Voltage Monitoring Research Articles

Battery Health Diagnosis Approach Integrating Physics‐Based Modeling with Electrochemical Impedance Spectroscopy

Herein, a battery health diagnosis approach that combines electrochemical performance aging and lumped thermal models with electrochemical impedance spectroscopy and voltage monitoring is proposed, allowing the segregation and quantification of ohmic, chemical, and diffusion‐mechanical related losses. This approach accurately identifies battery lifetime thresholds such as first‐life, second‐life, and turnaround points, by combining the use of a capacity indicator and overpotentials as battery health indicators. This approach, which is demonstrated at the cell level, is scalable to module and pack levels and applicable to different cell chemistries and battery configurations. This battery health diagnosis approach is validated with performance and degradation data from lithium iron phosphate and nickel–manganese–cobalt cells, showing good agreement when comparing the predicted capacity fade against measured values.

Design and Test of a Spoke-like Piezoelectric Energy Harvester.

With the development of industry IoT, microprocessors and sensors are widely used for autonomously transferring information to cyber-physics systems. Massive quantities and huge power consumption of the devices result in a severe increment of the chemical batteries, which is highly associated with problems, including environmental pollution, waste of human/financial resources, difficulty in replacement, etc. Driven by this issue, mechanical energy harvesting technology has been widely studied in the last few years as a great potential solution for battery substitution. Therefore, the piezoelectric generator is characterized as an efficient transformer from ambient vibration into electricity. In this paper, a spoke-like piezoelectric energy harvester is designed and fabricated with detailed introductions on the structure, materials, and fabrication. Focusing on improving the output efficiency and broadening the pulse width, on the one hand, the energy harvesting circuit is optimized by adding voltage monitoring and regulator modules. On the other hand, magnetic mass is adopted to employ the magnetic field of repulsive and upper repulsion–lower attraction mode. The spoke-like piezoelectric energy harvester suggests broadening the frequency domain and increasing the output performance, which is prepared for wireless sensors and portable electronics in remote areas and harsh environments.

Development of Broadband Resistive–Capacitive Parallel–Connection Voltage Divider for Transient Voltage Monitoring

The on-site measurement of transient voltages is of great significance in analyzing the fault cause of power systems and optimizing the insulation coordination of power equipment. Conventional voltage transformers normally have a narrow bandwidth and are unable to accurately measure various transient voltages in power systems. In this paper, a wideband parallel resistive–capacitive voltage divider is developed, which can be used for online monitoring of transient voltages in a 220 kV power grid. The structures of the high-voltage and low-voltage arms were designed. The internal electric field distribution of the high-voltage arm was analyzed. The influence factors and improvement techniques of the upper frequency limit were studied. The parameters of the elements of the divider were determined. The voltage withstand performances and scale factors under lightning impulses and AC and DC voltages, the temperature stabilities of scale factors and the step response and bandwidth of the developed voltage divider were tested. The results show that the deviations of the scale factors under various voltage waveforms and different temperatures ranging from −20 to 40 °C are within 3%. The withstand voltage meets the relevant requirements specified in IEC60071-1-2011. The step response 10~90% rise time is approximately 29 ns, and the 3 dB bandwidth covers the range of DC to 10 MHz.

Remote Monitoring of Wind Speed and Produced Voltage Measured by Anemometer

Anemometer is a device used to measure wind speed at weather measurement stations. An Anemometer, which is used to measure the wind speed of an area, is widely used in weather stations. With the anemometer, wind speed and weather forecasts of a certain region are made. In this study, the wind speed values of a sample anemometer in a certain region and the voltage produced by the anemometer for wind energy were remotely monitored via the Internet of Things. In the system created, Arduino Uno microcontroller development board for the control of the system, a sample anemometer for measuring wind speed and generating voltage, LCD shield for displaying wind speed and voltage values on the screen, esp8266 wifi module for sending instant data from the anemometer to the thingspeak IoT platform and for feeding the system. solar panel and battery charge regulator are used. In this study, the wind speed in a certain region and the monitoring of voltage produced depending on the wind speed was monitored on an internet basis. The system was operated in a certain region and the wind speed values and the generated voltage were monitored both instantaneously on the LCD screen and graphically on the thingspek an IoT platform as instantaneous, hourly, daily and weekly. With this system created, the thingview application was used for instant tracking on android devices.

