In the modern smart home, smart meters and Internet of Things (IoT) have been massively deployed to replace traditional analogue meters. It digitalises the data collection and the meter readings. The data can be wirelessly transmitted that significantly reduces manual works. However, the community of smart home network is vulnerable to energy theft. Such attacks cannot be effectively detected since the existing techniques require certain devices to be installed to work. This imposes a challenge for energy theft detection systems to be implemented despite the lack of energy monitoring devices. This paper develops an energy detection system called Smart Energy Theft System (SETS) based on machine learning and statistical models. There are 3 stages of decision-making modules, the first stage is the prediction model which uses multi-model forecasting System. This system integrates various machine learning models into a single forecast system for predicting the power consumption. The second stage is the primary decision making model that uses Simple Moving Average (SMA) for filtering abnormally. The third stage is the secondary decision making model that makes the final stage of the decision on energy theft. The simulation results demonstrate that the proposed system can successfully detect 99.96% accuracy that enhances the security of the IoT based smart home.

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This paper proposes a new control strategy of effective fifth and seventh harmonic elimination in the stator output voltage at the point of common coupling for a stand-alone doubly fed induction generator (DFIG) feeding a three-phase diode rectifier. This load regularly causes such harmonic distortions, which harmfully affect the performance of other loads connected to the DFIG. In order to allow the DFIG to deliver a pure sinusoidal stator output voltage, these harmonics must be rejected. The proposed elimination method is investigated based on the rotor current controller employing a proportional integral and a resonant controller, which is implemented in the fundamental reference frame. In this frame, both positive seventh and negative fifth voltage harmonic can be eliminated by using only single resonant compensator tuned at six multiples of synchronous frequency in the rotor current controller. The control scheme is developed in the rotor-side converter for the control and operation of the DFIG. Simulations and experimental results with 2.2-kW DFIG feeding a nonlinear load are shown to verify prominent features of the proposed control method.Index Terms-Doubly fed induction generator (DFIG), nonlinear loads, resonant controller, stand-alone system, wind turbine system. NOMENCLATUREv s , v r Induced stator voltage and rotor voltage. v P Stator output voltage at the point of common coupling. v N S The nonlinear voltage drop on the internal stator impedance. V dc DC-link voltage. i s , i r , i m s Stator current, rotor current, and stator magnetizing current. λ s , λ r Stator and rotor fluxes. L s , L r , L m Stator, rotor, and mutual inductances. R s , R r Stator and rotor resistences. ω s , ω r , ω sl Synchronous, rotational rotor, and slip speeds. θ s , θ r , θ sl Synchronous, rotational rotor, and slip angles. σ Total leakage factor. d/dt, Δ Differential operator and error value.

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In this paper, the control of a stand-alone doubly fed induction generator (DFIG)-based wind power conversion system with unbalanced and nonlinear loads is investigated. Under these load conditions, the quality of stator voltage and current waveforms of the DFIG is strongly affected due to the negative and distorted components, reducing the performance of other normal loads connected to the DFIG. To tackle this problem, the control strategy is comprehensively developed in both rotor-side converter (RSC) and load-side converter (LSC) of the DFIG. The LSC is used as an active power filter to compensate for unbalanced and distorted stator currents whereas the RSC is developed to fully eliminate unbalanced and harmonic voltages at the point of common coupling. The proposed compensation method is based on current controllers in either the RSC or the LSC, which employ a proportional integral plus a resonant controller. These current controllers are controlled in the positive synchronous reference frame so that the rotor current and stator current are directly regulated without decomposing sequential components. Analytical issues on how to eliminate unbalanced and distorted components in the stator voltage and current are also described in this paper. To verify the effectiveness of the proposed control strategy, experimental results with 2.2-kW DFIG topology are presented and discussed in the paper.