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Deep learning in computer vision is becoming increasingly popular and useful for tracking object movement in many application areas, due to data collection burgeoning from the rise of the Internet of Things (IoT) and Big Data. So far, computer vision has been used in industry predominantly for quality inspection purposes such as surface defect detection; however, an emergent research area is the application for process monitoring involving tracking moving machinery in real time. In steelmaking, the deployment of computer vision for process monitoring is hindered by harsh environments, poor lighting conditions and fume presence. Therefore, application of computer vision remains unplumbed. This paper proposes a novel method for tracking hot metal ladles during pouring in poor lighting. The proposed method uses contrast-limited adaptive histogram equalisation (CLAHE) for contrast enhancement, Mask R-CNN for segmentation prediction and Kalman filters for improving predictions. Pixel-level tracking enables pouring height and rotation angle estimation which are controllable parameters. Flame severity is also estimated to indicate process quality. The method has been validated with real data collected from ladle pours. Currently, no publications presenting a method for tracking ladle pours exist. The model achieved a mean average precision (mAP) of 0.61 by the Microsoft Common Objects in Context (MSCOCO) standard. It measures key process parameters and process quality in processes with high variability, which significantly contributes to process enhancement through root-cause analysis, process optimisation and predictive maintenance. With real-time tracking, predictions could automate ladle controls for closed-loop control to minimise emissions and eliminate variability from human error. [ABSTRACT FROM AUTHOR]

A three-phase distributed constants model for high-voltage windings of a transformer is presented. The mutual couplings between phase coils are considered introducing some approximations. Applying the Clarke transformation to the proposed model, the voltage and current surge waves are provided by a simple numerical method. In this way, the model can be used to design the insulation between the turns of a single coil and between the windings and the iron core. A comparison of the numeric results obtained by applying the proposed method with the results obtained by other authors confirms the validity of the model. Moreover, further results are obtained: the proposed approach allows also finding the voltage and current waveforms for asymmetric faults. Index Terms--Power transformer insulation, power transformer protection, time-domain analysis, transformer windings.

Active filters (AFs) compensate harmonic currents demanded by non linear or time variants loads, with the aim to draw sinusoidal currents from the source. Different control strategies for AF have been proposed: among them, p--q theory is the most popular. However, the p-q strategy presents some drawbacks. As already reported in the literature, unexpected harmonic frequencies are generated in the source current as a consequence of such a control strategy. The aim of this paper is to provide, by means of the space vector approach to the p--q theory, analytical expressions that allow to determine the order and the amplitude of the harmonic components in the source current as function of load current or voltage harmonic distortion. By means of these expressions the limits and drawbacks of p--q strategies are quantified and a tool able to quantitatively predict the results of such a control is provided. Simulation results presented in the literature are interpreted according to the proposed expressions; moreover, further simulations are carried out in order to analyze some relevant cases not considered in previous works. Index Terms--Active filters (AFs), compensation, harmonics, p-q theory, space vector.

This study explains how a Steinmetz compensator works. Past explanations are based on phasor diagrams and do not address the basic physical phenomena of electromagnetic energy flow. This paper uses the Poynting vector to detect and understand the process of compensation and restoration of symmetry in an unbalanced system. Index Terms--Compensation, power flow, Poynting vector (PV), three-phase systems.

Power quality disturbances commonly observed in power systems have been studied for decades, resulting in numerous algorithms for detecting the events that affect the voltage and/or current waveforms. However, a considerable amount of disturbances is not visually observable in the raw waveforms, especially switching operations. These events must be detected through an alternative feature, such as abrupt variations in the root-mean-square (rms) voltage profile. This study examines the methods commonly used for detecting power quality disturbances in the waveform or rms voltage profile domains and identifies their limitations. Afterwards, a novel step change detector is proposed based on a modified median filter and rms voltage gradient values to overcome the deficiencies of the existing methods. The effectiveness of the proposed method is assessed by applying it to both simulated and field data. This assessment shows that the method detects all switching events with no false positives for the datasets under analysis. [ABSTRACT FROM AUTHOR]

Z-source inverters (ZSIs) are single-stage power converters with both voltage buck and boost capabilities provided by the unique impedance network and the ability to operate during shoot-through states. This study proposes a novel non-linear adaptive backstepping method for dc-side controllers in a multi-loop control scheme of the ZSI in grid-tied photovoltaic (PV) systems. Despite the variability of the capacitor and inductor values in the ZSI impedance network, the proposed controller guarantees robust and stable operation under varying levels of PV irradiance and temperature. The shoot-through duty ratio of the ZSI is obtained directly from the output of an MPPT algorithm and the measured PV and inductor currents. This strategy overcomes the disadvantages of the conventional approach such as the non-minimum phase at the dc side of the ZSI. It also eliminates the need to linearise the voltage/current characteristics of the PV arrays and ZSI model. The ac-side controllers consist of an outer proportional-integral voltage controller and an inner deadbeat current controller to achieve unity power factor and stable capacitor voltage in spite of grid voltage fluctuations. The efficacy of the proposed adaptive backstepping controller and the multi-loop control scheme is validated by offline and hardware-in-the-loop real-time simulations. [ABSTRACT FROM AUTHOR]

A three-phase distributed constants model for high-voltage windings of a transformer is presented. The mutual couplings between phase coils are considered introducing some approximations. Applying the Clarke transformation to the proposed model, the voltage and current surge waves are provided by a simple numerical method. In this way, the model can be used to design the insulation between the turns of a single coil and between the windings and the iron core. A comparison of the numeric results obtained by applying the proposed method with the results obtained by other authors confirms the validity of the model. Moreover, further results are obtained: the proposed approach allows also finding the voltage and current waveforms for asymmetric faults. [ABSTRACT FROM AUTHOR]