Standby State Research Articles

Quantitative Influence of Wind Farm Reactive Power and Voltage Control Capability on Hunan Power Grid Thermal Power Spinning Reserve

Affected by factors such as the inverse distribution of power sources and loads in the province, and the mismatch between the construction of load center power sources and load growth, the problem of voltage stability in central and southern Hunan is prominent, which mainly restricts the thermal power maximum operating capacity of the Hunan Power Grid. Under the heavy load mode, the hydro power units and thermal power units operating in the province need to reserve a certain amount of spinning reserve to response the voltage stability problems in central and southern Hunan. Thus, it leads to insufficient power supply during peak load periods. In recent years, the grid load has maintained rapid growth, and the increase in power sources is mainly the wind power. Affected by the anti-peak-shaving characteristics of wind power, the lack of wind power has aggravated the problem of insufficient power supply. Actually, the wind turbine is in a hot standby state during standby/backup, and its grid-connected converter is still in a grid-connected state within four hours. Besides, the continuous running SVG in the wind farm booster station can still be used temporarily. The above devices can provide reactive power support to the power grid during the transient process. Therefore, this paper takes the southern Hunan region as an example, and quantified the reduced thermal power requirement reserve by analyzing the reactive power support effect of the grid-connected wind farms. In this way, the power supply capacity can be improved.

Two Modes of Drag Reduction for Magnetorheological Fluids

Magnetorheological fluids (MRFs) show a millisecond-level reversible response controlled by an external magnetic field and are, thus, widely used in many areas, especially vehicle dampers, clutches, and brakes. However, in the standby state, the piston or rotor of these devices still moves in the MRF and generates damping force or torque, which will deteriorate the performance and even significantly increases the energy consumption of the entire vehicle. To solve these problems, we propose two working modes of MRFs based on rheology: vertical shear and parallel shear modes. This paper designed relevant magnetic circuit implementations for drum-type rotary magnetorheological (MR) devices to realize these new modes and verified the drag reduction effects by using a modified rheometer. The experimental results indicate that the vertical shear and parallel shear modes reduce the drag torque of the MRF by approximately 10% and 9% at magnetic field strengths of approximately 3.5 and 0.1 kA/m, respectively. Therefore, MR devices utilizing these drag reduction modes can reduce standby damping to improve performance. In addition, this paper proposes two mechanisms to explain the significant decrease in damping torque with the increasing number of experiments under the vertical shear mode. In summary, research into these two modes promotes understanding of MRFs and the development of MR devices.

A 2.5-nW Radio Platform With an Internal Wake-Up Receiver for Smart Contact Lens Using a Single Loop Antenna

The human eye has been considered to be a promising platform for real-time diagnosis of various biomarkers in tears. The smart contact lens (SCL), as a device which directly accesses surface of human eye, is a miniaturized autonomous system integrating all the required functions on the surface of a thin film. This article presents the first implementation of a set of radio including a wake-up receiver required for SCL. The system performs RF transmission upon wake-up call using a single loop antenna. The receiver path has a baseline-tracking offset control loop to successfully detect wakeup signal in the standby state under noisy environment. The operating frequencies for uplink and downlink are 346 and 433 MHz, respectively. A magnetic-coupled wireless charging of an OFF-chip battery is also provided through the same loop antenna. The designed IC is fabricated using 0.18- μm CMOS process, consuming a power of 2.5 nW in wakeup-ready standby state. The IC is also verified with a loop antenna and a thin-film battery integrated on a substrate of SCL.

Design of a current switching system for high accuracy current sources in AC-DC Transfer applications

A current switching system for AC-DC transfer applications using Single Junction Thermal Converters (SJTC) was designed and tested at Instituto Nacional de Metrología (INM). This switch design can directly commute between a DC reference current source and an unknown AC current source generated by high accuracy calibrators such as Fluke 5720A and Fluke 5730A. Two vacuum latch relays with an estimated switching speed of less than 10 ms were used. A control unit developed over a MSP430 Microcontroller allowed the switching control and serial communication with instruments through LabVIEW. It was found that, it takes between 2 s and 3 s for high accuracy calibrators to switch between an operating DC current and an AC current, or vice versa; therefore, the current commutation time is limited by the calibrator. By using two calibrators and the implemented current switching system it was possible to reduce the commutation time to about 300 ms, which is less than the reported SJTC thermal time constant. The switching system must be fast enough to avoid the calibrators to go to a standby state. The research work showed that the switching system could be used to improve thermal converters operation for the calibration of high accuracy AC current sources and multimeters.

