IEC Classification

The material on this page is a summary of AQSystem's "AQ510 - Setting a New Standard". The original document can be found in the Documentation section of our AQ510 SoDAR page.

On the 3rd of March 2017 IEC 61400-12-1:2017 was published.  Copies can be obtained from the IEC Webstore at – https://webstore.iec.ch/publication/26603.

This new release of the standard covers the use of ground based remote sensing devices (RSDs), SoDARs and LiDARs, which are capable of providing accurate and consistent wind data. This will have a significant influence on the instrumentation and methodologies that are chosen for different wind industry applications, such as turbine power performance testing and optimization, and wind resource assessment.

Prior to undertaking the IEC classification process, AQ510 was already a well-proven technology with independent validation reports from DNV-GL, Ecofys and BBB Umwelttechnik. In addition to independent validations of the AQ510 system, every AQ510 SoDAR is calibrated against AQSystem's own 100m IEC compliant met tower in Sweden prior to delivery. AQ510 is the only SoDAR which has this level of testing before delivery.

The IEC classification process, as defined in the standard, provides a formally agreed and accepted method to assess and calculate uncertainties for remote sensing instruments thus enabling a uniform practice for using generated data in a project environment.

To classify a product per the standard it must be validated for accuracy, unit to unit consistency, and performance in different environmental and seasonal conditions, and ultimately assigned a standard uncertainty.

Annex L of IEC 61400-12-1:2017 specifies that a minimum of two RSDs must be tested at two separate sites for a minimum of three months so a large span of environmental parameters can be measured. In addition to this, at least one of the systems must be deployed at both sites in order to verify the reference anemometers used.

To give greater confidence to our customers, AQSystem chose to exceed the minimum testing requirements to give a clearer understanding of the impact of various environmental parameters. Four AQ510s with six deployments were used in the classification process with a total measurement period of twenty-six months. One system covered a whole year to provide information on how environmental parameters affect AQ510 measurements through all four seasons.

The large database of over 96,000 10-min data points from the four AQ510s enables a highly robust classification. All systems show similar sensitivities to each environmental parameter and deliver a standard uncertainty close to one another. With longer measurements, the standard uncertainty reduces further, which should be considered by AQ510 users when deciding the duration of a SoDAR measurement campaign.

The results obtained have been assessed and independently verified by Uppsala University of Sweden, one of Europe's leading technical universities.

When all analysis was completed, according to the procedure described in Annex L of the IEC guidelines, 61400-12-1, AQ510 achieved a mean standard uncertainty of 1.00% at 100m.