Intelligent Electronic Devices Research Articles

Fabrication of sustainable, toughening epoxy thermosets with rapidly thermal and light‐triggered shape memory property

AbstractShape memory epoxy thermosets (SMETs) have attracted more and more attention in artificial intelligence applications. However, the fabrication of lightweight and high‐strength bio‐based SMET with multiple‐response shape memory properties remains a challenge. Herein, a thermal and light‐triggered bio‐based SMET with excellent mechanical property and toughness is prepared. To fabricate the SMET, a bio‐based curing agent (CFMA) derived from cardanol, menthane diamine and furfural is utilized to react with epoxy resin E51 to prepare the SMET. The curing kinetics of SMET is measured by non‐isothermal DSC, and the reaction order is 0.784. The SMETs have excellent thermal stability and mechanical strength. Based on the toughening effect of the bio‐based curing agent, the SMETs exhibit excellent stretchability, and the toughness of the SMETs improves gradually with the increase in curing agent content. Furthermore, the SMET exhibits excellent thermal and light‐triggered shape memory properties, and the SMET with broad glass transition shows triple‐shape memory property. These multiple stimulus–response bio‐based SMETs with lightweight and high strength have potential applications in the field of actuators and intelligent electronic devices.

Serpentine-Inspired Strain Sensor with Predictable Cracks for Remote Bio-Mechanical Signal Monitoring.

Flexible strain sensors have attracted intense interest due to their application as intelligent wearable electronic devices. However, it is still a huge challenge to achieve a flexible sensor with simultaneous high sensitivity, excellent durability, and a wide sensing region. In this work, a crack-based strain sensor with a paired-serpentine conductive network is fabricated onto flexible film by screen printing. The innovative conductive network exhibits a controlled crack morphology during stretching, which endows the prepared sensor with outstanding sensing characteristics, including high sensitivity (gauge factor up to 2391.5), wide detection (rang up to 132%), low strain detection limit, a fast response time (about 40ms), as well as excellent durability (more than 2000 stretching/releasing cycles). Benefiting from these excellent performances, full-range human body motions including subtle physiological signals and large motions are accurately detected by the prepared sensor. Furthermore, wearable electronic equipment integrated with a wireless transmitter and the prepared strain sensor shows great potential for remote motion monitoring and intelligent mobile diagnosis for humans. This work provides an effective strategy for the fabrication of novel strain sensors with highly comprehensive performance.

A Non-Intrusive Approach for Enhancing Power-System Frequency Stability

This paper presents a novel protection strategy for assuring power-system frequency stability. After many years of use, the existing (static) under-frequency load-shedding concept has proven to be reliable and fast. However, it does not adapt well to volatile operating conditions, which might often lead to a system collapse. This developed into a major obstacle, since operational conditions of modern power systems are persistently subjected to fast and unpredictable changes. Therefore, there is a need to introduce a new capability in under-frequency load-shedding that would be able to fine-tune the mismatch in active power in any conditions. From the practical aspect, a systematic implementation of improvements should not threaten system stability. In terms of cost, a minimum intervention in the existing concept is desirable. This is why we developed an effective upgrade of the existing concept by introducing a specialized group of intelligent electronic devices supported by a principal component analysis technique. This group should be operated alongside the existing solution to monitor the actual frequency conditions and to take over power-balancing when fine-tuning is required. This supports the existing load-shedding and improves the process of frequency stabilization.

