Pablo Frias - Academia.edu (original) (raw)
Papers by Pablo Frias
The expected massive penetration of renewable energy sources (RES) in Spain, added to its limited... more The expected massive penetration of renewable energy sources (RES) in Spain, added to its limited electricity interconnection capacity, will demand not only the introduction of flexible resources in the Spanish power system but also a stronger transmission capacity between this country and Europe. In this context, this paper computes the economic additional interconnection capacity between Spain and Central Europe based on the trade-off between transmission capacity cost and RES spillage cost. For this purpose, a model that simulates the hourly operation of the Spanish power system for a period of one year is used to compute hourly spillage. This analysis covers the period of 2020-2050 and includes four scenarios of RES penetration. In addition, a sensitivity analysis in relation to the cost parameters is presented.
In order to meet the 20-20-20 European energy policy commitments Spain should continue increasing... more In order to meet the 20-20-20 European energy policy commitments Spain should continue increasing the amount of electricity production from renewable energy sources (RES) along this decade. This paper analyzes the impact of the future RES deployment on the Spanish power system. Six scenarios are defined by setting different RES installed capacity targets and considering the uncertainty in fuel prices. First, the generation mix is planned for the horizon 2010-20 calculating the investment required in conventional thermal generation for each scenario. Then the system operation, hour by hour, is simulated in 2020 for each generation mix in each scenario. Operational fuel and carbon emission costs are calculated. Costs associated with operational reserves and wind curtailment to counteract or wind power intermittency and predictability errors are also computed. Finally, total systems costs, both investment and operating costs, are compared in the considered scenarios. The economic impact on electricity prices and operational margins of actual power plants is also discussed.
This paper analyzes how traditional regul a- tion of distribution system operators (DSO) has to b... more This paper analyzes how traditional regul a- tion of distribution system operators (DSO) has to be im- proved to accommodate higher levels of distributed genera- tion (DG). In addition, new economic signals to be given to DG operators for system efficient integration are p roposed. Regulatory improvements at the European level are rec- ommended. Recommendations are centered on schemes for DSO revenue compensation to consider incremental net- work costs due to DG, distribution network planning inte- grating DG, and DSO incentives for improving network performance with active integration of DG. Regarding DG economic signals, recommendations are focused on the design of DG connection and use-of-system charges, the revision of current DG support mechanisms based on flat feed-in tariffs, and the provision of ancillary ser vices by DG for network voltage and flow controls and islanding.
IEEE Transactions on Power Delivery, 2010
This paper presents a high-efficiency voltage regulator, which combines robustness, low costs and... more This paper presents a high-efficiency voltage regulator, which combines robustness, low costs and easy maintenance without power electronics components. These characteristics make it suitable for rural networks, where investments and operational cost in power quality improvement are limited. The regulator consists of a multiwinding reduced-power transformer, and provides serial voltage compensation. Different voltage compensation steps are obtained by modifying the
IEEE Transactions on Energy Conversion, 2011
Frequency response analysis (FRA) is a very common test for the diagnosis of power transformers. ... more Frequency response analysis (FRA) is a very common test for the diagnosis of power transformers. This paper presents some relevant results on the application of FRA to the diagnosis of rotating machines. First, a reference rotor position for obtaining the reference FRA response of a rotating machine is proposed. Then, FRA with the proposed rotor position is used to identify faults in the stator of the machine. This paper studies turn-to-turn and ground faults in the stator for different fault resistance values. Several laboratory tests demonstrate the applicability and value of the use of FRA in the diagnosis of rotating machines.
IEEE Transactions on Energy Conversion, 2011
Abstract This paper presents a novel on-line rotor ground fault location method for synchronous m... more Abstract This paper presents a novel on-line rotor ground fault location method for synchronous machines, which, combined with rotor ground fault protection, can detect and locate faults in the rotor. This method is suitable for synchronous machines with static ...
