Ancillary Services in Hybrid AC/DC Low Voltage Distribution Networks

In the last decade, distribution systems are experiencing a drastic transformation with the advent of new technologies. In fact, distribution networks are no longer passive systems, considering the current integration rates of new agents such as distributed generation, electrical vehicles and energy storage, which are greatly influencing the way these systems are operated. In addition, the intrinsic DC nature of these components, interfaced to the AC system through power electronics converters, is unlocking the possibility for new distribution topologies based on AC/DC networks. This paper analyzes the evolution of AC distribution systems, the advantages of AC/DC hybrid arrangements and the active role that the new distributed agents may play in the upcoming decarbonized paradigm by providing different ancillary services.Ministerio de Economía y Competitividad ENE2017-84813-RUnión Europea (Programa Horizonte 2020) 76409

Centralized Control of Distribution Networks with High Penetration of Renewable Energies

Distribution networks were conceived to distribute the energy received from transmission and subtransmission to supply passive loads. This approach, however, is not valid anymore due to the presence of distributed generation, which is mainly based on renewable energies, and the increased number of plug-in electric vehicles that are connected at this voltage level for domestic use. In this paper the ongoing transition that distribution networks face is addressed. Whereas distributed renewable energy sources increase nodal voltages, electric vehicles result in demand surges higher than the load predictions considered when planning these networks, leading to congestion in distribution lines and transformers. Additionally, centralized control techniques are analyzed to reduce the impact of distributed generation and electric vehicles and increase their effective integration. A classification of the different methodologies applied to the problems of voltage control and congestion management is presented.Unión Europea Convenio 764090Ministerio de Ciencia e Innovación CER-2019101

Quantifying the Effects of Sustainable Urban Mobility Plans

This technical note uses the expert scoring information available in current scientific literature in order to explore the impacts and effects that different urban measures may have in planning for sustainability on a European wide level.JRC.J.1-Economics of Climate Change, Energy and Transpor

Investigation of domestic level EV chargers in the Distribution Network: An Assessment and mitigation solution

This research focuses on the electrification of the transport sector. Such electrification could potentially pose challenges to the distribution system operator (DSO) in terms of reliability, power quality and cost-effective implementation. This thesis contributes to both, an Electrical Vehicle (EV) load demand profiling and advanced use of reactive power compensation (D-STATCOM) to facilitate flexible and secure network operation. The main aim of this research is to investigate the planning and operation of low voltage distribution networks (LVDN) with increasing electrical vehicles (EVs) proliferation and the effects of higher demand charging systems. This work is based on two different independent strands of research. Firstly, the thesis illustrates how the flexibility and composition of aggregated EVs demand can be obtained with very limited information available. Once the composition of demand is available, future energy scenarios are analysed in respect to the impact of higher EVs charging rates on single phase connections at LV distribution network level. A novel planning model based on energy scenario simulations suitable for the utilization of existing assets is developed. The proposed framework can provide probabilistic risk assessment of power quality (PQ) variations that may arise due to the proliferation of significant numbers of EVs chargers. Monte Carlo (MC) based simulation is applied in this regard. This probabilistic approach is used to estimate the likely impact of EVs chargers against the extreme-case scenarios. Secondly, in relation to increased EVs penetration, dynamic reactive power reserve management through network voltage control is considered. In this regard, a generic distribution static synchronous compensator (D-STATCOM) model is adapted to achieve network voltage stability. The main emphasis is on a generic D-STATCOM modelling technique, where each individual EV charging is considered through a probability density function that is inclusive of dynamic D-STATCOM support. It demonstrates how optimal techniques can consider the demand flexibility at each bus to meet the requirement of network operator while maintaining the relevant steady state and/or dynamic performance indicators (voltage level) of the network. The results show that reactive power compensation through D-STATCOM, in the context of EVs integration, can provide continuous voltage support and thereby facilitate 90% penetration of network customers with EV connections at a normal EV charging rate (3.68 kW). The results are improved by using optimal power flow. The results suggest, if fast charging (up to 11 kW) is employed, up to 50% of network EV customers can be accommodated by utilising the optimal planning approach. During the case study, it is observed that the transformer loading is increased significantly in the presence of D-STATCOM. The transformer loading reaches approximately up to 300%, in one of the contingencies at 11 kW EV charging, so transformer upgrading is still required. Three-phase connected DSTATCOM is normally used by the DSO to control power quality issues in the network. Although, to maintain voltage level at each individual phase with three-phase connected device is not possible. So, single-phase connected D-STATCOM is used to control the voltage at each individual phase. Single-phase connected D-STATCOM is able maintain the voltage level at each individual phase at 1 p.u. This research will be of interest to the DSO, as it will provide an insight to the issues associated with higher penetration of EV chargers, present in the realization of a sustainable transport electrification agenda