Who is Charging My Phone? Identifying Wireless Chargers via Fingerprinting

With the increasing popularity of the Internet-of-Things (IoT) devices, the demand for fast and convenient battery charging services grows rapidly. Wireless charging is a promising technology for such a purpose and its usage has become ubiquitous. However, the close distance between the charger and the device being charged not only makes proximity-based and near-field communication attacks possible but also introduces a new type of vulnerabilities. In this article, we propose to create fingerprints for wireless chargers based on the intrinsic nonlinear distortion effects of the underlying charging circuit. Using such fingerprints, we design the WirelessID system to detect potential short-range malicious wireless charging attacks. WirelessID collects signals in the standby state of the charging process and sends them to a trusted server, which can extract the fingerprint and then identify the charger. We conduct experiments on eight commercial chargers over a period of five months and collect 8000 traces of signal. We use 10% of the traces as the training data set and the rest for testing. The results show that on the standard performance metrics, we have achieved 99.0% precision, 98.9% recall, and 98.9% $F1$ -score.

The contribution of economic intelligence to the firm performance

To the extent that the company is an “open system”, it must be in a continuous standby state. In this research work, we will try to focus on the contribution of economic intelligence strategies to the performance of the company. We will begin with a literature review to better understand the theoretical concepts. Then we will conduct a field study of 92 Tunisian industrial companies. Our work has revealed that economic intelligence has a positive but differential effect on the firm’s performance. But some determinants of performance do not seem to take full advantage of the strategies of economic intelligence to which companies should attach greater importance.

Deep learning framework for subject-independent emotion detection using wireless signals.

Emotion states recognition using wireless signals is an emerging area of research that has an impact on neuroscientific studies of human behaviour and well-being monitoring. Currently, standoff emotion detection is mostly reliant on the analysis of facial expressions and/or eye movements acquired from optical or video cameras. Meanwhile, although they have been widely accepted for recognizing human emotions from the multimodal data, machine learning approaches have been mostly restricted to subject dependent analyses which lack of generality. In this paper, we report an experimental study which collects heartbeat and breathing signals of 15 participants from radio frequency (RF) reflections off the body followed by novel noise filtering techniques. We propose a novel deep neural network (DNN) architecture based on the fusion of raw RF data and the processed RF signal for classifying and visualising various emotion states. The proposed model achieves high classification accuracy of 71.67% for independent subjects with 0.71, 0.72 and 0.71 precision, recall and F1-score values respectively. We have compared our results with those obtained from five different classical ML algorithms and it is established that deep learning offers a superior performance even with limited amount of raw RF and post processed time-sequence data. The deep learning model has also been validated by comparing our results with those from ECG signals. Our results indicate that using wireless signals for stand-by emotion state detection is a better alternative to other technologies with high accuracy and have much wider applications in future studies of behavioural sciences.

Development of flexible textile aluminium-air battery prototype

There is one component that virtually any embedded wearable needs—a power source. This paper proposes an energy source, which contains no harmful substances, can be stored in a stand-by dry state for indefinite time period, is flexible and has tactile characteristics similar to that of textile. The main feature of this energy source is the separation of the electrolyte and the electrodes—the electrolyte is applied only when the battery needs to be activated. This makes storage time in a dry state virtually infinite. It expands their potential use to storage solutions and healthcare/health monitoring solutions, because the design of the battery allows it to be used as an active sensor, which generates electric current, when it detects liquid. We stress that this solution is suitable for specific applications only, outlined in the paper. The main components of the battery include aluminium anode, air cathode and the cotton shell. The design includes only textile-based materials, which ensure greater flexibility and better fusion with textile materials, where the battery is intended to be integrated. Besides that, results of the experiments with multi-cell battery prototype are presented.

