The impact of energy storage devices used in conjunction with renewable embedded generators on the protection and control system

This paper has described the drivers and background to the development of renewable energy in the UK. Within this context the authors identified the New Electricity Trading Arrangements (NETA) as a potential risk to the continuing development of renewable generation and proposed the use of an energy storage system (ESS) as a mechanism to alleviate these concerns. An initial study has concluded that the use of a hybrid ESS/wind farm under the NETA conditions would result in an increase in operating revenue. However preliminary protection investigations have highlighted concerns over appropriate control and protection under the particular scenarios of a change in operating mode from load (i.e. as an electrolyser) to a generator (i.e. to a fuel cell) and vice versa. Work is continuing to produce more detailed modelling results of such a system. It is believed this work will have relevance to the wider spread study of the application of ESS devices in general, for example for use as large scale devices to ensure network security in a power system with high penetrations of local, small-scale embedded generation