Analytical Study Based Optimal Placement of Energy Storage Devices in Distribution Systems to Support Voltage and Angle Stability

Abstract

Larger penetration of Distributed Generations (DG) in the power system brings new flexibility and opportunity as well as new challenges due to the generally intermittent nature of DG. When these DG are installed in the medium voltage distribution systems as components of smart grid, further support is required to ensure smooth and controllable operation. To complement the uncontrollable output power of these resources, energy storage devices need to be incorporated to absorb excessive power and provide power shortage in time of need. They also can provide reactive power to dynamically help the voltage profile. Energy Storage Systems (ESS) can be expensive and only a limited number of them can practically be installed in distribution systems. In addition to frequency regulation and energy time shifting, ESS can support voltage and angle stability in power network. This thesis applies a Jacobian matrix-based sensitivity analysis to determine the most appropriate node in a grid to collectively improve the voltage magnitude and angle of all the nodes by active/reactive power injection. IEEE 14-bus distribution system is selected to demonstrate the performance of the proposed method due to its clear and simple configuration. The developed technique is also applied to the IEEE 123-bus system to further evaluate the effectiveness and demonstrate the performance for a more complicated system. As opposed to most previous studies, this method does not require an iterative loop with convergence problem nor a network-related complicated objective function.