International Electrotechnical Commission Research Articles

The JPEG AI Standard: Providing Efficient Human and Machine Visual Data Consumption

The Joint Photographic Experts Group (JPEG) AI learning-based image coding system is an ongoing joint standardization effort between International Organization for Standardization (ISO), International Electrotechnical Commission (IEC), and International Telecommunication Union - Telecommunication Sector (ITU-T) for the development of the first image coding standard based on machine learning (a subset of artificial intelligence), offering a single stream, compact compressed domain representation, targeting both human visualization and machine consumption. The main motivation for this upcoming standard is the excellent performance of tools based on deep neural networks, in image coding, computer vision, and image processing tasks. The JPEG AI aims to develop an image coding standard addressing the needs of a wide range of applications such as cloud storage, visual surveillance, autonomous vehicles and devices, image collection storage and management, live monitoring of visual data, and media distribution. This article presents and discusses the rationale behind the JPEG AI vision, notably how this new standardization initiative aims to shape the future of image coding, through relevant application-driven use cases. The JPEG AI requirements, the JPEG AI history, and current status are also presented, offering a glimpse of the development of the first learning-based image coding standard.

Adaptation and optimization of a photovoltaic system for a country house

This chapter provides the rationale for monitoring photovoltaic (photovoltaic) systems, its purpose, the need for proper measurement, and the frequency required to obtain meaningful results. The need for system monitoring falls into three groups: user feedback, performance review, and system evaluation. Each group is briefly summarized; other related topics include calibration, data storage, and data transfer. The text covers various monitoring modes such as performance testing, system evaluation, data collection and storage, as well as data analysis and reporting. The evaluation standards given by the International Electrotechnical Commission (IEC) are noted in the Data Analysis and Reporting section. The figures are provided to illustrate several types of displays that are an integral part of monitoring. Optimized modes of operation of the power part of a household photovoltaic system consisting of photovoltaic panels, an MRRT controller, an inverter and an electric energy storage unit, with Autonomous and network connection of the load. To build an optimal and cost-effective energy management strategy, it is necessary to take into account the energy profile of the resident, the characteristics of electricity production based on photovoltaic cells, and the electricity tariff for utilities. A photovoltaic system can be connected to the grid in order to receive energy from the grid or enter it into the network to eliminate the discrepancy between the generated, consumed and stored energy.

International Electrotechnical Commission 61850 Routable Generic Object-Oriented Substation Event Messages: A Secure Data-Centric Communication Approach

The necessity of critical communication between intelligent electronic devices (IEDs) in different substations led to expanding the Generic Object-Oriented Substation Event protocol (GOOSE) from the local area network (LAN) to the wide area network (WAN). International Electrotechnical Commission (IEC) 61850-90-5 has extended GOOSE messages as routable GOOSE (R-GOOSE) messages by adding network and transport layers. Therefore, the communication’s end-to-end latency and reliability against cyberattacks should be addressed.

A Micropower High-Performance ECG Recording Amplifier

This work introduces a novel micropowered single supply low-noise ECG amplifier that can be used with dry fabric-based paste-less electrodes for ambulatory electrocardiogram monitoring. The study emphasizes the need to include realistic values of source impedance as high as 10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{M}\Omega $ </tex-math></inline-formula> to assess amplifier performance parameters, such as magnitude response, time-domain response, common-mode input impedance, semiconductor noise, and common mode rejection ratio (CMRR). The effect on these parameters associated with high values of electrode impedance at different input frequencies has been extensively demonstrated in this work. The recommendations and standards published by the International Electrotechnical Commission (IEC) 60601 pertaining to electrocardiographic equipment have been used to evaluate the performance requirements of the amplifier to ensure minimal distortion of the ECG signal. The amplifier attains a minimum common-mode input impedance of 10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{G}\Omega $ </tex-math></inline-formula> at the input within a frequency range of 0.1–150 Hz. This boosted input impedance is preserved by neutralizing amplifier input capacitance using power supply bootstrapping. The amplifier also maintains a differential gain of 41 dB, the CMRR was measured at 84 dB at mains frequency, and the input referred semiconductor noise was measured at 32- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{V}$ </tex-math></inline-formula> peak-to-peak ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> Vpp) in a bandwidth of 250 Hz. The power consumption of the amplifier was <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$130 ~\mu \text{W}$ </tex-math></inline-formula> operating from 3.7-V lithium battery and is intended to provide for ECG signals having amplitudes in the range 0.1–10 mV. This small portable amplifier is intended for use in long-term ECG and heart-rate monitoring applications.

