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NETWORK / 21 / JULY/AUGUST 2017 delivery engineer then manages the con- struction of the job through to completion. In August 2015, the requirement to have planning permission before applying for a connection on the distribution system was li•ed, leading to an unprecedented influx of 1,200MW of DG applied for within a week. NIE Networks and SONI have engaged with industry stakeholders about how this considerable influx of applications for connection to an already heavily congested network can be managed in the most ef- ficient way. Shared network infrastructure One way in which NIE Networks has optimised the connection of renewable generation to the distribution network while respecting Northern Ireland's landscape and cultural heritage, is to group – or "clus- ter" – generators so they share network infrastructure. The purpose of "cluster substations" (110/33kV) is to ensure efficient transmission design while reducing envi- ronmental and visual impact by replacing multiple long 33kV circuits with one main 110kV circuit. The integration of DG such as wind turbines, anaerobic digestion plants and photovoltaic cells onto the network has meant that the management of network power flows, voltage, generator protection and power quality has become increasingly difficult. Moreover, the forecast uptake of low-carbon technologies (LCTs) such as heat pumps, electric vehicle charging points and photovoltaics will considerably increase de- mand on the distribution system as well as eroding the diversity that network planners have relied on for decades. Evolution in network planning To manage these challenges, an evolution has had to occur within the NIE Networks planning and operations department. DG is now considered from the long-term planning perspective right up to the real operational management of the network. DG was once never considered in network investment decisions, but with the incep- tion of engineering recommendation P2/6, NIE Networks now uses DG to contribute to security of supply, offering an alternative option to conventional capital investment. Moreover, DG embedded in the distribution network is used to offer reactive power sup- port to the greater system; and through in- novative voltage control methodologies, DG is used to ensure that local voltage remains within statutory limits. Considerable work has also been carried out to ensure that DG protection is appro- priate for an active distribution system. To allow higher levels of non-synchronous generation on the power system, measures are being taken across the island as part of the DS3 programme to increase system non- synchronous penetration on the island to 75% by 2020. SONI and EirGrid are currently operating the power system at 60% SNSP. Times are changing for distribution network operators (DNOs), and the roles and responsibilities of a DNO will have to evolve, creating a distribution system opera- tor (DSO) to deliver whole-system benefits for customers. To ensure that NIE Networks is suitably equipped to evolve into a DSO, the recent regulatory price control submis- sion (RP6) included expenditure to deliver five innovation projects. These projects will examine, among other things, the role of demand-side response and energy storage connected at distribution level. Work for the future There is no doubt that 1.21GW of connected renewable DG is a terrific achievement, but there is still considerable work ahead if that demanding 40% renewables target is to be met while maintaining and operating an ef- ficient and reliable distribution system. Who knows what the future holds? Sadly, NIE Networks can't jump into the future the way Doc and Marty McFly did all those years ago; but in the words of the Doc: "If you put your mind to it, you can accomplish anything." N The DeLorean conversion project The DeLorean conversion project, sponsored by NIE Networks, transformed the traditionally petrol guzzling car to a cleaner and greener electric model. It also provided students with a practical project to learn about electric vehicle technology and new 'smart' electric technologies. NI connected renewable generation Wind PV Hydro/tidal (0.2%) Other (1.8%) Anaerobic digestion/ biogas (4.6%) 78% 15.2% Total 1.21GW