Power Engineering Society, IEEE General Meeting, 2008
This paper presents a comprehensive design for reactive power markets. Under this approach, the S... more This paper presents a comprehensive design for reactive power markets. Under this approach, the System Operator purchases the required reactive power capacity for generation and absorption from the reactive power market agents. To introduce competition in the proposed market different agents are able to participate in the annual auction, such as generators, capacitor banks, shunt reactors, SVCs or STATCOM devices. The optimal purchase of the required capacity is performed using an optimization algorithm that minimizes the costs associated with the voltage control service. The reactive power requirements in the power system are calculated taking into account different operation scenarios, which include critical system contingencies.
This paper presents a new approach to design long-term zonal reactive power capacity markets. Und... more This paper presents a new approach to design long-term zonal reactive power capacity markets. Under this approach, in each voltage control area, an annual auction to procure reactive power capacity is conducted by the System Operator. A key contribution of the paper is the method to compute the zonal demand curve using the marginal utility function. This function is calculated as the variation of the expected operation costs when the reactive power capacity in the area is increased. The applicability of the approach is illustrated in a case study with one voltage control area.
IEEE Transactions on Power Systems, 2008
Abstract This paper presents a new approach to design reactive power capacity markets. Under this... more Abstract This paper presents a new approach to design reactive power capacity markets. Under this approach annual auctions to procure reactive power capacity are conducted by the system operator. Two products are defined, reactive power generation and absorption ...
2013 IEEE Grenoble Conference, 2013
ABSTRACT In order to comply with the European Union's ambitious renewable targets for 202... more ABSTRACT In order to comply with the European Union's ambitious renewable targets for 2020, extensive investments in wind generation capacity have been made. Wind power plants are located primarily where the resource is available, which can lead to local transmission constraints during certain periods. In order to avoid transmission congestions, short-term measures that increase system operation costs such as topological maneuvers, conventional generation redispatch and wind curtailment are taken by the system operator. In this context, this paper performs a cost-benefit analysis of the installation of a Flexible AC Transmission Systems (FACTS) device to avoid transmission congestions in a Spanish area dominated by wind generation contributing to a more efficient integration of wind power. Furthermore, it is computed the additional wind power that could be integrated with the installation of this device.
International Journal of Electrical Power & Energy Systems, 2009
This paper analyzes how traditional regulation of distribution system operators (DSO) has to be i... more This paper analyzes how traditional regulation of distribution system operators (DSO) has to be improved to accommodate higher levels of distributed generation (DG). In addition, new economic signals to be given to DG operators for system efficient integration are proposed. Regulatory improvements at the European level are recommended. Recommendations are centered on schemes for DSO revenue compensation to consider incremental network costs due to DG, distribution network planning integrating DG, and DSO incentives for improving network performance with active integration of DG. Regarding DG economic signals, recommendations are focused on the design of DG connection and use-of-system charges, the revision of current DG support mechanisms based on flat feed-in tariffs, and the provision of ancillary services by DG for network voltage management, power flow controls and islanding.
Energy Policy, 2009
The European Energy Policy promotes renewable energy sources and energy efficiency as means to mi... more The European Energy Policy promotes renewable energy sources and energy efficiency as means to mitigate environmental impact, increase security of supply and ensure economic competitiveness. As a result, the penetration levels of distributed generation (DG) in electricity networks are bound to increase. Distribution networks and distribution system operators (DSOs) will be especially affected by growing levels of DG. This paper reviews the current regulation of distribution in the European Union Member States, focusing on those aspects that might hinder the future integration of DG. Several regulatory issues that may hinder a successful integration of DG have been identified. Recommendations to improve the current situation are proposed. Regarding economic signals sent to DG, connection charges and cost-reflective use-of-system charges together with incentives to provide ancillary services are the key aspects. Concerning DSOs regulation, unbundling from generation and supply according to the European Electricity Directive, incentives for optimal planning and network operation considering DG, including energy losses and quality of service, and innovation schemes to migrate to active networks are the most relevant topics.
