Testing and performance verification activities

For temperature measurements WEST has 30 very high platinum probes to be used with one of the two AC bridges in order to obtain an accuracy in the measurement of the temperature difference of the order of ± 2.5 m ° K and an uncertainty in the measurement of the absolute temperature of ± 0.005 ° K A precision thermostatic bath allows periodic verification of the probes. WEST has also developed specific methods for on-site verification of the calibration. West equipment also includes oceanographic probes, numerous thermocouples and resistance thermometers. West has designed and built local speed meters that allow for the weighting of individual temperatures.

The uncertainty of the efficiency measurement expected is between ± 0.5% and ± 1.0% as a function of the net head.

For this type of measurement, WEST has over 100 current meters and relative counting units with 40 self-component current meters. The dedicated electronics allows to discriminate the direction of rotation. For canal measurements, the availability is four trolleys, for penstock measurements structures up to 8 m in diameter and more can be made. Finally, there is the availability of authoritative fish with head measurements. The analysis software allows different integration methods for a cross-check on the reliability of the measurements: the uncertainty of efficiency measurement expected is between ± 1.0% and ± 1.5%

West has developed and automated the dye tracer methodology, managing to reduce the concentration of die tracer introduced into the fluid up to 10 ppb. This allows a very modest environmental impact of the measures while maintaining remarkable levels of reliability and precision.

The expected efficiency measurement uncertainty is between ± 1.3% and ± 1.8%. This result is also the result of the double method of calculating the flow rate: both with the integral method and with the plateau method.

West has developed and automated pressure-time methodology both with differential pressure transducers and with separate measurement of the pressures in the two measurement sections. An automated system converges the calculation taking into account the pressure recovery curve. The expected efficiency measurement uncertainty is between ± 1.4% and ± 2.0%

WEST has three ultrasonic protrusion measuring devices (two with 8 trajectories and one with 4 trajectories) and two clamp-on devices with two trajectories each. West also has dedicated software for the analysis and control of ultrasound devices provided in the plant as a fixed installation, in order to assess the reliability of the measurements.

It is essential that each production unit is configured to obtain the best performance and in this sense it is important to check the conjugation between the blades and the wicket gates in Kaplan machines or the correct position of the deflectors in the Pelton machines. This optimization is often carried out with index type measures: very effective and rapid even if they would need validation through a primary method among those previously stated.

Flow rate measurement in cooling circuits can be carried out using calibrated turbines (WEST has 10 turbines in the range 500 ÷ 10 l / s), electromagnetic flow meters (80 ÷ 2 l / s) or external mounted ultrasound devices.

Pressure and level measurements and pressure drop determination and characterization of the different parts (tunnels, penstock, valves, etc.) made with strain-gauge or quartz precision transducers, equipped with microprocessor for compensation and linearization. The precision in determining the net head is typically ± 0.2% and in many cases ± 0.1%.

High precision electrical measurements downstream of CT and machine TV made with three-phase digital devices to detect current, voltage, frequency, active and reactive power, power factor etc. The precision in the determination of the power is typically ± 0.2% and in many cases ± 0.1%