IN developing countries, small (pico) hydro projects
producing power outputs in the range 1-10kW are found
attractive to electrify remote locations where utility power is
well out of reach. Consumer loads connected to these small
hydro schemes are normally single-phase lighting loads. 3-
phase SEIG is prescribed [1] for small hydro schemes
provided appropriate phase balancing and excitation
capacitors are used [3].
Apart from many advantages already reported [2] SEIG
has improved performance under line short circuit compared
to synchronous generator since the drop in voltage under short
circuit automatically reduces the excitation and limits the
short circuit current [5].
The behavior of SEIG feeding dynamic loads differs
considerably from that under static loads as the former
experiences voltage dips and inrush currents. Further, the
performance deteriorates under unbalanced conditions due to
excessive heating, insulation stress, winding stress, and shaft
vibrations caused by unequal phase currents and voltages.
Therefore, wider acceptance of the SEIG is dependent on the
methodology to be adopted to overcome the poor voltage and
frequency regulation, its capability to handle dynamic loading, and its performance under unbalanced The voltage and
frequency are maintained within acceptable values by
connecting resistive ballast, which maintains the sum of the
consumer load and the ballast load at a constant value.
This paper presents a novel digital control technique for the
ELC and analyses the steady state and transient behavior of an
uncontrolled micro-hydro-turbine-driven SEIG-ELC system
feeding both dynamic and static loads.