International Journal of Electrical Power & Energy Systems, 2014
Smart MV/LV substations will play a crucial role in the evolution towards a smarter distribution ... more Smart MV/LV substations will play a crucial role in the evolution towards a smarter distribution grid. The implementation of smart MV/LV substations can provide a significant improvement of continuity of supply. However, a large investment is required, so the optimal level of implementation must be found. This paper aims to provide a methodology to determine the optimal degree of automation comparing the costs of increasing automation to the benefits derived from the improvement of continuity of supply achieved. First, the impact of different degrees of implementation of smart MV/LV substations on continuity of supply is quantified using a reference network model (RNM). Then, an economic analysis is performed to assess automation costs and supply interruptions costs from two different perspectives, considering non supplied energy for network users and alternatively regulatory incentives for distribution companies. Finally, the optimal degree of automation is identified by comparing marginal costs. Furthermore, the methodology proposed is applied to two large scale test cases of an urban and a semi-urban network. The results obtained highlight the need to compare costs and benefits showing that there is indeed an optimal degree of automation different from the complete automation of the distribution system.
2012 3rd IEEE PES Innovative Smart Grid Technologies Europe (ISGT Europe), 2012
ABSTRACT The medium to low voltage transformer substation is a key element in the distribution sy... more ABSTRACT The medium to low voltage transformer substation is a key element in the distribution system. Therefore, smart transformer substations will play a crucial role in the evolution of distribution towards the smart grid. Smart transformer substations can provide a significant improvement of continuity of supply. However, a large investment is required, so the optimal degree of automation must be determined. The main objective of this paper is to quantify the impact of smart MV/LV transformer substations on continuity of supply, which is essential to determine the optimal automation degree. The analysis has considered different degrees of implementation of smart MV/LV substations for different configuration schemes of urban distribution networks. Furthermore, sensitivity analyses have been performed for the main parameters involved so that conclusions on reliability improvement achieved by MV/LV transformer substation automation can be scaled up.
2010 7th International Conference on the European Energy Market, 2010
Abstract-In order to meet the 20-20-20 European energy policy commitments Spain should continue i... more Abstract-In order to meet the 20-20-20 European energy policy commitments Spain should continue increasing the amount of electricity production from renewable energy sources (RES) along this decade. This paper analyzes the impact of the future RES deployment on the Spanish ...
2010 7th International Conference on the European Energy Market, 2010
... pt snapshot 1 -± [ Greenfield Expansion-planning model Initial grid model olnv.+maint. ..... more ... pt snapshot 1 -± [ Greenfield Expansion-planning model Initial grid model olnv.+maint. ... B.Reference network models The aforementioned RNMs are able to compute optimally adapted ...Network planning is performed through the interaction of heuristic planning algorithms and ...
IEEE Transactions on Power Systems, 2014
ABSTRACT
2007 IEEE Lausanne Power Tech, 2007
The increase of distributed generation (DG) in distribution networks is an important challenge fo... more The increase of distributed generation (DG) in distribution networks is an important challenge for distribution system operators (DSOs). DG integration not only impacts on DSO short-term costs but also involves new risk uncertainty regarding system reliability, security and network planning. Therefore, because DSO is mainly a regulated business, it is clear that new regulatory mechanisms should be designed. This paper analyzes how the traditional model of DSO regulation is impacted by increasing penetration of DG. A set of proposals on how this model can be improved are presented. Finally, some guidelines on regulatory improvements for the transition between the current and future situation with high penetration of DG are recommended.
The support of electricity generation from renewable energy sources (RES) and combined heat and p... more The support of electricity generation from renewable energy sources (RES) and combined heat and power (CHP) has led to increasing penetration levels of distributed generation (DG). Nevertheless, Large-scale connection of DG faces numerous regulatory, economic, social and technological challenges. Distribution networks were not originally designed to accommodate generation. Hence, distribution system operators (DSOs) face great uncertainties about the impacts of DG on distribution network planning and operation. This paper presents a quantification of how DG affects distribution network costs in three real distribution areas. Several scenarios of demand and DG have been analysed for each case study. Two reference network models (RNMs) have been used to consider the most critical snapshots within each scenario: maximum demand-minimum generation and maximum generation-minimum demand. Results yielded significant differences among the three case studies.
