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This paper reviews the applications of Internet of Things (IoT) and digital twin technology in electrical power systems. It begins by discussing the generalized IoT value chain, followed by the terminology of smart grid, with clarifying the role of IoT‐systems and the digital twin structure within the Smart Grid. A comparison between different short‐range and long‐range transports is presented. The paper then discusses the use of IoT and digital twin technology for effective energy management with applications in smart homes, smart buildings, smart grids, smart industries (Industry 4.0), smart transportation and smart cities. Additionally, the paper explores the use of IoT and digital twin technology for condition monitoring and diagnosis (CMD) in electrical power systems. Three different cases are presented for CMD, that is, CMD of power transformers, CMD of electrical grids and CMD of substations. IoT and digital twin applications are also highlighted in power electronic systems. Finally, the paper discusses the challenges and opportunities of applying IoT and digital twin technology to electrical power systems and provides recommendations for future research. [ABSTRACT FROM AUTHOR]

Wind energy integration in power grids is increasing day by day to reduce the use of fossil fuels, and consequently greenhouse gas emissions. Using the pulse-width modulated (PWM) power converters in wind turbine generators, specifically in doubly-fed induction generators, results in generating a common-mode voltage (CMV). This common-mode voltage causes a flow of common-mode current (CMC) that leaks through the stray capacitances in the generator structure. These currents impose a voltage on the generator bearing which may deteriorate them. In the current work, an active common-mode voltage canceler (ACMVC) is developed to eliminate the CMV produced by a PWM converter. The ACMVC generates a compensating voltage at the converter terminals to eliminate the CMV with a subsequent reduction of the voltage stress on the generator bearing. This compensating voltage has the same amplitude as CMV, but opposite polarity. A simulation of the ACMVC model is performed using the PSCAD/EMTDC (Electromagnetic Transient Design and Control) software package. Results confirm the effectiveness of ACMVC in canceling not only the CMV but the CMC and bearing voltage as well. In addition, the relationship between the rise time of CMV and the peak value of CMC is investigated. [ABSTRACT FROM AUTHOR]

• Based on impedance model of two-stage PV inverter in frequency domain, the passive equivalent impedance network of PV inverter connected to power grid is built. • The harmonic amplifying characteristic curve of PCC in full frequency range is established, and the influence of inverter parameters, reactive power compensation device and distributed transmission line model on harmonic characteristics is deeply analyzed. • A harmonic mitigation control strategy with superimposed multi-current resonance controllers and active damping controllers in synchronous rotating coordinate system is proposed, and the effectiveness of this control strategy is verified by simulation. To investigate the harmonic characteristics of a photovoltaic (PV) system connected to the weak grid, a passive impedance network is constructed using the impedance model of a PV inverter in the positive and negative sequence coordinate system. By analyzing the series resonance of the impedance network, the amplification coefficient of the harmonic voltage at the point of common coupling (PCC) is obtained. In addition, the effects of different PV inverter parameters, different reactive power compensation capacities, and different lengths of distributed transmission lines on the harmonic amplification are analyzed in detail. To solve the problem that the output harmonics exceed the standard under the background harmonic condition of the weak grid, a harmonic mitigation control strategy is implemented. This strategy is designed based on multiple resonant current controllers and active damping feedback to improve the ability of the PV inverter to suppress harmonics under the grid background harmonic conditions. The effectiveness of the harmonic mitigation control strategy is demonstrated by the simulation example of the inverter connected to the grid with symmetric and asymmetric background harmonics, respectively. [ABSTRACT FROM AUTHOR]