Aladin Zayegh

Foot Plantar Pressure Measurement System: A Review

Foot plantar pressure is the pressure field that acts between the foot and the support surface during everyday locomotor activities. Information derived from such pressure measures is important in gait and posture research for diagnosing lower limb problems, footwear design, sport biomechanics, injury prevention and other applications. This paper reviews foot plantar sensors characteristics as reported in the literature in addition to foot plantar pressure measurement systems applied to a variety of research problems. Strengths and limitations of current systems are discussed and a wireless foot plantar pressure system is proposed suitable for measuring high pressure distributions under the foot with high accuracy and reliability. The novel system is based on highly linear pressure sensors with no hysteresis.

Modeling of a Centralized Microgrid Protection System and Distributed Energy Resources According to IEC 61850-7-420

Microgrids have been proposed in an effort to handle the impact of distributed generators (DGs) and make conventional grids suitable for large scale deployments of DGs. However, the introduction of microgrids brings some challenges such as the protection of a microgrid and its entities. Due to the existence of generators at all levels of the distribution system, the fault currents vary substantially. Furthermore, grid connected and islanded modes introduce two different sets of fault currents. Consequently, the traditional fixed current relay protection schemes need to be improved. The authors developed a new protection system which utilizes extensive communication to monitor the microgrid and update relay fault currents according to the variations in the system. This system is designed to respond to dynamic changes in the system such as connection/disconnection of DGs. This paper presents the modeling of a microgrid protection system with logical nodes provided in IEC61850 and IEC61850-7-420 communication standards. It also demonstrates how the proposed communication takes place through logical nodes. Firstly, models for different DGs are provided to detail the implementation of the said logical nodes. Then, a case study is given on a sample microgrid to show how the proposed protection scheme can be run based on these models.

The Real-Time Publisher/Subscriber Communication Model for Distributed Substation Systems

In the past decade, new communication schemes have been designed and retrofitted into substations by utilities to integrate data from relays and intelligent electronic devices (IEDs) and capitalize on the protection, control, metering, fault recording and communication functions available in digital devices. The introduction of IEC 61850 has made it possible and justifiable to integrate station IEDs on a high-speed peer-to-peer communication network (Ethernet) through standardization. However, more advances are needed in order to establish an open and standard working environment allowing for more functions to be developed. In this paper, the authors propose a real-time publisher/subscriber communication model as a means of satisfying the unique behavior and communications needs of the IEC 61850 protocol. The authors provide a detailed design and implementation detail of this model along with interesting performance results. The target audience for this paper includes power system protection and automation engineers and technicians as well as research personnel who have at least a basic understanding of the IEC 61850 international standard and other technology mechanisms addressed in this paper.

Implementing Vehicle-to-Grid (V2G) Technology With IEC 61850-7-420

Electric Vehicles (EVs) have become very popular due to climate change concerns and carbon emission reduction schemes. Accordingly, in recent years the awareness of people about EVs has increased significantly. In addition to the well-known advantages such as cleaner environment, less oil-dependency, cheaper fuel, more silent operation etc., through smartgrids, EVs offer a unique benefit called vehicle to grid (V2G) technology. In order to define the role of EVs as distributed storage devices, simulation works undertaken in Paladin Designbase 4.0 are presented in this paper. It is shown that through V2G, EVs can support better operation of smartgrids in terms of reliability and storage. In order to achieve these, the components of smartgrids shall communicate and share information via communication lines. Having a universal communication standard is vital for implementing the plug-and-play concept in smartgrids. IEC 61850, the substation automation standard, could be used for this purpose. However, it is insufficient and must be expanded to cover missing links. In this paper, authors propose an extension to the IEC 61850-7-420 standard by defining the information model for controlling the charging and discharging of EVs.

A microgrid protection system with central protection unit and extensive communication

Microgrids have been proposed in order to handle the impacts of Distributed Generators (DGs) and make conventional grids suitable for large scale deployments of distributed generation. However, the introduction of microgrids brings some challenges. Protection of a microgrid and its entities is one of them. Due to the existence of generators at all levels of the distribution system and two distinct operating modes, i.e. Grid Connected and Islanded modes, the fault currents in a system vary substantially. Consequently, the traditional fixed current relay protection schemes need to be improved. This paper presents a conceptual design of a microgrid protection system which utilizes extensive communication to monitor the microgrid and update relay fault currents according to the variations in the system. The proposed system is designed so that it can respond to dynamic changes in the system such as connection/disconnection of DGs.