The expected massive penetration of renewable energy sources (RES) in Spain, added to its limited... more The expected massive penetration of renewable energy sources (RES) in Spain, added to its limited electricity interconnection capacity, will demand not only the introduction of flexible resources in the Spanish power system but also a stronger transmission capacity between this country and Europe. In this context, this paper computes the economic additional interconnection capacity between Spain and Central Europe based on the trade-off between transmission capacity cost and RES spillage cost. For this purpose, a model that simulates the hourly operation of the Spanish power system for a period of one year is used to compute hourly spillage. This analysis covers the period of 2020-2050 and includes four scenarios of RES penetration. In addition, a sensitivity analysis in relation to the cost parameters is presented.
In order to meet the 20-20-20 European energy policy commitments Spain should continue increasing... more In order to meet the 20-20-20 European energy policy commitments Spain should continue increasing the amount of electricity production from renewable energy sources (RES) along this decade. This paper analyzes the impact of the future RES deployment on the Spanish power system. Six scenarios are defined by setting different RES installed capacity targets and considering the uncertainty in fuel prices. First, the generation mix is planned for the horizon 2010-20 calculating the investment required in conventional thermal generation for each scenario. Then the system operation, hour by hour, is simulated in 2020 for each generation mix in each scenario. Operational fuel and carbon emission costs are calculated. Costs associated with operational reserves and wind curtailment to counteract or wind power intermittency and predictability errors are also computed. Finally, total systems costs, both investment and operating costs, are compared in the considered scenarios. The economic impact on electricity prices and operational margins of actual power plants is also discussed.
This paper analyzes how traditional regul a- tion of distribution system operators (DSO) has to b... more This paper analyzes how traditional regul a- tion of distribution system operators (DSO) has to be im- proved to accommodate higher levels of distributed genera- tion (DG). In addition, new economic signals to be given to DG operators for system efficient integration are p roposed. Regulatory improvements at the European level are rec- ommended. Recommendations are centered on schemes for DSO revenue compensation to consider incremental net- work costs due to DG, distribution network planning inte- grating DG, and DSO incentives for improving network performance with active integration of DG. Regarding DG economic signals, recommendations are focused on the design of DG connection and use-of-system charges, the revision of current DG support mechanisms based on flat feed-in tariffs, and the provision of ancillary ser vices by DG for network voltage and flow controls and islanding.
IEEE Transactions on Power Delivery, 2010
This paper presents a high-efficiency voltage regulator, which combines robustness, low costs and... more This paper presents a high-efficiency voltage regulator, which combines robustness, low costs and easy maintenance without power electronics components. These characteristics make it suitable for rural networks, where investments and operational cost in power quality improvement are limited. The regulator consists of a multiwinding reduced-power transformer, and provides serial voltage compensation. Different voltage compensation steps are obtained by modifying the
IEEE Transactions on Energy Conversion, 2011
Frequency response analysis (FRA) is a very common test for the diagnosis of power transformers. ... more Frequency response analysis (FRA) is a very common test for the diagnosis of power transformers. This paper presents some relevant results on the application of FRA to the diagnosis of rotating machines. First, a reference rotor position for obtaining the reference FRA response of a rotating machine is proposed. Then, FRA with the proposed rotor position is used to identify faults in the stator of the machine. This paper studies turn-to-turn and ground faults in the stator for different fault resistance values. Several laboratory tests demonstrate the applicability and value of the use of FRA in the diagnosis of rotating machines.
IEEE Transactions on Energy Conversion, 2011
Abstract This paper presents a novel on-line rotor ground fault location method for synchronous m... more Abstract This paper presents a novel on-line rotor ground fault location method for synchronous machines, which, combined with rotor ground fault protection, can detect and locate faults in the rotor. This method is suitable for synchronous machines with static ...
