Modeling and Application of Dynamic Compensation Devices in Active Distribution Networks with Energy Storage Facilities

Dynamic compensation devices (DCDs) such as dynamic voltage restorers, static synchronous compensators, and unified power quality conditioners provide significant support to the operation of active distribution networks (ADNs) with energy storage facilities. This paper concerns on the modeling of DCDs and their application incorporated with optimal scheme problem. Firstly, the on-load tap changer is replaced by an ideal transformer without loss and a constant impedance to avoid frequent inversions of Jacobi matrix. Then, the mathematical model which describes the charging/discharging process and energy conversion of energy storage facilities is proposed. This model also limits the charging/discharging power and initial/terminal state of energy storage facilities. Moreover, three types of DCDs are modelled in dynamic and steady states based on their series-connection or parallel-connection accesses to ADNs. The power flow equations are modified accordingly to take their dynamic compensation into account. Their applications are realized by distribution automation system incorporated with optimal schemes. Finally, the case study is conducted on a practical 110-bus ADN of China Southern Power Grid. With the modeling and application of DCDs, the optimal schemes are obtained in multiple aspects such as electric energy and charging/discharging power of energy storage facilities, et al. The charging and discharging processes of energy storage facilities are verified to be independent. DCDs and optimal schemes significantly improve the operating conditions of ADNs in the aspect of network losses.