Power quality and electromagnetic compatibility: special report, session 2

The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

Expansion planning of power distribution systems considering reliability : a comprehensive review

One of the big concerns when planning the expansion of power distribution systems (PDS) is reliability. This is defined as the ability to continuously meet the load demand of consumers in terms of quantity and quality. In a scenario in which consumers increasingly demand high supply quality, including few interruptions and continuity, it becomes essential to consider reliability indices in models used to plan PDS. The inclusion of reliability in optimization models is a challenge, given the need to estimate failure rates for the network and devices. Such failure rates depend on the specific characteristics of a feeder. In this context, this paper discusses the main reliability indices, followed by a comprehensive survey of the methods and models used to solve the optimal expansion planning of PDS considering reliability criteria. Emphasis is also placed on comparing the main features and contributions of each article, aiming to provide a handy resource for researchers. The comparison includes the decision variables and reliability indices considered in each reviewed article, which can be used as a guide to applying the most suitable method according to the requisites of the system. In addition, each paper is classified according to the optimization method, objective type (single or multiobjective), and the number of stages. Finally, we discuss future research trends concerning the inclusion of reliability in PDS expansion planning

Interruption reduction at substations using battery energy storage systems.

Masters Degree. University of KwaZulu-Natal, Durban.Reliable electrical power supply is vital in the modern society and electrical distribution utilities are responsible for ensuring continuity of supply. South Africa is experiencing a rapid increase in electrical power demand; with the number of people requiring electrification growing continuously. Eskom’s capacity to generate excess electricity is completely used up as the currently installed transformers are of a certain fixed rating and cannot accommodate the rapid continuous growth, resulting in the utility not being able to meet the power demand. The concept of load shedding is utilized when supply cannot meet demand due to certain system constraints and demand reduction is required; it is also regarded as a last resort action taken to prevent the collapse of the power system and protect the current electrical power equipment connected to the system. The constraints are mainly due to the incapability to store the power at any point in the supply, traditionally electrical power generation plants typically produce more energy than necessary to ensure adequate power quality at the points of transmission and distribution as a large percentage of the energy is lost in the power station as waste heat and even more losses occur at the power lines when the generated is transmitted for use; thus raising a need to implement a system to save as much of the discarded energy in between the points of the life-cycle of electricity such as battery energy storage systems (BESS). BESS is useful for its prompt capacity to adjust power well as the characteristics of storage and supply capability. The utilization of BESS for the reduction of network power loss and management of network congestion is the key factor to realize the optimal operation of distribution networks as it can store excess power that can be later utilized when there’s a shortage in the system. In this dissertation, the integration of BESS into electrical Distribution systems is investigated, with the objective to reduce the power supply interruptions that occur at the substations (planned/unplanned) and know-how BESS can be used to improve the performance of a distribution system. The proposed methodology consists of two main parts. The first one is of design and simulation of a balanced substation; It’s important to ensure that the substation is operating within its specifications as a standalone before any external features are added to improve the already existing adequate performance. And separately, a BESS with a control method for State of Charge (SoC) for the battery considering the network power loss during both grid and off-grid operation to ensure smooth BESS operation without compromising the voltage regulation performance of the network; as the basis of the investigation, consecutively. The second part consists of integrating the two models (Substation & BESS) and conducting simulation studies to obtain unique scenario-based outcomes. The optimal placement of BESS is investigated as the efficiency of integrating it into large-scale distribution networks depends on it. The substation and BESS are modelled and simulated using MATLAB Simulink to verify the effectiveness of the proposed methodology and based on the research it is evident that BESS integrated distribution systems solutions to overcome shortage created by load shedding or any other interruptions (planned/unplanned) are the best way to go in maintaining continuity of supply to customers.List of figures and tables are on page viii-ix

Efficient and Risk-Aware Control of Electricity Distribution Grids

This article presents an economic model predictive control (EMPC) algorithm for reducing losses and increasing the resilience of medium-voltage electricity distribution grids characterized by high penetration of renewable energy sources and possibly subject to natural or malicious adverse events. The proposed control system optimizes grid operations through network reconfiguration, control of distributed energy storage systems (ESSs), and on-load tap changers. The core of the EMPC algorithm is a nonconvex optimization problem integrating the ESSs dynamics, the topological and power technical constraints of the grid, and the modeling of the cascading effects of potential adverse events. An equivalent (i.e., having the same optimal solution) proxy of the nonconvex problem is proposed to make the solution more tractable. Simulations performed on a 16-bus test distribution network validate the proposed control strategy