Enabling All In-Edge Deep Learning: A Literature Review

In recent years, deep learning (DL) models have demonstrated remarkable achievements on non-trivial tasks such as speech recognition, image processing, and natural language understanding. One of the significant contributors to the success of DL is the proliferation of end devices that act as a catalyst to provide data for data-hungry DL models. However, computing DL training and inference still remains the biggest challenge. Moreover, most of the time central cloud servers are used for such computation, thus opening up other significant challenges, such as high latency, increased communication costs, and privacy concerns. To mitigate these drawbacks, considerable efforts have been made to push the processing of DL models to edge servers (a mesh of computing devices near end devices). Recently, the confluence point of DL and edge has given rise to edge intelligence (EI), defined by the International Electrotechnical Commission (IEC) as the concept where the data is acquired, stored, and processed utilizing edge computing with DL and advanced networking capabilities. Broadly, EI has six levels of categories based on the three locations where the training and inference of DL take place, e.g., cloud server, edge server, and end devices. This survey paper focuses primarily on the fifth level of EI, called all in-edge level, where DL training and inference (deployment) are performed solely by edge servers. All in-edge is suitable when the end devices have low computing resources, e.g., Internet-of-Things, and other requirements such as latency and communication cost are important such as in mission-critical applications (e.g., health care). Besides, 5G/6G networks are envisioned to use all in-edge. Firstly, this paper presents all in-edge computing architectures, including centralized, decentralized, and distributed. Secondly, this paper presents enabling technologies, such as model parallelism, data parallelism, and split learning, which facilitates DL training and deployment at edge servers. Thirdly, model adaptation techniques based on model compression and conditional computation are described because the standard cloud-based DL deployment cannot be directly applied to all in-edge due to its limited computational resources. Fourthly, this paper discusses eleven key performance metrics to evaluate the performance of DL at all in-edge efficiently. Finally, several open research challenges in the area of all in-edge are presented.

A Self-Balancing PSO-Tunned PI Controller for Integrating Parallel Converters with Variable Renewable Sources

This study aims to propose a system designed to fulfill the current and future energy requirements of commercial and domestic consumers. Recently, renewable energy generation methods obtained a higher priority in industrial applications to reduce and replace using hazardous fossil fuel-based energy generation methods. Conventional power generators generate AC voltage, which is incompatible with many modern appliances, requiring power conversion circuits. Power conversion circuits can make the overall system expensive and induce superfluous complexity in the system structure and control. In contrast, most renewable energy sources, such as photovoltaic and fuel cells, have inherent DC output voltage, and thus, the importance of DC systems inevitably surpasses the application of AC systems. In this framework, this paper focuses on the generation of multiple DC voltage levels. Three DC voltage levels were considered according to the IEC 60038 standard of the International Electrotechnical Commission. To generate multiple DC voltage levels, a parallel combination of power cells is used, where each power cell consists of a DC-DC converter. For adequate control, a particle swarm optimization tunned proportional integral (PSO-PI) controller applies. Three case studies evaluated the performance of the proposed system based on transient response and voltage ripples. For case study 1, the input and output conditions are kept constant; for case study 2, the input voltage is iterated, and the output load is kept constant; for case study 3, the input voltage is iterated, respectively the output load is also iterated with different load settings. In all case studies, the transient response is less than 0.15 s, and the voltage ripple is less than 5%. Keywords: DC-DC converters, power cells, renewable energy, particle swarm optimization, controller. https://doi.org/10.55463/issn.1674-2974.50.2.8

