Grid Operation Assessment under a Specific EV Chargers Deployment Plan in the City of Heraklion

The development of electric vehicles (EVs) as part of the electrification of the transportation sector plays a significant role in energy transition to a low-carbon and highly renewable society. The use of EVs has been promoted through the development of inclusive strategies for electromobility in the recent years. Apart from actions directed and funded by the European Union, national strategies have also been employed to support electromobility. Such a strategic plan has already been enacted by the Hellenic Ministry of Environment and Energy, funding municipalities to prepare siting and sizing plans for electric vehicle chargers. In this paper, the final study of this strategic plan for the municipality of Heraklion in Crete is used as a case study to investigate the effect of EV chargers on the operation of the Cretan power system. Their selected siting points are evaluated by performing a power flow analysis at the level of 150 kV. Thus, they are aggregated in each 20 kV/150 kV distribution substation of the electrical grid with the aim of investigating their effect on substation loading and transmission line losses. Generally, extensive fast charging should be avoided to minimize the risk of sudden stress of the existing cities’ grids and control strategies should be implemented to mitigate the need for upscale substation equipment or even postpone reinforcements.

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Determinants and barriers of PV self-consumption in Spain from the perception of the installers for the promotion of distributed energy systems

ECONOMICS AND POLICY OF ENERGY AND THE ENVIRONMENT ◽

10.3280/efe2020-001007 ◽

2020 ◽

pp. 153-169

Author(s):

José Ángel Gimeno ◽

Eva Llera Sastresa ◽

Sabina Scarpellini

Keyword(s):

European Union ◽

Energy Transition ◽

Legal Framework ◽

Low Carbon ◽

The European Union ◽

Distributed Energy ◽

Sustainable Solutions ◽

Highly Sensitive ◽

Transition Scenario

Currently, self-consumption and distributed energy facilities are considered as viable and sustainable solutions in the energy transition scenario within the European Union. In a low carbon society, the exploitation of renewables for self-consumption is closely tied to the energy market at the territorial level, in search of a compromise between competitiveness and the sustainable exploitation of resources. Investments in these facilities are highly sensitive to the existence of favourable conditions at the territorial level, and the energy policies adopted in the European Union have contributed positively to the distributed renewables development and the reduction of their costs in the last decade. However, the number of the installed facilities is uneven in the European Countries and those factors that are more determinant for the investments in self-consumption are still under investigation. In this scenario, this paper presents the main results obtained through the analysis of the determinants in self-consumption investments from a case study in Spain, where the penetration of this type of facilities is being less relevant than in other countries. As a novelty of this study, the main influential drivers and barriers in self-consumption are classified and analysed from the installers' perspective. On the basis of the information obtained from the installers involved in the installation of these facilities, incentives and barriers are analysed within the existing legal framework and the potential specific lines of the promotion for the effective deployment of self-consumption in an energy transition scenario.

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Impedance Matching-Based Power Flow Analysis for UPQC in Three-Phase Four-Wire Systems

Energies ◽

10.3390/en14092702 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2702

Author(s):

Xiaojun Zhao ◽

Xiuhui Chai ◽

Xiaoqiang Guo ◽

Ahmad Waseem ◽

Xiaohuan Wang ◽

...

Keyword(s):

Power Flow ◽

Control Strategies ◽

Impedance Matching ◽

Flow Analysis ◽

Point Of View ◽

Impedance Model ◽

Power Flow Analysis ◽

Three Phase ◽

System Node ◽

Power Quality Conditioner

Different from the extant power flow analysis methods, this paper discusses the power flows for the unified power quality conditioner (UPQC) in three-phase four-wire systems from the point of view of impedance matching. To this end, combined with the designed control strategies, the establishing method of the UPQC impedance model is presented, and on this basis, the UPQC system can be equivalent to an adjustable impedance model. After that, a concept of impedance matching is introduced into this impedance model to study the operation principle for the UPQC system, i.e., how the system changes its operation states and power flow under the grid voltage variations through discussing the matching relationships among node impedances. In this way, the nodes of the series and parallel converter are matched into two sets of impedances in opposite directions, which mean that one converter operates in rectifier state to draw the energy and the other one operates in inverter state to transmit the energy. Consequently, no matter what grid voltages change, the system node impedances are dynamically matched to ensure that output equivalent impedances are always equal to load impedances, so as to realize impedance and power balances of the UPQC system. Finally, the correctness of the impedance matching-based power flow analysis is validated by the experimental results.