Conceptual methods of starting and controlling operating modes of compressorless combined cycle gas turbine unit

A method for operation study of a compressorless combined-cycle gas turbine (CCCGT) unit during transients from one steady-state mode to another, including during start-up and shutdown, is proposed. As an example, studies of the transients of an energy complex with a capacity of 60 MW are given. A variant of an algorithm concept for start/stop and transients of such an energy complex is proposed. This concept includes algorithms for starting from the three initial states of the energy complex (cold, hot and standby). For these algorithms, the time and energy consumption characteristics are estimated. It is shown that from a cold state, such an energy complex can be started and brought to the nominal mode in 1.5-2 hours. At the same time, the energy costs will not exceed energy consumption for its own needs in a nominal mode. The start-up time from the hot state can be reduced to 20-25 minutes, and the start-up from the standby state can be 2.5-3 minutes. The proposed concept of control algorithms for transient modes is such, so that a temperature state of the main components and parts of the energy complex is provided at a constant temperature. Thus, the time of transients will be determined only by the speed of the regulatory authorities. Consequently, power systems operating on the CCCGT cycle can operate equally efficiently, both in the basic mode and in the power control mode.

A New Method for Computation the Success Probability of Coverage for Switch Unit in the Switching Systems

Redundancy technique is used to improve performance and achieving to increase the lifetime of a system. Nowadays, the redundancy method is applied in many industries. One of the common methods of redundancy is its utilization in the switching systems. In switching systems, one or more components are considered active mode and the others in the standby state to be used by switch if necessary. In order to be fully utilized all the components in the redundant device, the switch unit must perform its function, such as switching, perfectly. Successful coverage by switch unit is expressed with a probability. In this paper, a new approach to the likelihood of switch success is proposed, and showing that as increases switching in the system, the efficiency and performance of the switch gradually decreases. The analysis of this method was based on the stress-strength method. Finally, a few numerical examples for the validation of results were applied.

Application analysis of efficient heat dissipation of electronic equipment based on flexible nanocomposites

• The efficient cooling of electronic device was designed and analyzed. • A flexible ultra-high thermal conductivity nanocomposites material used. • Model analysis, simulation and experiment proved the effectiveness. The efficient heat dissipation of electronic equipment is very important, its heat dissipation performance directly determines the life of the equipment itself. A hand-held electronic communications equipment, when used in surface temperature is exorbitant, need to heat dissipation equipment efficiently, to ensure that the use of comfort in the handheld. In accordance with this requirement, this article presents a flexible composite material based on nano-efficient cooling methods that can keep the layout, through the improvement of internal thermal path, it can achieve the effective heat dissipation. The network thermal resistance method is used to analyze the heat transfer in the equipment, and the thermal analysis of the local thermal resistance is carried out. At the same time, through the modeling of electronic equipment and the analysis of finite elements, the temperature drop of the equipment after improvement is accurately judged. Finally, the device experimental performance comparison before and after the optimization of the standby mode and working mode is verified. The results show that the optimized equipment heat source temperature can be reduced by up to 8.5°C, the surface temperature of the equipment can be reduced by about 5°C~7°C, and the final control equipment in the steady standby state of the temperature of about 39±0.5°C, to ensure the comfort of use, and also improved the service life of the equipment. The efficient thermal design of electronic equipment based on flexible nanocomposites can provide a convenient and reliable cooling solution for high-heat flow density devices.

Discussion on Topologies of Quick Response IPPS Suitable for Closed-Loop Control of EML

High energy density makes inductive pulsed power supply (IPPS), a research focus of supplies for electromagnetic launch (EML). However, in existing IPPS topologies, the charging and discharging stages of the inductors cannot be separated, so the response time of IPPS can be as long as ten or even tens of milliseconds. For this reason, the real-time closed-loop control of the output current and muzzle velocity based on IPPS is nearly impossible, which might be one of its biggest drawbacks compared to the capacitive pulsed power supply (CPPS). In this article, a novel current maintainable meat grinder (CMMG) circuit capable of fast response for EML applications is proposed, in which the antiparallel diode can provide a current maintaining path. After the inductor completes its charging process, the current can be maintained for a period of time. Thus, the circuit can be in a hot standby state and can be triggered with a very short delay. Subsequently, two commutation methods for the CMMG circuit are explored. The first one is to introduce the inverse current commutation with semiconductor device (ICCOS) branch. In its experiment with an inductance energy of 22 kJ, the circuit maintains 77% of the charging energy in the first 10 ms and is triggered successfully after 28 ms with almost zero response delay. The second method is the superconducting switching technology, based on which the CMMG with self-shutdown circuit is proposed and simulated.