ESTABLISHMENT OF THE SECOND LIST OF UNION PROJECTS OF COMMON INTEREST: EVALUATION OF CANDIDATE PROJECTS OF COMMON INTEREST IN THE FIELD OF SMART GRIDS

The document presents the outcome of the evaluation process of candidate Projects of Common Interest in the area of Smart Grids, under the trans-European energy infrastructure regulation. The evaluation follows the guidelines of the assessment framework for Smart Grid projects, developed by the JRC within the EC Smart Grid Task Force.JRC.F.3-Energy Security, Systems and Marke

Smart grids for rural conditions and e-mobility - Applying power routers, batteries and virtual power plants

Significant reductions of greenhouse gas emission by use of renewable energy sources belong to the common targets of the European Union. Smart grids address intelligent use and integration of conventional and renewable generation in combination with controllable loads and storages. Two special aspects have also to be considered for smart grids in future: rural conditions and electric vehicles. Both, the increasing share of renewable energy sources and a rising demand for charging power by electrical vehicles lead to new challenges of network stability (congestion, voltage deviation), especially in rural distribution grids. This paper describes two lighthouse projects in Europe (“Well2Wheel” and “Smart Rural Grid”) dealing with these topics. The link between these projects is the implementation of the same virtual power plant technology and the approach of cellular grid cells. Starting with an approach for the average energy balance in 15 minutes intervals in several grid cells in the first project, the second project even allows the islanded operation of such cells as a microgrid. The integration of renewable energy sources into distribution grids primary takes place in rural areas. The lighthouse project “Smart Rural Grid”, which is founded by the European Union, demonstrates possibilities to use the existing distribution system operator infrastructure more effectively by applying an optimised and scheduled operation of the assets and using intelligent distribution power routers, called IDPR. IDPR are active power electronic devices operating at low voltage in distribution grids aiming to reduce losses due to unbalanced loads and enabling active voltage and reactive power control. This allows a higher penetration of renewable energy sources in existing grids without investing in new lines and transformers. Integrated in a virtual power plant and combined with batteries, the IDPR also allows a temporary islanded mode of grid cells. Both projects show the potential of avoiding or postponing investments in new primary infrastructure like cables, transformers and lines by using a forward-looking operation which controls generators, loads and batteries (mobile and stationary) by using new grid assets like power routers. While primary driven by physical restrictions as voltage-band violations and energy balance, these cells also define and allow local smart markets. In consequence the distribution system operators could avoid direct control access by giving an incentive to the asset owners by local price signals according to the grid situation and forecasted congestions.Peer ReviewedPostprint (published version

A Review and Synthesis of the Outcomes from Low Carbon Networks Fund Projects

The Low Carbon Networks Fund (LCNF) was established by Ofgem in 2009 with an objective to “help Distribution Network Operators (DNOs) understand how they provide security of supply at value for money and facilitate transition to the low carbon economy”. The £500m fund operated in a tiered format, funding small scale projects as Tier 1 and running a Tier 2 annual competitive process to fund a smaller number of large projects. By 31st March 2015, forty Tier 1 projects and twenty-three Tier 2 projects had been approved with project budgets totalling £29.5m and £220.3m respectively. The LCNF governance arrangements state that projects should focus on the trialling of: new equipment (more specifically, that unproven in GB), novel arrangements or applications of existing equipment, novel operational practices, or novel commercial arrangements. The requirement that learning gained from projects could be disseminated was a key feature of the LCNF. The motivation for the review reported here was a recognition that significant learning and data had been generated from a large volume of project activity but, with so many individual reports published, that it was difficult for outside observers to identify clear messages with respect to the innovations investigated under the programme. This review is therefore intended to identify, categorise and synthesise the learning outcomes published by LCNF projects up to December 2015

Evaluation of Smart Grid projects for inclusion in the third Union-wide list of Projects of Common Interest: Evaluation of candidate projects in the TEN-E priority thematic area of smart grids deployment

The document presents the outcome of the evaluation process of candidate Projects of Common Interest in the priority thematic area of ‘smart grids deployment’, as set out in the trans-European energy infrastructure regulation. The evaluation follows the guidelines of the assessment framework for smart grid Projects of Common Interest, 2017 update, developed by the JRC and adopted by the smart grid Regional Group. The report aims to assist the smart grids Regional Group in proposing projects of common interest in the area of smart grids deployment to be included in the 3rd Union list of Projects of Common Interest.JRC.C.3-Energy Security, Distribution and Market