Calibration matters: I. Sound level meter basics

Calibration is an essential component of audiology practice to ensure the accuracy of the equipment for audiometric tests and the transferability of test results across different clinics and countries. The ability to check the accuracy of the equipment and the ambient noise levels allows clinicians to monitor the functions of their equipment, to reduce noise distractors in the testing environment, and to have confidence in their test results, especially in humanitarian or field test settings. Sound level meters are the primary instruments to measure the sound pressure levels of the transducers and the test rooms used for audiometric testing. The International Electrotechnical Commission released a 3-part IEC 61672 standard of the specifications of sound level meters in 2013, and it is adopted by the standards organizations of many countries. This first installment of the tutorial series references this international standard and discusses basic acoustics concepts, calibration principles, and key functions of sound level meters in the application of audiometric calibration. Subsequent installments will discuss how to measure the ambient noise levels, how to determine whether a test room is suitable for testing hearing thresholds using different transducers, and how to determine whether different transducers of audiometers meet the national or international standards.

Microgrid Protection Using Magneto-Resistive Sensors and Superimposed Reactive Energy

The concept of microgrids has emerged as an effective way to integrate distributed energy resources (DERs) into distribution networks. The presence of DERs in microgrids leads to challenges in the formulation of protection for microgrids. Protection problems arise in a microgrid due to varying fault current levels in different operating scenarios. In order to overcome the practical challenges arising from varying fault current levels leading to short-circuit faults in microgrids, this paper proposes a MagnetoResistive (MR) sensors-based protection scheme, with fault localization through SuperimposedReactiveEnergy (SRE). The process is initiated by employing highly sensitive non-intrusive magnetic sensors to detect the magnetic field at each end of the distribution line. The magnetic field is then used to calculate the total harmonic distortion and thus detect faults in microgrids. After detection of faults, the proposed scheme uses SRE to identify faulty zones in microgrids. Finally, SI components of the current are extracted for fault classification. Extensive simulations on the International Electro-technical Commission (IEC) microgrid are performed in MATLAB/Simulink to validate the efficacy of the proposed scheme. Simulation results show that the proposed scheme can effectively detect, classify and isolate different faults in microgrids, while operating under various modes with varying fault locations and resistances, with the efficiency of approximately 97–98%.

Decentralized TSO-DSO coordination for voltage regulation purposes based on renewable energy sources management – Sensitivity and robustness analyses

