POTENCIA INDUS TRIAL, S. A.
Av. Año de Juarez 205
Granjas San Antonio
Mexico City, D.F. 09070
+52 (55) 5686.7303
+52 (55) 5686.7246
Established in 1958, Potencia Industrial ofers engineering and manufacturing of special
application high-efciency electrical motors, generators, M-G sets and power systems.
Foro ver thirty years we have dedicated to the advance of rotary electrical machinery
technologies, constantly setting new industry benchmarks. We provide creative
solutions that meet and exceed the toughest technical requirements while maintaining
the highest reliability and efciency.
Nearly 90% of our production was destined for the U.S. and Canada in the last 5 years;
we delivered equipment equivalent to 2,000 MW of wind power, 60 MW of hydroelectric
power and 100 MW of industrial electric capacity. Our state of the art hydrogenerators,
installed at several hydro sites around the world, are custom built, suitable for Pelton,
Francis or Kaplan turbines, vertical or horizontal, for high, low or variable speed.
Built to Spec
Very High Efciency
Up to 20 MW
http://hydroreview.hotims.com RS #42
www.hydroworld.com July 2017 / HYDRO REVIEW 39
found in the ASME FFS- 1 standard, using
the following equation:
ε L = εLu • exp – – αsl 1+ m2 σ 1+σ 2+σ 3 σe 13
εL is the limiting triaxial strain;
εLu is the uniaxial strain limit;
αsl is the material factor for multiaxial
α1, α2 and α3 are the principle stresses;
αe is the equivalent (von Mises) stress.
Te acceptability per the local failure criterion was assessed by calculating the ratio
between equivalent plastic strain and triaxial
Ratio values in the modeled gate that were
less than one satisfy Equation 2 (i.e. equivalent
plastic strain is less than triaxial strain limit).
As all the areas showed a ratio of less than
1, the spillway gate satisfed the local failure
Additionally, it was determined that under
the current levels of deformation and metal
loss, the most critical location corresponds to
the top plate at the center of beam A3.
Based on the results of the FFS assessment,
it was concluded that spillway gate 2 at the
Karapiro Power Station was ft for service as it
met both the global collapse and local failure
Tis assessment showed that the lack of
design information (e.g., corrosion allowance was not known) can be overcome by
engineering assessments that are compliant
with recognized standards, allowing for an
informed decision. ■
Vitor Lopes Garcia is a consulting engineer with Quest
Integrity. David Osuna was a consulting engineer with the
company at the time the work discussed in this article
1Fitness-for-Service Standard, Appendix B, American Society
of Mechanical Engineers, New York City.
2 Waikato Hydro System: Hydraulic Structures Hydrological
Data Book, Mercury Energy, Auckland, New Zealand.
Osuna, David, “Engineering Assessment of Deformed
Spillway Gate,” Proceedings of HydroVision International
2016, Penn Well Corp., Tulsa, Okla., 2016.
Several articles have been published previously
about gates, including spillway gates. Below
are two articles from Hydro Review that
provide further reading on the subject. Find
them at Hydro World.com:
Anami, Keiko, et al, “Method for
Identifying Dynamic Instability of Tainter
Gates,” Hydro Review, Volume 35, No. 6, July
Peterson, Josh, and Peter Haug, “Preparing
for the Worst,” Hydro Revie w, Volume 35, No.
5, June 2016, www.hydroworld.com/articles/