Stability and dynamics of active distribution networks (ADNs) with D-PMU technology: a review

Massive integration of converter-interfaced distributed energy resources (CDERs) has resulted in many emerging stability issues and significantly complicated the dynamics of active distribution networks (ADNs). Large quantities of CDER systems with complex structures, time-varying parameters and ‘black-box’ controllers not only make the system modelling nearly an impossible task, but also considerably increase the dimension of dynamic models and thus the computational burden for the model-based stability analysis and control. Distribution-level phasor measurement unit (D-PMU) technology has a superior capability of monitoring, analyzing and controlling the real-time system dynamics. This paper provides a comprehensive overview on the state-of-the-art techniques of dynamics monitoring, analysis and control based on D-PMU technology in ADNs. A special emphasis is placed on the emerging instability incidents induced by CDERs. Although stability monitoring, analysis and control techniques based on PMU technology are well established in the transmission systems, substantial research efforts are required to extend these techniques to deal with the different dynamic characteristics of distribution systems. The application of big-data analytics in analyzing D-PMU data streams becomes prevalent, which can dig more information and thus provide more effective measures for stability analysis and control of ADNs.