Les récents développements dans le domaine de l'ingéniérie française en matière d'énergie hydroélectriqne

Recent developments in the field of french engineering relating to hydro-electric generation

Délégué Général de l'UNIPEDE

Abstract

The World-scale development of hydro-electric power stations continues in France too, notwithstanding the considerable pressures on resources, where substantial means have been made available for hydro-electric generation. As regards civil engineering work, the salient developments in the techniques in France to construct dams were : design (concrete dams, "ski-jump" spillways in narrow valleys, progress in the construction of arches in large valleys, use of confined flow spillways ; embakment dams : new solutions for sealing systems, and the study and treatment of the foundations), computations (use of computer and semi-probabilistic methods), construction (two procedures should be mentioned : the construction of mobile dams on dry land, outside the lower bed and construction underwater without deponding the foundations - application at Denouval) and operation (inspection and surveillance rules). The design of water intake structures fitted with automatic scours has solved the problem of intake structures at high altitudes. Tunnelling machines are already in use in France on major developments, and are being growincly used for boring galleries and tilted shafts. The salient events as regards underground stations relate to : design (single main excavation or several excavations to house units of equipment) and boring and earth retaining techniques (value of prior cutting and development of the use of batched concrete). The prospects opened up by the use of tidal energy are reexamined ; the Rance plant was still the only operating project in the World fifteen years after it entered into service. Feasibility studies in the technical, economic and environmental fields are presently under way. The most striking aspects relating to electro-mechanical equipment are chiefly linked to the enhancement of the characteristics of sets (unit power, head, rotational speed, entailing problems of size, high pressure and cooling) and their operating mode (automatic systems and remote control, secondary regulation of frequency and voltage). The number of binary sets has also grown (considerable progress in characteristics) ; a prototype of a two-stage pump-turbine, each stage being fitted with a regulatable distributing valve is being installed at the Truel plant. Some progress has also been made in the generator motor field (characteristics, pump-mode startup procedure) and confined flow conduits (method of installation, new steels).