• A decentralized coordination between a Transmission System Operator (TSO) and a Distribution System Operator (DSO) implemented via a standardized Business Use Case (BUC) for scheduling and deploying optimal reactive power exchanges in the DSO's boundary for improved voltage control in the TSO's networks is proposed. • The interoperability between the TSO, the DSO, and other stakeholders is solved by designing and developing the BUC within the framework of the International Electrotechnical Commission (IEC) Common Information Model (CIM) family of standards IEC61970, IEC61968, and IEC62325. • The standardized BUC is demonstrated on real-world Slovenian TSO's and DSO's networks. On one hand, a sensitivity analysis is conducted to evaluate to which extent different Renewable Energy Sources (RES), such as capacitor banks and different Distributed Generators (DGs), viz. hydropower, photovoltaic (PV), and thermal (co-generation) units, impact on the high voltage (HV) for different network topologies, DGs’ operating scenarios, and capacitor banks’ sizes and locations. On the other hand, a robustness analysis is conducted to evaluate the capability of the proposed approach to regulate the HV voltage by managing the reactive power injected by these different RES in the different simulated scenarios. • The proposed data exchange mechanism based on the standardized BUC can successfully exchange data between the TSO, the DSO, and other stakeholders, such as the Significant Grid Users (SGUs) and Meter Operators, as a CIM Common Grid Model Exchange Standard (CGMES) format. • The proposed approach can manage DGs at the DSO's boundary toward contributing additional (positive or negative) reactive power to reduce the voltage deviations in the grid, improve the power quality at the DSO's boundary by reducing the flow of reactive power from the TSO's to the DSO's networks and vice versa, and keep the HV within safe values. The increasing penetration of Renewable Energy Sources (RES) in distribution networks has led traditional voltage regulation to their boundaries. In order to develop advanced techniques for voltage control in this new context, an adequate and real-time coordination and communication between Transmission System Operators (TSOs) and Distribution System Operators (DSOs) is needed. In this paper, a decentralized TSO-DSO coordination approach for scheduling and deploying optimal reactive power exchanges in the DSO's boundary for improved voltage control in the TSO's networks is proposed. The proposed approach is implemented via a standardized Business Use Case (BUC). The interoperability between the TSO, the DSO, and other stakeholders is solved by designing and developing the BUC within the framework of the International Electrotechnical Commission (IEC) Common Information Model (CIM) family of standards IEC61970, IEC61968, and IEC62325. In view of the lack of pilot tests in the field, the proposed standardized BUC is demonstrated on real-world Slovenian TSO's and DSO's networks. The simulation experiments presented in this paper are twofold. On one hand, the proposed data exchange mechanism based on the standardized BUC demonstrates the feasibility of successfully exchanging data between the TSO, the DSO, and other stakeholders, such as the Significant Grid Users (SGUs) and Meter Operators, as a CIM Common Grid Model Exchange Standard (CGMES) format. On the other hand, the capability of the proposed decentralized TSO-DSO coordination approach to regulate the High Voltage (HV) by managing the reactive power injected by different RES, such as capacitor banks and different Distributed Generators (DGs), viz. hydropower, Photovoltaic (PV), and thermal (co-generation) units, is validated via sensitivity and robustness analyses for different network topologies, DGs’ operating scenarios, and capacitor banks’ sizes and locations. The simulation results show that the proposed approach can manage DGs toward contributing additional (positive or negative) reactive power to reduce the voltage deviations in the grid, improve the power quality at the DSO's boundary by reducing the flow of reactive power from the TSO's to the DSO's networks and vice versa, and keep the HV voltage within safe values. Unfortunately, this is not the case for the capacitor banks, where the capability of the proposed approach to manage their injected reactive power to regulate the HV voltage is highly dependent on their sizes and location, being necessary to be studied on a case-by-case basis.

ОГЛЯД МЕТОДІВ РОЗРАХУНКОВОЇ ПЕРЕВІРКИ ТРАНСФОРМАТОРІВ СТРУМУ, ЯКІ ПРАЦЮЮТЬ В КОЛАХ РЕЛЕЙНОГО ЗАХИСТУ

Systematized existing methods of calculation verification of current transformers that work in the circuits of modern relay protection devices. The requirements of the Ukrainian rules for the arrangement of electrical installations differ from the requirements of the standard of the International Electrotechnical Commission IES 61869-2. The difference concerns the absence of contact vibration and not exceeding the maximum allowable current error of 50% in the case of an internal short circuit is a separate case of the requirements for electromechanical protections and these requirements cannot be used for microprocessor protection devices. For any relay protection device, there is no concept of the permissible value of "voltages at the current inputs". The voltage at the terminals of the secondary winding and the voltage at the "input of the relay protection device" are two completely different voltages. There are no methods for calculating errors in the case of switching on protection based on the sum of the currents. Companies producing microprocessor relay protection devices specify in their instructions individual requirements for current transformers for each individual device. Compliance with these requirements guarantees the correct operation of the relay protection even for large values of the time constant of the primary network. Leading manufacturers of microprocessor relay protection devices develop and recommend software tools for checking the correct selection of current transformers. But they are not freely available. To increase the accuracy of the calculation of the limit multiplicity, it is advisable to use complex supports of the secondary winding and load of current transformers. Depending on the initial data and conditions, the permissible load resistance can be calculated using four methods. The question of whether the allowable load of a current transformer can exceed its nominal load requires further research. The scientific novelty is consists in the systematization of existing methods of calculation verification of current transformers that work in the circles of modern relay protection devices. The practical significance of the work is that checking current transformers that are connected to microprocessor relay protection devices do not need to check the maximum permissible current error of 50%; to check the correct operation of microprocessor relay protection devices, it is advisable to use the instructions for the requirements for current transformers of device manufacturers; for a more accurate calculation of the limit multiplicity, it is advisable to use complex supports of the secondary winding and load of current transformers.

