The paper reports an overview of main issues related to hosting capacity and harmonic disturbances caused by EV penetration in a Smart Grid, taking into account renewable energy sources and energy storage systems as well as non-linear loads. A new mixed deterministic and probabilistic method based on algorithms and new control strategies, able to perform EVs charging controls, is presented. The methodology shows as it is possible to achieve high levels of power quality thanks to a pre-evaluation of harmonic disturbance. Studies on real networks are reported in order to carry out indices able to define a preliminary assessment of the network hosting capacity. Suggestions and guidelines about the management of EVs charging stations are proposed and discussed in order to properly integrate them in a smart grid concept.
Unobtrusive and continuous monitoring of vital signs is becoming more and more important both for patient monitoring in the home environment and for sports activity tracking. Even though many gadgets and clinical systems exist, the need for simple, low-cost and easily applicable solutions still remains, especially in view of a more widespread use within everyone’s reach. The paper presents a fully wearable and wireless sensorized belt, suitable to simultaneously acquire respiratory and cardiac signals employing a single acquisition channel. The adopted method relies on a 50-kHz current injected in the subject thorax through a couple of textile electrodes and on envelope detection of the trans-thoracic voltage acquired from a couple of different embedded electrodes. The resulting signal contains both the baseband electrocardiogram (ECG) signal and the trans-thoracic impedance signal, which encodes respiratory acts. The two signals can be easily separated through suitable filtering and the cardio–respiratory rates extracted. The proposed solution yields performances comparable to those of a spirometer and a two-lead ECG. The whole system, with a realization cost below 100 €, a wireless interface, and several hours (or even days) of autonomy, is a suitable candidate for everyday use, especially if complemented by motion artifact removal techniques, currently under implementation.
30 April 2024 in IEEE Transactions on Instrumentation and Measurement
The article introduces a novel four-coil probe designed for eddy current (EC) nondestructive testing (NDT) on conductive materials. The key innovation lies in its capability to identify small surface and subsurface cracks regardless of their orientation. This is achieved through a suitable probe developed using two pairs of exciting coils that allow to generate two orthogonal magnetic fields. Using two excitation currents with an amplitude modulation approach, a rotation of the ECs induced in the conductive sample is obtained. This novel approach ensures the effective detection of deep and arbitrarily oriented cracks. Both numerical tests and experimental evaluations were employed to assess the performance of the proposed probe. The probe’s effectiveness was particularly observed in detecting a buried crack measuring 5 mm in length, 1 mm in height, and 0.1 mm in thickness at depths up to 3 mm in an aluminum plate. The results demonstrated the robustness of the probe’s detection capability, affirming its potential as a reliable tool for NDT in industrial applications.
Impedance pneumography is a technique which allows the monitoring of respiratory activity through the measurement of variations in the impedance between two points located on the thoracic surface. In this paper, a low-cost, easily portable, and re-configurable measurement system is presented, suitable to perform impedance pneumography investigations. The system is based on a LabVIEW virtual instrument and employs only a data acquisition card. A preliminary metrological assessment of the system is performed, showing that the basic accuracy of the instrument is adequate for monitoring patients lying in a bed. Acquisitions made on several volunteers have evidenced the feasibility of the proposed system in monitoring the breath activity of a patient and in extrapolating the relevant diagnostic parameters. With the aid of suitable signal processing and hardware optimizations the instrument might become a truly portable and non-invasive breath rate monitoring system.
The reliability of systems and components is a fundamental need for the efficient development of a smart distribution grid. In fact, the presence of a fault in one component of the grid could potentially lead to a service interruption and loss of profit. Since faults cannot be avoided, the introduction of a diagnostic scheme could predict the fault of a component in order to carry out predictive maintenance. In this framework, this paper proposes a novel Fault Detection and Isolation (FDI) scheme for AC/DC converters in MV/LV substations. In order to improve the reliability of the FDI procedure, the system architecture includes also an Instrument Fault Detection and Isolation section for identifying faults that could occur on the instruments and sensors involved in the monitoring process of the AC/DC converter. The proposed architecture is scalable, easily upgradable, and uses cost-effective sensors. Tests, carried out on a real test site, have demonstrated the efficacy of the proposal showing very good IFDI diagnostic performance for the 12 types of faults tested. Furthermore, as the FDI diagnostic performance regards, it shows a detection rate close to 100%.
Many people suffer from gastric or gastroesophageal reflux disorder (GERD) due to a malfunction of the cardia, the valve between the esophagus and the stomach. GERD is a syndrome caused by the ascent of gastric juices and bile from the stomach. This article proposes a non-invasive impedance measurement method and demonstrates the correlation between GERD and impedance variation between appropriately chosen points on the patient’s chest. This method is presented as an alternative to the most widely accepted diagnostic techniques for reflux, such as pH-metry, pH-impedance measurement, and esophageal manometry, which are invasive because they use a probe that is inserted through a nostril and reaches down to the esophagus.