Smart Meters Enabling Voltage Monitoring and Control: The Last-Mile Voltage Stability Issue

This article investigates the voltage monitoring and control feature for smart meters and identifies the impact of this feature on both power distribution and communication systems. Regarding the voltage monitoring, a cosimulation platform is developed using GridLAB-D and ns-3 to analyze the impact of adding voltage measurements to smart meter readings and assess the mitigation strategies for reducing timeout errors and packet drops of smart meter data. Regarding the voltage control, a new voltage stability control scheme is developed, which applies the voltage stability margin as the control objective, instead of the traditional voltage magnitude. The proposed control scheme makes use of existing advanced metering infrastructure and distributed energy resources (DERs), requiring small marginal costs. It is indicated that integrating the voltage monitoring and control feature, smart meters could enable the voltage stability issues being solved at end-user sides, i.e., the “last-mile” segment. It is also implied that the new feature could support the coordination of the local and system-level voltage controls using both customer-owned and utility-scale DERs.

A Study of the Cleansing Effect of Precipitation and Wind on Polluted Outdoor High Voltage Glass Cap and Pin Insulator

In this work, the extent of natural cleansing effect of rainfall, wind and fog or a combination of these on an insulator string were investigated. Results showed that pollution losses progress with time, with a considerable fraction of losses occurring within 15 minutes of testing. While wind alone played little or no role in surface cleansing, it increases the extent of cleansing by rainfall. The topsides of insulators were found to be more affected by natural cleansing compared to the underside. Equivalent Salt Deposit Density (ESDD) and Non-Soluble Deposit Density (NSDD) measurements were carried out. ESDD was found to be higher in the lower disc irrespective of the weather condition the insulator string has been subjected to. NSDD measurements established no pattern on how natural cleansing was impacted by disc position on a string, demonstrating the random nature of pollution-cleansing cycle of outdoor insulators. Insulator performance was assessed by high voltage AC tests and monitoring of partial discharge events using Radio Frequency antennas and a High Frequency Current Transformer (HFCT). Measured output by the HFCT showed that leakage current decreases uniformly with time, and the speed at which this occurs is an indication of the intensity of natural cleansing activity.

Overhead Transmission Lines Sag and Voltage Monitoring Method Based on Electrostatic Inverse Calculation

Transmission line sag and voltage are key information to reflect the real-time operation state of power grid. Contactless measurement method has great advantages of no electrical contact, flexibility and mobility, but it is also vulnerable to environmental changes. In this article, a novel overhead transmission line contactless sag and voltage monitoring method is proposed, which only needs a simple potential measurement array and can apply to dynamic conductor measurement. The electrostatic coupling model between the transmission lines and the measuring points is established. The sag and voltage inversion calculation model is proposed and the ill-posed problem is solved. The measurement array and the data acquisition method are designed. The equivalent measurement area (EMA) is determined considering the difference between 3-D model and 2-D model of overhead line. Finally, the effectiveness of the proposed method is verified by single-circuit transmission line simulation and scale-down experiment.

Design, Implementation, and Deployment of Modular Battery Management System for IIoT-Based Applications

This paper proposes design and implementation of a battery management system (BMS) for the industrial internet of things (IIoT) enabled applications. The hardware and software development of this BMS is briefly presented in this paper. In terms of hardware development, the presented BMS have modular topology and has 1) high fault tolerance and 2) has exceptionally flexible deployment owing to its topology having multiple local management units (LMUs) connected to a central management unit (CMU). This hardware design approach aims to address the overall design efficiency and cost trade-off of BMS deployment. The hardware design efficiency is tested using actual deployment. In terms of fault tolerance using 1 – 3 LMUs at fault, the voltage monitoring accuracy is maintained for each LMUs. An average of 0.00017 V, 0.0008 V and 0.001 V voltage difference is yielded for 1, 2, and 3 modules at fault respectively. Additionally, core BMS sub-circuit is tested to verify hardware design efficiency such as the DC-to-DC converter which yielded 92.74%. Furthermore, the CMU is integrated with a wireless communication circuit that enables IIoT-based applications such as the emerging edge-based, and a plethora of intelligent deployment. In terms of software, the presented BMS aims to realize state-of-the-art processing through IIoT based approach. For software testing and verification, the BMS is deployed to an unmanned ground vehicle (UGV). The signal stability is tested for UGV based application at a 3500s deployment time whereas an average of 0.0010V voltage difference is yielded. This is verified using time markers which is further analyzed using software-based signal processing and acquisition simulation. Concisely, the proposed BMS aims to converge IIoT applications to its actual deployment. The proposed BMS is designed, implemented, and successfully deployed to test its viability both in the simulation platform and actual deployment.