A central microgrid protection system for networks with fault current limiters

Large deployments of Distributed Generators (DGs) have substantial impacts on the structure of existing networks. In order to tackle these issues, it has been proposed to divide the network into smaller manageable sets which can be more effectively and efficiently operated. This very concept is called the ‘Microgrid’. However, due to their unprecedented structure, these smaller grids experience very significant protection issues. Conventional fault current protection schemes cannot be used and should be modified due to the existence of generators at all levels of the distribution system. Furthermore, two distinct operating modes (grid connected and islanded modes) exist in microgrids causing the fault currents in a system to vary substantially. It is also a challenge to operate Inverter Interfaced DGs (IIDGs) and estimate their fault currents. Fault current limiters have thus been proposed for proper operation of DGs in a network. This paper presents a conceptual design of a microgrid protection system which makes use of current limiters in fault current estimation. It utilizes extensive communication to monitor the microgrid and update relay fault currents according to the variations in the system. The proposed system is designed so that it can respond to dynamic changes in the system such as the connection/disconnection of DGs.

The Application-View Model of the International Standard IEC 61850

The introduction of IEC 61850 as the de facto SA standard for the communication between devices in a substation and the related system requirements has made it possible and justifiable to integrate station Intelligent Electronic Devices (IEDs) on a high-speed peer-to-peer communication network (Ethernet) through standardization. IEC 61850 presents a set of standard object-oriented (OO) data models to describe the processes to be implemented and controlled in a substation and a set of service models for the interactions between devices in a substation and the transfer of all sorts of IED data. IEC 61850 proposes the concept of standardizing IED data using data objects referred to as logical nodes. This makes it possible to achieve the ldquoplug and playrdquo capability so that information and commands can be shared on a single network independent from any implementation. In this paper, the authors describe the standards application-view model and present the use of OO methodology and techniques for the implementation of the Logical Node (LN) application-view data model of the standard. The target audience for this paper includes power system protection and automation engineers and technicians as well as research personnel who have at least a basic understanding of the IEC 61850 international standard and other technology mechanisms addressed in this paper.

Object Modeling of Data and DataSets in the International Standard IEC 61850

In the past decade, new communication schemes have been designed and retrofitted into substations by utilities to integrate data from relays and intelligent electronic devices (IEDs). The idea of standardizing the language of communication between IEDs has evolved as the key for the advancement of connectivity and interoperability within a SA system. The most important outcome of this standardization process has been the IEC 61850 standard. IEC 61850 is an abstract application layer protocol aimed at providing interoperability between a variety of substation and feeder devices by describing how devices are to communicate in a substation as well as the related system requirements. In this paper, the authors describe the standards application-view model and present the use of OO methodology and techniques for the modelling and implementation of the data and dataset application-view object models of the standard. The target audience for this paper includes anyone interested in getting an overview of the IEC 61850 international standard, and understanding how the object-oriented models proposed in the standard standardize the data found in IEDs and the communication of this date between substation devices.

Electric Vehicle Potential in Australia: Its Impact on Smartgrids

The availability of the technology and the promising acceptance of hybrid electric vehicles (HEVs) has encouraged car manufacturing companies to take solid steps toward the electric vehicle (EV) market. As it is spread over a vast surface area, Australia has high car usage and ownership rates, and the inefficiency of the public transportation system contributes to this. Therefore, Australia has a very large potential market for EVs. In addition to the well-known advantages, such as zero direct emissions, reduced dependency on oil, cheaper fuel, and more silent operation through smart grids, EVs also offer a unique benefit called vehicle-to-grid (V2G) technology. Through V2G technology, EVs can support better operation of the smart grids in terms of reliability and storage. Based on reliable statistics and social studies, this article studies the EV potential of Australia and envisages the impact of large EV utilization therein. The statistics indicate that the growing population will demand more cars, and acceptance of EVs could also benefit other areas, such as environmental conservation, finance, and energy production. Accordingly, a microgrid system with V2G technology has been modeled and simulated in three different conditions: islanded, IEEE-T14-bus system, and IEEE-34-bus system. The results are presented to forecast the necessary changes in the power networks for the large deployment of EVs.

Identification of Foot Pathologies Based on Plantar Pressure Asymmetry

Foot pathologies can negatively influence foot function, consequently impairing gait during daily activity, and severely impacting an individual’s quality of life. These pathologies are often painful and correspond with high or abnormal plantar pressure, which can result in asymmetry in the pressure distribution between the two feet. There is currently no general consensus on the presence of asymmetry in able-bodied gait, and plantar pressure analysis during gait is in dire need of a standardized method to quantify asymmetry. This paper investigates the use of plantar pressure asymmetry for pathological gait diagnosis. The results of this study involving plantar pressure analysis in fifty one participants (31 healthy and 20 with foot pathologies) support the presence of plantar pressure asymmetry in normal gait. A higher level of asymmetry was detected at the majority of the regions in the feet of the pathological population, including statistically significant differences in the plantar pressure asymmetry in two regions of the foot, metatarsophalangeal joint 3 (MPJ3) and the lateral heel. Quantification of plantar pressure asymmetry may prove to be useful for the identification and diagnosis of various foot pathologies.