CIRED - Open Access Proceedings Journal

The voltage and current unbalances are serious power quality problems with interaction on each other and mainly affecting low-voltage electricity distribution three-phase systems. In a three-phase system, the current unbalance is due to load unbalance, while it is considered as the main cause of voltage unbalance. The electricity utilities and distribution network operators are responsible for pro... View full abstract»

This study is based on the ongoing evolution of the power grid for supporting a much more flexible and dynamic grid with a high penetration of renewable energy sources and storages. The foreseen applications required for controlling and protecting this new grid are further mapped against the emerging 5G technology, identifying both the challenges as well as the opportunities, by assessing the powe... View full abstract»

Electrical energy is one of the most important energy sources in our life. The need for electrical energy is rapidly growing with developing technology and increasing population. Due to the growing population, the cities considerably expanded and the electrical network has to lie within the living spaces. Especially, uses of medium voltage transformers for distribution systems become widespread in... View full abstract»

The expansion of IEC 61850 outside of the substation is the next step in the evolution of the standard that improves its functionality in order to better serve the smart grid. The study discusses the definition of a routable Generic Object Oriented Substation Event (GOOSE) message, the differences with the conventional GOOSE, and its applications for distribution automation and protection systems. View full abstract»

Recently, losses reduction gained a great deal of attention in distribution system due to low-voltage level and the high-current passing through the lines, pushing the distribution utilities to improve their profit margins on one hand by reducing the unnecessary operational cost, and improving their delivered power quality on the other hand by maintaining the system reliability, and the continuity... View full abstract»

Portugal has been one of the European countries where distributed generation (DG) has taken a high level of importance for the overall system. In 2015, about 50% of the Portuguese electrical energy consumption was produced at the distribution network. This high level of DG has given rise to new challenges for the distribution system operator (DSO), one of the latest concerns the protection require... View full abstract»

Overheating of metallic ground screen connections at accessories of single core cables are the root cause of severe insulation failures in the distribution network. The overheating is due to a high transition resistance of the connections combined with high induced currents in the ground screens during operation. For copper screened cables equipped with a metallic laminate, overheating causing fai... View full abstract»

Ageing electrical switchgear infrastructure is a threat to the reliability of power networks. As the cost of downtime continues to rise, engineers and electrical distribution stakeholders need a strategy for either upgrading or replacing ageing switchgear. This study reviews the benefits of investing in an upgrade strategy. Costs and production downtime scenarios are analysed and low- and medium-v... View full abstract»

TNB has developed an asset management framework in accordance with ISO 55001:2014. One of the key elements of the framework is the asset life cycle management. This study presents TNB experience in managing the on-load tap changers (OLTC) over their complete lifecycle to improve performance and reliability. Using failure mode, effect and criticality analysis based on the previous failure data, lif... View full abstract»

The study addresses the application of artificial intelligence (AI), defined as artificial neural networks, in energy distribution. AI is quickly emerging as a valuable tool in decision- making, holding out the promise for systems that can apply, analyse, evaluate and create autonomously. Currently, no published experience exists of applying an AI in network planning on distribution level. The aut... View full abstract»

The protection functions applied for sensitive directional earth-fault protection in compensated medium-voltage (MV)-networks are based on the measurement of residual current and voltage, and the derivation of the resistive operation quantity thereof. In this study, the importance of residual current measurement accuracy on earth-fault protection performance in compensated MV-networks is analysed.... View full abstract»

Open ring networks have been commonly used; they have been protected with either phase and earth simple or directional overcurrent protection relays. The biggest drawback of open ring electrical power networks is that a line/cable fault will disconnect the customers that are connected downstream from that fault location until manual or automatic reconfiguration of the network is done. How could we... View full abstract»

In power network analysis it is increasingly desirable to implement controller and power systems models within different software environments. This stems from, among other things, an increasing influence of new and distributed control functions within smart grids and a growing influence of market operations. The computation time resulting from the use of multiple simulation environments can cause... View full abstract»

