Electrical Characteristics

IEC TR 61400-21-3:2019 provides guidance on principles which can be used as the basis for determining the application, structure and recommendations for the WT harmonic model. For the purpose of this Technical Report, a harmonic model means a model that represents harmonic emissions of different WT types interacting with the connected network. This document is focused on providing technical guidance concerning the WT harmonic model. It describes the harmonic model in detail, covering such aspects as application, structure, as well as validation. By introducing a common understanding of the WT representation from a harmonic performance perspective, this document aims to bring the overall concept of the harmonic model closer to the industry (e.g. suppliers, developers, system operators, academia, etc.). A standardized approach of WT harmonic model representation is presented in this document. The harmonic model will find a broad application in many areas of electrical engineering related to design, analysis, and optimisation of electrical infrastructure of onshore as well as offshore WPPs.

IEC 61400-21-1:2019 includes: - definition and specification of the quantities to be determined for characterizing the electrical characteristics of a grid-connected wind turbine; - measurement procedures for quantifying the electrical characteristics; - procedures for assessing compliance with electrical connection requirements, including estimation of the power quality expected from the wind turbine type when deployed at a specific site. The measurement procedures are valid for single wind turbines with a three-phase grid connection. The measurement procedures are valid for any size of wind turbine, though this part of IEC 61400 only requires wind turbine types intended for connection to an electricity supply network to be tested and characterized as specified in this part of IEC 61400. This first edition cancels and replaces the second edition of 61400-21 published in 2008. This edition includes the following new items with respect to 61400-21: a) frequency control measurement; b) updated reactive power control and capability measurement, including voltage and cos φ control; c) inertia control response measurement; d) overvoltage ride through test procedure; e) updated undervoltage ride through test procedure based on Wind Turbine capability; f) new methods for the harmonic assessment.