  The energy generation of a run of river hydropower plant depends upon the
flow of river and the variations in the water flow makes the energy production
unreliable. This problem is usually solved by constructing a small pond in
front of the run of river hydropower plant. However, changes in water level of
conventional single pond model results in sags, surges and unpredictable power
fluctuations. This work proposes three pond model instead of traditional single
pond model. The volume of water in three ponds is volumetrically equivalent to
the traditional single pond but it reduces the dependency of the run of river
power plant on the flow of river. Moreover, three pond model absorbs the water
surges and disturbances more efficiently. The three pond system, modeled as
non-linear hydraulic three tank system, is being applied with fuzzy inference
system and standard PID based methods for smooth and efficient level
regulation. The results of fuzzy inference system are across-the-board improved
in terms of regulation and disturbances handling as compared to conventional
PID controller.
