ZephIR - industry accepted validation

All lidar systems need to be successfully validated to an industry accepted standard before customers commence deployment. Banks’ engineer Garrad Hassan have worked with us in defining the principles of our certification process for all new systems. This provides the traceability which is a key element of formal energy prediction reports used by the financial community. Before shipping, each ZephIR undergoes several stages of rigorous checks. These processes are repeated as part of the routine maintenance whenever a unit returns to Natural Power.

Velocity and Directional Accuracy
The velocity and directional accuracy are checked in the laboratory against a calibrated moving target, to an accuracy of better than 0.5%. The velocity calibration depends only on laser wavelength and scanner cone angle, so there is no risk of drift even over an extended period of operation. Velocity resolution of ZephIR is very high and its accuracy is measured to be 0.003m/s against a calibrated moving belt target.

Focussing at Height
ZephIR focus is calibrated at the factory and its range is set by a closed loop positioning system.

Calibrated Reference Unit
Each ZephIR undergoes an outdoor test to measure wind speed side-by-side against a Reference Unit. The Reference Unit has been checked against at a tall mast such as at Risø’s Høvsøre test site; this provides traceability to measurements. Risø are the National Laboratory for Sustainable Energy at the Technical University of Denmark - DTU.

The reference system is compared below left to the fixed anemometry at the test site showing strong correlation and a gradient close to 1. A typical new ZephIR system is compared below right to the reference system and again shows strong correlation and a gradient close to 1: