Investigation of on load tap changer control in smart distribution network

Abstract

Penetration level, location and intermittent behaviour of the Distributed Generations (DGs) integrated with the distribution system will have great impacts on the system performance and stability. One of the subjects is high voltage rise at tail end of radial feeder. Electric utilities use On Load Tap Changer (OLTC) attached to Medium Voltage (MV) transformer to regulate voltage levels. Traditionally, in passive network tap changers receive control signals from single bus and change the tap positions to maintain voltages at pre-defined reference voltage. In the active smart distribution network, and with the advantages of smart meters, OLTC can pick up control signals from different voltage buses and change the tap positions of the transformers accordingly. In this research, typical UK Low Voltage (LV) network with DGs is modeled on Matlab/Simulink and OLTC is installed at both MV and LV transformers (T/F). Logical controller is designed to select the most appropriate control signals from the system buses to optimize the operation of both MV and LV transformer collaboratively. Recommendation of integrating Energy Storage Systems at distribution network is discussed in this research in order to level up the load profile and stabilize the system voltages.