Ti3C2Tx/g-C3N4 heterostructure films with outstanding capacitance for flexible Solid-state supercapacitors

With the popularity of intelligent portable electronic devices, bendable and flexible electronic equipment, such as portable miniature devices, wearable electronics, smart clothing, electronics, display, skin flexible smartphones and implantable medical devices have become a development trend.As potential energy storage device, flexible supercapacitors have attracted extensive attention. Ti3C2Tx MXenes, which has high capacitance, mechanical strength and flexibility, perfectly meets the requirements of flexible energy storage devices.In order to avoid stacking, increase layer spacing, and enhance charge transfer efficiency, the Ti3C2Tx/g-C3N4 heterostructure is constructed by self-assembly method.The flexible self-supporting electrode is prepared by vacuum assisted filtration, which successfully widen the potential window and significantly improve the capacitance performance. The specific capacitance of the electrode in 1 M H2SO4 electrolyte reaches 414F/g at 1A/g.The electrode can simultaneously act as a fluid collector to construct a simple ultra-thin device.The flexible all-solid symmetric supercapacitor is assembled and the energy density reaches 23.98Wh/Kg when the power density is 139.66 W/Kg. Encouragingly, the device can maintain stable performance under 180° bending conditions.The above excellent performance confirms the applicability of supercapacitors based on Ti3C2Tx/g-C3N4 heterostructure films for future portable, flexible or wearable electronic energy storage devices.

Analysis and Design of a Smart Controller for Managing Penetration of Renewable Energy Including Cybersecurity Issues

This article presents an optimal distributed energy resource management system for a smart grid connected to photovoltaics, battery energy storage, and an electric vehicle aggregator. These management systems are one of the key factors for the optimal control of power converters connected to the grid. The proposed management system includes the communication architecture necessary for realizing the information flow between the individual control of the distributed generators and the master supervisory control algorithm. The work carried out on two levels is first to design a control strategy for energy management and validate it with the grid in real-time hardware-in-the-loop simulation integrating the IEC61850 communication layer and physical intelligent electronic devices. The second is to analyze the vulnerabilities of the designed methodology for cybersecurity threats explicitly with the extension of IEC61850 to electric vehicle aggregators for communication with the master energy management. A man-in-the-middle attack conducted in the supervisory communication layer enabled us to investigate the effects of such an attack on the performance and operation of the smart electric grid.

Investigation of flexible warp-knitted metal meshes for electromagnetic interference shielding

This paper develops four novel warp-knitted structures with two bars of the one-in one-out threading mode and describes the investigation of electromagnetic interference (EMI) shielding metal meshes composed of contiguous ultra-fine metal wires fabricated using warp-knitting technology. The mechanical properties, electrical conductivity, and microwave shielding effectiveness (SE) of the flexible meshes are assessed in terms of the mesh structure, mesh material, and warp run-in parameter. The results reveal that the metal mesh has a flexible and stable mechanical property, good electrical conductivity, and optimal EMI performance when the mesh structure is open lap atlas. The gold-coated molybdenum mesh exhibits the lowest electrical resistivity (5.18 × 10−5 ohm/sq) and optimal average EMI SE (–21.04 dB), making it a candidate for EMI shields for intelligent wearable electronic devices. The warp run-in can adjust the EMI SE, and the optimum average EMI SE (–25.52 dB) can be obtained when the warp run-in is set at the 2580 rack. Moreover, the warp-knitted metal meshes show desirable EMI shielding efficiency persisting at >70% even at large strain deformations and under cyclic bending and twisting deformations. Conductive warp-knitted meshes with a millimeter period and micron-scale wire diameter exhibit an adequately large scale, satisfactory mechanical stability, excellent flexibility, permanent conductivity, and strong microwave reflection, simultaneously. Moreover, the EMI SE of warp-knitted metal mesh reaches the protection level (–20 dB) prescribed by standard electronic devices. Therefore, the warp-knitted metal meshes show great potential in flexible and wearable EMI shielding devices.