A State-Observer-Based Protection Scheme for AC Microgrids with Recurrent Neural Network Assistance

The microgrids operate in tie-up (TU) mode with the main grid normally, and operate in isolation (IN) mode without the main grid during faults. In a dynamic operational regime, protecting the microgrids is highly challenging. This article proposes a new microgrid protection scheme based on a state observer (SO) aided by a recurrent neural network (RNN). Initially, the particle filter (PF) serves as a SO to estimate the measured current/voltage signals from the corresponding bus. Then, a natural log of the difference between the estimated and measured current signal is taken to estimate the per-phase particle filter deviation (PFD). If the PFD of any single phase exceeds the preset threshold limit, the proposed scheme successfully detects and classifies the faults. Finally, the RNN is implemented on the SO-estimated voltage and current signals to retrieve the non-fundamental harmonic features, which are then utilized to compute RNN-based state observation energy (SOE). The directional attributes of the RNN-based SOE are employed for the localization of faults in a microgrid. The scheme is tested using Matlab® Simulink 2022b on an International Electrotechnical Commission (IEC) microgrid test bed. The results indicate the efficacy of the proposed method in the TU and IN operation regimes on radial, loop, and meshed networks. Furthermore, the scheme can detect both high-impedance (HI) and low-impedance (LI) faults with 99.6% of accuracy.

A review of the technology standards for enabling digital twin

In the process of developing digital twin enabling applications, a lack of reference to standards related to digital twin terms, architecture and models leads to differences between users' understanding of digital twin, and it is difficult to realize the interconnection of data, models, and services between different enterprises or fields. Therefore, digital twin, by its nature of interoperability between multiple domains, requires standardization as a pilot tool for implementation. This paper provides the background and introduction of digital twin technology based on the digital twin five-dimension model, then refers to the latest developments of digital twin standardization. We further analyze the challenges and provide suggestions of future digital twin standardization. The analysis of the standards landscape for digital twin consolidates information from governing bodies such as the International Organization for Standardization (ISO), International Electrotechnical Commission (IEC), International Telecommunication Union (ITU), and Institute of Electrical and Electronics Engineers (IEEE)

RETRACTED: Repeatability in measurements and control settings of a small francis turbine test rig

A reduced scaled-down hydraulic turbine test setup has been designed. The test setup is made to investigate the mitigation of pressure pulsations like the rotating vortex rope (RVR) and its formation and problems related to prototype operation. The setup arrangements and instrumentations follow mostly the international electro-technical commission (IEC) standards. This paper presents the runner hub modification, calibration procedure, repeatability and systematic uncertainty estimation, and measurement methods as per the guidelines given in IEC 60193 and IEC 60041. The calibration and regression curves of all devices are presented. A LABVIEW program for open-loop operation at a constant head and closed-loop operation at constant discharge is also presented. Finally, the systematic and random uncertainty of hydraulic efficiency is discussed. • Design and development of small turbine test rig. • Design modification of runner cone profile. • Working of control feedback system using Partial Integral Differential (PID) controller. • Calibration of different instruments used in the small turbine test rig. • Random and systematic uncertainty of the small turbine test rig.

