Extended Harmonic Domain Model of a Wind Turbine Generator for Harmonic Transient Analysis

This paper presents an extended harmonic domain (EHD) model of a wind turbine generator (WTG) system based on a doubly fed induction generator. The proposed EHD WTG model includes both electrical and mechanical subsystems and permits monitoring step-by-step the harmonics time variation; this allows, among other applications, to detect contingency scenarios, such as resonance problems caused by a specific harmonic. Moreover, control efficiency can be improved by means of the power-quality indices which are instantaneously available by the EHD WTG model. The proposed model is capable of accounting for an arbitrary number of harmonics; however, the more harmonics that are included, the larger the system becomes. This affects the central-processing unit time by the transient simulation. An efficient heuristic remedy is proposed in this paper which consists of accounting for “high-impact” harmonics only, based on the converter's frequency spectrum. The EHD WTG model is validated with the power system computer-aided design/electromagnetic transients including dc (PSCAD/EMTDC) software tool via a case study.