Power Engineering Society, IEEE General Meeting, 2008
This paper presents a comprehensive design for reactive power markets. Under this approach, the S... more This paper presents a comprehensive design for reactive power markets. Under this approach, the System Operator purchases the required reactive power capacity for generation and absorption from the reactive power market agents. To introduce competition in the proposed market different agents are able to participate in the annual auction, such as generators, capacitor banks, shunt reactors, SVCs or STATCOM devices. The optimal purchase of the required capacity is performed using an optimization algorithm that minimizes the costs associated with the voltage control service. The reactive power requirements in the power system are calculated taking into account different operation scenarios, which include critical system contingencies.
This paper presents a new approach to design long-term zonal reactive power capacity markets. Und... more This paper presents a new approach to design long-term zonal reactive power capacity markets. Under this approach, in each voltage control area, an annual auction to procure reactive power capacity is conducted by the System Operator. A key contribution of the paper is the method to compute the zonal demand curve using the marginal utility function. This function is calculated as the variation of the expected operation costs when the reactive power capacity in the area is increased. The applicability of the approach is illustrated in a case study with one voltage control area.
IEEE Transactions on Power Systems, 2008
Abstract This paper presents a new approach to design reactive power capacity markets. Under this... more Abstract This paper presents a new approach to design reactive power capacity markets. Under this approach annual auctions to procure reactive power capacity are conducted by the system operator. Two products are defined, reactive power generation and absorption ...
2013 IEEE Grenoble Conference, 2013
ABSTRACT In order to comply with the European Union's ambitious renewable targets for 202... more ABSTRACT In order to comply with the European Union's ambitious renewable targets for 2020, extensive investments in wind generation capacity have been made. Wind power plants are located primarily where the resource is available, which can lead to local transmission constraints during certain periods. In order to avoid transmission congestions, short-term measures that increase system operation costs such as topological maneuvers, conventional generation redispatch and wind curtailment are taken by the system operator. In this context, this paper performs a cost-benefit analysis of the installation of a Flexible AC Transmission Systems (FACTS) device to avoid transmission congestions in a Spanish area dominated by wind generation contributing to a more efficient integration of wind power. Furthermore, it is computed the additional wind power that could be integrated with the installation of this device.
International Journal of Electrical Power & Energy Systems, 2009
This paper analyzes how traditional regulation of distribution system operators (DSO) has to be i... more This paper analyzes how traditional regulation of distribution system operators (DSO) has to be improved to accommodate higher levels of distributed generation (DG). In addition, new economic signals to be given to DG operators for system efficient integration are proposed. Regulatory improvements at the European level are recommended. Recommendations are centered on schemes for DSO revenue compensation to consider incremental network costs due to DG, distribution network planning integrating DG, and DSO incentives for improving network performance with active integration of DG. Regarding DG economic signals, recommendations are focused on the design of DG connection and use-of-system charges, the revision of current DG support mechanisms based on flat feed-in tariffs, and the provision of ancillary services by DG for network voltage management, power flow controls and islanding.
Energy Policy, 2009
The European Energy Policy promotes renewable energy sources and energy efficiency as means to mi... more The European Energy Policy promotes renewable energy sources and energy efficiency as means to mitigate environmental impact, increase security of supply and ensure economic competitiveness. As a result, the penetration levels of distributed generation (DG) in electricity networks are bound to increase. Distribution networks and distribution system operators (DSOs) will be especially affected by growing levels of DG. This paper reviews the current regulation of distribution in the European Union Member States, focusing on those aspects that might hinder the future integration of DG. Several regulatory issues that may hinder a successful integration of DG have been identified. Recommendations to improve the current situation are proposed. Regarding economic signals sent to DG, connection charges and cost-reflective use-of-system charges together with incentives to provide ancillary services are the key aspects. Concerning DSOs regulation, unbundling from generation and supply according to the European Electricity Directive, incentives for optimal planning and network operation considering DG, including energy losses and quality of service, and innovation schemes to migrate to active networks are the most relevant topics.