An Exact Solution of Telegraph Equations for Voltage Monitoring of Electrical Transmission Line

Telegraph equations are derived from the equations of transmission line theory. They describe the relationships between the currents and voltages on a portion of an electric line as a function of the linear constants of the conductor (resistance, conductance, inductance, capacitance). Their resolution makes it possible to determine the variation of the current and the voltage as a function of time at each point of the line. By adopting a general sinusoidal form, we propose a new exact solution to the telegraphers’ partial differential equations. Different simulations have been carried out considering the parameter of the 12/20 (24) kV Medium Voltage Cable NF C 33,220. The curves of the obtained solution better fit the real voltage curves observed in the electrical networks in operation.

Microcontroller-Based Lead-Acid Battery Balancing System for Electric Vehicle Applications

In application of lead-acid batteries for electrical vehicle applications, 48 V of four 12 V batteries in a series configuration are required. However, the battery stack is repeatedly charged and discharged during operation. Hence, differences in charging and discharging speeds may result in a different state-of-charge of battery cells. Without proper protection, it may cause an excessive discharge that leads to premature degradation of the battery. Therefore, a lead-acid battery requires a battery management system to extend the battery lifetime. Following the LTC3305 balancing scheme, the battery balancing circuit with auxiliary storage can employ an imbalance detection algorithm for sequential battery. It happens by comparing the voltage of a battery on the stack and the auxiliary storage. In this paper, we have replaced the function of LTC3305 by a NUCLEO F767ZI microcontroller, so that the balancing process, the battery voltage, the drawn current to or from the auxiliary battery, and the surrounding temperature can be fully monitored. The prototype of a microcontroller-based lead-acid battery balancing system for electrical vehicle application has been fabricated successfully in this work. The batteries voltage monitoring, the auxiliary battery drawn current monitoring, the overcurrent and overheat protection system of this device has also successfully built. Based on the experimental results, the largest voltage imbalance is between battery 1 and battery 2 with a voltage imbalance of 180 mV. This value is still higher than the target of voltage imbalance that must be lower than 12.5 mV. The balancing process for the timer mode operation is faster 1.5 times compared to the continuous mode operation. However, there were no overcurrent or overtemperature occurred during the balancing process for both timer mode and continuous mode operation. Furthermore, refinement of this device prototype is required in the future to improve the performance significantly.

Four Channel 6.5 kV, 65 A, 100 ns–100 µs Generator with Advanced Control of Pulse and Burst Protocols for Biomedical and Biotechnological Applications

Pulsed electric fields in the sub-microsecond range are being increasingly used in biomedical and biotechnology applications, where the demand for high-voltage and high-frequency pulse generators with enhanced performance and pulse flexibility is pushing the limits of pulse power solid state technology. In the scope of this article, a new pulsed generator, which includes four independent MOSFET based Marx modulators, operating individually or combined, controlled from a computer user interface, is described. The generator is capable of applying different pulse shapes, from unipolar to bipolar pulses into biological loads, in symmetric and asymmetric modes, with voltages up to 6.5 kV and currents up to 65 A, in pulse widths from 100 ns to 100 µs, including short-circuit protection, current and voltage monitoring. This new scientific tool can open new research possibility due to the flexibility it provides in pulse generation, particularly in adjusting pulse width, polarity, and amplitude from pulse-to-pulse. It also permits operating in burst mode up to 5 MHz in four independent channels, for example in the application of synchronized asymmetric bipolar pulses, which is shown together with other characteristics of the generator.