Construction of gradient conductivity cellulose nanofiber/MXene composites with efficient electromagnetic interference shielding and excellent mechanical properties

The development of electronic communication technology leads to a complex electromagnetic (EM) environment, which is urgent for the design of high-performance EM interference (EMI) shielding materials. In this work, cellulose nanofiber (CNF) and MXene were used to construct ordered multi-layer composite films with a controllable conductive gradient by layer-by-layer vacuum filtration method. Especially, the films were composed of four transition layers (with low MXene content) and one reflection layer (with high MXene content), which not only effectively reduced the reflection of EM waves on the surface of materials but also greatly increased the multiple internal reflections of reflected EM waves. Besides, the dielectric loss provided by MXene, and the coordination of polarization with loss at the interfaces contribute to the outstanding EMI shielding effectiveness (EMI SE) (39 dB) and absorption effectiveness (28 dB) of the films. And practical application simulation proves that the composite membrane can limit the mobile phone communication signal. Moreover, the nacre-like structure was constructed by 1D CNF and 2D MXene, resulting in high tensile strength of 90.5 ± 6.7 MPa and elongation at a break of 8.0 ± 1.0%. Therefore, this work provided a feasible approach for preparing gradient composite films with high EMI shielding and mechanical properties, which is highly promising to be a competitive candidate for the application in the new-generation of intelligent electronic devices.

Bio-inspired soft actuator with contact feedback based on photothermal effect and triboelectric nanogenerator

The development of film soft actuators with contact feedback and outstanding environmental robustness is desirable. In this work, a film-based soft actuator laminated by polyethylene glycol terephthalate (PET), carbon black ink, and polydimethylsiloxane (PDMS) is proposed. Due to the enormous difference in thermal expansion coefficients between these materials, the actuator achieves a large bending deformation angle and a high response speed. Without the shape-memory materials, the actuator can return to its original shape under light-induced after being subjected to mechanical stress. Meanwhile, the actuator maintains its shape after being exposed to extreme temperatures of up to 200 °C and immersion in a variety of solvents. Furthermore, based on the triboelectric effect, the actuator can generate remarkable real-time electrical signals when it mimics the tongue of frogs, bends deformation, and simulates mechanical grippers. This work demonstrates a simple method for building various intelligent and flexible electronic devices and provides promising applications for soft robots.

Anomaly-Aware Adaptive Sampling for Electrical Signal Compression

Intelligent electronic devices for power systems often entail high frequency sampling of electric signals, enabled to capture anomalous signal behavior. However, in normal operation this oversampling is redundant and leads to excessive data being stored or transmitted. This gives rise to a new compression problem where the collected samples should be further subsampled and quantized based on the presence of an anomaly in the underlying signal. We propose an Anomaly-aware Compressive Sampler (ACS) which tests the signal for the presence of an anomaly in a block of samples, and subsamples in a hierarchical manner to retain the desired sampling rate. ACS has been designed keeping hardware constraints in mind, using integer operations, an appropriate bit-packing, a simple iterated delta filter, and a streaming data pipeline. We present a mathematical formulation of the problem and analyze the performance of ACS, establishing theoretically its ability to identify anomalies in the signal and adapt the sampling rate. ACS competes with the state-of-the-art algorithm for the better-behaved transmission system data from DOE/EPRI, and outperforms it significantly on real-time distribution system data recorded in our laboratory. Finally, ACS is lightweight and was implemented on an ARM processor.

Attack and defence methods in cyber‐physical power system

With the development of digitalisation and intelligence, the power system has been upgraded from the traditional single energy transmission and conversion system to a complex cyber-physical power system (CPPS) with tightly coupled energy and information flows. The cyber-physical power system achieves the controllability and observability of the power system through ubiquitous sensing technology, advanced measurement technology, and powerful information processing technology. However, the large number of intelligent electronic device accesses and frequent information interactions in CPPS make it more vulnerable and susceptible to be attacked than any previous single structured system. Viruses and intrusions can attack the CPPS through the cyber subsystem, which in turn can deal a fatal blow to the energy supply physical system. Because of the above problems, malicious attacks against CPPS have been occurring in recent years and have generated a great deal of scholarly attention. This paper precisely focusses on this problem, by profiling the structure of CPPS and the potential threats, conducting an in-depth analysis of CPPS attack modes from the cyber and physical subsystems, and summarising the three-level security defence methods for CPPS in detail. Finally, the future technological development prospects of CPPS security research are explicitly addressed, which will provide technical support for building reliable, safe, and robust energy systems.