An electricity supply smart contract was developed and demonstrated to perform pre-time-of-use price negotiation between demand and generation and post-time-of-use settlement and payment. The smart contract was demonstrated with 1000 loads/generators with usages simulated using lognormal probability distributions. It combines payment of deposit, negotiation of price based on estimates, settlement ... View full abstract»

Optimal power flow problems and market clearing approaches are converging: cost-optimal scheduling of loads and generators should be performed while taking the grid's physics and operational envelopes into account. Within the SmartNet project, the idea is to consider the grid's physical behaviour in market clearing approaches. Taking the physics of power flow into account, while managing solution ... View full abstract»

Considering time varying nature of load in conventional distribution system, network reconfiguration is combinatorial complex optimisation problem. In this study, a hybrid configuration of particle swarm optimisation (PSO) method with ant colony optimisation (ACO) algorithm called hybrid PSO–ACO algorithm is presented for optimal network reconfiguration in distribution network in the presence of d... View full abstract»

In order to have a viable design of low-voltage direct current (LVDC) protection devices like circuit breakers and fuses, it is important to design them for the correct short-circuit ratings keeping the network configuration in account. In this study, fault characteristics for different future LVDC network configurations are simulated (PLECS) (PLECS is a simulation platform for power electronic sy... View full abstract»

Low-voltage direct current (LVDC) distribution is considered as one of the new promising technologies for better integration of distributed generation, and supplying local loads in more efficient way compare to AC systems. However, DC protection is still considered as one of the outstanding challenges that holds back the wide deployment of LVDC in the last mile utility applications. Most of existi... View full abstract»

Cyber security deployment first focused on being compliant to standards and regulations. This approach has been very beneficial for the entire industry because it has increased the level of awareness about cyber security even if it may have led to oversimplifications (such as focusing on transmission only, removing serial communications, defining security perimeters etc.). As the electrical grid i... View full abstract»

When a low-voltage (LV) DC distribution system installation is realised in a public power distribution network, an extensive specification is required to ensure electrical and equipment safety and compatibility between the existing grids and customer-end installations. The goal of the study is to give to a reader an understanding what is required for safe and reliable operation of the LVDC distrib... View full abstract»

This study presents the first performance results of a large battery energy storage system (BESS) that is connected to a medium-voltage distribution network and used simultaneously by multiple stakeholders. This study presents the background of the purpose of a BESS as part of the Nordic power system and markets, and the functionalities it is able to perform. The first test cases ran in the fall 2... View full abstract»

Smart cities provide citizens with information on various urban services and allow them to track the impact of their resource consumption on the overall sustainability of their city. Energy management is one of the most demanding issues within such urban centres owing to the complexity of the energy systems and their vital role. Therefore, significant attention and effort need to be dedicated to t... View full abstract»

The technology of sensors and other control equipment installed on power transformers has improved rapidly in last few years, with the number of new solutions and measuring methods also continuously growing. Monitoring systems contain a large variety of different measurements and calculated data related to measured values and standards. Monitoring systems on power transformers are not only a new f... View full abstract»

A new solution for the phase and earth fault directional detection used in fault passage indicators (FPI) is presented in this study.The solution is based on several low-power voltage sensors using capacitor on bushing, on head cable or resistive sensors. The principle of the phase directional detection remains on the conventional principle of protection relays (ANSI 67). The main algorithm improv... View full abstract»

This study describes applications for micro-phasor measurement unit (μPMU) technology that address emerging issues in the distribution system due to stresses from dependencies on high DER penetration and microgrids. Lessons from the deployment of μPMU technology at a major utility and microgrid are shared here, offering opportunities for enhanced analytics to inform command and control methods to ... View full abstract»

