widespread implementation will substantially impact electric distribution systems planning an operation. The analysis of future development scenarios and the impact of new control techniques are, therefore, preparatory for the evolution of the planning and operation of electric networks, specifically the distribution networks. The simulations reported in this paper integrates the network data, including a georeferenced description of the distribution network, with external public databases information. Thanks to the proposed approach, the impact of the new equipment can be studied considering different scenario hypotheses investigating the evolution of the distribution network in detail. In particular, the methodology is applied to the distribution network of Brescia, a city in Northern Italy.
The recent increase of distributed generation in distribution networks has determined the necessi... more The recent increase of distributed generation in distribution networks has determined the necessity of developing new control strategies for the mitigation of power quality issues. One of these functions, considered as one of the most promising solutions for the management of voltage congestions, is represented by the droop control of DG units. The traditional Power Flow formulation often does not allow an easy integration of these functionalities in the simulation environment and alternative techniques are normally used in order to study the effects of local controllers on the network electrical quantities. This paper proposes a simple modification for canonical Power Flow engines that allows the integration of local controllers for distributed generation. The described method guarantees a robust and fast solution of network simulations even for non-linear/piecewise droop control functions.
The increasing share of renewables is creating new challenges for distribution grids and operator... more The increasing share of renewables is creating new challenges for distribution grids and operators have to adopt more and more advanced tools for the evaluation of network investments, especially for scenarios in which distributed generation is expected to drastically grow. In particular, the maximum connectable power (Hosting Capacity) as well as the benefits that Smart Grid technology can bring to the distribution system have to be analyzed in detail and in multiple scenarios. The paper proposes a probabilistic approach for the calculation of the Hosting Capacity based on the random allocation of generation resources, which models the uncertainty related to their position within the network in the next future. Thanks to this approach, control solutions can be exhaustively evaluated and their performance can be compared in several possible scenarios of distributed generation expansion.
Since the last decade, distribution networks are facing a continuously growing penetration of dis... more Since the last decade, distribution networks are facing a continuously growing penetration of distributed generation, mostly thanks to the “clean energy” incentives promoted by national governments. In particular, these initiatives have enhanced the presence of renewable-based generators in electricity grids. Taking advantage of their intermittent nature, the curtailment of a small portion of production does not significantly impacts on the total injected energy but it can provide significant benefits for distribution networks. The paper analyzes some of the most common curtailment strategies applied on different kind of renewable resources, demonstrating their high potential in terms of hosting capacity increase.
Active Distribution Networks (ADNs), which are distribution networks with high presence of Distri... more Active Distribution Networks (ADNs), which are distribution networks with high presence of Distributed Generation (DG) — in particular from Renewable Energy Sources (RESs) — represent a challenge for Distributed System Operators (DSOs). In recent years, the installation of Electrical Storage Systems (ESSs) managed by the DSO is under investigation as a possible option for increasing the flexibility of network operation, enhancing the Power Quality, improving voltage profiles and managing energy losses. The optimization of the connection point in the planning phase (i.e. seasonally, weekly…), obtained through an objective function minimizing network losses under voltage and current constraints, is fundamental for these resources and represents a further option to increase their effectiveness. The paper discusses the definition of a proper metric to rank the different connection points. Besides, it describes a related automatic procedure implemented in an Italian network in order to show the advantage of the methodology.
The fast growth of distributed generation (DG), in particular from non-programmable renewable res... more The fast growth of distributed generation (DG), in particular from non-programmable renewable resources, poses many challenges on the management of MV networks. Storage systems, operated by the Distributor System Operator (DSO) or by third parties, may mitigate both the local and global effects of the DG. A major challenge is the identification of the optimal position and power exchange according to the desired objective. This paper introduces an innovative approach for the identification of the optimal position and the optimal exchange power profile for storage systems. The proposed approach, oriented to the minimization of the energy losses, has been based on simple analytical expressions, which gives a fast and immediate perception of the efficiency problem and a detailed physical explanation of the differences between the selected positions. This method could be extended from the storage system to all the local resources.
In order to perform significant cost/benefit and scalability/replicability analyses, it is necess... more In order to perform significant cost/benefit and scalability/replicability analyses, it is necessary to process a large set of distribution networks. However, the small number of networks available in literature is one of the main limitations on studying the impact of advanced control systems and their industrialization potential. To overcome this problem a methodology to generate artificial and realistic networks is presented. The methodology is based on a preliminary study carried out on real networks models. Starting from them the main topology, electrical and energetic information are identified and processed by means of an automatic procedure aimed at creating new networks with the desired characteristics.
The local environmental concerns and the need to replace fossil fuels with renewable sources to d... more The local environmental concerns and the need to replace fossil fuels with renewable sources to decrease carbon dioxide emissions, are driving the spread of new technologies, such as electric heating/cooling systems, residential photovoltaic generators, and electric mobility. These new equipment will be mostly connected to the electricity distribution networks, managed by distribution system operators. The definition of realistic future scenarios, in terms of network topology and user characteristics, is essential to determine the impact of these resources. This paper shows a methodology for integrating the network data with external public databases information to forecast the future impact of electromobility. In particular, the electromobility scenario is defined by exploiting public information regarding the position of public parking areas and the Origin-Destination (O-D) matrixes. This information, together with a georeferenced description of the distribution network, can be used to determine the impact on the network of electric vehicles recharge. The methodology is applied to the distribution network of Brescia, a city in Northern Italy.
The reduction of greenhouse emissions will require that renewable energy sources represent a sign... more The reduction of greenhouse emissions will require that renewable energy sources represent a significant portion of the generation energy mix. An important contribution is expected by resources installed at the distribution network level, such as photovoltaic generators. The distribution networks will then play a key role for the decarbonisation of the power system and they will require both conventional reinforcements and innovative control solutions. These issues are not new, since in the past years some countries already faced the problem of combining network refurbishment and advanced control strategies to install a significant share of distributed generation. The objective of this paper consists of showing how historical data can be used to estimate the future evolution of the power system. The analysis is focused on the Italian electricity distribution system, where the distributed generation already represents a large percentage of the energy mix.
The centralized control is one of the methods proposed, also by the Italian Regulatory Authority ... more The centralized control is one of the methods proposed, also by the Italian Regulatory Authority (consultation 255/15), to integrate more renewable energy sources in the electrical networks. Due to the limited number of available measurements in the distribution system, one of the key problems for a centralized control scheme is the correct estimation of the network state. In general, the placement of the measurement devices on the network is performed in order to obtain an averagely accurate state estimation. However, the paper demonstrates how centralized controllers efficacy highly depends on the accurate monitoring of few strategic areas of the network while the impact of the global uncertainty of the state estimation in other grid nodes is marginal.
Uploads