Paris distribution system Principles Performance Future

Radial (225 kV) –Concentric (20 kV) structure 400-225 kV substation 225 kV cable (1 or 2) 20 kV 6* (cable x 4) 225-20 kV substation 1x70 MVA or 2*70 MVA Or 1x100 MVA

Forces and weaknesses High energy density 225 kV feeders Load dispatch between feeders Quick service restoration in case of failure SAIDI 8 min, SAIFI 0.97 outages/year Scheduled load redispatch for planned works Important length of MV feeders Some with aging technologies/sensitive accessories Complex exploitation Protection scheme and automation

Expectation Slow but steady growth High Quality of service expected From 2.75 GW (2008) up to 3.25 GW (2030) 3.75 GW if strong development of EV High Quality of service expected Target : SAIDI <5 min SAIFI < 0.5 outage/year Preserve/enhance « operationnal flexibility » Prevent reliability drift due to aging MV cables Reduce total length Remove/replace sensitive assets Reduce necessity of large transformers 100 MW needs self for default current elimination Minimize costs

An evolutionnary structure Optimized existing feeders New feeders Optimized transfo size

Results expected Optimize length Possibility to avoid large transfo Build MV connection between circular feeders + 1 300 km Reduce length of circular feeders MV length down from 5 000 km to 2 700 km Possibility to avoid large transfo Only on low load scenario Quality target Reduced costs compare to same structure