Rafael Cossent

Assessment of the Impact of Plug-in Electric Vehicles on Distribution Networks

Plug-in electric vehicles (PEVs) present environmental and energy security advantages versus conventional gasoline vehicles. In the near future, the number of plug-in electric vehicles will likely grow significantly in the world. Despite the aforementioned advantages, the connection of PEV to the power grid poses a series of new challenges for electric utilities. This paper proposes a comprehensive approach for evaluating the impact of different levels of PEV penetration on distribution network investment and incremental energy losses. The proposed approach is based on the use of a large-scale distribution planning model which is used to analyze two real distribution areas. Obtained results show that depending on the charging strategies, investment costs can increase up to 15% of total actual distribution network investment costs, and energy losses can increase up to 40% in off-peak hours for a scenario with 60% of total vehicles being PEV.

Reference Network Models: A Computational Tool for Planning and Designing Large-Scale Smart Electricity Distribution Grids

Reference Network Models (RNMs) are large-scale distribution network planning tools. RNMs can be used by policy makers and regulators to estimate efficient distribution costs. This is a very challenging task, particularly being network planning a combinatorial problem, which is especially difficult to solve due to the vast size of the distribution areas, and the use of several voltage levels. This chapter presents the main features of RNMs developed by the authors, including high performance requirements related to the type and size of the problem. The model can be used to plan distribution networks either from scratch or incrementally from existing grids. Different case studies illustrate the applicability of these models to the assessment of the impact of massive deployment of renewable distributed generation, demand response actions, and plug-in electric vehicle penetration on distribution costs. The results obtained provide valuable information to guide strategic policy-making decisions regarding the implementation of renewable energy programs and smart grid initiatives.

Assessing the impact of distributed generation on distribution network costs

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.

Mitigating the impact of distributed generation on distribution network costs through advanced response options

Nowadays, the presence of distributed generation (DG) is steadily growing. This growth can produce significant effects on the costs incurred by distribution system operators (DSOs). This impact can be particularly negative if DG keeps playing a passive role, not reacting to network conditions. However, the implementation of advanced response options or active network management (ANM) may mitigate the adverse effects of large DG penetration levels. This paper considers the adoption of ANM planning strategies and provides an estimate of the distribution network costs reduction that can be achieved through the implementation of advanced response options. Two large-scale distribution planning models, called reference network models (RNMs), have been used to calculate these cost estimates. Three actual distribution areas are studied, taking into account different scenarios of load and DG for each one of them. These areas are located in The Netherlands, Germany and Spain and were chosen to reflect a wide range of different types of consumers, load concentration and DG technologies.

Remuneration assessment of a VPP providing distribution capacity services

A Distribution System Operator (DSO) might consider a capacity contract as a planning alternative to defer grid investments. A Virtual Power Plant (VPP) might be able to provide such capacity and change its production as requested by the DSO. This article presents an assessment of the impact of this type of distribution capacity contract (DCC) on VPPs remuneration. This assessment is done by comparing the optimal production / bidding strategy which maximize its profit, under presence or absence of these contracts. The impact of intermittent generation and storage while evaluating these scenarios will be investigated as well. A stochastic unit commitment will be used to determine the VPPs strategy under uncertainties from wind power, load, market prices, and the requested power by the DSO. The model showed that the VPP involvement in distribution capacity contracts can improve its remuneration when certain types of Distributed Energy Resources (DER) are used to provide the service.

Setting regulatory incentives for continuity of supply in smart distribution grids

Incentive regulation of distribution system operators (DSOs) brought about the need to set additional mechanisms so as to avoid cost reductions at the expense of deteriorating the levels of quality of service. Since continuity of supply is the quality aspect more intimately related with distribution network investment and maintenance costs, regulatory incentives focus on the interruptions suffered by electricity consumers. The transition towards smarter distribution grids can change how network users perceive quality of service as well as the technologies available to DSOs for improving continuity levels. This paper discusses how smart distribution grids can affect the way regulatory incentives to improve continuity of supply have been traditionally determined and identifies several regulatory changes that may be needed in the upcoming future distribution grids.

Evaluating the determinants of the scalability and replicability of islanded operation in medium voltage networks with cogeneration

The development of smart grid solution concepts, such as islanding, make it possible to improve the security of supply in networks. The results experimented in real-life test systems must be extrapolated to wider areas and in other locations, which is not straightforward. The scalability and replicability analysis (SRA) aims to identify the relevant factors that affect smart grid implementations and understand the effects of their variation on the results achieved by smart grid solutions. This paper presents the SRA of an islanding use case in a medium voltage network using cogeneration. Furthermore, the results obtained have been used to obtain a set of scalability and replicability rules for islanding use cases that can be applied in other cases.