Development of a Smart Supercapacitor Energy Storage System for Aircraft Electric Power Systems

This paper presents the development of a supercapacitor energy storage system (ESS) aimed to minimize weight, which is very important for aerospace applications, whilst integrating smart functionalities like voltage monitoring, equalization, and overvoltage protection for the cells. The methodology for selecting the supercapacitor cells type/size is detailed to achieve the safest and most energy-dense ESS. Additionally, the development of the interface electronics for cells’ voltage monitoring and overvoltage protection is presented. The proposed design implements a modular distributed architecture coordinated using communication buses to minimize the wirings and associated complexity and to enable system reconfiguration and expansions, as well as fault diagnoses. Validating the proposed ESS functionalities has been done via experimental testing and the results are presented and discussed.

Design of power lithium battery management system based on digital twin

The accurate estimation of the State of Charge (SoC) of batteries has always been the focus of Battery Management System (BMS). However, the current BMS has problems such as difficult data sharing, weak data processing capability and limited data storage capacity, so the simplest ampere-time integration method is used to estimate the SoC, and the estimation results are highly biased. In this paper, an innovative digital twin-driven battery system framework is proposed and successfully developed. A joint HIF-PF online algorithm for estimating SoC under the experimental condition Beijing Bus Dynamic Stress Test (BBDST) is also proposed, which is comparable to the conventional Extended kalman filter (EKF), HIF and Particle Filter (PF). The results demonstrate the superiority of the algorithm. Then, we applied the algorithm to estimate SoC. In addition, the system implements functions such as real-time voltage and current monitoring and visualization.

A Novel Optical Sensing Technology for Monitoring Voltage and Current of Overhead Power Lines

We propose herein a novel optical sensing technology using liquid crystal based transducers to measure simultaneously voltage and current from overhead power lines in real time. Doing so, we implemented a proof-of-principle system based on this approach and we demonstrated not only good accuracy, but also small phase shift and adequate bandwidth for power quality and fault monitoring applications. This is supported by experimental results for current, voltage and power monitoring, which include transient measurements and show excellent agreement with commercial reference probes. The system presented in this paper has been developed for single wire earth return (SWER) lines operating at 12.7 kV or 19.1 kV, but can be adapted to work at higher or lower voltages with appropriate modifications. We conclude by discussing the calibration process improvements that would be required for the technology to meet industry standards.

Optical voltage sensor based on a piezoelectric thin film for grid applications.

Continuous monitoring of voltages ranging from tens to hundreds of kV over environmental conditions, such as temperature, is of great interest in power grid applications. This is typically done via instrument transformers. These transformers, although accurate and robust to environmental conditions, are bulky and expensive, limiting their use in microgrids and distributed sensing applications. Here, we present a millimeter-sized optical voltage sensor based on piezoelectric aluminum nitride (AlN) thin film for continuous measurements of AC voltages <350kVrms (via capacitive division) that avoids the drawbacks of existing voltage-sensing transformers. This sensor operated with 110μW incident optical power from a low-cost LED achieved a resolution of 170mVrms in a 5kHz bandwidth, 0.04% second harmonic distortion, and a gain deviation of +/-0.2% over the temperature range of ~20-60°C. The sensor has a breakdown voltage of 100V, and its lifetime can meet or exceed that of instrument transformers when operated at voltages <70kVrms with capacitive division. We believe that our sensor has the potential to reduce the cost of grid monitoring, providing a path towards more distributed sensing and control of the grid.

Features selection and substitution in PEM fuel cell water management failures diagnosis

AbstractA data‐driven strategy considering sensor reliability and cost is presented for polymer electrolyte membrane fuel cell (PEMFC) fault diagnosis. An increase of pressure drop in the flow field is a reliable indicator of PEMFC flooding fault. Still, it highly depends on the pressure measurement accuracy of the stack inlet and outlet. The abnormal sensor will mislead the diagnosis results, and an extra pressure sensor in the outlet means higher system cost. Thus, the related behavior is investigated. The throttle opening set, one of the control signals, is chosen to replace the cathode pressure drop. The throttle opening set, the stack voltage, and cell voltage monitoring (CVM) standard deviation are employed as diagnostic features, and the support vector machine (SVM) is used as the classifier. Compared to the approach using single‐cell voltages, the strategy mentioned above minimizes extra sensors and avoids the computation load of dimensionality reduction. High accuracy in diagnosing flooding and dehydration via identifying experimental data of different fault severity verifies the effectiveness of the presented strategy.

