Robust coordinated voltage control in low-voltage networks validated through an experimental study – Collaboration of an on-load tap changer and a battery energy storage

This study proposes a robust and completely independent coordinated voltage control (CVC) method for low-voltage (LV) networks as a solution for the overvoltage problem created by distributed generation. The CVC coordinates an operation of an on-load tap changer transformer at a secondary substation and a redox flow battery energy storage at a customer supply point in an LV network based on real-time measurements of the LV grid. The novelty of this CVC is that control decisions are based on relatively simple deterministic logic, which is fast to execute, does not require a detailed grid model, and provides always a solution, has minimal need of information exchange between components of the control system, and it may operate independently without supervision of control centre or information exchange between CVC solution and IT systems of the control centre. This study presents the developed CVC method and explains the practical aspects of implementation for robust and independent solution. The CVC was developed, implemented and tested at the smart grid laboratory of the TU Dortmund University as a part of a master thesis. The most relevant outcome of this master thesis is presented in this study.