Clean Electric Power
The push for sustainable energy solutions has led to the development of advanced clean electric power equipment. Installations exposed to the wind, waves, and magnetic loads due to large currents for example.
Reliability is essential and low noise emission is critical for acceptance of new energy installations, turbines, transformers, distribution lines and stations.
Some measurement techniques in noise and vibration are already common in noise and vibration control in the power industry; vibration monitoring, modal analysis, insertion loss measurements, sound power determination. The lightness and compact dimensions of the burden of the Qsources shakers and sound sources help making these measurements lighter and more efficient.
Some other techniques have become possible with high numbers of almost identical wind turbines, inverters, or distribution transformers. The investment in more complex measurements is off-set by better specification and/or lower costs. More complex diagnosis measurements and model verification measurements like TPA, ASQ, inverse load identification, dynamic sub-structuring allow better verification or optimization.
The extremely compact self-supporting Qsources shakers and the compact and light weight sound sources are enablers for refined and lower cost clean energy.
It requires designs that do not involve resonances that combine with Strouhal frequencies when exposed to wind or flow. Acoustic and structural excitation techniques play a crucial role in ensuring these technologies are efficient, durable, and reliable. Examples of these applications include:
Wind Turbines: Vibration analysis is used to monitor the condition of wind turbine blades, bearings, and gearboxes. It helps in detecting issues like blade imbalance, bearing wear, and gear misalignment, which can lead to catastrophic failures if not addressed.
Solar Panels: While solar panels themselves do not generate significant vibrations, the mounting structures and inverters can be subject to vibrations due to wind and other environmental factors. Vibration analysis helps ensure the structural integrity and proper functioning of these components.
Durability and Reliability: Clean power equipment is often subjected to harsh environmental conditions, such as high winds, temperature fluctuations, and mechanical loads. Structural excitation helps test the resilience of these components, ensuring they can withstand such conditions. Engineers can identify weak points and reinforce them to improve durability and reliability.
In the rapidly evolving field of clean energy, the application of acoustic and structural excitation techniques is vital for developing superior equipment. Through careful analysis and testing, manufacturers can ensure their products are efficient, durable, and reliable, ultimately contributing to a sustainable and quieter future. This meticulous approach to design and production leads to higher performance and greater consumer satisfaction.
Some applications
Wind Turbine transmission noise
Tonal noise is a main concern for on-shore wind turbines. The often necessary transmission between the main shaft and generator poses risks especially for gear tooth noise. The quasi static torque is massive and there are limits to the accuracy of the moving parts and stiffness of the transmission supports.
Inverse load identification of the transmission’s dynamic support forces helps make better estimation of the requirements, better loads for models. Some highly compact Qsources shakers now allow accurate measurements on-site in the nacelle in operation ready installations. Furthermore the measurements are also far more efficient in the lab or production line. The new shakers allow to gather sensitivity, stiffness, and full mechanical impedance matrices.
On the noise emission side, the volume sound sources and sound power reference sources allow determination of sound power in the production line, or estimation of equivalent sound power in the nacelle. Quantification of the emission part of several parts of the transmission inside the nacelle is possible using ASQ analysis, which requires dedicated volume sound sources.
Power transformer noise
Transformers involve massive internal magnetic forces at 50/60 Hz, even more at 100/120 Hz and several higher harmonics and this leads to vibrations at support and interface locations and outer panels. And it is not just the transformer that radiates noise as many systems are mechanically coupled, as well as the support structure of the heavy transformers.
Reference sound power sources allow on-site sound power identification. (see also below section on sound power determination) or high power omni-directional sources can be used to measure on-site attenuation across partitions, encapsulations, sound barriers and determine the effective decay over distance.
To address the transformer construction and improve the design for low noise it is necessary to identify interface forces, magnetic forces and the contributions of various elements downstream: core-supports, tank surfaces, tank-supports, power lines, cooling units and to combine these forces to vibro-acoustic transfer to quantify noise contributions.
Transfer path analysis can be applied at different levels of interfaces to determine the dominant or most sensitive elements. The measurements require application of artificial excitation at, or near, interfaces and use reciprocity where excitation access is impossible due to oil or because of lacking space. Some shakers for this application:
The most suitable sound source for reciprocal determination of vibro-acoustic transfer on power and distribution transformers:
Sound power determination
Sound power (directly, or via sound pressure in defined acoustic boundary conditions) is the most common way to specify and verify noise emission of various installations. But it is often in-efficient or dangerous to apply sound intensity and well defined acoustic boundary conditions are even more rare for energy installations.
Using reference sound sources in combination with sound pressure measurements is an attractive alternative. The most basic procedure is well described in ISO 3747. For this level of sound power determination Qsources provides the most compact and light weight reference sound sources, satisfying ISO 6926 for sound power measurement:
These sources are not the same as the traditional ventilator based reference sources. Both the Qref and Qmir are much smaller, lighter, and have very good approximation of hemi-omnidirectionality. Furthermore allows the design/construction for easy placement at any inclination.
Because of this the power identification is not just possible in the restrictive ISO 3747 conditions. For example; smaller rooms, placement near supporting equipment, near the walls/floor, low absorption in the environment, etc. In that case the reference source is placed against multiple surfaces of the machine and the calculation includes averaging over those multiple locations or the calculation uses power based inversion. And it can also result in more accurate and better reproducing measurements
Experimental Modal Analysis
Nummerical (FE) models are used to assure that various elements such as rotors, blades, brackets and panels meet the stiffness and resonance requirements. Sometimes, a measurement is needed. For example because the new material is uncertain in its properties, or a new fixation method is used. The experimental modal analysis, EMA, with model correlation helps to improve the model quality for prediction. The Qsources may seem too small to be able to excite large structures. However technology has advanced on the sensors, the signal analysis and on the power density of the Qsources shakers. Some highly efficient shakers for these EMA tests on large structures:
All described measurements also require software and sensors, of which several are available in the market. Depending on the exact application our partners,
Siemens, Polytec, Head Acoustics
All propose leading full chain solution including the Qsources excitation sources and shakers