Blockchain based energy trading in ADN with its probable impact on aggregated load profile, available distribution capability and loadability margin

AbstractPower grids monitoring, operation, control, and commercialisation are transforming gradually due to technological advancements, and new frontiers of distinct applications are emerging in this field. Global emphasis on increasing the dependence on renewable sources of generation and the introduction of electric vehicles as means of transformation can potentially affect the traditional notion of grid analysis, monitoring, and control. The prevalence of communicable intelligent devices enables peers to transact and sell/buy power locally or to the grid. Ensuring security, privacy, and avoidance of double‐spending in these transactions could be manifested by utilising the developments in blockchain technologies. In this paper, modified IEEE 123 bus distribution system has been considered. The effect of incorporating the energy transactions over block‐chain in ADN on Available Distribution Capability, aggregated load profile, and load‐ability is evaluated. The effect has been quantified using blockchain efficiency factor proposed in this article. It has been observed that enabling intelligent electronic devices peers to transact over blockchain can improve the performance of the ADN.

Objective evaluation of wearable thermoelectric generator: From platform building to performance verification.

Wearable thermoelectric generators can harvest heat from the human body to power an intelligent electronic device, which plays an important role in wearable electronics. However, due to the complexity of human skin, there is still no unified standard for performance testing of wearable thermoelectric generators under wearable conditions. Herein, a test platform suitable for a wearable thermoelectric generator was designed and built by simulating the structure of the arm. Based on the biological body temperature regulation function, water flow and water temperature substitute blood flow and blood temperature, the silicone gel with some thickness simulates the skin layer of the human arm, thus achieving the goal of adjusting the thermal resistance of human skin. Meanwhile, the weight is used as the contact pressure to further ensure the reliability and accuracy of the test data. In addition, the environment regulatory system is set up to simulate the outdoor day. Actually, the maximum deviation of the performance of the thermoelectric generator worn on the test platform and human arm is ∼5.2%, indicating the accuracy of objective evaluation.

Force-Sensitive Interface Engineering in Flexible Pressure Sensors: A Review.

Flexible pressure sensors have received extensive attention in recent years due to their great importance in intelligent electronic devices. In order to improve the sensing performance of flexible pressure sensors, researchers are committed to making improvements in device materials, force-sensitive interfaces, and device structures. This paper focuses on the force-sensitive interface engineering of the device, which listing the main preparation methods of various force-sensitive interface microstructures and describing their respective advantages and disadvantages from the working mechanisms and practical applications of the flexible pressure sensor. What is more, the device structures of the flexible pressure sensor are investigated with the regular and irregular force-sensitive interface and accordingly the influences of different device structures on the performance are discussed. Finally, we not only summarize diverse practical applications of the existing flexible pressure sensors controlled by the force-sensitive interface but also briefly discuss some existing problems and future prospects of how to improve the device performance through the adjustment of the force-sensitive interface.

Integrating Smart Grid Devices into the Traditional Protection of Distribution Networks

Smart grids are a reality in distribution systems. They have assisted in the operation, control, and most of all, the protection of urban networks, significantly solving the contingencies of these networks. This paper treats the initial stage of implementing smart grid switching devices in distribution networks. In this stage, smart grid technologies need to operate with the traditional protection elements (such as fuses, reclosers, and sectionalizers). This fact can create trouble in the protection schemes because there are two distinctive philosophies. In some companies, especially those without substantial capital, these two protection philosophies can run together for many years. The most popular intelligent electronic devices (IEDs) available in the market are studied to verify their features and the possibility to incorporate techniques to allow the two philosophies to work together. After that, the proposed approach shows how the existing IEDs can interact with the traditional devices. Special functions can also be incorporated to inform the control center of an operational problem, increasing the observability of the network. With the proposed approach, the IEDs are transformed into intelligent agents. Practical examples using real distribution systems are presented and discussed, proving the efficacy of the proposed methodology.