Analysis of the Reliability of the Butter-Oil Processing Plant using CAS Mathematica and Maxima

The aim of the present paper is to analysis the reliability of the system by using CAS Mathematica and also, it’s comparative study with CAS Maxima. The butter oil manufacturing plant consists of seven units i.e. separator, pasteurizer, continuous butter making, melting vats, butter oil clarifier, packaging and standby state. Model is developed by using Markov birth-death process. The first order differential equations are derived by using model and then solved for comparative study of reliability to give accuracy in result. By using Mathematica, we calculate probability of each state, which is beneficial to plant owners because better accuracy in result enhance reliability of the plant Graphs are plotted and tables are developed with the help of CAS Mathematica and Maxima, graphs show the variation and tables shows the fluctuations in reliability in comparative manner.

Hybrid Data Protection Framework to Enhance A2O Functionality in Production Database Virtualization

Deluge of information flows in the unprecedented scenario of smart city development trend, hence prone to issues on stability, reliability and availability. Smart data storage resources are vulnerable to provide functionality Always Available Online (A2O) due to their inherent heavy dependence on System Down Time (SDT), Redundant Systems and Software Failure (RS2F) or whole/ multiple site failures. In the absence of Production Database Management Services (PDMS), duplicate deployment of similar data on disjoint but similar architecture provides a Tightly Coupled Ultimate System (TCUS), which assures A2O mutually exclusive services. In this paper, we investigated active Data Guard (aDG) and Data Guard (DG) role management or switchover for a real time transition performed for database at standby state to cope up both planned maintenance and accidental RS2F events. We expose our results for deep integration of aDGs with ODB in-terms of Fast Sync to align synchronously at an ease of zero of wait states for disk I/O and configurability to Null Data Loss (NDL). Over a large range of remote or standby databases NDL make it certain to zero failover. The impact of aDG Fast-Start Failover in the cloud proximity make sure guaranteed NDL in synchronously and near NDL protection asynchronously. Hence, avoids unusual overhead impeding disk I/O and eventually on a primary database. We observe the key performance indicator in failover does not restart the standby database for primary role resumption, but introduce cloud proximity as a new primary database and the process is performed without any intervention of manual migration. The reliability of aDG Redo is flexible across not only standby databases but also primary sites running different operating system over diverse hardware platforms. The Redo capability enables migration with minimal downtime for any transaction in the clouds, therefore adds an inevitable functionality to big data applications.

Developing Separate Effects Transient Test Experiments Using an Out-of-Pile Flowing Water Loop

In 2017 the Transient Reactor Test (TREAT) Facility was restarted after having been placed in a standby state in 1994. The TREAT reactor’s restart has since enabled the progressive development of new nuclear technologies within the United States that previously were outsourced to other countries. While the reactor’s restart was a large feat worthy of recognition, the experimental use of its characteristics has required further development of an in-pile experimental infrastructure sufficient to support programmatic needs. This hardware has taken the form of capsule designs (compact and elongated) as well as loop concepts representing the phenomena of interest for a subset of the separate effects tests desired for each respective testing campaign. The transient testing program has been a large integrated effort that aligns with the U.S. Department of Energy’s current needs. This study complements those programmatic elements by developing, fabricating, and demonstrating a full-scale flowing water loop in an out-of-pile environment. The goal of this effort is to develop a pragmatic understanding of the engineering capabilities and limitations associated with geometric form factors, metering technology, and controls logic under the representative thermal-hydraulic conditions that would be experienced within the TREAT reactor during an in-pile reactivity-initiated accident test. The outcomes of this study result in an evaluation of the conceptual design of a comprehensive flowing water loop, including objective figures of merit for comparing unique instrumentation and the basis for their selection during operations. These efforts directly contribute to and are required for the further advancement of transient testing capabilities within the United States.

