April 2014: Relief Valve control for pneumatic power regulation
by Kieran Monk
Production – 4,851 kWhrs Operational hours – 254 Hrs
April saw the plant properly return to operation, although inconstant wave conditions were experienced.
During this time Pico engineer and PhD candidate Kieran Monk got the opportunity to test his relief valve control strategy for optimising the plant performance. The system is based on short term wave forecasting using Auto-regressive forecast models. By predicting the up-coming short period of wave action based entirely from real-time observations made at the plant and the recent past it is possible to produce forecast of reasonable accuracy up to around 10 seconds. With this information the relief valve of the plant is adjusted in order to optimise the chamber pressure for greater transfer power efficiency to the turbine as well as reducing the frequency and severity of stall events that are linked with vibrations and the accelerated fatigue of the machine.
The system requires further testing but early results are promising.
Short term wave forecasting of the chamber water surface elevation green line is the present time and the blue is the statistical future