Relevant to both the topic of older technologies sometimes being more resilient, and the original topic of old hydro plants: the latest issue (Vol. 6, No. 4) of Rexel's "Power Outlet" magazine includes an article about the company furnishing materials for a replacement cooling-pump control panel at Pacific Gas and Electric's Tiger Creek plant in California's Sierra Nevada mountains.
The article said that PG&E specified relays, rather than a PLC for the panel due to the lack of appropriately skilled technicians at the plant's isolated location, and because PLCs could be more sensitive to power fluctuations. PG&E's project manager stated "We've found that relays are tried and true, so we stick with them."
[This message has been edited by Albert (edited 10-04-2006).]
