Wind Measuring Device Of Anemometer Tower
The anemometer tower has equipment for measuring wind. It includes an anemometer to check wind speed. There is also a wind vane sensor and software. It also has a thermometer, a barometer, a hygrometer, and more.
An anemometer is an instrument designed to measure wind speed and pressure. Instruments for gauging wind speed include rotary anemometers, heat-dissipating anemometers, acoustic anemometers, ultrasonic wind speed sensors, among others.
Most wind farms predominantly utilize rotary anemometers. We categorize these rotary devices into wind cup anemometers and propeller anemometers.
A wind cup anemometer consists of three or four hemispherical or parabolic cone-shaped hollow shells. Mount a three-pronged bracket that forms a 120° angle or a cross-shaped bracket that forms a 90° angle with each other to these cup-shaped anemometers, ensuring the concave sides of the cups all face the same direction.
The team affixes the entire cross arm to a vertical rotational axis. When the wind blows, the wind cups spin around the axis at a speed that is directly proportional to the wind speed.
Another variant of rotary anemometer is the propeller anemometer, which features a three-blade or four-blade propeller mounted at the front of a wind vane, allowing it to align with the wind direction at all times. The blades rotate around a horizontal axis at a speed that correlates with the wind speed.
wind speed measuring
The design of the wind tower dictates the positioning of wind speed measuring devices at different elevations. To reduce the “tower shadow effect” from the anemometer tower, mount the anemometer on a strong support. This support should extend out from the tower’s main structure and keep a certain distance from it. For a truss wind tower, this distance should be more than three times the tower’s width. For a cylindrical wind tower, it should be more than six times the tower’s diameter.
You must align the anemometer’s mounting bracket horizontally. Additionally, you should maintain the angle between the anemometer’s bracket and the prevailing wind direction in the measurement area between 30 and 90 degrees.
Moreover, the radiating anemometer operates by correlating the heat dissipation rate of a heated object with the velocity of the air around it. This characteristic enables the device to measure wind speed, although users primarily utilize it for detecting low wind speeds. Acoustic anemometers do not have moving parts. They respond quickly and can measure wind speed in any direction. However, they are quite expensive. Typically, people employ rotary anemometers to gauge wind speed.
Wind Vane Sensor
The wind direction sensor is the most prevalent tool for determining wind direction, encompassing types such as single-wing, double-wing, and streamlined models. A wind vane usually has an unbalanced design with four main parts: the tail, pointing rod, counterweight, and main shaft. The alignment of the center of gravity with the axis of the supporting shaft allows the entire wind vane sensor to pivot freely around the vertical axis.
Wind vane installing
The technician mounts the wind vane sensor at the specified height on the anemometer tower. You need to attach it to a strong beam. This beam should be more than three times the diameter of the truss wind tower. It should also be six times the diameter of the round tube wind tower. Align this installation with the primary wind direction, position the beam at a 90° angle to this direction, and adjust it horizontally. Furthermore, you must calibrate the wind vane according to the local magnetic declination and orient it towards the actual “north” direction.
Wind direction is typically represented in 16 compass points, including North-North East (NNE), Northeast (NE), East-Northeast (ENE), East (E), East-Southeast (ESE), Southeast (SE), South-Southeast (SSE), South (S), South-Southwest (SSW), Southwest (SW), West-Southwest (WSW), West (W), West-Northwest (WNW), Northwest (NW), North-Northwest (NNW), and North (N).
Additionally, you can denote wind direction by angles, using true north as the reference point and rotating clockwise: an east wind measures 90°, a south wind measures 180°, a west wind measures 270°, and a north wind measures 360°.
Wind measurement software
The main job of the wind measurement software is to record data. It tracks wind speed, wind direction, temperature, and atmospheric pressure. This data comes from the sensors on the wind tower. This data collection enables the wind resource engineer to conduct further analysis of the wind resource information.