Weakly Coupled Multicore Fiber Technology, Deployment, and Systems

Space-division multiplexing (SDM) technology is a promising candidate to achieve massive parallelism in optical fiber cables and overcome the capacity limitation of the conventional single-mode fiber (SMF). Among the several kinds of SDM fiber, a weakly coupled multicore fiber (MCF) is advantageous in that it can be easily upgraded for use in existing equipment and requires no complex signal processing for optical multi-input multi-output (MIMO). In this article, we discuss the progress and standardization activity of MCF technologies from the viewpoint of accelerating the practical application of SDM technology. We first describe the possible application areas of SDM fibers and then show the recent progress of the essential technologies to construct the MCF link: the MCF itself, its splicing and connectorization, and the input/output techniques. We also discuss the availability and deployability of MCF as a large-capacity transmission medium and detail the progress on establishing a new international standard for SDM technology, which includes both historical progress and more recent endeavors on the standardization of optical fiber cables and SDM technology in International Telecommunication Union Telecommunication Standardization Sector (ITU-T) and International Electrotechnical Commission (IEC). We close with a summary of MCF technology and its standardization activity with an eye to next-generation transmission systems and the long-term development of ultralarge capacity SDM transmission technology.

Empirical Wavelet Transform-Based Intelligent Protection Scheme for Microgrids

Recently, the concept of the microgrid (MG) has been developed to assist the penetration of large numbers of distributed energy resources (DERs) into distribution networks. However, the integration of DERs in the form of MGs disturbs the operating codes of traditional distribution networks. Consequently, traditional protection strategies cannot be applied to MG against short-circuit faults. This paper presents a novel intelligent protection strategy (NIPS) for MGs based on empirical wavelet transform (EWT) and long short-term memory (LSTM) networks. In the proposed NIPS, firstly, the three-phase current signals measured by protective relays are decomposed into empirical modes (EMs). Then, various statistical features are extracted from the obtained EMs. Afterwards, the extracted features along with the three-phase current measurement are input to three different LSTM network to obtain exact fault type, phase, and location information. Finally, a trip signal based on the obtained fault information is generated to disconnect the faulty portion from the rest of the MG. The significant feature of the proposed NIPS is that it does not need adaptive relaying and communication networks. Moreover, it is independent of the operating scenario and hence fault current magnitude. To evaluate the efficacy of the proposed NIPS, exhaustive simulations are performed on an international electro-technical commission (IEC) MG. The simulation results confirm the efficiency of the proposed NIPs in terms of accuracy, dependability, and security. Moreover, comparisons with existing intelligent protection schemes validate that the proposed NIPS is highly accurate, secure, and dependable.

Advances in Solar PV Systems; A Comprehensive Review of PV Performance, Influencing Factors, and Mitigation Techniques

PV power plants utilizing solar energy to generate electricity on a large scale has become a trend and a new option that has been adopted by many countries; however, in actuality, it is difficult to anticipate how much electricity PV plants will generate. This analysis of existing photovoltaic (PV) power plants provides guidelines for more precise designs and performance forecasting of other upcoming PV technologies. In the literature, some authors have put their efforts into reviewing studies on PV power systems; however, those reviews are too focused on specific aspects of the topic. This study will review, from a broader perspective, recent investigations on PV power systems in the literature that were published between 1990 and 2022. The present study is divided into three main parts. Firstly, a performance assessment review of PV power plants is presented by taking different performance parameters into consideration, which were developed by the “International Electrotechnical Commission (IEC 61724-1)”. These parameters include reference yield, final yield, performance ratio, capacity utilization factor, and system efficiency. Secondly, different identifying factors that were investigated in previous studies, and which affect PV performance, were considered. These factors include solar irradiance, PV technology type, ambient temperature, cell temperature, tilt angle, dust accumulation, and shading effect. Thirdly, different methods were adopted and suggested to counter the effects of these influencing factors to enhance the performance efficiency of the PV power system. A hybrid cooling and cleaning system can use active techniques to boost efficiency during high solar irradiances and ambient temperatures while depending on passive techniques for everyday operations. This comprehensive and critical review identifies the challenges and proposed solutions when using photovoltaic technologies and it will be helpful for researchers, designers, and investors dealing with PV power systems.