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A Flexible Top-Down Data-Driven Stochastic Model for Synthetic Load Profiles Generation

Energies ◽

10.3390/en15010269 ◽

2021 ◽

Vol 15 (1) ◽

pp. 269

Author(s):

Enrico Dalla Maria ◽

Mattia Secchi ◽

David Macii

Keyword(s):

Stochastic Model ◽

Power Flow ◽

Distribution Systems ◽

Control Strategies ◽

Flow Analysis ◽

Gaussian Mixture Models ◽

Gaussian Mixture ◽

Operating Conditions ◽

Time Varying ◽

Top Down

The study of the behavior of smart distribution systems under increasingly dynamic operating conditions requires realistic and time-varying load profiles to run comprehensive and accurate simulations of power flow analysis, system state estimation and optimal control strategies. However, due to the limited availability of experimental data, synthetic load profiles with flexible duration and time resolution are often needed to this purpose. In this paper, a top-down stochastic model is proposed to generate an arbitrary amount of synthetic load profiles associated with different kinds of users exhibiting a common average daily pattern. The groups of users are identified through a preliminary Ward’s hierarchical clustering. For each cluster and each season of the year, a time-inhomogeneous Markov chain is built, and its parameters are estimated by using the available data. The states of the chain correspond to equiprobable intervals, which are then mapped to a time-varying power consumption range, depending on the statistical distribution of the load profiles at different times of the day. Such distributions are regarded as Gaussian Mixture Models (GMM). Compared with other top-down approaches reported in the scientific literature, the joint use of GMM models and time-inhomogeneous Markov chains is rather novel. Furthermore, it is flexible enough to be used in different contexts and with different temporal resolution, while keeping the number of states and the computational burden reasonable. The good agreement between synthetic and original load profiles in terms of both time series similarity and consistency of the respective probability density functions was validated by using three different data sets with different characteristics. In most cases, the median values of synthetic profiles’ mean and standard deviation differ from those of the original reference distributions by no more than ±10% both within a typical day of each season and within the population of a given cluster, although with some significant outliers.

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Active Distribution Grid Power Flow Analysis using Asymmetrical Hybrid Technique

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v7i4.pp1738-1748 ◽

2017 ◽

Vol 7 (4) ◽

pp. 1738 ◽

Cited By ~ 1

Author(s):

Paramet Wirasanti ◽

Egon Ortjohann

Keyword(s):

Power Flow ◽

Flow Analysis ◽

Load Flow ◽

Hybrid Technique ◽

Distribution Grid ◽

Performance Study ◽

Power Flow Analysis ◽

Flexible Mode ◽

Decoupling Analysis ◽

Grid Operation

A conventional distribution power flow analysis has to be improved regards the changes in distribution network. One of the changes is a grid operation because a new grid concept, e.g. micro-grid and aggregation, is aimed to be operated based on area itself. Consequently, each area can be actively operated in either grid connected mode or islanding mode. Hence, this paper proposes an asymmetrical power flow analysis using hybrid technique to support this flexible mode change. The hybrid technique offers an opportunity to analyze power flow in a decoupling way. This means that the power flow analysis can be performed separately in each grid area. Regards the distributed generation, this paper also introduces a model based on inverter-based operation, i.e. grid forming, grid supporting and grid parallel. The proposed asymmetrical hybrid load flow method is examined in three case studies, i.e. a verification study with the DIgSILENT PowerFactory, a demonstration of decoupling analysis approach and a performance study with the Newton-Raphson method.

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SimBench—A Benchmark Dataset of Electric Power Systems to Compare Innovative Solutions Based on Power Flow Analysis

Energies ◽

10.3390/en13123290 ◽

2020 ◽

Vol 13 (12) ◽

pp. 3290 ◽

Cited By ~ 3

Author(s):

Steffen Meinecke ◽

Džanan Sarajlić ◽

Simon Ruben Drauz ◽

Annika Klettke ◽

Lars-Peter Lauven ◽

...

Keyword(s):

Power Systems ◽

Power Flow ◽

Flow Analysis ◽

Added Value ◽

Voltage Level ◽

Study Results ◽

Benchmark Datasets ◽

Automated Algorithms ◽

Grid Operation ◽

Grid Planning

Publicly accessible, elaborated grid datasets, i.e., benchmark grids, are well suited to publish and compare methods or study results. Similarly, developing innovative tools and algorithms in the fields of grid planning and grid operation is based on grid datasets. Therefore, a general methodology to generate benchmark datasets and its voltage level dependent implementation is described in this paper. As a result, SimBench, a comprehensive dataset for the low, medium, high and extra-high voltage level, is presented. Besides grids that can be combined across several voltage levels, the dataset offers an added value by providing time series for a whole year as well as future scenarios. In this way, SimBench is applicable for many use cases and simplifies reproducing study results. As proof, different automated algorithms for grid planning are compared to show how to apply SimBench and make use of it as a simulation benchmark.

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Integrated Power Flow Analysis with Large-scale Solar Photovoltaic Power Systems Employing N-R Method

International Journal of Emerging Electric Power Systems ◽

10.1515/ijeeps-2018-0013 ◽

2019 ◽

Vol 20 (1) ◽

Author(s):

Girisha H Navada ◽

K. N. Shubhanga

Keyword(s):

Power Systems ◽

Power System ◽

Power Flow ◽

Large Scale ◽

Control Strategies ◽

Linear Equations ◽

Flow Analysis ◽

Load Flow ◽

Flow Equations ◽

Single Machine Infinite Bus

Abstract A method is proposed to modify the conventional load flow programme to accommodate large-scale Solar PhotoVoltaics (SPV) power plant with series power specifications. The programme facilitates easy handling of any number of SPV systems with standard control strategies such as pf-control and voltage-control, considering solar inverter’s power constraints. In this method, the non-linear equations related to SPV systems, located at multiple locations, are solved with the main load flow equations in an integrated fashion, considerably reducing the implementation task. This task is achieved by augmenting the inverter buses to the existing power system network in such a way that the changes required in the conventional programme are minimal. To show the effectiveness of the proposed method, it is compared with the alternate-iteration method popularly followed in the literature. The workability of the proposed method has been demonstrated by using a Single Machine Infinite Bus (SMIB) system and the IEEE14-bus power system with SPV systems. Various test cases pertaining to meteorological variables and control strategies are also presented.

