IEC TS 61400-21-4:2025

IEC TS 61400-21-4:2025 specifies a uniform methodology, defining measurement, testing and assessment procedures of electrical characteristics of wind turbine components and subsystems, as basis for the verification of the electrical capabilities of wind turbines and wind turbine families.
This document includes the following aspects:
- definitions of test bench, subsystems and interface;
- definitions of system requirements for the test bench to perform relevant measurements (grid strengths, short circuit power, THD, …);
- measurement procedures for quantifying the electrical characteristics;
- test and measurement procedures for verifying and validating the electrical characteristics of components and subsystems in relation to grid compliance requirements;
- procedures for the transferability of the component and subsystem test results, measured at the test bench, to WT product families;
- documentation requirements and validation procedures of components, subsystems and wind turbines.
The results of the measurements and assessments of the wind turbine components and subsystems will be used as input for the verification of electrical capabilities as described in IEC 61400-21-1 and for the validation and verification of the electrical simulation models for wind power plants (WPP) as described in IEC 61400-27.