WK55/WK35 UPS Self Duplex Constant Voltage Monitoring and Control System

WK55/WK35 UPS Self Duplex Constant Voltage Monitoring and Control System

A high-sensitivity, low-noise dual-band RF energy harvesting and managing system for wireless bio-potential acquisition

This paper proposes a high-sensitivity, low-noise dual-band RF energy harvesting and managing system for wireless bio-potential acquisition. The proposed system consists of a dual-band RF energy harvester, a voltage monitor, and a power management unit (PMU). The proposed dual-band RF energy harvester adopts the hybrid threshold voltage self-compensation technology, which effectively reduces the equivalent threshold voltage of transistors and improves the power conversion efficiency (PCE). To match the input power and the load power with the minimum current consumption, a low-power voltage monitor is proposed in this paper. Moreover, the proposed PMU combines a voltage bootstrap circuit and a low-noise high-PSRR LDO to avoid the use of off-chip inductors and suppress output ripple. The proposed chip was implemented in a 0.18-μm deep n-well CMOS process, occupying a core area of 1.30 mm✕2.06 mm. The measured results show the dual-band RF energy harvester outputs a DC voltage of 1 V in two different frequency bands at the input power as low as −18.5 dBm. The PMU outputs stable DC voltages of 1 V and 1.8 V in working mode. In sleep mode, only the voltage monitor is working, and the average quiescent current is only 0.6 μA.

Substation Load Management for Electric Power Distribution's Sustainability

In Nigeria, perhaps due to lack of conscious and planned preventive maintenance culture coupled with inadequate measuring equipment, power system equipment such as transformers are not adequately monitored for preventive maintenance. As a result, most are left to work until a breakdown occurs. Poor loading and uneven distributions are also common phenomena in many of these distribution transformers. Hence, there is a frequent power outage and supply interruption. This paper reports daytime monitoring of voltage, current and apparent power from three transformer substations at Federal Polytechnic Ilaro, Nigeria to ascertain loading and transformer conditions. The work involved data acquisition using Lutron DW 609 power harmonic analyzer of the parameters of interest (voltage, current and apparent power) for 2-4 hours using 5 min logging interval. The data were assessed using the computer system for analysis. The range of loading conditions encountered was: Substation 1: 75.00−80.60 kVA which was 15−16.14% of transformer rating; Substation 2: 73.70−90.30 kVA representing 14.74−18.08% of the transformer rating; Substation 3: 19.04−19.28 kVA representing 3.81−3.85% of the rated transformer capacity. Load factors of 0.97, 0.87, and 0.99 were obtained for the three substations respectively indicating that energy usage was relatively constant during the period under consideration. An ANOVA test at a 5% significant level on each transformer phase current reading yielded F-Values of 4475.38, 859.92 and 239117.68 respectively for the substation transformers indicating a huge level of imbalance in the transformer loading. Load balancing is recommended for a sustainable electric power distribution in the locality.

Establishment of transition point in operating mode for Constant Current Constant Voltage (CC-CV) charging of Li-ion batteries

The present-day Li-ion batteries when operated, needs precise monitoring of the charging voltage. Several charging techniques have been tested so far with varying degrees of success. One of the most widely used charging techniques is the CC-CV (constant current constant voltage) charging. When performing this, the safety considerations must be maintained with respect to over voltage charging which is a very common problem during constant current charging. In order to prevent over voltage charging, the charging mode must be then shifted from CC to CV mode. So, this transition point of the charging mode from CC to CV is very crucial for the safe operation and health of the battery in the long run. The problem is that, this transition point doesn’t remain the same for the battery. So, in this paper the factors on which it depends are discussed and a Li-ion battery was charged in a few different charging rates using the CC-CV technique to demonstrate the process.