A blockchain-based lightweight identity authentication scheme for the IEDs of security and stability control system

As an important part of the second defense line of the power system, the Security and Stability Control System (SSCS) is of great significance to ensure the reliable operation of the power system. However, SSCS still lacks an effective security mechanism and is easily accessed by attackers, thus posing a threat to the stable and reliable operation of the power system. To tackle this issue, we propose a blockchain-based identity authentication scheme for Intelligent Electronic Devices (IEDs) of SSCS. We first propose an identity authentication system model for IEDs and design the deployment of consortium chain nodes on IEDs, with architectural characteristics of SSCS and the working scenario of IEDs taken into consideration. The consortium chain is used to store credentials required for authentication, ensuring that they are tamper-proof. We combine IP address, port number and physical ID, and propose the unique identification of IEDs, with a data structure designed for the identification. We also propose a lightweight identity authentication method based on renewable hash chains, with hash chains used as one-time authentication passwords, and introduce a renewal mechanism of hash chains. Further, the detailed processes of registration and authentication phase are designed. Finally, the security analysis shows that our identity authentication scheme can resist various attacks, and the feasibility of our scheme is verified by experiments.

Sustainable Natural Bio-Origin Materials for Future Flexible Devices.

Flexible devices serve as important intelligent interfaces in various applications involving health monitoring, biomedical therapies, and human–machine interfacing. To address the concern of electronic waste caused by the increasing usage of electronic devices based on synthetic polymers, bio‐origin materials that possess environmental benignity as well as sustainability offer new opportunities for constructing flexible electronic devices with higher safety and environmental adaptivity. Herein, the bio‐source and unique molecular structures of various types of natural bio‐origin materials are briefly introduced. Their properties and processing technologies are systematically summarized. Then, the recent progress of these materials for constructing emerging intelligent flexible electronic devices including energy harvesters, energy storage devices, and sensors are introduced. Furthermore, the applications of these flexible electronic devices including biomedical implants, artificial e‐skin, and environmental monitoring are summarized. Finally, future challenges and prospects for developing high‐performance bio‐origin material‐based flexible devices are discussed. This review aims to provide a comprehensive and systematic summary of the latest advances in the natural bio‐origin material‐based flexible devices, which is expected to offer inspirations for exploitation of green flexible electronics, bridging the gap in future human–machine–environment interactions.

Simplified and Low-Cost Characterization of Medium-Voltage Low-Power Voltage Transformers in the Power Quality Frequency Range

The distribution network is experiencing a massive deployment of intelligent electronic devices (IEDs) such as energy meters, protective devices, and phasor measurement units (PMUs). This phenomenon resulted, on the one hand, in (i) the availability of distributed measurement systems capable of monitoring and collecting measurements from the distribution network, and (ii) increasing awareness of the system operator about the status of the network. On the other hand, such a significant number of devices require to be characterized, over the years, and assessed in both sinusoidal and distorted conditions. However, the characterization process may require a huge investment of money and time considering the low availability of reference instruments and accredited laboratories. To this purpose, this paper presents a simple and fast test procedure, performed with cheap and low-voltage instrumentation, to characterize two off-the-shelf low-power medium-voltage sensors in the power quality frequency range. In detail, the paper describes the measurement setup developed for the characterization and the performed tests. In addition, the method was also reproduced with reference equipment for validation purposes. Lastly, for both tests, an uncertainty evaluation was performed to quantify the goodness of the proposed method. From the results, it is possible to appreciate that the designed cheap and simple test can achieve as accurate results as those of a sophisticated and expensive equipment.