Energy Saving Analysis of No-load Loss of Electric Welding Equipment

In this paper, two types of electric welding equipment are studied. First of all, YD / k-505fl4 and bx3-500 type welding machines do not have the function of self power off in standby state. It is necessary to install an intelligent welding machine power saving system to control the power off of the primary side of the transformer under the no-load state of the welding machine, and then cut off the no-load loss of the welding machine. Secondly, yd-500-kr II series welding machine has the function of standby, delay and self power off. Due to the unreasonable setting of welding parameters, the uneconomical selection of welding cable and the unreasonable layout of welding machine, the overall energy loss of welding machine is large. Finally, weathering steel is used in the welding process design, and the performance, energy consumption and economic practicability of the material are analyzed.

Warm-spare provisioning computing network with switching failure, common cause failure, vacation interruption, and synchronized reneging

The loss of a node in a computing network, either for unplanned reasons, such as hardware failure, or planned outages, such as upgrades, can result in degraded computing network performance or loss of redundancy. To reduce this possibility, a spare node is kept powered on and visible on the network. In this paper, we study the Markovian warm-spare nodes provisioning computing network where spare nodes may also be predisposed to failure in switching from standby state to the operating state. In addition to switching failure and common cause failure, the realistic and economical maintenance server’s modified multiple working vacation policy and failed nodes’ synchronized reneging are also considered. Reliability characteristics of the computing network for I/O operations have been derived using transient-state probabilities which have been computed using the theory of the Quasi-Birth-and-Death process, Laplace transforms, Eigenvalue and Eigenvector. The critical analysis of reliability characteristics has also been done and the paper has been enriched with numerical results in the form of tables and graphs to provide a glance at the investigation. The concluding remarks and future scope have also been included.

Operation of Distribution Network Considering Compressed Air Energy Storage Unit and Its Reactive Power Support Capability

Energy storage is playing an increasingly important role in power system operation due to its ability to shave the peak and fill the valley. Advanced adiabatic compressed-air energy storage (AA-CAES) is a clean and scalable energy storage technology and has attracted wide attention recently. This paper proposes a multi-state operation model of AA-CAES capturing the dynamic change of internal physical status. A stand-by state is introduced, at which AA-CAES works like a condenser that produces only reactive power. It brings two benefits. First, the facility is started up and shut down less frequently, which helps extend its service time. Second, it can provide continuous reactive power support all day long, unlike on-load tap changers or shunt capacitors whose voltage regulation strategy is discrete and suffers from a very low switching frequency. Taking AA-CAES into account, the optimal operation of a distribution network is formulated as a bi-objective dynamic optimal power flow problem. Nash bargaining is employed to extract a single Pareto optimal solution that fairly compromises two objectives. To solve the operation problem in a tractable manner, the bargaining objective and power flow constraints are convexified, giving rise to a mixed-integer second-order cone program. A feasibility recovery algorithm is developed to find a physically meaningful solution whenever the convex relaxation on power flow is inexact. Case studies on the IEEE 33-bus system demonstrate the effectiveness and advantages of the proposed method.

Bolt loose judging device for offshore wind turbine

For the problem of bolt loose in the long-term operation of offshore wind turbine, we proposed a bolt loose judging device for offshore wind turbine. The bolt loose judging device for offshore wind turbine included vibration sensor, signal receiving and transmitter, CCD sensor, data analyzer, power supply, the communication line and the power supply line. The combination of data analyzer and CCD sensor was used to analyze whether the prefabricated symbols on the bolts change, so as to judge whether the bolts are loose. The whole system (except vibration sensor) has been in standby and dormant state at ordinary times, which is more simple and reliable under the harsh conditions at sea.

Simulation and Analysis of Induced Current of HV Parallel Reactor Disconnector for 500kV Double Circuit Line on the Same Tower

The 500 kV double circuit line with HV parallel reactors has a long outage time in ice melting operation.In this paper, we discussed the possibility of directly switching HV parallel reactor disconnector under the cold standby state,in order to further optimize the operation mode of DC ice melting line.We calculated the induced current of the HV parallel reactors disconnector in the 500kV LG A and B lines, and analyzed the related factors. We also calculate the overvoltage level of the HV parallel reactor disconnector, and put forward the parameter requirements, which provides reference for the type selection.