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Comparison of Wind Sensors - Ultrasonic versus Wind Vane/Anemometer. Kenneth G. Wastrack Doyle E. Pittman John E. Hatmaker L. Wayne Hamberger Tennessee Valley Authority. Background. Problem - Obsolete Wind Sensors Difficulty obtaining spare parts (sensor, switch controller, etc)
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Comparison of Wind Sensors - Ultrasonic versus Wind Vane/Anemometer Kenneth G. Wastrack Doyle E. Pittman John E. Hatmaker L. Wayne Hamberger Tennessee Valley Authority [NUMUG] Comparison of Wind Sensors
Background • Problem - Obsolete Wind Sensors • Difficulty obtaining spare parts (sensor, switch controller, etc) • Routine bearing replacement • Occasional history of mechanical failures • Requirements - Sensor Specifications • Comply with RG 1.23 requirements. • Wind direction +/-5 degrees. • Wind speed +/-0.5 mph. • Less maintenance than existing sensors. [NUMUG] Comparison of Wind Sensors
Vaisala 425AHUltrasonic Wind Sensor • Sonic Wind Sensors • All-electronic • Minimal maintenance • Vaisala* (formerly Handar) 425AH ultrasonic wind sensor most suitable • Manufacturer specifications • Capabilities for integration • System meets RG 1.23 [NUMUG] Comparison of Wind Sensors
System Performance [NUMUG] Comparison of Wind Sensors
Principle of Operation • Transmit signal along axis • Send in reverse direction • Calculate time differences • Convert to WS along axis • Repeat for other axes • Compute WD and WS [NUMUG] Comparison of Wind Sensors
Wind Tunnel Tests [NUMUG] Comparison of Wind Sensors
Field Tests • Establish that sensor works as expected. • Document that data are comparable to wind vane/anemometer data. • Verify software and hardware changes. • Provide maintenance experience. [NUMUG] Comparison of Wind Sensors
Field Sampling Configuration Anemometer mounted due North of wind vane. [NUMUG] Comparison of Wind Sensors
Comparison of Wind Roses Climet Vaisala [NUMUG] Comparison of Wind Sensors
Statistical Results Note: N, d, s, C, M, K are specified in ASTM D 4430-96, “Standard Practice for Determining Operational Comparability of Meteorological Measurements”. [NUMUG] Comparison of Wind Sensors
Problems Encountered • Wind Tunnel Tests • Tunnel Configuration • Echo Effect • Software Changes • Alignment Error • Error Handling • Tower Shadow Effect [NUMUG] Comparison of Wind Sensors
Results Vaisala Ultrasonic Wind Sensor is equivalent to the existing Climet wind vane/anemometer system. • Lower starting threshold • Continued functioning during icing conditions Additional Benefits [NUMUG] Comparison of Wind Sensors
Pre-Operational Issues • EMI/RFI potential • Uniformity of sensors • Changes to operational practices and revision of procedures System Changes • Removal of wind translators • Connection of ultrasonic sensors directly to data logger computer • Software changes • Discontinue strip-charts [NUMUG] Comparison of Wind Sensors
Conclusion The Vaisala ultrasonic wind sensor meets the accuracy requirements of RG 1.23 and can be used as a replacement for the Climet wind speed/anemometer system. TVA plans to install the ultrasonic wind sensors at its nuclear plants as soon as EMI/RFI testing is completed and applicable documentation (procedures, FSARs, etc.) are updated. [NUMUG] Comparison of Wind Sensors