This study aims to present a comprehensive distribution loss analysis in typical distribution network of Mashhad in medium and low-voltage networks, which can be useful for network operators. Also the experience with efforts for distribution loss reduction in a residential and a commercial section in Mashhad are reviewed. Unfortunately, non-technical loss is the major part of distribution loss in ... View full abstract»

The current transmission and distribution network relies on SF6technology because of its remarkable arc quenching properties and dielectric insulation. However, SF6is a greenhouse gas with an extremely significant impact on global warming. It is one of the six gasses listed in the 1997 Kyoto Protocol designed to lower greenhouse gas emissions worldwide. In addition, as a fluo... View full abstract»

In December 2015, a confirmed cyber-attack targeting several electric power utilities in Eastern Europe has resulted in a power outage that impacted hundreds of thousands of utility customers. This event strongly indicates that distribution system operators (DSOs) systems are vulnerable and are high risk of being targeted. With many new connected components inside the DSO's systems and readily ava... View full abstract»

Sein Island (French Brittany) has an isolated and autonomous network (Fig. 1) that is not connected to the continental electricity grid. It is essential on these islands is to ensure the highest possible degree of robustness and quality-of-service. Currently, power is provided almost solely by diesel generators (gensets) with a high kWh cost and greenhouse gas ... View full abstract»

Transformers are important equipment in distribution networks which their optimal siting and sizing is one the important issues in planning and operation of distribution networks. In traditional methods, the optimal capacity of transformers is determined considering the average load consumption and temperature. In the presence of non-linear loads, the current and voltage distortions are increased ... View full abstract»

Due to today's increased demands on grid operation management, new methods for earth fault localisation and detection are needed. The fault localisation should be performed as quickly as possible and under the condition that the fault current at the fault location will not be significantly increased. Up to now, the third harmonic was never used as a directional earth fault indicator, as the third ... View full abstract»

The power industries have paying their attention on distributed generations (DGs) due to the improvement in new technology like fuel cell, wind turbine, and photovoltaic. Hence, DGs have attained a lot of consideration in the power industry due to market deregulations and ecological concerns. This study presented the optimal reclosing of circuit breakers for the DG connected IEEE nine bus system. ... View full abstract»

Modern communication standards and techniques are the way forward in the simplification and improvements of today's protection application. Different communication services in international electrotechnical commission (IEC) 61850 standard Ethernet-based station bus enable possibility to simplify the design of the medium-voltage switchgear. This study discusses the factors related to testing and co... View full abstract»

An innovative distribution network expansion planning tool for smart distribution systems is proposed in this study. The tool supports the smart grid concept by evaluating the value of flexibility of generation and load in the optimal expansion planning of the distribution system in addition to the traditional infrastructure and operating costs. Additional to the classical decision variables in pl... View full abstract»

In Kansai Electric Power Co., Inc., smart meter data is transmitted from meter to the concentrator by radiofrequency mesh system or power line communication (PLC) system. The authors mainly apply PLC system to multi-dwelling buildings. In order to extend the coverage and improve usefulness of PLC system, the authors developed new PLC system, especially for the multi-dwelling buildings receiving el... View full abstract»

The aim of this study is to show the dynamic behaviour of the renewable plant for grid code requirements regardingQandV. The document is focused on big amplitude grid voltage variations because this can be considered as the most critical point regarding dynamic behaviour of generally of the renewable power plant (RPP). Static synchronous compensator (STATCOM), mec... View full abstract»

The installation of phasor measurement units (PMUs) by Enduris, one of the distribution network operators in the Netherlands to monitor their 50 kV ring distribution grid has resulted in increased observability of the power flows and voltages. However, with the increased observability, there is a need to analyse the distribution grid based on the data generated by the PMU monitoring system. This s... View full abstract»

Photovoltaic (PV) grid-connected system becomes one of the most important and promising applications for solar energy, the interfacing of these systems to the grid requires efficient control strategies for operation, control and power quality (PQ) improvement. The operational objectives of PV system are fulfilled by many control modes, during sunlight, the system sends active power to the grid and... View full abstract»

