The Institution of Engineering and Technology (IET)
IET Generation Transmission & Distribution vol:9 issue:10 pages:929-936
The design of battery storage systems includes technology choices for the batteries and for the inverter. The
impact of the inverter design on the optimal design and operation of the storage system has not been analysed before.
Therefore four inverter designs are compared with this research. The most basic inverter model assumes only
symmetric active power exchange; the most advanced inverter model allows interphase active power transfer and
reactive power control. A multi-objective optimisation method is used, to visualise the trade-offs between two technical
objective functions for cycling control – voltage regulation and peak power reduction – for a given annual cost. The
method is applied to a real-world scenario, based on an existing feeder in a residential part of a city in Flanders,
Belgium. Internal losses and losses in the grid are quantified for the different designs. Modelling a battery storage
system purely as a finite source/sink of active power in a low-voltage grid, strongly underestimates the potential
because of the existing phase unbalance. Counteracting phase unbalance through an inter-phase power transfer
capable inverter, even more so than adding reactive power control, improves the performance of battery storage systems.