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There are both economic and environmental urges for transition from the current outdated power grid to a sensor-embedded smart grid that monitors system stability, integrates distributed energy and schedules energy consumption for household users. Especially with the proliferation of intelligent measurement devices, exponential growth of data empowers this transition and brings new tools for the development of different applications in power system. Under this context, this paper presents a holistically overview on the state-of-the-art of big data technology in smart grid integration. First, the features of smart grid and the multisource of energy data are discussed. Then, this paper comprehensive summarizes the applications leveraged by big data in smart grid, which also contains some brand new applications with the latest big data technologies. Furthermore, some mainstream platforms and knowledge extraction techniques are looked to promote the big data insights. Finally, challenges and opportunities are pointed out in this paper as well. [ABSTRACT FROM AUTHOR]

Improving the operational reliability of distribution networks is an important goal in many countries and regions. The increase in the total length of feeders and the proportion of cable lines creates a larger single-phase-to-ground fault current, which makes the grounding arc difficult to self-extinguish, and then it may easily cause permanent fault events in the distribution network. The ground fault regulation device, also known as an arc-suppression device, is regarded as an important piece of equipment for the reliable and safe operation of ineffective grounding distribution networks. However, owing to the extensive access of cable lines and power electronic devices in the distribution network, the proportion of harmonic and active power contents in the ground fault current has increased, resulting in higher requirements for arc-suppression device performance. Based on the aforementioned, this study systematically summarizes the research work regarding arc-suppression devices from three aspects, namely, the topology of the arc-suppression device with its evolution trend, the control strategy of the arc-suppression device with its optimization method, and the functional integration method of the arc-suppression and electrical power regulation devices. Furthermore, the most representative topologies and control methods in each category are thoroughly described and briefly compared. The main challenges and critical problems of arc-suppression devices in the new distribution network are analyzed and summarized. [Display omitted] • The present situation of the topologies and control methods for the arc suppression devices is systematically studied. • The active and passive hybrid arc suppression devices can effectively integrate the high performance and low cost. • The functional integration of arc suppression and power control is the future development trend of arc suppression device. [ABSTRACT FROM AUTHOR]

Series-connected voltage sources converters (SVSCs), (i.e., dynamic voltage restorer, fault current limiter, electrical spring, etc.), have been widely used in the electricity grid to improve the electricity grid performances in terms of voltage fluctuation compensation, flexible power flow regulation, fault overcurrent limitation, flexible access of renewable energy, etc. However, SVSCs have a relatively short effective operating time and a low utilization rate, because they are generally operated during abnormal grid conditions. The new trend is to increase the utilization by extending the functions of SVSC, e.g., integrating the voltage compensation and overcurrent limiting in a single SVSC. On the other hand, the series connection architecture results in the SVSCs experiencing overvoltage and overcurrent from the main grid, and consequently the reliability of SVSC is challenged. Based on these details, this paper systematically studies the state of the art multifunctional techniques and the corresponding strategies of SVSCs, which can be mainly divided into three categories as follows: function integration between different SVSC; function coordination between SVSC and parallel-connected VSC(PVSC); function integration between SVSC and PVSC. The most representative topology and control optimization method in each category is elaborated, and a brief comparison of them is conducted as well. On this basis, the key problems and challenges in the research and engineering application of multifunctional SVSC system are summarized. • The state of the art multifunctional techniques of SVSCs is systematically studied. • The function coordination between SVSC and parallel-connected devices improves the output performance of the parallel part. • The multifunctional SVSC with fault current limiting capability can protect itself and the power grid actively. • The function integration between SVSC and PVSC open a new way to improve the utilization rate of power electronic devices. • The multifunctional SVSC with minimized additional physical switches and topology complexity needs further studied. [ABSTRACT FROM AUTHOR]

Microgrid is becoming an attractive concept to meet the increasing demands for energy and deal with air pollutions. Distributed energy sources (DERs) in Microgrid are usually interfaced with the utility grid by inverters, so the characteristics of Microgrid stability are much different from that of a traditional grid. However, the classifications, guidelines, and analysis method of Microgrid stability are well behind of the Microgrid development. In this paper, a Microgrid stability classification methodology is proposed on the basis of the of Microgrid characteristics investigation, which considers the Microgrid operation mode, types of disturbance and time frame. Then a comprehensive review of the body of research on Microgrid stability is presented in order to identify and advance the field. Finally, some challenges and suggestions of Microgrid stability for further researches are discussed. [ABSTRACT FROM AUTHOR]