Currently distribution system operators in Europe are performing rollouts of smart metering systems relying on power line communication (PLC). Some costumers are refusing the installation due to privacy issues, others from fear of additional electromagnetic field (EMF) exposure. Due to voltage signals in the frequency range of 30–95 kHz at a few volts level, there are very limited electric and mag... View full abstract»

One of the most challenging discussions in distribution companies is power quality. Harmonics is one of power quality issues which generated in any non-linear electrical/electronic systems. The presence of harmonics in distribution networks can lead to various problems in terms of performance and operation. High-pressure sodium (HPNa) lamps are currently the main lamps used in public lighting. How... View full abstract»

High breaking capacity (HBC) fuse is today one of the most used low- and medium-voltage protective devices. Its operation principle presents two singular current values of difficult interruption, ‘critical current’ and ‘minimum breaking current.’ These fuses, in general are not able to break any current that begins the melting process. An introduction about the HBC fuse design characteristics and ... View full abstract»

Modern communication standards and techniques are the way forward in the simplification and improvements of today's protection application. Different communication services in IEC 61850 standard Ethernet-based bus enable new type of applications and possibility to simplify the design of the medium-voltage switchgear. This study describes how IEC 61850-9-2 together with non-conventional measuring d... View full abstract»

For a guarantee of durability and reliability in the manoeuvre, the breaking capacity that the contacts must support, and number of operations or manoeuvres required are fundamental parameters to select equipment. The breaking capacity is a critical parameter within the design and application of the auxiliary relay, (Tripping signal, Multiplication of signals, Current amplification, Signal for Ope... View full abstract»

Renewable energies and digital technologies are two of the strongest drivers for the ongoing energy transition. Due to current transformations new business models appear, while conventional ones vanish. This threatens incumbents, but also provides manifold opportunities. The current transition leads to falling barriers, changing roles and markets, and the appearance of new players – this rapidly c... View full abstract»

While the study of activating the immense potentials of demand response (DR) in load side attracts widespread attention, a simulation platform with the ability of ‘source–grid–load’ interactive operation is essential. Nevertheless, it is an enormous challenge to incorporate the DR resources in real-time simulation as the characteristics of mass, diversity, and responsiveness. This study presents a... View full abstract»

In this study, a modified version of IEEE 34-bus test feeder with two fixed speed wind generators is considered. In the proposed method, at first, the type of short circuit is determined using the 3-phase current data that are measured at the substation. Then, to train and test the Artificial Neural Network (ANN), different operating patterns are produced for each type of short circuit. In order t... View full abstract»

Electric buses have gained a large public interest lately. In Gothenburg, Sweden, a demonstration project is currently underway where electrical and hybrid electric buses are being tried. This study investigates the impacts on the electrical distribution system from the fast-charging stations used to power the electric buses. Alternatives to mitigate the impacts including demand response (DR) and ... View full abstract»

Power cables are usually subjected to electrical, thermal, mechanical, and environmental stresses when they are in service. These stresses will lead to premature cable failure causing unplanned outages. This paper will show a better understanding of MV underground cable failure in Alexandria Electricity Distribution Company (AEDC) by analyzing data in connection with cable failures and by identify... View full abstract»

The growth of distributed generation in the UK has led to the increase in the number of flexible distributed energy resource (DER) connections and services required at distribution level. In some parts of the UK, flexible connections are offered to distributed generators (DG) via the use of active network management (ANM) systems. In exchange for a cheaper, quicker connection to the network, DG ma... View full abstract»

This paper presents the activities of the CIGRE/CIRED C6.25/B5 joint working group (JWG), focusing on the control and automation systems for the future electric networks. This JWG is mainly focused to evaluate the level of automation and control necessary to better manage distribution networks with large penetrations of distributed energy resources, as seen from both the TSO and DSO perspectives. View full abstract»