Local Fault Location in Meshed DC Microgrids Based On Parameter Estimation Technique

Accurate locating of the faulty section is desired in dc microgrid due to the presence of power electronic converters and low-impedance cables. Some of the existing schemes consider power sources at only one end of the line; thus, assume that the fault current is injected from only one end of the line. This assumption is not true in the case of meshed dc microgrids, where fault current would be supplied from both ends. Moreover, existing communication-based methods require either a fast communication network or data synchronization. To address the aforementioned issues, this article proposes a novel local fault location scheme for meshed dc microgrids. Low- and high-impedance faults are located by measuring the current by localized intelligent electronic device. Based on the parameter estimation approach, the fault location is estimated by sampling the peak values of the fault current. The effectiveness of the proposed strategy is evaluated based on offline digital time-domain simulations in MATLAB/Simulink software environment for a meshed test microgrid system and experimentally verified by implementing in a laboratory-scale hardware setup. Comparing the proposed method with other existing methods proves the effectiveness of the proposed technique for different types of faults.

Hardware Development and Interoperability Testing of a Multivendor-IEC-61850-Based Digital Substation

Substations are becoming increasingly reliant on international electrotechnical commission (IEC)-61850-enabled devices. However, device compatibility with these standards does not guarantee interoperability when devices are taken from different manufacturers. If interoperability of multivendor devices can be achieved, then power utilities will be in a position to implement multivendor devices in substations. The study here presents the development and testing of a digital substation test platform that incorporates devices from different manufacturers. The process bus communication and protection operation of the intelligent electronic devices (IEDs) were tested to validate device interoperability. The testbed was tested for two IED process bus communications, generic object-oriented substation event (GOOSE) and sampled measured value (SMV). The GOOSE is travelling between IED to IED with an end-to-end (ETE) delay of 2 ms and the SMV read by the IEDs are the same as the injected real-time substation inputs 220 kV and 1 kA. Three IED protection studies (overcurrent, earth fault, and overvoltage) were performed, and IED response curves were obtained. In addition, data monitoring and client–server communications were studied using installed software tools. The testbed configuration in this study has faced some real-time challenges regarding differences in device edition, device firmware, and ethernet switch due to its multivendor approach. All the mentioned configuration issues were resolved in this study with successful testing and validation of the testbed. The study of this testbed will provide solutions to the problems associated with a multivendor system faced by substation engineers and will help them in opting for multivendor installations. This system can be extended in the future by installing more multivendor devices with complex network topology and a SCADA system.

Reachability-Based False Data Injection Attacks and Defence Mechanisms for Cyberpower System

With the push for higher efficiency and reliability, an increasing number of intelligent electronic devices (IEDs) and associated information and communication technology (ICT) are integrated into the Internet of Things (IoT)-enabled smart grid. These advanced technologies and IEDs also bring potential vulnerabilities to the intelligent cyber–physical smart grid. State estimation, as a primary step of system monitoring and situational awareness, is a potential target for attackers. A number of other smart grid applications, such as voltage stability assessment and contingency screening, utilize state estimation results as input data. False data injection (FDI) is a specific way to attack state estimation by manipulating input data. Existing research mainly focuses on the mathematical analysis of FDI attacks; however, in these methods, discussions of reachability requirements to compromise measurements considering cyberinfrastructure are limited. Reachability is defined as a measure that estimates the number of hosts to compromise for the possible FDI. Most of the existing FDI attack methods require the simultaneous manipulation on multiple measurement devices in different substations, in order to bypass the bad data detection, which may be impractical. In this paper, a new type of reachability-based FDI attack considering the cybernetwork with a practical attack is proposed and validated on two IEEE test systems. The corresponding defence mechanisms are (a) decentralized state estimation (DSE), (b) DSE with additional backup computational nodes, (c) communication network rerouting, and (d) intrusion detection system, and they were developed and presented with validation for two IEEE test systems with superior performance for an IoT-enabled intelligent smart grid system.