International Journal of Electrical Power & Energy Systems, 2014
Smart MV/LV substations will play a crucial role in the evolution towards a smarter distribution ... more Smart MV/LV substations will play a crucial role in the evolution towards a smarter distribution grid. The implementation of smart MV/LV substations can provide a significant improvement of continuity of supply. However, a large investment is required, so the optimal level of implementation must be found. This paper aims to provide a methodology to determine the optimal degree of automation comparing the costs of increasing automation to the benefits derived from the improvement of continuity of supply achieved. First, the impact of different degrees of implementation of smart MV/LV substations on continuity of supply is quantified using a reference network model (RNM). Then, an economic analysis is performed to assess automation costs and supply interruptions costs from two different perspectives, considering non supplied energy for network users and alternatively regulatory incentives for distribution companies. Finally, the optimal degree of automation is identified by comparing marginal costs. Furthermore, the methodology proposed is applied to two large scale test cases of an urban and a semi-urban network. The results obtained highlight the need to compare costs and benefits showing that there is indeed an optimal degree of automation different from the complete automation of the distribution system.
2012 3rd IEEE PES Innovative Smart Grid Technologies Europe (ISGT Europe), 2012
ABSTRACT The medium to low voltage transformer substation is a key element in the distribution sy... more ABSTRACT The medium to low voltage transformer substation is a key element in the distribution system. Therefore, smart transformer substations will play a crucial role in the evolution of distribution towards the smart grid. Smart transformer substations can provide a significant improvement of continuity of supply. However, a large investment is required, so the optimal degree of automation must be determined. The main objective of this paper is to quantify the impact of smart MV/LV transformer substations on continuity of supply, which is essential to determine the optimal automation degree. The analysis has considered different degrees of implementation of smart MV/LV substations for different configuration schemes of urban distribution networks. Furthermore, sensitivity analyses have been performed for the main parameters involved so that conclusions on reliability improvement achieved by MV/LV transformer substation automation can be scaled up.
2010 7th International Conference on the European Energy Market, 2010
Abstract-In order to meet the 20-20-20 European energy policy commitments Spain should continue i... more Abstract-In order to meet the 20-20-20 European energy policy commitments Spain should continue increasing the amount of electricity production from renewable energy sources (RES) along this decade. This paper analyzes the impact of the future RES deployment on the Spanish ...
2010 7th International Conference on the European Energy Market, 2010
... pt snapshot 1 -± [ Greenfield Expansion-planning model Initial grid model olnv.+maint. ..... more ... pt snapshot 1 -± [ Greenfield Expansion-planning model Initial grid model olnv.+maint. ... B.Reference network models The aforementioned RNMs are able to compute optimally adapted ...Network planning is performed through the interaction of heuristic planning algorithms and ...
IEEE Transactions on Power Systems, 2014
ABSTRACT
2007 IEEE Lausanne Power Tech, 2007
The increase of distributed generation (DG) in distribution networks is an important challenge fo... more The increase of distributed generation (DG) in distribution networks is an important challenge for distribution system operators (DSOs). DG integration not only impacts on DSO short-term costs but also involves new risk uncertainty regarding system reliability, security and network planning. Therefore, because DSO is mainly a regulated business, it is clear that new regulatory mechanisms should be designed. This paper analyzes how the traditional model of DSO regulation is impacted by increasing penetration of DG. A set of proposals on how this model can be improved are presented. Finally, some guidelines on regulatory improvements for the transition between the current and future situation with high penetration of DG are recommended.
The support of electricity generation from renewable energy sources (RES) and combined heat and p... more The support of electricity generation from renewable energy sources (RES) and combined heat and power (CHP) has led to increasing penetration levels of distributed generation (DG). Nevertheless, Large-scale connection of DG faces numerous regulatory, economic, social and technological challenges. Distribution networks were not originally designed to accommodate generation. Hence, distribution system operators (DSOs) face great uncertainties about the impacts of DG on distribution network planning and operation. This paper presents a quantification of how DG affects distribution network costs in three real distribution areas. Several scenarios of demand and DG have been analysed for each case study. Two reference network models (RNMs) have been used to consider the most critical snapshots within each scenario: maximum demand-minimum generation and maximum generation-minimum demand. Results yielded significant differences among the three case studies.