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Power Flow Analysis of MMC-HVDC System with Margin Voltage and Voltage Droop Control Strategies

10.48011/sbse.v1i1.2264 ◽

2020 ◽

Author(s):

Maxwel Da Silva Santos ◽

Luciano Sales Barros ◽

Rafael Lucas da Silva França ◽

Flavio Bezerra Costa ◽

Kai Strunz

Keyword(s):

Power Flow ◽

Control Strategies ◽

Flow Analysis ◽

Open Circuit ◽

Droop Control ◽

Power Flow Control ◽

Hvdc System ◽

High Voltage Direct Current ◽

Modular Converter ◽

The One

High voltage direct current (HVDC) systems are an alternative for transmission of energy with higher efficiency and lower electrical losses over long distances. HVDC systems have become more common with the evolution of power electronics, promoting the interest of research in power flow control techniques. The main objective of this paper is to perform evaluations of the power flow in a meshed multiterminal HVDC (MT-HVDC) system based on the multilevel modular converter (MMC). Two different control strategies were considered; The margin voltage; and the voltage droop strategies. Two assessment scenarios were considered: when an active power reference takes place in the system; and when a DC transmission line is open-circuit due to a failure in the DC grid. For both of these test cases, the system with the margin voltage control obtained a new balance of power flow with less oscillations in power andvoltage than the one with the voltage droop control.

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The latest generation of EU Smart city projects: turning "clean energy for all" into "clean benefits for all

10.47472/rpab1969 ◽

2019 ◽

Author(s):

Adriano Bisello ◽

◽

Daniele Vettorato ◽

Keyword(s):

Smart City ◽

Smart Cities ◽

Energy Transition ◽

Clean Energy ◽

Well Being ◽

Urban Life ◽

Positive Energy ◽

Low Carbon ◽

The European Union ◽

Ongoing Research

The European Union is in the process of updating its energy policy and legislative framework under the motto “Clean Energy for All Europeans”. This will facilitate the low carbon energy transition, make it fit for the 21st century, and delivering the EU’s Paris Agreement commitments. Besides expected climate-energy benefits, the EU narrative is introducing new elements to persuade citizens and stakeholders to change their perspective, shifting the general perception from mitigation costs to development opportunities. For example, impact assessment of the new directives estimated that they would generate 900,000 jobs and an increase of up to 1% in EU GDP over the next decade. However, this is just one among several multiple benefits that could be gained thanks to the smart energy transition of cities and neighborhoods (e.g. increased value of refurbished properties, improved health and well-being, enhanced social cohesion, etc.) Starting from this premise, the ongoing research will analyses 12 ongoing EU smart cities and communities projects started between 2014 and 2017, in order to investigate their capability in using the multiple benefits as an effective communication tool, or even including them among the key performance indicators to be used in the assessment phase. In that respect, the Positive energy district concept that permeates the smart city approach of latest calls for funding provides, even more, an interesting nexus and testbed opportunity for EU ambitions. However, ongoing and future projects need to be understood not only as marketing devices for new energy efficient technologies but powerful tools requiring a radical change in management and planning of cities and urban life. In this way, positive energy districts including good habits and behaviors of urban citizens will provide equitable solutions and clear benefits for all.

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Smart Altitude

10.1553/smart-altitude ◽

2021 ◽

Author(s):

Gianni Baldessari ◽

Oliver Bender ◽

Domenico Branca ◽

Luigi Crema ◽

Anna Giorgi ◽

...

Keyword(s):

Energy Transition ◽

Decision Support Tool ◽

Final Report ◽

Low Carbon ◽

The European Union ◽

Mountain Areas ◽

Support Tool ◽

Winter Tourism ◽

Living Labs ◽

Alpine Space

This final report summarizes the outcomes of the Smart Altitude project. The Smart Altitude project ran from June 2018 to April 2021 and was carried out by ten partners from six different countries in the Alpine Space (Austria, France, Italy, Germany, Slovenia, and Switzerland). The project was co-financed by the European Union via Interreg Alpine Space. The aim of the project was to enable and accelerate the implementation of low-carbon policies in winter tourism regions by demonstrating the efficiency of a step-by-step decision support tool for energy transition in four Living Labs. The project targeted policymakers, ski resort operators, investors, tourism, and entrepreneurship organizations. The Smart Altitude approach was designed to ensure suitability across the Alpine Space, thereby fostering its replication and uptake in other winter tourism regions and thus increasing the resilience of mountain areas.

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