4.2. Dependability analysis
Dependability analysis is carried out to ensure the minimum
flow that will be available for the generation of power throughout
the year. Longer the flow data series available, more reliable will be
the generation of power. Table 1 presents the ten daily average
discharge hydrological data for Nauty stream located in Western
Himalayas for 27 years i.e., from 1982 to 2008. Hence, representing
36 discharge data for each year. In Table 2, year wise average
discharge has been computed from the data given in Table 1, and
arranged in descending order in column 2 of the same table for the
purpose of dependability analysis. For hydro power plant generally,
75% and 90% dependability analysis is carried out. Dependable flow
for generation of electric power by a hydro power plant is
computed by the following formula: