水利水电技术（中英文）

针对水电站现场安装的超声流量计测量误差较大的现象，首先分析了其误差来源，以此提出了从几何参数精测、实际流场扰动计算、绝对流量法对比三个方面开展超声流量计的现场校准方案，并在国内一大型水电站的两台混流式机组上实际应用。校准结果表明，校准后的超声流量计在50%额定流量以上时的测量数据与绝对流量法的偏差在1%以内，测量偏差对额定流量的占比在1%以内，超声流量计测量准确性相对校准前大于2%的测量偏差有了显著提升。研究结果表明，超声流量计在实验室理想条件下校准后的测量准确度不能代表现场安装后的测量准确度，须经过现场校准方可测得准确的水轮机流量。实践成果为国内水电站超声流量计投运后的现场校准提供了有益的借鉴，有助于超声流量计在水电站的可靠运行。

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.