TSO/DSO Coordination for RES Integration: A Systematic Literature Review

The increasing penetration of large-scale Renewable Energy Sources (RESs) has raised several challenges for power grid operation. Power management solutions supporting the integration of RESs, such as those based on energy storage technologies, are generally costly. Alternatively, promoting a more proactive role of the Distribution System Operator (DSO) to successfully manage RESs’ uncertainty, and take advantage of their flexible resources for the provision of ancillary services, can avoid installing expensive devices in the network and reduce costs. In this line, improved coordination between Transmission System Operators (TSOs) and DSOs is highly desirable. In this paper, the feasibility of solving different aspects of the integration of RESs through an improved TSO/DSO coordination is evaluated. In particular, a Systematic Literature Review (SLR) is conducted to study the most relevant TSO/DSO coordination approaches, exclusively focused on integrating distributed RESs, currently available in the literature. Their main operational, managerial, economic, and computational challenges, advantages, and disadvantages are discussed in detail to identify the most promising research trends and the most concerning research gaps to pave the way for future research toward developing a solid TSO/DSO coordination mechanism for integrating RESs efficiently. The main results of the SLR show a clear trend in implementing decentralized TSO/DSO coordination models since they provide efficient facilitation of RESs’ services, while reducing computational burden and communication complexity and, consequently, reducing operative costs. In addition, while different aspects of the TSO/DSO coordination implementation, such as reactive power and voltage regulation, operational cost minimization, operational planning, and congestion management, have been thoroughly addressed in the literature, further research is needed regarding data exchange mechanisms and RESs’ uncertainty modeling and prediction. In this line, the development of standardized communication solutions, based on the Common Grid Model Exchange Standard (CGMES) of the International Electrotechnical Commission (IEC), has shown promising interoperability results, whereas the use of learning-based approaches to predict RESs’ uncertain behavior and distribution networks’ responses, using only historical data, which relieves the need for access to commercially sensitive and proprietary network data, has also shown itself to be a promising research direction.

Is there correlation between measured and console CTDIvol in multislice CT scanners?

This study investigated the relationship between measured and console volume computed tomography dose index (CTDIvol) in multislice CT scanners. The measured CTDI values were determined from kerma length product measured using pencil ionization chamber inserted in the holes of standard CT phantoms with diameters 16 and 32 cm, which respectively mimic adult head and body using the procedures recommended by International Electro-technical Commission. Significantly large deviations were observed between the measured and console CTDI vol values in multislice CT scanners.

Voltage Distortion Influence on Flicker Severity Measurement by AMI Energy Meters

This article addresses the problem of proper flicker severity assessment by smart energy meters. Flicker severity occurs for a typical voltage “clipped cosine” distortion caused by operation of power electronic devices in the power grid. The voltage distortion caused only by higher harmonics does not cause voltage fluctuations, and therefore does not cause flicker. This article presents the research results for some models of advanced metering infrastructure (AMI) smart meters, for which irregularities are observed in the voltage variation severity assessment if the typical voltage distortion occurs in the power grid. Possible mistakes in implementation of flickermeter signal chain as defined by International Electrotechnical Commission (IEC) in smart meters that influence the measurement results have been explained. The analysis of the influence of typical voltage distortion on the indicator <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$P_{st}$</tex-math></inline-formula> measurement has been carried out analytically and in numerical simulation studies using the modeled flickermeter signal chain.

Standardization Activities for Optical Fiber and Cable Technology in International Electrotechnical Commission

Standardization Activities for Optical Fiber and Cable Technology in International Electrotechnical Commission