Study and practice of site calibration on ultrasonic flowmeter in hydropower station

Abstract

Focused on the measuring uncertainty of ultrasonic flowmeters installed at hydropower plants, the sources of measuring errors of ultrasonic flowmeter installed in hydropower stations are analyzed firstly in this paper, then a solution of site calibration is proposed which consist of actual measurement of geometric parameters, disturbance simulation and comparison to absolute discharge measurement. Site calibration is applied on two Francis turbines in a large hydropower station in China. Calibration result above 50% rated discharge show that, the deviation of ultrasonic discharge after calibration to absolute measurement is below 1% and also the deviation is less than 1% of rated discharge. The measuring accuracy of ultrasonic flowmeter is improved significantly compared to the deviation above 2% before calibration. Study and practice in this paper provides a solution to proceed site calibration on ultrasonic flowmeter in hydropower stations which is helpful for the reliable operation of flow monitoring.

Keywords

hydropower station / prototype turbine / turbine discharge / ultrasonic flowmeter / site calibration