Closed-Loop Control of a Storage-Supported Hybrid Compensation System for Improving the Power Quality in Medium Voltage Networks

Abstract

Both the operation of power electronic feeders as well as consumers in electrical grids and the transition to electricity generation based on renewable plants create challenges with regard to voltage quality in electrical grids. Therefore within this thesis a control concept of a storage supported device for the simultaneous provision of various system services is elaborated, analyzed and evaluated. Moreover, an approach for the energy and power management of the energy storage of this plant is presented. Essential topics of the examination are the determination of the present level of power quality, the derivation of suitable power quality indicators as well as the power distribution to the system services. In addition, the storage technologies redox-flow battery and flywheel storage, are implemented using models and combined into a hybrid storage system. For operation of the storage system with maximum efficiency an approach depending on the power values and state of charge values of the stores is investigated.