A Practical Approach for Coordination of Plugged- In Electric Vehicles To Improve Performance and Power Quality of Smart Grid

This PhD research is undertaken by supplications including 14 peer-reviewed published articles over seven years research at Curtin University. This study focuses on a real-time Plugged-in Electric Vehicle charging coordination with the inclusion of Electric Vehicle battery charger harmonics in Smart Grid and future Microgrids with incorporation of Renewable Energy Resources. This strategy addresses utilities concerns of grid power quality and performance with the application of SSCs dispatching, active power filters or wavelet energy

Optimized charging control method for plug-in electric vehicles in LV distribution networks

207 p.Title: Optimized charging control method for plug-in electric vehicles in low voltage distributionnetworksKeywords: plug-in electric vehicles, smart charging, V2G, distribution networks, smart grids, multiobjectiveoptimization, demand side management, voltage unbalances, DIgSILENT PowerFactory[EN] This thesis proposes a new methodology to integrate plug-in electric vehicles in low voltagedistribution networks. Charging a significant number of plug-in electric vehicles will lead to severalimpacts in low voltage distribution networks such as increase of energy losses, overloads of linesand distribution transformers, voltage drops and unbalances, etc. These impacts will dependlargely on the charging control method used. Furthermore, there can be a conflict of interestsbetween electric vehicle users and electric utilities. In this context, this thesis proposes a newmethodology to efficiently integrate plug-in electric vehicles and, at the same time, it reducescharging costs for electric vehicle users. This new methodology is based on a multi-objectiveoptimization which objective functions are minimizing load variance and charging costs. Inaddition, an improvement has been proposed to coordinate the charging of multiple PEVs in orderto reduce voltage drops and unbalances. Furthermore, the proposed solution has beenimplemented in a decentralized architecture which provides several advantages. Aspects such asusers¿ privacy, reliability and scalability are improved compared to centralized controlarchitectures. A real distribution network located in Borup (Denmark) has been used as model totest the effectiveness of the proposed methodology. Simulation results show that the newmethodology improves load factor, limits energy losses, reduces charging costs and limits voltagedrops and unbalances. Considering all these aspects, the proposed methodology improves theintegration of plug-in electric vehicles in low voltage distribution networks.[SP] La presente tesis doctoral propone una nueva metodología para integrar los vehículoseléctricos enchufables en las redes de baja tensión. La carga de un número significativo devehículos eléctricos producirá varios impactos en las redes de baja tensión como son el aumentode pérdidas, la sobrecarga de líneas y transformadores, caídas de tensión, desequilibrios detensión, etc. Estos impactos dependerán en gran medida del método de control de carga utilizado.Además, puede existir un conflicto de intereses entre los usuarios de vehículos eléctricos y lascompañías distribuidores de electricidad. En este contexto, la presente tesis propone una nuevametodología para integrar eficientemente los vehículos eléctricos enchufables y, al mismo tiempo,reducir los costes de carga. Esta metodología está basada en una optimización multiobjetivo cuyasfunciones objetivo son la minimización de la varianza de la carga y de los costes de carga.Asimismo, se introduce una mejora para coordinar la carga de los vehículos eléctricos enchufablescon el objeto de reducir los desequilibrios y las caídas de tensión. Igualmente, la soluciónpropuesta ha sido implementada en una arquitectura descentralizada que proporciona una seriede mejoras adicionales. Aspectos como la privacidad de los usuarios, la fiabilidad y la modularidadson mejorados respecto a soluciones con arquitecturas centralizadas. Un modelo de una red dedistribución real, localizada en el municipio de Borup (Dinamarca), ha sido utilizado paracomprobar la eficacia de la metodología propuesta. Los resultados obtenidos en las simulacionesdemuestran que la nueva metodología mejora el factor de carga, limita las pérdidas de energía,reduce los costes de carga y limita los desequilibrios y caídas de tensión. Teniendo en cuenta todosestos aspectos, la metodología propuesta mejora la integración de los vehículos eléctricosenchufables en las redes de distribución de baja tensión