The blossom of renewable energy worldwide and its uncertain nature have driven the need for a more intelligent power system with the deep integration of smart power electronics. The smart inverter is one of the most critical components for the optimal operation of Smart Grid. However, due to the deep information and communication technology (ICT) infrastructure implementation that most inverter-based smart power systems tend to have, they are vulnerable to severe external threats such as cyberattacks by hackers. This paper presents a comprehensive review of the system structure and vulnerabilities of typical inverter-based power system with distributed energy resources (DERs) integration, nature of several types of cyberattacks, state-of-the-art defense strategies including several detection and mitigation techniques, and an overview and comparison of testbed and simulation tools applicable for cyber-physical research. Finally, challenges, unsolved problems, and future direction of the field will be discussed and concluded at the end of the journal. This paper provides an all-inclusive survey at the state of the art smart grid cybersecurity research and paves the path for potential research topics in the future.

This study introduces a sliding mode control (SMC) strategy for three-phase dynamic voltage restorers (DVRs) with 12-switch voltage source inverter (VSI). The compensating voltage references needed in the SMC strategy are generated by an adaptive notch filter (ANF) which exhibits excellent performance under grid voltage anomalies such as voltage sags, swells, unbalanced and distorted grid voltage conditions. The consequence of using ANF eliminates the use of phase lock loop (PLL) or frequency lock loop (FLL) and low pass filter (LPF) which makes it distinguishable from the existing reference signal generation solutions. In addition, the use of SMC strategy with its attractive properties makes the control implementation simple. Theoretical results are supported by simulation results as well as real-time laboratory results over a range of grid voltage anomalies. These results show that the proposed control strategy not only offers an excellent dynamic response independent from the parameter variations and disturbances, but also compensates the voltage sags, swells and harmonics on the load terminals under the defined limits of the IEEE-519 standard.

The photovoltaic (PV) generation is increasingly popular nowadays, while typical loads require more high-power quality. Basically, one PV generator supplying to nonlinear loads is desired to be integrated with a function as an active power filter (APF). In this paper, a three-phase three-wire system, including a detailed PV generator, dc/dc boost converter to extract maximum radiation power using maximum power point tracking, and dc/ac voltage source converter to act as an APF, is presented. The instantaneous power theory is applied to design the PV-APF controller, which shows reliable performances. The MATLAB/SimpowerSystems tool has proved that the combined system can simultaneously inject maximum power from a PV unit and compensate the harmonic current drawn by nonlinear loads.