This part of IEC 61400 provides a framework from which production-based performance indicators of a WTGS (wind turbine generator system) can be derived. It unambiguously describes how data is categorised and provides examples of how the data can be used to derive performance indicators.

The approach of this part of IEC 61400 is to expand the time allocation model, introduced in IEC TS 61400‑26‑1, with two additional layers for recording of the actual energy production and potential energy production associated with the concurrent time allocation.

It is not the intention of this Technical Specification to define how production-based availability shall be calculated. Nor is it the intention to form the basis for power curve performance measurements, which is the objective of IEC 61400‑12.

This document also includes informative annexes with: