Abstract:
Extensive field experience in micro-hydroelectric systems in remote rural commumties
demonstrates the use of a typical Automatic Voltage Regulator (AVR) supplied as with a
synchronous alternator can be the cause of unsatisfactory system performance. This paper
presents the published evidence, and verifies it with measured results from a full scale microhydroelectric
test rig. Anecdotal advice suggesting the cause of instability results from the
response of the two competing feedback control systems (the ballast load frequency controller and
the AVR) is verified. System modelling also confirms the Under Frequency Roll-off (UFRO)
characteristic of the AVR contributes significantly to unsatisfactory performance.
